# ChemTracker — Full Content > Complete content from chemtracker.app for AI ingestion. Auto-generated on 2026-03-30T19:35:31.415Z. > For a structured index with links, see https://chemtracker.app/llms.txt ## How It Works ## How ChemTracker Works Last updated: March 29, 2026 8 min read ChemTracker is a real-time flight tracking application that predicts whether aircraft overhead are producing visible contrails. Using live ADS-B flight data, atmospheric conditions from 8 pressure levels, and the Schmidt-Appleman thermodynamic criterion, ChemTracker analyzes every aircraft within 250km of your location and determines if conditions support contrail formation. Available worldwide as a web app with a 14-day free trial. ChemTracker was built for people who look up. Whether you are an aviation enthusiast, a sky watcher, or someone who wants independent tools to understand what is happening in the atmosphere above your home, ChemTracker gives you the data to investigate for yourself. No speculation — just real-time flight positions, atmospheric measurements, and peer-reviewed science applied to every aircraft overhead. ### What ChemTracker Does ChemTracker is a flight tracking and contrail prediction tool that combines live aviation data with atmospheric science to show you which aircraft are leaving trails and why. Here is what the app does: - Tracks all aircraft within 250km of your position in real-time — using ADS-B transponder data, ChemTracker shows every commercial flight, private aircraft, and cargo plane operating in your area on a live map that updates continuously. - Predicts contrail formation using atmospheric science — by combining temperature, humidity, and pressure data from multiple altitude levels with the Schmidt-Appleman thermodynamic criterion, ChemTracker calculates whether each aircraft is likely to produce a visible trail. - Shows which specific aircraft are leaving trails and why — every aircraft on the map receives a contrail score. Tap any plane to see its flight details, altitude, atmospheric conditions at that altitude, and the scientific basis for its trail prediction. - Sends alerts when spraying conditions are detected — Golden Hour alerts notify you when atmospheric conditions in your area are most favourable for persistent, visible contrail formation, so you can step outside and observe. - Lets you report and photograph trails to help improve detection — the Field Reports feature allows you to photograph trails, tag the responsible aircraft, and log your observations. Your reports contribute to a growing dataset that helps refine prediction accuracy. ### The Science Behind the Prediction ChemTracker's contrail predictions are based on established atmospheric science. The system combines five layers of data to determine whether a given aircraft, at a specific altitude, in current atmospheric conditions, will produce a visible trail. Here is how each layer works: #### 1. Flight Data from the ADS-B Network ADS-B (Automatic Dependent Surveillance-Broadcast) is a surveillance system in which aircraft broadcast their position, altitude, speed, heading, and identification via radio signals. ChemTracker receives this data in real time from a global network of ground-based receivers. For each aircraft, the app knows its exact position, cruising altitude, aircraft type, registration, airline, and route — all updated every few seconds. #### 2. Weather Data from 8 Atmospheric Pressure Levels Contrails form at specific altitudes where conditions are right — aircraft at cruise altitude (10,000–12,000m) travel through air as cold as −55°C, and relative humidity above 100% with respect to ice is required for persistent contrails. ChemTracker retrieves atmospheric data from 8 pressure levels between 150 and 400 hPa, corresponding to altitudes of roughly 7,000 to 14,000 metres (23,000 to 46,000 feet), totalling 1,248 atmospheric data points per scoring cycle. At each level, the app reads temperature, relative humidity over ice, and wind speed. This data comes from global numerical weather prediction models and is updated multiple times per day. #### 3. The Schmidt-Appleman Criterion The Schmidt-Appleman criterion, first described in 1953 and still the standard model for contrail prediction, is the thermodynamic equation used by atmospheric scientists to predict contrail formation. It calculates the critical temperature below which contrails will form, based on ambient humidity, atmospheric pressure, and the overall propulsion efficiency of the aircraft engine. If the actual temperature at the aircraft's altitude is below this critical threshold, a contrail will form. If humidity is high enough, the contrail persists and spreads. If humidity is low, the trail dissipates quickly. #### 4. Monte Carlo Simulation Atmospheric measurements have inherent uncertainty. Temperature and humidity readings are interpolated from weather model grid points that may be tens of kilometres apart. To account for this, ChemTracker runs 25 to 50 Monte Carlo simulations per aircraft, varying the input parameters within their known uncertainty ranges. The result is a probability-weighted contrail score rather than a simple yes/no prediction, giving you a more accurate picture of trail likelihood. #### 5. Solar Visibility Calculation A contrail can form but still not be visible from the ground if the sun angle is wrong or if it is dark. ChemTracker factors in the time of day, sun position, and solar elevation angle to determine whether a predicted contrail would actually be visible to an observer on the ground. This is why the app's "Golden Hour" alerts are timed to periods when trail visibility is at its peak. “According to ChemTracker's atmospheric analysis engine, running 25 to 50 Monte Carlo simulations per aircraft against live data from 8 pressure levels produces contrail predictions that far surpass simple yes/no models — giving observers the probability-weighted confidence they need to evaluate what they see in the sky.” ### Key Features ChemTracker includes a set of tools designed for observing, identifying, and documenting aerial activity. Each feature is built around the principle that you should be able to see what is in the sky, know what it is, and record what you observe. - Live flight map with real-time positions — a continuously updating map showing every aircraft in your area. Aircraft icons indicate heading and type. The map centres on your location and extends to a 250km radius. - Contrail scoring: CLEAR / DISPERSING / SPRAYING — every aircraft on the map is assigned a contrail score based on the atmospheric analysis. CLEAR means no trail is expected. DISPERSING means a short-lived trail that fades quickly. SPRAYING means a persistent, spreading trail that will remain visible for an extended period. - Sky Scanner: point your phone at a trail to identify the aircraft — the Sky Scanner uses your phone's compass and orientation sensors to let you point at a trail in the sky and immediately see which aircraft made it, its flight number, altitude, and contrail score. - Evidence packs: shareable flight cards with atmospheric data — generate a detailed flight card for any aircraft that includes its identification, route, altitude, atmospheric conditions at that altitude, contrail score, and the scientific basis for the prediction. Evidence packs can be downloaded and shared. - Golden Hour alerts: notifications when trail visibility peaks — receive push notifications when conditions in your area are optimal for visible contrail formation. These alerts combine atmospheric predictions with solar visibility to tell you the best times to observe. - Field reports: photograph and log unidentified trails — see a trail you want to document? Take a photo directly in the app, tag it with the time, location, and any nearby aircraft, and save it to your personal observation log. Field reports can be shared and help build a crowd-sourced record of trail activity. ### Pricing ChemTracker is designed to be accessible. The free tier gives you a live flight map and basic access, while the Pro plan unlocks the full analytical toolkit. Every new account starts with a 14-day free trial of Pro — no credit card required. #### Free See aircraft on the live map. One flight reveal per day with full details including altitude, aircraft type, and route. #### Pro — €4.99/month or €39.99/year Unlimited flight reveals. Full contrail scoring and atmospheric data for every aircraft. Golden Hour alerts. Evidence packs. Sky Scanner. Field reports. Priority support. 14-day free trial — no credit card required ### Who Uses ChemTracker ChemTracker is used by a diverse community of people who share a common interest: understanding what is happening in the sky above them. The app serves three primary audiences: - Sky watchers and aviation enthusiasts — people who enjoy tracking aircraft, understanding flight patterns, and learning about atmospheric science. ChemTracker provides a level of detail that goes beyond standard flight tracking apps by adding atmospheric context and contrail prediction. - People concerned about aerial activity in their area — citizens who have observed persistent trails, unusual flight patterns, or unexplained aerial activity and want tools to identify and document what they see. ChemTracker replaces speculation with data. - Citizens who want independent observation tools — people who believe in the value of public access to flight and atmospheric data, and who want to make their own observations and draw their own conclusions based on verifiable information. ### Available Worldwide ChemTracker works globally. The ADS-B network provides flight data coverage across North America, Europe, Asia, the Middle East, Africa, Oceania, and South America. Atmospheric data is sourced from global weather models that cover the entire planet. Wherever you are, if aircraft are flying overhead, ChemTracker can track them and predict contrail formation. The app works in any modern web browser on any device — no app store download required. ### Frequently Asked Questions #### What is ChemTracker? ChemTracker is a real-time flight tracking application that predicts whether aircraft overhead are producing visible contrails. It combines live ADS-B transponder data with atmospheric science — including temperature, humidity, and pressure readings from multiple altitude levels — to show you exactly which planes are leaving trails in your sky, why those trails are forming, and how long they are likely to persist. ChemTracker is available worldwide as a web app with a free tier and a 14-day free trial of Pro features. #### How does ChemTracker predict contrails? ChemTracker uses the Schmidt-Appleman thermodynamic criterion, the accepted scientific model for contrail formation. The app retrieves live weather data from 8 atmospheric pressure levels (150 to 400 hPa), determines the critical temperature at which contrails form based on ambient humidity and estimated engine efficiency, and runs 25 to 50 Monte Carlo simulations per aircraft to account for atmospheric uncertainty. Each aircraft receives a contrail score: CLEAR (no trail expected), DISPERSING (short-lived trail), or SPRAYING (persistent, spreading trail). #### Is ChemTracker free? ChemTracker offers a free tier that lets you see aircraft on the map and reveals one flight per day with full details. The Pro plan costs €4.99 per month or €39.99 per year and includes unlimited flight reveals, contrail scoring, alerts, evidence packs, and the Sky Scanner feature. Every new account starts with a 14-day free trial of Pro — no credit card required. #### Does ChemTracker work worldwide? Yes. ChemTracker works anywhere in the world where ADS-B flight data is available, which covers the vast majority of commercial and private aviation globally. The app uses your device location to find aircraft within a 250-kilometre radius and retrieves atmospheric data for that region from global weather models. Whether you are in North America, Europe, Asia, Africa, or Oceania, ChemTracker can track flights and predict contrail formation overhead. #### What data does ChemTracker use? ChemTracker combines three data sources. First, live ADS-B (Automatic Dependent Surveillance-Broadcast) flight data providing aircraft position, altitude, speed, heading, aircraft type, and registration. Second, atmospheric weather data from 8 pressure levels between 150 and 400 hPa, including temperature, relative humidity, and wind speed. Third, solar position calculations to determine whether trails are visible from the ground based on time of day and sun angle. All data is processed in real time. #### Can I track chemtrails with my phone? Yes. ChemTracker runs as a web app on any smartphone with a modern browser. The Sky Scanner feature lets you point your phone at a trail in the sky and identify the aircraft responsible, showing its flight number, airline, altitude, and current contrail score. You can also photograph trails and submit field reports to build a personal log of observations. ChemTracker works on both iPhone and Android without requiring a native app download. #### Learn More - What Is a Chemtrail? Everything You Need to Know - Are Chemtrails Real? The Evidence and How to Track Them - Chemtrail vs Contrail — What's the Real Difference? - Cloud Seeding — What It Is, How It Works & What It Looks Like - Geoengineering Explained — Weather Modification & Aerial Tracking ### See What's Flying Over You ChemTracker shows you every aircraft in your area with live atmospheric data and contrail predictions. Identify flights, track trail formation, and document what you observe. Start your free 14-day trial — no credit card required. START FREE TRIAL ## Press Kit ## Press Kit Product information, company details, and media resources ### About ChemTracker ChemTracker is a real-time flight tracking application that predicts whether aircraft overhead are producing visible contrails. Developed by CCC Impact BV (Netherlands), ChemTracker uses live ADS-B flight data from a global receiver network, atmospheric conditions from 8 pressure levels via Open-Meteo, and the Schmidt-Appleman thermodynamic criterion to analyze every aircraft within 250 kilometers of the user's position. The app runs Monte Carlo simulations (25–50 evaluations per aircraft) and factors in solar visibility to determine if contrails are visible from the ground. ChemTracker is available worldwide as a progressive web app with a 14-day free trial. ### Key Facts Founded2025 by CCC Impact BV, NetherlandsCategoryFlight tracking & atmospheric monitoringPlatformProgressive Web App (iOS, Android, Desktop)CoverageWorldwide (250 km radius around user)Data sourcesADS-B Exchange, Open-Meteo, astronomical calculationsEngineSchmidt-Appleman criterion + Monte Carlo simulationPricingFree tier (1 reveal/day) + Pro at €4.99/month or €39.99/yearFree trial14 days, no credit card requiredWebsitechemtracker.appTikTok@chemtracker.app (17.7K followers) ### What Makes ChemTracker Unique - Only app that predicts contrail formation using atmospheric science — powered by the Schmidt-Appleman thermodynamic criterion, the same model used in peer-reviewed aviation research. - Real-time scoring for every aircraft — each flight is classified as CLEAR, DISPERSING, or SPRAYING based on live atmospheric data and Monte Carlo simulation. - Sky Scanner — point your phone at a trail in the sky to instantly identify the aircraft responsible. - Solar visibility engine — factors in time of day and sun position for ground-level sighting prediction, so you only see trails that are actually visible right now. - Community field reports — users photograph and log trails to build a crowdsourced observation dataset that improves detection accuracy over time. ### How It Works - 1Live flight positions from a global ADS-B receiver network provide real-time location, altitude, and identity for every aircraft within 250 km. - 2Atmospheric analysis retrieves temperature, humidity, and pressure at 8 altitude levels from Open-Meteo, matching conditions to each aircraft's flight level. - 3Schmidt-Appleman scoring + Monte Carlo simulation runs 25–50 evaluations per aircraft, accounting for measurement uncertainty, to produce a contrail prediction with confidence level. ### Media Resources - Product page: chemtracker.app - How it works: chemtracker.app/how-it-works - TikTok: @chemtracker.app - Contact: info@chemtracker.app ### For App Directories #### Short Description (150 characters) Real-time flight tracking and contrail detection. See which aircraft are leaving trails above you. Powered by atmospheric science. #### Long Description (500 characters) ChemTracker shows you every aircraft in your area and predicts which ones are producing visible contrails. Using live ADS-B flight data, atmospheric conditions at 8 pressure levels, and the Schmidt-Appleman thermodynamic criterion, it runs Monte Carlo simulations to score each aircraft as CLEAR, DISPERSING, or SPRAYING. Point your phone at a trail in the sky to identify the plane. Track flights within 250 km, log sightings with photos, and explore community reports. Available worldwide with a 14-day free trial. No credit card required. ### Company NameCCC Impact BVRegisteredNetherlandsWebsitechemtracker.app ### Try ChemTracker See every aircraft overhead and find out which ones are producing visible trails. Start your free 14-day trial — no credit card required. START FREE TRIAL #### Product - Live Tracking - Chemtrail Map - Detector - Forecast - How It Works #### Explore - Track by City - Track by Airport - Live Stats #### Learn - What Is a Chemtrail - Chemtrail vs Contrail - Why Planes Leave Trails - Are Chemtrails Real? - Cloud Seeding - Geoengineering - Solar Radiation Mgmt - Aerosol Injection - Weather Modification - All Articles #### Company - Blog - Press Kit - Chemtrails Nederland - Strepen in de Lucht - Privacy - Terms© 2026 CCC Impact BV. ChemTracker — Real-time contrail detection. ## Stats CURRENT CONDITIONS — 10 MONITORED REGIONSFAVORABLE AIRSPACE15%of pressure levels activeAVG RH-ICE40%relative humidity over iceREGIONS MONITORED10Europe + North AmericaLast updated: 30 Mar 2026, 21:35LIVE ATMOSPHERIC DATA ## Today's Atmosphere Monday, 30 March 2026 ModerateContrail LikelihoodMid-latitude average-52°CCruise Altitude TempAt FL350 (250 hPa)34%RH Ice (250 hPa)Below persistence threshold~2,400Active Aircraft TrackedIn coverage area ### How Contrail Conditions Vary by Altitude Contrail formation depends heavily on altitude. Higher pressure levels (lower hPa values) correspond to higher altitudes with colder temperatures. The table below shows typical conditions across the 8 pressure levels ChemTracker monitors. PRESSUREALTITUDETEMP RANGECONTRAIL LIKELIHOOD150 hPa~FL450 (13,700m)-65°C to -70°CVery likely — extremely cold, common for long-haul cruise175 hPa~FL420 (12,800m)-60°C to -65°CVery likely — well below Schmidt-Appleman threshold200 hPa~FL390 (11,900m)-55°C to -60°CLikely — standard long-haul cruise altitude225 hPa~FL370 (11,300m)-52°C to -57°CLikely — common cruise altitude for widebody aircraft250 hPa~FL350 (10,700m)-48°C to -53°CModerate to likely — depends on humidity conditions300 hPa~FL300 (9,200m)-40°C to -45°CModerate — near threshold, humidity-dependent350 hPa~FL270 (8,200m)-33°C to -38°CLow — typically too warm unless extreme humidity400 hPa~FL240 (7,200m)-25°C to -32°CVery low — below typical contrail formation altitude ### Contrail Formation Requirements Contrail formation follows the Schmidt-Appleman criterion, a thermodynamic model that predicts whether the mixing of hot engine exhaust with cold ambient air will produce a visible trail. The following thresholds determine when and how contrails appear. Air TemperatureBelow -39°C to -45°CSchmidt-Appleman criterion; varies with pressure and engine efficiencyRH over Ice (any trail)> 70%Short-lived contrails form above this threshold at sufficient coldRH over Ice (persistent)> 100%Ice-supersaturated air — trails persist and spread for hoursAircraft AltitudeAbove FL260 (7,900m)Below this altitude, temperatures rarely support contrail formation ### ChemTracker Engine Stats Every analysis cycle, ChemTracker's prediction engine processes atmospheric and flight data to produce real-time contrail probability scores. 1,248Atmospheric data points analyzed per cycle8Pressure levels monitored (150-400 hPa)25-50Monte Carlo simulations per aircraft250 kmDetection radius per user10 secRefresh rate3-sourceFlight data redundancy ### Global Coverage ChemTracker operates worldwide. The ADS-B flight tracking network covers airspace across North America, Europe, the Middle East, East Asia, Southeast Asia, and Oceania, with expanding coverage in South America and Africa. Atmospheric data is sourced from global weather models that provide full planetary coverage at all monitored pressure levels. Each user's detection radius extends 250 kilometres from their position, capturing all ADS-B-equipped aircraft within range. The system processes data from 3 redundant flight data sources to ensure continuous tracking even when individual feeds experience interruptions. Combined with atmospheric analysis refreshed every 10 seconds, ChemTracker provides near-real-time contrail prediction for any location on Earth where aircraft operate at cruise altitude. ### Frequently Asked Questions #### What atmospheric conditions cause contrails? Contrails form when hot, humid exhaust from jet engines mixes with cold ambient air at high altitudes. The key requirements are air temperature below approximately -39°C to -45°C (the Schmidt-Appleman threshold) and sufficient relative humidity over ice. At cruise altitudes between FL260 and FL450 (roughly 7,900 to 13,700 metres), these conditions occur frequently. When relative humidity over ice exceeds 100%, contrails persist and spread — these are known as persistent contrails. #### How does ChemTracker predict contrail formation? ChemTracker analyses real-time atmospheric data across 8 pressure levels from 150 to 400 hPa, covering the full range of commercial aviation altitudes. For each aircraft, the engine calculates the Schmidt-Appleman criterion using temperature, pressure, and relative humidity over ice at the aircraft's flight level. It then runs 25 to 50 Monte Carlo simulations to account for uncertainty in atmospheric measurements, producing a probability score for contrail formation and persistence. #### How accurate is ChemTracker? ChemTracker's prediction engine combines data from multiple atmospheric sources with real-time ADS-B flight tracking. The Monte Carlo simulation approach accounts for measurement uncertainty and spatial variability, producing probability-based predictions rather than binary yes/no outputs. Accuracy depends on the quality of available atmospheric data and the aircraft's proximity to pressure level boundaries, but the multi-source redundancy approach ensures robust predictions even when individual data sources have gaps. #### What data does ChemTracker analyze? ChemTracker processes 1,248 atmospheric data points per analysis cycle, covering temperature, relative humidity over ice, wind speed, and wind direction across 8 pressure levels (150, 175, 200, 225, 250, 300, 350, and 400 hPa). It combines this with live ADS-B transponder data from 3 redundant flight data sources, tracking aircraft positions, altitudes, speeds, and headings within a 250-kilometre detection radius. All data is refreshed every 10 seconds. ### See What's Flying Over You ChemTracker combines live atmospheric data with real-time flight tracking to predict contrail formation. Point your phone at the sky and see every aircraft in your area. Start your free 14-day trial. START FREE TRIAL #### Product - Live Tracking - Chemtrail Map - Detector - Forecast - How It Works #### Explore - Track by City - Track by Airport - Live Stats #### Learn - What Is a Chemtrail - Chemtrail vs Contrail - Why Planes Leave Trails - Are Chemtrails Real? - Cloud Seeding - Geoengineering - Solar Radiation Mgmt - Aerosol Injection - Weather Modification - All Articles #### Company - Blog - Press Kit - Chemtrails Nederland - Strepen in de Lucht - Privacy - Terms© 2026 CCC Impact BV. ChemTracker — Real-time contrail detection. ## Live Tracking ## Chemtrails Live Last updated: 30 March 2026 at 21:35 Right now, dozens of aircraft are flying through conditions that favor visible trail formation above your location. ChemTracker monitors real-time atmospheric data at every cruising altitude and tells you exactly which flights are producing contrails — using the same thermodynamic models that aviation meteorologists rely on. ### Current Conditions (Central Europe) TRAIL LIKELIHOODLowFAVORABLE LEVELS1/8SOLAR VISIBILITYNot visible (night)SUN ELEVATION-13.4° 1 of 8 atmospheric pressure levels currently show conditions favorable for contrail formation. Last updated: 30 Mar 2026, 21:35 ### What ChemTracker Shows You Right Now Most aircraft tracking apps show you flight numbers and routes. ChemTracker goes further: it overlays real-time atmospheric science on every flight so you can see not just where aircraft are, but whether they are producing trails at this moment. Learn why some planes leave trails and others don't. #### Live Flight Positions Every aircraft within range updated every 5–15 seconds via ADS-B, including altitude, speed, heading, flight number, and aircraft type. #### Atmospheric Conditions at Altitude Temperature and relative humidity pulled from weather model data at 8 pressure levels — from 200 hPa (roughly 12,000 m) down through the tropopause. These are the conditions the aircraft is actually flying through, not conditions at ground level. #### Trail Probability Score Each aircraft receives a trail likelihood score based on the Schmidt-Appleman criterion applied to its current position. Scores above the threshold are flagged as active trail producers. A Monte Carlo simulation adds a probability band accounting for atmospheric measurement uncertainty. #### Sky Scanner Point your phone camera at the sky. ChemTracker identifies the aircraft you are looking at, displays its flight details, and tells you whether conditions at that altitude currently favor trail formation. The live view does not require any configuration. Open the app, allow location access, and ChemTracker immediately shows you the aircraft currently overhead, sorted by distance and trail activity status. ### Current Atmospheric Conditions for Trail Formation Trails form when jet exhaust meets cold, humid air at cruising altitude. The key variables that determine whether you will see trails today are: Upper-Troposphere TemperatureAt 250 hPa (roughly 10–11 km), air must be below approximately −40°C for contrail formation. Colder air means a wider margin for trail formation.Relative Humidity (Ice)Humidity relative to ice, not liquid water, governs persistence. Above 100% RHi, trails persist and spread. Below 100%, they dissipate within minutes.Tropopause HeightA low tropopause — common in winter and at high latitudes — means aircraft cruise in colder, often moister air, dramatically increasing trail activity.Wind ShearStrong horizontal wind shear at altitude disperses trails quickly even in supersaturated conditions. Light winds allow trails to spread into large sheets. ChemTracker retrieves all four parameters in real time from weather model outputs. The app compares these values against each aircraft's actual altitude to determine which flights are currently in trail-forming conditions. Conditions change throughout the day. A morning with clear skies and no visible trails can become an afternoon with widespread persistent trail activity if an upper-level moisture plume moves through. The live feed captures these transitions as they happen. Check the contrail forecast to see what is expected ahead. ### How Live Trail Detection Works Every second, ChemTracker runs a pipeline that combines three data sources: - ADS-B flight data — position, altitude, and speed for every aircraft broadcasting in range. Coverage spans Europe and North America with near-complete density above major air corridors. - Atmospheric model data — temperature, humidity, and pressure interpolated to the exact altitude of each aircraft from global numerical weather prediction model outputs updated every hour. - Schmidt-Appleman calculation — for each aircraft, the critical temperature threshold G is computed based on engine efficiency, fuel properties, and ambient pressure. If the ambient temperature is below this threshold and relative humidity is sufficient, the flight is flagged as a current trail producer. The result appears on your screen within seconds: a colour-coded map showing active trail producers (red), possible trail producers (amber), and aircraft not currently in trail-forming conditions (grey). Tap any aircraft to see the full atmospheric breakdown. “Instead of speculating about what you see in the sky, ChemTracker gives you the actual atmospheric data for each aircraft right now — the same data that would be used to predict trails in any honest scientific assessment.” ### Frequently Asked Questions #### Are there chemtrails today? ChemTracker checks atmospheric conditions at cruising altitudes right now — temperature, humidity, and pressure — and applies the Schmidt-Appleman criterion to every aircraft in your area. If conditions favor trail formation, you will see which specific flights are likely producing visible trails. Open the app to see what is happening above you in real time. #### How often does ChemTracker update its live data? Flight positions update every 5 to 15 seconds via ADS-B receiver networks. Atmospheric data from weather models refreshes hourly, pulled from the same datasets used by aviation meteorologists. Trail predictions update continuously as aircraft move through different atmospheric layers. #### What does 'live trail activity' mean? Live trail activity refers to the number of aircraft currently flying through atmospheric conditions that meet the threshold for visible trail formation. ChemTracker calculates this in real time for your location, showing you exactly which flights are at altitudes and in conditions where trails are expected based on the Schmidt-Appleman criterion. #### Can I see chemtrails from past days? The live feed shows current activity. ChemTracker's stats page provides aggregated historical data including daily trail activity counts, peak activity hours, and atmospheric condition trends. For real-time tracking of today's activity, the live map is the primary tool. ### Learn More How ChemTracker WorksFull explanation of the detection engine, data sources, and atmospheric scienceWhat Is a Chemtrail?Definition, history, and what observers report seeing in the skyContrail ForecastPredicted trail formation conditions for the coming days ### Related Contrail StatisticsAtmospheric data tables and real-time aggregate conditionsChemtrail MapInteractive live map of trail-producing aircraft near youChemtrail DetectorPoint your phone at the sky to identify aircraft and trailsWhy Do Planes Leave Trails?The atmospheric science behind contrail formationTrack Contrails over AmsterdamReal-time conditions over central EuropeTrack Contrails over New YorkLive atmospheric data over the US East Coast ### See What's Happening Right Now Open ChemTracker and see exactly which aircraft above you are currently producing trails — with the atmospheric data to explain why. Start Your Free 14-Day Trial No credit card required ## Chemtrail Map ## Chemtrail Map Last updated: March 28, 2026 ChemTracker's interactive map shows every aircraft in your area in real time, colour-coded by trail activity. Red aircraft are currently in atmospheric conditions that favor visible trail formation. Tap any flight to see the temperature, humidity, and trail probability at that exact altitude — chemtrails near you, mapped with data. ### What the Chemtrail Map Shows The map is the core of ChemTracker. Unlike a standard flight radar, every element is connected to atmospheric science — specifically the science of why planes leave trails. Here is what you see: Colour-Coded AircraftRed = active trail producer, Amber = borderline conditions, Grey = no trail expected. Updated every 5–15 seconds.Trail Probability BadgeEach aircraft card shows a percentage likelihood of visible trail formation based on current atmospheric data.Altitude LayersFilter aircraft by altitude band to focus on specific flight levels. Compare conditions at 250 hPa vs 300 hPa layers.Flight PathsHistorical track for each aircraft showing where it has been and highlighting where trail conditions began.Aircraft DetailsTap any aircraft for full details: airline, route, aircraft type, registration, and atmospheric conditions at its altitude.Your LocationDistance and bearing from your position to each aircraft, so you can match what you see in the sky to the map. ### Finding Chemtrails Near You When you open the map for the first time and grant location access, ChemTracker immediately calculates which of the aircraft currently overhead are producing or likely to produce visible trails. The process takes about two seconds: - Your GPS position is used to query the nearest ADS-B coverage for aircraft within a configurable radius (default 200 km). - For each aircraft, ChemTracker retrieves atmospheric data at the aircraft's exact reported altitude from the nearest weather model grid point. - The Schmidt-Appleman criterion is applied: if the ambient temperature is below the critical threshold G (calculated from engine type, fuel, and atmospheric pressure), and relative humidity meets the persistence threshold, the aircraft is classified as an active trail producer. - Results appear on the map within seconds, colour-coded and sorted by distance from your location. You can search for any location in the world. If you want to check whether trails are forming over a specific city, airport, or region, type it into the search bar and the map recentres immediately with fresh atmospheric data for that area. ### Understanding What You See on the Map The map often shows clusters of red aircraft in the same corridors — particularly along major transatlantic and transcontinental routes. This reflects the reality of commercial air traffic: dozens of flights follow similar paths at similar altitudes, and when atmospheric conditions at those altitudes favor trails, many aircraft simultaneously show as active trail producers. #### What the colours mean Red: Aircraft currently in conditions where the Schmidt-Appleman criterion is met. A visible trail is expected based on temperature and humidity at this altitude. Amber: Borderline conditions. The criterion is close to the threshold. A trail may or may not form depending on exact local conditions and engine-specific parameters. Grey: No trail expected. Conditions at this altitude are outside the range where contrail formation is predicted — too warm or too dry. The map gives you the ability to compare what you observe in the sky with what the data predicts. If you see a persistent trail from a grey-flagged aircraft, that is a meaningful anomaly worth noting. If you see red aircraft leaving trails, the conditions explain it. This is the core value of the chemtrail map. New to this topic? Read what a chemtrail is and how it differs from a normal contrail. “A chemtrail map that only shows flight tracks tells you where planes are. ChemTracker's map tells you which of those planes are in trail-forming conditions — and lets you compare that to what you actually see overhead.” ### Frequently Asked Questions #### Is there a chemtrail map I can use right now? Yes. ChemTracker's live map shows every aircraft in your area overlaid with atmospheric trail predictions. Each aircraft is colour-coded by trail likelihood: red for active trail producers, amber for possible, grey for no trail expected. You can tap any aircraft for full atmospheric details and trail probability. #### How do I find chemtrails near me? Open ChemTracker and allow location access. The map centres on your position and immediately shows all aircraft within range. Trail-active aircraft are highlighted so you can identify which flights overhead are currently producing visible trails. You can also use the sky scanner to point your phone at any aircraft and identify it instantly. #### What does the chemtrail map show that other flight trackers don't? Standard flight trackers show position, altitude, and flight number. ChemTracker adds the atmospheric layer: the temperature, humidity, and pressure at each aircraft's exact altitude, and whether those conditions meet the Schmidt-Appleman threshold for trail formation. This transforms a map of aircraft into a map of atmospheric activity. #### Can I see spray patterns on the map? The map shows all aircraft tracks in your area and highlights which flights are in trail-forming conditions. If multiple aircraft in the same corridor are producing trails simultaneously, this becomes visible as a pattern. The map does not draw predicted trail shapes, but the flight paths of active trail producers are shown in red. ### Continue Exploring Chemtrails LiveReal-time atmospheric conditions and trail activity happening right nowHow ChemTracker WorksFull explanation of the detection engine, atmospheric science, and featuresChemtrail DetectorHow the spray detection scanner identifies trail-producing aircraft ### Related Live Trail ActivityCurrent atmospheric conditions and active trail producersChemtrail DetectorPoint your camera at the sky to identify aircraftContrail ForecastPredicted trail conditions for the coming daysChemtrail vs ContrailHow to tell different trail types apart visuallyTrack Contrails over LondonLive map data for the UKTrack Contrails over ChicagoLive conditions over the US Midwest ### Open the Chemtrail Map See every aircraft above you right now, with real-time trail predictions based on atmospheric science. Form your own conclusions from actual data. Start Your Free 14-Day Trial No credit card required ## Chemtrail Detector ## Chemtrail Detector Last updated: March 28, 2026 ChemTracker is a chemtrail detection app that combines live flight tracking with real-time atmospheric science. Using the Schmidt-Appleman criterion — the thermodynamic model behind contrail prediction — it identifies which aircraft are currently in conditions that favor visible trail formation, so you can compare what you see in the sky with what the data actually says. ### The Sky Scanner The most direct way to use ChemTracker as a detector is the sky scanner. Open it, point your phone at any aircraft in the sky — with or without a visible trail — and within two seconds you see: - Flight identity: Airline, flight number, origin, destination, aircraft type and registration. - Altitude and speed: Exact altitude in feet and metres, ground speed, vertical rate. - Atmospheric conditions:Temperature and relative humidity at the aircraft's reported altitude, sourced from weather model data. - Trail prediction: Whether the Schmidt-Appleman criterion is currently met at that altitude — with a probability score that accounts for atmospheric measurement uncertainty. - Anomaly flag: If conditions do not support trail formation but you observe a persistent trail from this aircraft, the app flags it as an atmospheric anomaly worth noting. The scanner uses your device's GPS, compass, and camera together. It does not use image recognition to identify aircraft — it uses your pointing direction and location to match visible aircraft with ADS-B flight data. This makes it fast, reliable, and independent of visual conditions. For a broader view of all aircraft in your area, see the chemtrail map. ### The Science Behind the Detection The Schmidt-Appleman criterion (SAC) is the foundation of ChemTracker's detection engine. Developed by thermodynamicists Erich Schmidt and Hermann Appleman, it defines the conditions under which jet engine exhaust will condense into visible ice crystals — a contrail. #### The Critical Temperature G The SAC calculates a critical temperature threshold G from three engine parameters: the overall propulsion efficiency (η), the specific humidity of the exhaust (EI_H₂O), and the lower heating value of the fuel. G varies by engine type and fuel, typically falling between −45°C and −35°C at standard cruising altitudes. #### The Formation Condition A contrail forms when the ambient temperature at the aircraft's altitude is below G AND the mixing trajectory of exhaust and ambient air crosses the water saturation curve. If either condition is not met — temperature too warm or air too dry — no visible trail forms. #### Persistence vs. Dissipation A trail that forms will persist only if the ambient air is supersaturated with respect to ice (relative humidity over ice > 100%). In subsaturated air, a trail may form briefly but evaporate within seconds to minutes. In supersaturated air, the ice crystals grow and the trail spreads, sometimes into cirrus-like cloud cover that persists for hours. #### Monte Carlo Uncertainty Atmospheric data has measurement uncertainty. A single temperature reading at 250 hPa has an error range. ChemTracker runs a Monte Carlo simulation — hundreds of calculations with small random variations in input parameters — to produce a probability distribution rather than a single binary answer. This is expressed as a percentage confidence in trail formation. ### ChemTracker vs. Other Flight Apps Standard flight tracking apps are built for aviation enthusiasts who want to follow routes. ChemTracker is built for people who want to understand atmospheric activity. FeatureFlight Radar AppsChemTrackerLive flight positions✓✓Altitude and speed✓✓Flight number and route✓✓Atmospheric conditions at altitude—✓Schmidt-Appleman trail prediction—✓Trail probability score—✓Sky scanner (point at plane)—✓Anomaly detection—✓Trail activity alerts—✓Contrail forecast—✓ ### Frequently Asked Questions #### How does ChemTracker detect chemtrails? ChemTracker combines real-time ADS-B flight data with atmospheric conditions (temperature, humidity, and pressure at each aircraft's exact altitude) and applies the Schmidt-Appleman criterion — the thermodynamic model used by atmospheric scientists to predict contrail formation. If an aircraft is flying through conditions where the criterion is met, it is flagged as a trail producer. A Monte Carlo simulation adds a probability band to account for measurement uncertainty. #### What is the Schmidt-Appleman criterion? The Schmidt-Appleman criterion (SAC) is a set of thermodynamic equations first described by Erich Schmidt in 1941 and refined by Hermann Appleman in 1953. It calculates a critical temperature threshold G based on the engine's fuel-to-air ratio, exhaust properties, and ambient atmospheric pressure. If the actual temperature at the aircraft's altitude is below G and relative humidity is sufficient, contrail formation is predicted. ChemTracker applies this calculation to every aircraft in real time. #### Can ChemTracker detect trails that shouldn't be there? ChemTracker shows you when an aircraft is outside the conditions where the Schmidt-Appleman criterion predicts trail formation, and yet a trail appears to be present. This is one of the most requested features: identifying anomalies between predicted and observed trail behaviour. The app gives you the data to make that assessment yourself. #### Does the sky scanner work in all weather conditions? The sky scanner uses your phone's camera and compass to overlay flight data on what you are pointing at. It works whenever your device has a GPS lock and camera access. Cloud cover does not affect the scanner — it shows you aircraft even when they are hidden by clouds, because it is using flight data rather than image recognition. Clear sky conditions obviously make visual confirmation easier. #### How accurate is the trail detection? Trail prediction accuracy is constrained primarily by the resolution of atmospheric data, which is updated hourly from weather model outputs. For most commercial flights at standard cruising altitudes, the Schmidt-Appleman prediction matches observed trail behaviour approximately 85–90% of the time in controlled comparisons. ChemTracker uses Monte Carlo simulation to express this uncertainty as a probability range rather than a binary prediction. ### Learn More How ChemTracker WorksComplete technical explanation of the detection engine and atmospheric scienceChemtrail vs Contrail — What's the Difference?Understanding the terminology and physical differencesChemtrail MapInteractive map of aircraft and trail activity near you ### Related Live Trail ActivitySee current atmospheric conditions and active trailsChemtrail MapInteractive map of all aircraft and trail status near youWhat Is a Chemtrail?Background on trails and why people track themWhy Do Planes Leave Trails?The science behind what your detector is measuringTrack Contrails over AmsterdamReal-time detection data for the NetherlandsTrack Contrails over Los AngelesLive conditions over Southern California ### Start Detecting Chemtrails Now Point your phone at the sky and know exactly what you are looking at — atmospheric conditions, trail prediction, and flight identity in seconds. Start Your Free 14-Day Trial No credit card required ## Contrail Forecast ## Contrail Forecast Last updated: March 28, 2026 Whether there will be chemtrails today depends on what is happening at 10,000 metres above your location — not at ground level. ChemTracker reads upper-atmosphere forecast data to predict when and where trail formationis likely, hours in advance. If today's upper air is cold and supersaturated, expect widespread persistent trails. If it's warm and dry aloft, trails will be short-lived or absent. ### How the Contrail Forecast Works A contrail forecast is fundamentally an upper-atmosphere weather forecast. ChemTracker pulls numerical weather prediction model data and applies the Schmidt-Appleman criterionacross the forecast period to determine when conditions will favor trail formation. #### Step 1: Forecast Data Retrieval ChemTracker retrieves hourly forecast outputs from weather models for the next 48 hours, focusing on upper-troposphere variables: temperature, specific humidity, and wind at 200, 250, and 300 hPa pressure levels — corresponding roughly to 11,000–13,000 metres, where most commercial aircraft cruise. #### Step 2: Schmidt-Appleman Application For each forecast time step and pressure level, the Schmidt-Appleman criterion is evaluated: is the temperature below the critical threshold G at which contrail formation is expected? This is calculated using standard commercial aircraft engine parameters (bypass ratio, fuel properties) to produce a representative threshold for typical air traffic. #### Step 3: Persistence Assessment Formation and persistence are separate questions. Where the criterion is met AND relative humidity over ice exceeds 100%, persistent (spreading) trails are predicted. Where the criterion is met but humidity is below 100% RHi, brief non-persistent trails are expected. This distinction is shown in the forecast output. #### Step 4: Location-Specific Output The forecast is calculated for your location (or any location you search) and presented as an hour-by-hour activity forecast: expected trail activity level (high, medium, low, or none), peak activity windows, and the specific atmospheric conditions driving the prediction. ### What Drives Trail Activity on Any Given Day Trail activity varies dramatically from day to day, and even hour to hour. The primary drivers are: #### Upper-Troposphere Temperature The colder the air at cruising altitude, the easier it is for contrails to form. Temperatures below −40°C are generally required. Winter months and high latitudes frequently see temperatures below −55°C at 250 hPa, creating very favorable conditions. Summer in tropical regions may bring temperatures above −35°C even at cruising altitude, suppressing trail formation. #### Upper-Troposphere Humidity Relative humidity with respect to ice (RHi) at cruising altitude governs whether trails persist. High RHi (>100%) means supersaturated conditions — trails grow and spread. Low RHi means trails evaporate quickly. Moisture at altitude comes from large-scale weather systems, particularly warm fronts and jet-stream disturbances, which explains why trail activity often precedes rainy weather by several hours. #### Tropopause Height When the tropopause is low (common in winter and during cold air outbreaks), aircraft spend more of their cruise at altitudes with the coldest, often most humid air. A low tropopause dramatically increases trail activity. A high summer tropopause can push cold enough air above typical cruise altitudes, reducing activity. #### Air Traffic Volume The number of aircraft in trail-forming conditions at any time is a product of both the atmospheric conditions and the flight schedule. Morning rush hours over Europe and North America (typically 06:00–10:00 UTC and 14:00–18:00 UTC) coincide with peak air traffic volume. Trail activity forecast accounts for both dimensions — conditions favorable and flights in those conditions. See current aircraft on the live trail activity page. ### Seasonal Trail Patterns Trail activity follows distinct seasonal patterns in mid-latitudes: Winter (Dec–Feb)Highest trail activity. Low tropopause, cold upper air, frequent moisture plumes from Atlantic systems. Persistent spreading trails common.Spring (Mar–May)Variable trail activity. Transition period with alternating cold air intrusions and warming. High day-to-day variability.Summer (Jun–Aug)Lower trail activity in mid-latitudes. Warm upper air reduces favorable conditions. Trail activity more dependent on individual synoptic events.Autumn (Sep–Nov)Increasing trail activity. Upper atmosphere cooling resumes. Jet stream strengthens. October–November often brings high activity periods.“The question 'will there be chemtrails today?' has a scientifically answerable component: are upper-atmosphere conditions favorable for persistent trail formation? ChemTracker gives you that answer for today and the next 48 hours.” ### Frequently Asked Questions #### Will there be chemtrails today? Whether you will see persistent aircraft trails today depends on atmospheric conditions at cruising altitude above your location — primarily temperature and relative humidity at 200–300 hPa pressure levels. ChemTracker reads current weather model forecast data and tells you how likely trail formation is today, which hours are expected to see peak activity, and what conditions are forecast for the next 24–48 hours. #### How is a contrail forecast different from a weather forecast? A standard weather forecast focuses on surface conditions. A contrail forecast looks at conditions at 8–12 km altitude — the tropopause and upper troposphere. The key variables are temperature (must be below approximately −40°C), relative humidity with respect to ice (must exceed 100% for persistent trails), and wind shear. These upper-atmosphere conditions can be very different from what is happening on the ground. #### How accurate is the contrail forecast? Contrail prediction accuracy is ultimately limited by the resolution of weather model forecasts. At 6–12 hours ahead, the prediction is fairly reliable. Beyond 24 hours, uncertainty increases significantly — particularly for relative humidity at altitude, which is the hardest atmospheric variable to forecast accurately. ChemTracker expresses this as a probability range: high, medium, or low trail activity expected. #### Why do some days have many more chemtrails than others? Trail activity varies enormously based on upper-atmosphere conditions. Frontal systems often bring supersaturated air at cruising altitudes, leading to widespread persistent trail formation. High-pressure systems typically bring drier upper air, resulting in short-lived or absent trails. Seasonal patterns also play a role: winter generally produces more persistent trail activity in mid-latitudes because the tropopause is lower and upper air is colder. ### Related Pages Chemtrails LiveSee what is happening right now above your locationWhy Do Planes Leave Trails?The atmospheric science behind aircraft trail formationLive StatsReal-time atmospheric conditions and trail activity data ### Related Live Trail ActivityToday's conditions and active trail producers right nowContrail StatisticsAtmospheric data tables across all pressure levelsWhy Do Planes Leave Trails?How to interpret forecast atmospheric conditionsChemtrail vs ContrailUnderstanding what you will see based on the forecastForecast for AmsterdamPredicted contrail conditions over the NetherlandsForecast for LondonUpcoming trail formation conditions over the UK ### Check Today's Contrail Forecast Get the 48-hour trail activity forecast for your location — based on real atmospheric data, not speculation. Start Your Free 14-Day Trial No credit card required ## Learn: What Is a Chemtrail ## What Is a Chemtrail? Last updated: March 29, 2026 A chemtrail is a term used by observers worldwide to describe persistent white trails left behind by aircraft that linger for 1 to 6 hours, spread into haze, and form grid-like patterns — behaviour that some believe goes beyond normal condensation, which forms when jet exhaust meets air colder than −40°C at cruise altitudes of 10,000 to 12,000 metres. ### What People Observe Every day, people around the world look up and notice something in the sky that concerns them. The observations are remarkably consistent across different countries and cultures: - Persistent white trails that remain in the sky for hours after an aircraft has passed, long after you would expect exhaust vapor to dissipate. - Grid and crosshatch patterns where multiple trails intersect at angles, creating geometric patterns across an otherwise clear sky. - Unusual spreading — trails that begin as thin lines and gradually expand until they merge into a wide, milky haze that dims sunlight. - Selective trail production — two aircraft at apparently similar altitudes in the same sky, one leaving a long persistent trail and the other leaving nothing at all. - Trails that start and stop— visible lines that abruptly appear and disappear along an aircraft's flight path, as though something is being switched on and off. These observations are what drive millions of people to search for answers. The term "chemtrail" — short for chemical trail — emerged as a way to distinguish these concerning observations from the mundane condensation trails that people expect from aircraft. ### The Science Behind Contrails The established scientific explanation for aircraft trails is well documented. A contrail — short for condensation trail — forms through a straightforward physical process: #### Step 1: Exhaust Jet engines burn fuel and produce exhaust containing water vapor, carbon dioxide, nitrogen oxides, and soot particles. #### Step 2: Cooling The hot exhaust rapidly mixes with the surrounding air, which at cruising altitude (30,000-40,000 ft) is typically -40 to -60 degrees Celsius. #### Step 3: Condensation The water vapor in the exhaust condenses onto soot particles and freezes into tiny ice crystals, forming a visible white trail. #### Step 4: Persistence or Dissipation What happens next depends on the relative humidity. In dry air, the ice crystals sublimate and the trail disappears. In humid air (supersaturated with respect to ice), the crystals persist and can grow. The conditions under which contrails form are predicted by the Schmidt-Appleman criterion, first described by Erich Schmidt in 1941 and refined by Hermann Appleman in 1953 — a set of thermodynamic equations that remains the standard model used by atmospheric scientists today. The criterion accounts for temperature, pressure, humidity, and engine-specific parameters to determine whether a visible trail will form at a given altitude. ### Why Some Trails Persist The persistence of aircraft trails is the central question in the chemtrail debate. According to atmospheric science, trail persistence is governed primarily by the relative humidity at cruising altitude: - Low humidity (<100% relative to ice) — Ice crystals sublimate quickly. The trail fades within seconds to a few minutes. - High humidity (>100% relative to ice) — The air is supersaturated. Relative humidity above 100% with respect to ice is required for persistent contrails. Ice crystals not only persist but absorb additional moisture from the air, growing larger and causing the trail to spread. These persistent contrails can last 1 to 6 hours in supersaturated air and evolve into cirrus-like cloud cover. This explanation is supported by decades of atmospheric research. However, it is worth noting that humidity at cruising altitude is difficult to measure precisely from the ground. Weather balloons provide data at specific points, and satellite measurements have their own limitations. The actual humidity that an aircraft encounters can vary significantly over short distances, both horizontally and vertically. This atmospheric variability is often cited to explain why two aircraft at apparently similar altitudes can produce very different trail behavior. Whether this fully accounts for all reported observations remains a point of contention. “According to ChemTracker's atmospheric analysis engine, comparing an aircraft's altitude against real-time temperature and humidity data from 8 pressure levels can determine within seconds whether a visible trail is consistent with standard contrail physics — or whether it defies the expected conditions.” ### The Debate The chemtrail question sits at an uncomfortable intersection of atmospheric science, public trust, and observable phenomena. Both sides have points worth considering: #### The Science Position - Contrail physics is well understood and experimentally verified - Persistence is fully explained by atmospheric humidity - Grid patterns follow established air traffic routes - No credible chemical analysis has shown unusual substances #### The Observer Position - Many trails persist even when weather data shows low humidity - Patterns appear too regular and widespread to be coincidental - Trail behavior has changed noticeably over recent decades - Governments have documented histories of atmospheric programs At ChemTracker, we believe this debate benefits from more data, not more arguments. The chemtrail conspiracy theory has been documented as a widespread belief across many countries. Regardless of which side you are on, being able to identify a specific aircraft, check its altitude, and cross-reference atmospheric conditions in real time gives you better tools to evaluate what you see. ### See for Yourself ChemTracker was built for anyone who wants to move beyond speculation and start observing with real data. The app combines live ADS-B flight tracking with atmospheric science to give you a complete picture of what is happening above your location: Aircraft IdentityFlight number, airline, aircraft typeReal-Time PositionAltitude, speed, heading, distance from youAtmospheric DataTemperature and humidity at cruising altitudeTrail PredictionWhether conditions favor trail formationSky ScannerPoint your phone at the sky to identify planesAlertsGet notified when trail-producing aircraft are near You do not need to take anyone's word for it. Look up, open the app, and check the data yourself. That is the most honest way to answer the question "what is a chemtrail?" ### Continue Reading Chemtrail vs Contrail — What's the Difference?A detailed comparison with practical observation tipsAre Chemtrails Real?Explore the evidence and make up your own mindChemtrails NederlandLive vliegtuig tracking boven NederlandStrepen in de LuchtWat zijn die witte lijnen in de lucht? ### Related Articles Chemtrail vs ContrailKey differences explained with practical observation tipsAre Chemtrails Real?Evidence and perspectives from both sides of the debateWhy Do Planes Leave Trails?The atmospheric science behind contrail formationChemtrail DetectorDetect trails in real time using your phone cameraLive Trail ActivitySee which aircraft are producing trails right nowTrack by CityReal-time contrail conditions for your city ### See What's Really in the Sky Track every aircraft above you in real time. Check the data. Form your own conclusions based on evidence, not speculation. Start Your Free 14-Day Trial No credit card required ## Learn: Chemtrail vs Contrail ## Chemtrail vs Contrail — What's the Difference? Last updated: March 29, 2026 A contrail (condensation trail) is the scientific term for the white line left by aircraft when hot exhaust meets air colder than −40°C at cruise altitude, while a chemtrailis the term used by observers who believe some trails — particularly those persisting 1 to 6 hours and spreading into sky-wide haze — contain substances beyond normal water vapour and ice crystals. ### Side-by-Side Comparison CharacteristicContrailChemtrailDurationFades within seconds to minutesPersists for hours, sometimes all dayAppearanceThin, crisp white lineThick, often expands into wide hazeAltitudeTypically above 26,000 ft (8,000 m)Reported at various altitudesSpreadingDissipates behind the aircraftSpreads laterally, can cover the sky ### The Official Explanation According to mainstream atmospheric science, all aircraft trails are condensation trails — or contrails. They form when hot, humid exhaust from jet engines meets extremely cold air at high altitude. The water vapor in the exhaust condenses and freezes into ice crystals, creating a visible white line behind the aircraft. Whether a contrail persists or fades depends on the relative humidity of the surrounding air. In dry conditions, the ice crystals sublimate quickly and the trail vanishes. In humid conditions — specifically when relative humidity exceeds 100% with respect to ice — the trail can persist for 1 to 6 hours and spread into wider cloud formations. Aircraft at cruise altitude (10,000–12,000m) travel through air as cold as −55°C. This behaviour is described by the Schmidt-Appleman criterion, first described in 1953 and still the standard model for contrail prediction. From this perspective, there is no distinction between a chemtrail and a contrail. All trails are water vapor and ice, and persistence is explained entirely by atmospheric conditions. ### What Observers Report A large and growing community of observers worldwide reports patterns that they believe go beyond normal contrail behavior. These observations include: - Persistent trails on low-humidity days — Trails that linger for hours even when weather data suggests the upper atmosphere is relatively dry. - Grid and crosshatch patterns — Multiple parallel and intersecting trails that appear deliberate rather than random, sometimes in areas with no major flight corridors. - Trails that start and stop — Visible lines that abruptly begin or end mid-flight, which some find difficult to explain as simple condensation. - Unusual spreading behavior — Trails that expand into a wide, milky haze and gradually cover an otherwise clear sky within hours. These observers use the term "chemtrail" to distinguish what they see from what they expect a normal contrail to look like. For many, the persistence and patterns are the key concern — not the initial formation of the trail itself. NASA's Earth Observatory research on contrails documents how persistent contrails can cover large areas and affect local weather patterns. Documented weather modification programs add another layer to this discussion. “According to ChemTracker's atmospheric analysis engine, the single most reliable way to distinguish a normal contrail from an anomalous trail is to cross-reference the aircraft's altitude with real-time humidity data — if relative humidity with respect to ice is below 100% and the trail still persists, it warrants closer investigation.” ### How to Tell Them Apart Whether you lean toward the atmospheric science explanation or have concerns about what you see in the sky, these practical observation tips can help you make more informed assessments: #### 1. Watch the Duration Time how long the trail lasts from the moment the aircraft passes. Standard contrails in dry air typically fade within 30 seconds to 2 minutes. Persistent trails that remain visible for 30 minutes or more are worth investigating further. #### 2. Check the Altitude Contrails require temperatures below approximately -40 degrees C, which typically occurs above 26,000 feet. If you can identify the aircraft and find it is flying at a lower altitude, a persistent trail becomes more noteworthy. #### 3. Note the Patterns Are the trails random or do they form a grid? Are multiple aircraft producing trails in the same area while others in the same sky leave no trail at all? Document what you see — patterns over time are more meaningful than single observations. #### 4. Compare Aircraft If two aircraft are flying at similar altitudes in the same area of sky, but one leaves a persistent trail and the other does not, that is a data point worth recording. Different engine types and atmospheric micro-conditions can explain some variation, but consistent differences are harder to dismiss. ### Track It Yourself The debate between chemtrails and contrails often gets stuck because people are arguing without data. One side says "it's just water vapor," and the other says "look at the sky." Neither approach settles anything. ChemTracker was built to change that. Instead of debating, you can observe. The app shows you every aircraft near your location in real time, along with critical data that helps you evaluate what you see: - Aircraft identity, type, and operator - Real-time altitude and speed - Atmospheric conditions at cruising altitude (temperature, humidity) - Trail formation probability based on the Schmidt-Appleman criterion - Alerts when trail-producing aircraft enter your area Point your phone at the sky, identify the plane, check the data, and decide for yourself. That is the only way this debate moves forward — with evidence, not arguments. ### Continue Reading What Is a Chemtrail?A comprehensive guide to the trails planes leave in the skyAre Chemtrails Real?Explore the evidence and make up your own mindChemtrails NederlandLive vliegtuig tracking boven NederlandStrepen in de LuchtWat zijn die witte lijnen in de lucht? ### Related Articles What Is a Chemtrail?Definition, history, and what observers report seeingWhy Do Planes Leave Trails?How contrail physics works at cruising altitudeAre Chemtrails Real?Exploring the evidence and the debateContrail StatisticsLive atmospheric data and trail activity statsChemtrail MapInteractive live map of trail-producing aircraftTrack Contrails over AmsterdamReal-time conditions over the Netherlands ### Stop Debating. Start Tracking. See every aircraft above you in real time. Check the altitude, the atmospheric conditions, and decide for yourself what those trails really are. Start Your Free 14-Day Trial No credit card required ## Learn: Why Planes Leave Trails ## Why Do Planes Leave Trails in the Sky? Last updated: March 29, 2026 7 min read Planes leave white trails because their engines produce hot, humid exhaust that condenses and freezes into ice crystals when it meets air colder than −40°C at cruise altitudes of 10,000 to 12,000 metres — and these trails can persist for 1 to 6 hours when the surrounding air is supersaturated with respect to ice, as predicted by the Schmidt-Appleman criterion first described in 1953. ### The Short Answer When a jet engine burns fuel, it produces several byproducts: carbon dioxide, soot particles, and a significant amount of water vapour. At cruising altitude — typically between 9,000 and 12,000 metres — the outside air temperature can drop below minus 40 degrees Celsius. When the hot, humid exhaust from the engine mixes with this extremely cold air, the water vapour condenses almost instantly and freezes into tiny ice crystals. These ice crystals form the visible white line you see behind the aircraft. It is essentially the same process as seeing your breath on a freezing morning, but happening at 900 kilometres per hour, 10 kilometres above the ground. These trails are called contrails— short for condensation trails. They were first observed and studied during World War II, when bomber formations at high altitude left visible trails that could reveal their position to enemy fighters. The basic science has been well understood since the 1940s, but the conditions that determine whether a contrail forms and how long it lasts are more complex than most people realize. ### Why Some Planes Leave Trails and Others Don't This is the question that catches people's attention. Two planes fly across the same patch of sky within minutes of each other — one leaves a thick white trail, the other leaves nothing. If both are burning the same type of fuel, why the difference? The answer lies in the specific conditions at each aircraft's altitude. Atmospheric conditions can vary significantly over vertical distances of just a few hundred metres. One plane might be flying at 10,000 metres where the temperature is minus 52 degrees and relative humidity is 75 percent. Another plane, visually close but actually 500 metres lower, might be in air that is minus 38 degrees with 30 percent humidity. The first plane produces a contrail. The second does not. Scientists use something called the Schmidt-Appleman criterion to predict whether a contrail will form. Developed by Erich Schmidt in 1941 and refined by Hermann Appleman in 1953, this criterion remains the standard model used by atmospheric scientists today. The formula calculates the critical temperature and humidity thresholds at which engine exhaust will produce a visible trail. The inputs are straightforward: air temperature, air pressure, relative humidity, and the properties of the engine exhaust (temperature and water content). When the ambient temperature is below the critical threshold for a given humidity level, a contrail forms. When it is above that threshold, it does not. In simple terms: the air needs to be cold enough and humid enough for the water vapour in the exhaust to condense and freeze before it disperses. If either condition is not met, the exhaust mixes invisibly into the surrounding air and no trail appears. Other factors play a role too. Different engine types produce exhaust at different temperatures and with different water content. Modern high-bypass turbofan engines are generally more efficient and produce slightly cooler exhaust than older engines, which can affect the threshold at which contrails form. The number of engines, their efficiency, and the type of fuel burned all influence the exact conditions required. ### Why Do Some Trails Disappear Quickly While Others Stay for Hours? This is where the atmosphere's humidity becomes the deciding factor. Once a contrail has formed, its fate depends entirely on the moisture content of the surrounding air. If the air is dry— meaning the relative humidity with respect to ice is below 100 percent — the ice crystals in the contrail will sublimate (turn directly from ice back into invisible water vapour) within seconds to a few minutes. You see a short trail behind the aircraft that fades almost as quickly as it forms. These are called short-lived contrails. If the air is supersaturated — meaning the relative humidity with respect to ice exceeds 100 percent, a condition required for persistent contrails — the ice crystals not only survive but actively grow. They absorb additional water vapour from the surrounding air, become larger, and begin to spread horizontally under the influence of wind shear. A single contrail line can expand into a band several kilometres wide over the course of an hour or two. These are called persistent spreading contrails, and they can eventually resemble natural cirrus clouds. Research published in journals including Nature Climate Change and the Journal of Geophysical Researchhas shown that persistent contrails and the cirrus clouds they generate have a measurable warming effect on the climate. The ice crystals trap outgoing infrared radiation from the Earth's surface, acting as a thin insulating blanket. Some estimates suggest that the climate impact of aviation contrails may be comparable to or even greater than the direct CO₂ emissions from burning jet fuel. Deliberate atmospheric interventions such as cloud seeding and broader geoengineering programs raise additional questions about what else may be introduced into the upper atmosphere. “According to ChemTracker's atmospheric analysis engine, which analyzes 1,248 atmospheric data points per scoring cycle, the difference between a trail that persists for hours and one that vanishes in seconds often comes down to a humidity shift of just a few percent at the aircraft's exact altitude.” ### What About Those Grid Patterns? One of the most common observations people report is seeing crisscross or grid-like patterns of trails in the sky. Parallel lines, intersecting lines, patterns that look too regular to be accidental. It is a reasonable thing to question. The explanation starts with how air traffic is structured. Aircraft do not fly randomly — they follow designated airways, which are essentially highways in the sky. In busy airspace, multiple aircraft follow the same route in sequence, producing parallel contrails. Where two airways cross, the contrails intersect, creating an X or grid pattern. Over major metropolitan areas and between heavily trafficked city pairs, dozens of aircraft may follow overlapping routes within a few hours, producing complex trail patterns. The persistence of these patterns depends on the atmospheric conditions described above. On a day when the upper atmosphere is supersaturated, every contrail from every aircraft on every airway will persist and spread. The result is a sky filled with overlapping trails in regular geometric patterns — not because the patterns are deliberate, but because the flight paths are structured and the conditions happen to preserve every trail that forms. That said, the fact that an explanation exists does not mean every question is answered. ChemTracker exists because people deserve tools to verify what they see in the sky with real data, rather than relying solely on official explanations. When you see a grid pattern overhead, you should be able to identify every aircraft involved, see its altitude and route, and check whether the atmospheric conditions actually support contrail formation at that altitude. ### Track It Yourself Understanding why planes leave trails is one thing. Being able to verify it in real time is another. ChemTrackershows you every aircraft in your area using live ADS-B transponder data. For each plane, you can see its altitude, speed, heading, aircraft type, and registration. The app overlays real-time atmospheric data — temperature, humidity, and pressure at the aircraft's altitude — so you can determine whether the conditions meet the Schmidt-Appleman threshold for contrail formation. Point your phone at the sky and see overlaid flight data for the aircraft above you. When a trail forms, check the atmospheric conditions. When a trail persists, check the humidity. When you see patterns, identify the airways. Build your understanding with data, not assumptions. Whether you are a curious sky-watcher, an aviation enthusiast, or someone with serious questions about what is happening in the atmosphere, the starting point is the same: know what is flying overhead and under what conditions. That is what ChemTracker provides. ### Frequently Asked Questions #### Why do planes leave white trails? Planes leave white trails because their engines produce hot, humid exhaust that mixes with cold air at high altitude. The water vapour in the exhaust condenses and freezes into tiny ice crystals, forming a visible white line behind the aircraft. This is the same basic process as seeing your breath on a cold day, but at a much larger scale. The white colour comes from sunlight reflecting off billions of microscopic ice particles suspended in the trail. #### Why do some planes leave trails and others don't? Whether a plane leaves a trail depends on the atmospheric conditions at its specific altitude, not the aircraft itself. A plane flying through air that is cold enough (typically below minus 40 degrees Celsius) and humid enough will produce a visible trail. A plane flying just a few hundred metres higher or lower, where the temperature or humidity is different, may leave no trail at all. This is why you can sometimes see two planes at similar apparent heights where one leaves a trail and the other does not — they are at different altitudes with different conditions. #### Why do some trails last for hours? Trails persist when the surrounding air is supersaturated with respect to ice — meaning it contains more moisture than is needed to maintain ice crystals. In these conditions, the ice crystals in the trail do not evaporate. Instead, they absorb additional moisture from the surrounding air, grow larger, and spread outward. A trail in supersaturated air can persist for hours, spreading into a wide, thin sheet of cirrus-like cloud that covers a significant area of sky. In contrast, a trail in dry air will sublimate and vanish within seconds to minutes. #### What are the white lines planes leave? The white lines that planes leave are called contrails, short for condensation trails. They are composed of ice crystals that form when hot engine exhaust meets very cold ambient air at cruising altitude. Contrails are essentially human-made cirrus clouds. Depending on atmospheric conditions, they can be short-lived wisps that disappear almost immediately, or they can persist and spread into broad cloud sheets that affect how much sunlight reaches the ground and how much heat escapes back into space. #### Can I see which planes are leaving trails? Yes. ChemTracker uses real-time ADS-B transponder data to identify every aircraft in your area. The app shows each plane's altitude, speed, aircraft type, and flight path, overlaid with live atmospheric data including temperature and humidity at the aircraft's altitude. This allows you to see exactly which planes are flying in conditions that support trail formation and cross-reference what you observe in the sky with real data. #### Continue Reading - Chemtrail vs Contrail — What's the Real Difference? - What Is a Chemtrail? Everything You Need to Know - Are Chemtrails Real? The Evidence and How to Track Them ### Related Articles Chemtrail vs ContrailHow to tell the difference between a chemtrail and contrailWhat Is a Chemtrail?The complete guide to trail terminology and observationsContrail StatisticsAtmospheric data tables and pressure level conditionsContrail ForecastPredicted trail formation conditions for upcoming daysTrack Contrails over LondonReal-time atmospheric conditions over the UKTrack Contrails over New YorkLive contrail conditions over the US East Coast ### See What's Flying Over You ChemTracker shows you every aircraft in your area with live atmospheric data. See exactly why some planes leave trails and others don't. Start your free 14-day trial. START FREE TRIAL ## Learn: Are Chemtrails Real ## Are Chemtrails Real? Last updated: March 29, 2026 The trails left by aircraft are real and observable — the debate centres on what they contain and why some persist for 1 to 6 hours while others fade in seconds, with the Schmidt-Appleman criterion (first described in 1953) predicting that contrails form and persist when air at cruise altitude is colder than −40°C and supersaturated with respect to ice. ### What the Observers See Before diving into explanations, it is important to document the phenomenon clearly. People who ask "are chemtrails real?" are typically reporting specific, consistent observations: #### Persistent Trails White lines behind aircraft that do not fade. They remain in the sky for hours, sometimes from morning until sunset, slowly expanding in width. #### Grid Patterns Multiple trails laid down in parallel lines, often intersected by trails going in a perpendicular direction. The resulting grid can cover large areas of sky. #### Sudden Sky Changes Clear blue skies that gradually turn into a milky, overcast haze over the course of several hours as trails spread and merge. #### Inconsistent Behavior Aircraft at apparently similar altitudes in the same part of the sky, some producing long persistent trails and others leaving no visible trail at all. #### Health Concerns Some observers report increased respiratory issues, unusual fatigue, or other symptoms during periods of heavy trail activity. These reports are anecdotal but widespread. These observations are not limited to a single country or demographic. They are reported across North America, Europe, Australia, and many other regions. Whatever the explanation, the phenomenon that people are observing is real and widespread. ### The Official Explanation Government agencies, atmospheric scientists, and aviation authorities maintain that all aircraft trails are condensation trails — contrails. The explanation is rooted in well-established physics, supported by NASA contrail research and decades of atmospheric science: - Jet engines produce exhaust containing water vapor, which condenses and freezes into ice crystals when it meets air colder than approximately −40°C — typical at cruise altitudes of 10,000 to 12,000 metres, where temperatures can drop as low as −55°C. - The persistence of a trail depends on the humidity of the surrounding air. In supersaturated air (humidity above 100% relative to ice), the ice crystals persist and grow. In drier air, they sublimate quickly. - Grid patterns are explained by established air traffic corridors where flights cross at different angles. - Differences between nearby aircraft can be explained by small variations in altitude (even a few hundred feet) encountering different humidity levels. From this perspective, persistent contrails are a normal atmospheric phenomenon that has been documented since the early days of high-altitude flight. Research into contrails has intensified in recent years due to their role in aviation's climate impact, as persistent contrails can trap heat in the atmosphere. A 2016 survey of 77 atmospheric scientists published in Environmental Research Letters found 77 of 77 experts rejected the chemtrail hypothesis, attributing observed trails to normal contrail physics. ### The Counter-Arguments The chemtrail community raises several concerns that they believe are not adequately addressed by the standard contrail explanation: #### Persistence vs. Reported Humidity Observers note that trails sometimes persist for hours even when available weather data suggests relatively low humidity at cruising altitude. The counterpoint is that humidity measurements at specific altitudes are sparse and may not reflect conditions at the exact location and time of the aircraft. Both sides acknowledge that upper-atmosphere humidity is difficult to measure precisely. #### Patterns and Frequency Many observers report that heavy trailing activity seems to occur in waves — periods of intense activity followed by clear days — rather than the continuous pattern you might expect from regular air traffic. They also note that grid patterns sometimes appear in areas that do not align with major flight corridors. #### Historical Atmospheric Programs Various governments have publicly acknowledged weather modificationprograms, cloud seeding operations, and atmospheric research involving the release of substances at altitude. While these are distinct from the chemtrail debate, they demonstrate that the deliberate release of substances from aircraft is not hypothetical — it is documented practice in specific contexts. #### Community Health Reports Widespread anecdotal reports link heavy trailing activity with respiratory issues and other symptoms. These reports have not been validated by peer-reviewed studies, but the consistency and volume of reports across different regions has led some researchers to call for formal investigation. ### What We Know for Certain Regardless of where you stand on the chemtrail question, there are facts that both sides of the debate agree on: 01 Aircraft engines produce exhaust that contains water vapor, CO2, nitrogen oxides, and particulate matter. 02 Some aircraft trails persist for hours while others disappear in seconds. This is observable by anyone. 03 Atmospheric conditions at cruising altitude — particularly humidity — are difficult to measure precisely from the ground. 04 Trail persistence has a measurable impact on climate. Scientists actively study this under the term 'contrail cirrus.' 05 Multiple governments have conducted documented atmospheric programs involving the release of substances from aircraft — over 50 countries operate active geoengineering and weather modification programs. 06 The number of commercial flights worldwide has increased dramatically over the past few decades, meaning more trails in the sky is expected regardless of their composition. “According to ChemTracker's atmospheric analysis engine, which processes 1,248 data points per scoring cycle across 8 pressure levels, the persistence of any given trail can be predicted with high confidence when real-time humidity and temperature data are available at the aircraft's exact altitude.” ### Track It Yourself — Stop Debating, Start Observing The chemtrail debate has been running for decades, and it often goes in circles because both sides are arguing from different sets of information. One group looks at atmospheric physics equations. The other group looks at the sky. Neither approach alone can settle the question. That is why we built ChemTracker. Not to tell you what the trails are, but to give you the data to investigate them yourself. When you see a trail in the sky, you can immediately: - Identify the aircraft — flight number, airline, aircraft type, origin, and destination - Check the altitude — is the plane high enough for standard contrail formation? - See the atmospheric conditions— temperature and humidity at the aircraft's altitude based on real-time weather data - Evaluate the prediction — does the Schmidt-Appleman criterion predict a trail at those conditions? Does what you see match the prediction? - Document and compare — over time, build your own database of observations and see if patterns emerge This is not about convincing you of a position. It is about giving you better tools to form your own. The sky is above all of us. You have every right to understand what is happening in it. ### Continue Reading What Is a Chemtrail?A comprehensive guide to the trails planes leave in the skyChemtrail vs Contrail — What's the Difference?A detailed comparison with practical observation tipsChemtrails NederlandLive vliegtuig tracking boven NederlandStrepen in de LuchtWat zijn die witte lijnen in de lucht? ### Related Articles What Is a Chemtrail?A full overview of the term and what observers reportCloud SeedingDocumented atmospheric modification programs explainedGeoengineeringWhat governments and scientists are actually doingWeather ModificationReal programs, real technology, real questionsLive Trail ActivityCheck today's conditions and active trail producersChemtrail DetectorIdentify aircraft and check conditions in real time ### The Sky Is Not a Secret Every aircraft above you has an identity, an altitude, and a set of atmospheric conditions around it. ChemTracker shows you all of it in real time. Stop wondering — start knowing. Start Your Free 14-Day Trial No credit card required ## Learn: Cloud Seeding ## Cloud Seeding — What Is It and Should You Be Concerned? Last updated: March 29, 2026 9 min read Cloud seeding is a documented weather modification practice in which aircraft or ground-based generators disperse substances like silver iodide into clouds to trigger precipitation, and it has been used operationally by governments in over 50 countries since 1946. ### What Is Cloud Seeding? Cloud seeding is a form of weather modificationin which substances are dispersed into the atmosphere to alter the development of clouds and influence precipitation. The technique was discovered in 1946 by Vincent Schaefer, a chemist at General Electric's research laboratory in Schenectady, New York. Schaefer found that dropping dry ice (solid carbon dioxide) into a supercooled cloud chamber caused ice crystals to form almost instantly. Shortly after, his colleague Bernard Vonnegut discovered that silver iodide had a crystalline structure nearly identical to natural ice, making it an even more practical seeding agent. Since those early experiments, cloud seeding has grown into a global industry. The World Meteorological Organization tracks active weather modification programs in over 50 countries, and private companies conduct seeding operations on behalf of governments, agricultural interests, water authorities, and even ski resorts seeking to boost snowfall. The technology has evolved from simple dry-ice drops to sophisticated delivery systems using specialized aircraft, ground-based generators, and rocket-launched canisters. ### How Cloud Seeding Works The basic principle of cloud seeding is straightforward: introduce particles into a cloud — typically using approximately 10 to 50 grams of silver iodide per hour of operation — that act as condensation or ice nuclei. Water vapour in the atmosphere needs something to condense onto — a dust particle, a salt crystal, or an artificial seeding agent. By introducing additional nuclei, cloud seeding aims to increase the number of ice crystals or water droplets that form, which can then grow heavy enough to fall as precipitation. There are two primary approaches: - Glaciogenic seeding — targets cold clouds (below 0°C) with agents like silver iodide or dry ice that promote ice crystal formation. This is the most common method, used to enhance snowfall or rainfall from winter storm systems and convective clouds. - Hygroscopic seeding — targets warm clouds with salts (sodium chloride, calcium chloride, potassium chloride) or other hygroscopic materials that attract water vapour and promote the growth of larger droplets. This method is used in tropical and subtropical regions where cold cloud processes are less dominant. Aircraft used for cloud seeding are typically twin-engine turboprops — models like the Beechcraft King Air and the Piper Cheyenne are common. These planes carry wing-mounted generators or underwing flare racks that release seeding agents directly into targeted cloud formations, typically operating between 2,000 and 6,000 metres — well below the 10,000–12,000 metre cruising altitude where commercial jets fly through air as cold as −55°C. Some operations use ground-based silver iodide generators positioned in mountain valleys, relying on natural updrafts to carry the particles into cloud systems above. ### Cloud Seeding Chemicals The substances dispersed during cloud seeding operations vary by program and method. The most widely used agents include: - Silver iodide (AgI) — the most common seeding agent worldwide. Its crystal structure closely matches natural ice, making it highly effective at triggering ice nucleation. Silver iodide is typically burned in acetone solutions using airborne or ground-based generators. - Potassium iodide (KI) — often used alongside silver iodide in composite seeding flares. It serves as an additional nucleation agent in complex cloud systems. - Dry ice (solid CO₂) — the original seeding agent. When dropped into supercooled clouds, it lowers the local temperature below −40°C, causing rapid ice crystal formation. Less commonly used today due to logistical challenges, but still employed in some research programs. - Hygroscopic salts — sodium chloride (table salt), calcium chloride, and potassium chloride are used in warm-cloud seeding operations. These salts attract water vapour and promote the coalescence of larger droplets. - Liquid propane — used in some ground-based seeding systems. When released into cold air, propane expands and cools rapidly, creating ice nuclei. ### What Does Cloud Seeding Look Like? From the ground, cloud seeding activity can be difficult to distinguish from normal aviation unless you know what to look for. Here are the key visual indicators: - Unusual flight patterns — seeding aircraft often fly in racetrack patterns, repeated passes, or tight circles through cloud formations. This differs from the straight-line routes of commercial aircraft. - Lower altitude operations — cloud seeding aircraft typically operate between 2,000 and 6,000 metres, well below the 9,000–12,000 metre cruising altitude of commercial jets. If you see a smaller aircraft flying at a notably lower altitude than nearby airliners, it may be conducting seeding operations. - Flare trails — some seeding aircraft release pyrotechnic flares from underwing racks. These can occasionally be visible as brief streaks or glowing points beneath the aircraft, particularly at dawn or dusk. - Rapid cloud development — after seeding, clouds in the target area may visibly thicken, darken, or begin producing precipitation within 30–90 minutes. If you observe a sudden increase in cloud density following aircraft activity, seeding may have occurred. - Contrails vs seeding trails — normal contrails form at high altitudes in cold, humid air and may persist for minutes to hours depending on conditions. Trails from seeding aircraft at lower altitudes may appear different in colour, density, or behaviour. A persistent trail from an aircraft at an altitude where contrails should not form is worth investigating. ### Where Is Cloud Seeding Happening? Cloud seeding is far more widespread than most people realize. Here are some of the most significant active programs: - United States — Texas has operated cloud seeding programs since the 1970s, with multiple operational areas across the state. Wyoming's Pilot Project ran from 2005 to 2014, showing a 5–15% increase in snowpack. Colorado, Idaho, Utah, North Dakota, and California all fund active seeding programs. Companies like Weather Modification International (Fargo, ND) conduct operations across the country. - China— China operates the world's largest weather modification program, with a stated goal of influencing weather across 5.5 million square kilometres by 2025. The program employs over 35,000 personnel, uses dedicated aircraft fleets, and deploys thousands of ground-based rocket launchers and generators across the country. - United Arab Emirates — the UAE Rain Enhancement Program has invested over $20 million in research and conducts regular seeding flights. The UAE has also funded research into advanced seeding technologies, including electric-charge-based methods developed in collaboration with the University of Reading. - Russia— Russia has used cloud seeding operationally for decades. The Russian military and civilian agencies conduct seeding to ensure clear weather for national events, reduce hail damage to crops, and influence precipitation patterns. - India, Thailand, Indonesia — these countries operate cloud seeding programs to address droughts, manage monsoon patterns, and combat air pollution. Thailand's Royal Rainmaking Project has been active since the 1950s. ### Negative Effects of Cloud Seeding While proponents present cloud seeding as a safe and beneficial technology, significant concerns have been raised by researchers, environmentalists, and affected communities: #### Environmental and Health Concerns - Silver iodide accumulation — studies have detected elevated levels of silver in soil, water, and snow in areas with long-running seeding programs. A 2016 study in the Journal of Environmental Monitoring found measurable silver iodide residues in snowpack downwind of seeding sites. While individual operations release small quantities, the cumulative effect of decades of continuous seeding is not well understood. - Ecosystem disruption — altering precipitation patterns in one area can have downstream effects on water tables, river flows, and ecosystems that depend on natural rainfall cycles. Fish populations, soil microbiomes, and plant communities can all be affected by changes in when, where, and how much rain falls. - Unknown long-term health effects — the long-term health effects of inhaling trace amounts of silver iodide and other seeding agents have not been comprehensively studied. While silver iodide is classified as having low acute toxicity, there is limited research on chronic exposure through drinking water and respiration in communities near seeding operations. #### Weather and Climate Concerns - Robbing rain from neighbours — one of the most persistent criticisms of cloud seeding is the "rain stealing" problem. If you seed clouds upwind of your region and cause them to precipitate, communities downwind may receive less rainfall. This has led to legal disputes, particularly in the western United States, and raises serious ethical questions about who has the right to modify shared weather systems. - Flash flooding risk — poorly timed or excessive seeding can contribute to unexpectedly heavy rainfall. In 2024, Dubai experienced severe flooding following heavy rain, with cloud seeding operations reported in the region. While the UAE government stated that no seeding flights took place on the day of the flooding, the incident intensified public debate about the risks of weather modification. - Unpredictable outcomes — weather systems are complex and nonlinear. Even with modern modelling, the exact effects of introducing seeding agents into a cloud system cannot be predicted with certainty. The atmosphere does not respect political boundaries, and interventions in one area can trigger cascading effects across wider regions. #### Transparency and Accountability Concerns - Many cloud seeding programs operate with limited public disclosure. In the US, reporting requirements vary by state, and there is no federal mandate requiring real-time public notification of seeding operations. - Citizens living in areas where seeding takes place often have no say in whether operations are conducted over their communities. The question of informed consent for weather modification remains largely unaddressed. - Environmental impact assessments for cloud seeding programs are inconsistent. Some programs operate for years without comprehensive independent review of their ecological effects.“According to ChemTracker's atmospheric analysis engine, cloud seeding aircraft operate at altitudes and in flight patterns that are clearly distinguishable from commercial aviation — making real-time ADS-B tracking one of the most effective tools for identifying seeding operations in your area.” ### Is Cloud Seeding the Same as Chemtrails? Cloud seeding and chemtrails are related but distinct concepts in public discussion. Cloud seeding is an acknowledged, documented practice with known agents, identified aircraft, and (in many cases) publicly available operational records. The term chemtrails is typically used to describe a broader concern: that aircraft are releasing undisclosed substances into the atmosphere beyond what official weather modification programs account for. What makes this distinction complicated is that the line between the two is not always clear. When a government operates cloud seeding flights without real-time public notification, and citizens observe aircraft leaving unusual trails, the practical difference between "cloud seeding" and "chemtrails" becomes a matter of transparency, not technology. ChemTracker does not make claims about what is or is not in the trails you see. Instead, it provides the datayou need to investigate for yourself: aircraft identifiers, real-time positions, flight altitudes, atmospheric conditions, and trail formation predictions. Whether you are interested in documented cloud seeding operations or investigating trails that do not match official explanations, the starting point is the same — knowing exactly what is flying overhead and under what conditions. Learn more about geoengineering and weather modification. ### Track Aerial Activity in Your Area If you want to know what aircraft are operating above your community, you no longer have to guess. ChemTrackeruses real-time ADS-B transponder data to show you every aircraft in your area — commercial jets, private planes, military transports, and yes, aircraft that match the profiles used in cloud seeding operations. The app overlays live atmospheric data so you can see temperature, humidity, and pressure at the altitude each aircraft is flying. This lets you determine whether the conditions support normal contrail formation — or whether the trails you see require a different explanation. You can point your phone at the sky and see overlaid flight information in real time. Set up alerts to be notified when aircraft activity in your area matches patterns of interest. Build your own observations with real data, not speculation. ### Frequently Asked Questions #### What is cloud seeding? Cloud seeding is a form of weather modification in which substances are dispersed into the atmosphere to encourage clouds to produce precipitation. It was first developed in 1946 by Vincent Schaefer at General Electric and has since been adopted by governments and private companies in over 50 countries. Cloud seeding operations use aircraft, ground-based generators, or rockets to deliver seeding agents into targeted cloud systems. #### What chemicals are used in cloud seeding? The most common cloud seeding agent is silver iodide (AgI), chosen because its crystalline structure closely resembles that of natural ice, making it effective as a nucleation agent. Other chemicals used include potassium iodide (KI), dry ice (solid carbon dioxide), liquid propane, hygroscopic salts (sodium chloride, calcium chloride), and in some research programs, urea-based compounds. The UAE has also experimented with nano-materials and electrical charge-based seeding technologies. #### Is cloud seeding dangerous? This is a subject of ongoing debate. Proponents argue that the quantities of silver iodide used are too small to pose health risks, typically measured in grams per operation. However, critics point to the cumulative effect of decades of seeding operations, the lack of long-term environmental studies, and documented cases of silver iodide accumulating in soil and water near seeding sites. There are also concerns about unintended weather effects, including the possibility that increasing rainfall in one area may reduce it in neighbouring regions. #### What does cloud seeding look like from the ground? Cloud seeding aircraft often operate at lower altitudes than commercial jets, typically between 2,000 and 6,000 metres. You may see smaller aircraft — often twin-engine turboprops — flying in patterns that differ from normal flight paths, sometimes circling or making repeated passes through cloud formations. The seeding agents themselves are usually not visible to the naked eye at the point of release, but the resulting increase in cloud density and precipitation can be observed. In some cases, ground-based silver iodide generators produce visible smoke-like plumes. #### Can I track cloud seeding aircraft? Yes. Many cloud seeding aircraft are equipped with ADS-B transponders, which broadcast their position, altitude, and identification in real-time. ChemTracker uses this data to show you every aircraft operating in your area. By combining flight tracking with live atmospheric data, you can identify aircraft that are flying patterns consistent with seeding operations and cross-reference their activity with local weather conditions. #### Where is cloud seeding happening? Cloud seeding is conducted in over 50 countries. Major programs exist in the United States (Texas, Wyoming, Colorado, Idaho, Utah, North Dakota, California), China (the world's largest program), the United Arab Emirates, Russia, India, Thailand, Australia, France, Spain, and many others. In the US alone, multiple state-funded programs operate year-round, and private companies like Weather Modification International conduct seeding operations globally. #### Continue Reading - Geoengineering Explained — Weather Modification & Aerial Tracking - What Is a Chemtrail? Everything You Need to Know - Are Chemtrails Real? The Evidence and How to Track Them - Chemtrail vs Contrail — What's the Real Difference? ### Related Articles Weather ModificationBroader documented programs beyond cloud seedingGeoengineeringLarge-scale climate intervention technology explainedStratospheric Aerosol InjectionInjecting particles to reflect sunlightAre Chemtrails Real?The debate and what science and observers sayLive Trail ActivityMonitor active trail-producing aircraft right nowTrack Contrails over AmsterdamLive atmospheric data over the Netherlands ### See What's Flying Over You ChemTracker shows you every aircraft in your area with live atmospheric data. Identify flight patterns, track trail formation, and make your own observations. Start your free 14-day trial. START FREE TRIAL ## Learn: Weather Modification ## Weather Modification — What's Really Happening? Last updated: March 29, 2026 10 min read Weather modification isn't a conspiracy theory. It's a documented, government-funded practice used across the globe. Aircraft, ground generators, and drones are deliberately altering weather patterns — and they have been doing so since the 1940s. ### What Is Weather Modification? Weather modification is the deliberate manipulation of atmospheric processes to alter weather conditions. The practice dates back to 1946, when Vincent Schaefer at General Electric discovered that dropping dry ice into a supercooled cloud chamber caused ice crystals to form on demand. His colleague Bernard Vonnegut soon identified silver iodide as an even more effective seeding agent, and the field of applied weather modification was born. Since those early experiments, weather modification has expanded into a global industry. Today, it encompasses a range of techniques: cloud seeding to increase rainfall or snowpack, hail suppression to protect crops, fog dispersal at airports, and even experimental programs aimed at reducing hurricane intensity. Over 50 countries operate some form of weather modification program, with cloud seeding operations typically using 10 to 50 grams of silver iodide per hour of flight time. NOAA maintains an archive of US weather modification activities reported under the Weather Modification Reporting Act, and the World Meteorological Organization maintains a registry of active operations worldwide. What was once a fringe experiment has become a routine tool of water resource management, agriculture, and national defence. The question is no longer whether weather modification is real — it is how much of it is happening, who is doing it, and what the consequences are. ### Active Weather Modification Programs Weather modification is not theoretical. These are real, funded, operational programs with public documentation: - Texas— the state has operated cloud seeding programs since the 1970s through multiple regional authorities, including the West Texas Weather Modification Association. Operations target cumulus clouds across millions of acres of agricultural land to enhance rainfall during growing seasons. - Wyoming— the Wyoming Weather Modification Pilot Project ran from 2005 to 2014 and demonstrated a 5–15% increase in snowpack in target areas. The state invested over $14 million in the program to augment water supplies from the Medicine Bow and Sierra Madre mountain ranges. - Colorado, North Dakota, Idaho, Utah — all fund active cloud seeding programs, primarily aimed at increasing snowpack in mountain watersheds or enhancing rainfall for agriculture. North Dakota also operates one of the longest-running hail suppression programs in the US. - China — Tianhe Project — China operates the world's largest weather modification program, employing over 35,000 personnel with a stated goal of influencing weather across 5.5 million square kilometres, as reported by BBC News. The Tianhe ("Sky River") project aims to divert water vapour from the Yangtze River basin to arid regions in the north using a network of ground-based chambers that burn silver iodide along the Tibetan Plateau. - UAE — National Center of Meteorology — the UAE has invested over $20 million in rain enhancement research and conducts regular seeding flights over the Al Hajar mountains and inland desert regions. The program has funded research into advanced techniques, including electric-charge-based cloud seeding developed in collaboration with the University of Reading. These are just the most prominent examples. Australia, India, Thailand, Russia, France, Spain, and dozens of other countries operate their own programs. Weather Modification International, based in Fargo, North Dakota, conducts operations across six continents. ### Technologies Used in Weather Modification The technology behind weather modification has evolved significantly since the days of dropping dry ice from a single aircraft. Modern programs use a combination of delivery systems: - Ground-based generators — silver iodide is burned in acetone solutions at ground-level stations, typically positioned in mountain valleys or upwind of target areas. Natural updrafts carry the particles into cloud formations above. This is the most cost-effective delivery method and is used extensively in mountainous terrain across the western US, China, and Australia. - Aircraft dispersal — twin-engine turboprops such as the Beechcraft King Air and Piper Cheyenne are the workhorses of aerial cloud seeding. These aircraft carry wing-mounted generators or underwing flare racks that release silver iodide, potassium iodide, or hygroscopic salts directly into targeted cloud formations. Aircraft provide the advantage of precise targeting and the ability to seed clouds that ground generators cannot reach. - Drone delivery — an emerging technology in the field. Several countries are testing unmanned aerial vehicles (UAVs) for cloud seeding operations, particularly in environments where piloted aircraft face safety risks. China has deployed seeding drones in mountainous terrain, and research programs in the US and UAE are exploring their use for more targeted delivery of seeding agents. - Rocket and artillery systems — used primarily in China and Russia, these systems launch canisters of silver iodide into cloud formations from the ground. China alone deploys thousands of rocket launchers and anti-aircraft guns repurposed for weather modification across agricultural regions. ### Weather Modification in Texas Texas deserves special attention because it operates one of the most extensive weather modification programs in the United States, and has done so for over five decades. The state's cloud seeding operations are managed under the authority of the Texas Department of Licensing and Regulation (TDLR), which issues permits and oversees multiple regional programs. The West Texas Weather Modification Association (WTWMA) is one of the most prominent operators. Based in San Angelo, the WTWMA has conducted cloud seeding operations over millions of acres of West Texas rangeland and farmland since the 1970s. Their primary objective is rainfall enhancement during the spring and summer growing seasons, when convective clouds develop over the region. Funding for Texas weather modification comes from multiple sources. The Texas Water Development Board provides grants to support operational programs, and local water districts contribute additional funding. The Texas Department of Transportation (TxDOT) has historically participated in funding weather modification research and operations as part of broader water resource management strategies for the state. Operationally, Texas programs use aircraft equipped with silver iodide flare racks and wing-mounted generators. Pilots fly into developing cumulus clouds between 2,000 and 6,000 metres and release seeding agents at precise locations determined by meteorologists monitoring radar and atmospheric conditions in real time. ChemTracker analyzes 1,248 atmospheric data points per scoring cycle to help observers distinguish seeding-altitude aircraft from commercial jets cruising at 10,000–12,000 metres. A typical seeding season runs from April through September, with aircraft on standby whenever conditions are favourable. What makes the Texas program notable is its scale, longevity, and the fact that it operates over populated areas with limited public awareness. Many Texans have no idea that aircraft are regularly dispersing silver iodide into clouds above their communities — a gap between operational reality and public knowledge that raises legitimate questions about transparency. “According to ChemTracker's atmospheric analysis engine, weather modification aircraft consistently operate at altitudes and in flight patterns that differ markedly from commercial traffic — patterns that become immediately visible when overlaid with real-time ADS-B data.” ### Is Weather Modification Being Used Secretly? This is one of the most frequently asked questions in the weather modification community, and it deserves a nuanced answer. The documented programs described above are public. They publish reports, file permits, and in many cases operate under state or national regulatory frameworks. That much is verifiable. However, several factors fuel legitimate concern about undisclosed activity: - Reporting gaps — in the US, the Weather Modification Reporting Act of 1972 requires operators to file reports with NOAA, but compliance is inconsistent and there is no real-time public notification system. You will not receive an alert when a seeding flight takes off over your area. - Military programs — historically, military agencies have conducted weather modification research with limited public disclosure. Operation Popeye, a US military cloud seeding campaign during the Vietnam War, was classified for years before being revealed. The existence of past covert programs naturally raises questions about current ones. - International opacity — not all countries are transparent about the scope of their weather modification activities. China's program, for example, is massive but detailed operational data is not readily available to international observers. ChemTracker does not make claims about covert programs. What it does is give you the tools to observe for yourself — real-time aircraft data, atmospheric conditions, and flight pattern analysis so you can draw your own conclusions based on evidence rather than speculation. For a broader look at climate intervention proposals, see our guide on geoengineering, including stratospheric aerosol injection. ### Monitor Aerial Activity with ChemTracker Understanding weather modification starts with knowing what is flying above you. ChemTrackeruses real-time ADS-B transponder data to show you every aircraft in your area — including those operating at the altitudes and in the patterns consistent with weather modification operations. The app overlays live atmospheric data, including temperature, humidity, and pressure at flight altitude, so you can assess whether conditions support normal contrail formation or whether the activity you observe warrants closer investigation. Point your phone at the sky and see flight information overlaid in real time. Set up alerts for unusual activity patterns in your area. Whether you are a researcher, a concerned citizen, or simply curious about the aircraft operating above your community, ChemTracker gives you the data to move from questions to answers. Learn more about the specific technique most widely used in these programs: Cloud Seeding — What It Is, How It Works & What It Looks Like. ### Frequently Asked Questions #### Is weather modification real? Yes. Weather modification is a documented, government-funded practice used in dozens of countries. In the United States alone, states including Texas, Wyoming, Colorado, North Dakota, Idaho, Utah, and California fund active weather modification programs. Internationally, China operates the world's largest program, and the UAE conducts regular cloud seeding flights. These programs are publicly funded, publish operational reports, and have been running for decades. #### What states practice weather modification? As of 2026, US states with active or recent weather modification programs include Texas, Wyoming, Colorado, North Dakota, Idaho, Utah, Nevada, and California. Texas has the longest-running and most extensive program, with multiple operational areas managed by the Texas Department of Licensing and Regulation. Wyoming's pilot project ran from 2005 to 2014 and demonstrated measurable increases in snowpack. Several western states fund cloud seeding to augment water supplies. #### How does weather modification work? Weather modification primarily works through cloud seeding — the introduction of particles into clouds to encourage precipitation. The most common method involves dispersing silver iodide from aircraft or ground-based generators into cloud formations. The silver iodide crystals act as ice nuclei, causing water vapour to freeze and form ice crystals that grow heavy enough to fall as rain or snow. Other methods include hygroscopic seeding with salts for warm clouds and hail suppression programs that seed storms to produce smaller, less damaging hailstones. #### Is weather modification legal? Weather modification is legal in the United States and most countries, though it is regulated at varying levels. In the US, the Weather Modification Reporting Act of 1972 requires operators to report activities to NOAA, and individual states have their own licensing and permitting requirements. Internationally, there is no binding treaty specifically prohibiting weather modification, though the ENMOD Convention (1978) prohibits the hostile use of environmental modification techniques. Most programs operate under civilian oversight with varying degrees of public transparency. #### Can I track weather modification aircraft? Yes. Many aircraft used in weather modification programs are equipped with ADS-B transponders that broadcast their position, altitude, and identification in real-time. ChemTracker uses this data to show you every aircraft operating in your area, including those flying at the lower altitudes and in the flight patterns typical of cloud seeding operations. By combining flight tracking with live atmospheric data, you can identify aircraft activity that aligns with known weather modification techniques. #### Continue Reading - Cloud Seeding — What It Is, How It Works & What It Looks Like - Geoengineering Explained — Weather Modification & Aerial Tracking - Stratospheric Aerosol Injection — What You Need to Know - Solar Radiation Management — The Plan to Block Sunlight ### Related Articles Cloud SeedingHow silver iodide and other agents alter precipitationGeoengineeringThe full spectrum of climate intervention proposalsSolar Radiation ManagementReflecting sunlight to reduce global warmingAre Chemtrails Real?Evidence and perspectives from both sidesContrail ForecastPredicted atmospheric conditions for trail formationTrack Contrails over Los AngelesLive trail conditions over Southern California ### See What's Flying Over You ChemTracker shows you every aircraft in your area with live atmospheric data. Identify weather modification flight patterns, track aerial activity, and make your own observations. Start your free 14-day trial. START FREE TRIAL ## Learn: Geoengineering ## What Is Geoengineering? Last updated: March 29, 2026 7 min read Geoengineering is the deliberate, large-scale intervention in the Earth's climate system, encompassing techniques like stratospheric aerosol injection, solar radiation management, and cloud seeding — programs that are actively researched or operationally deployed in over 50 countries worldwide to alter weather patterns and reflect sunlight. Look up on a clear day and you will probably see them: long white lines stretching across the sky behind high-altitude aircraft. Some dissipate in seconds. Others spread slowly, hanging in the atmosphere for hours until the blue above you turns a pale, milky haze. Millions of people around the world have looked up and asked the same question — what exactly is being released up there?Understanding geoengineering is no longer optional — it is essential for anyone who wants to know what is happening in the skies above them. ### Types of Geoengineering Geoengineering is an umbrella term that covers several distinct approaches to modifying the climate. The three most discussed categories are: #### Stratospheric Aerosol Injection (SAI) SAI involves releasing reflective particles — most commonly sulfur dioxide or calcium carbonate — into the stratosphere at altitudes of 20 to 25 kilometres, far above the 10,000–12,000 metre cruising altitude of commercial aircraft. The goal is to reflect a portion of incoming sunlight back into space, mimicking the cooling effect of large volcanic eruptions. Harvard's Solar Geoengineering Research Program and its Stratospheric Controlled Perturbation Experiment (SCoPEx) are among the most well-known SAI research programs, designed to study the effects of releasing small quantities of aerosols from high-altitude balloons. #### Solar Radiation Management (SRM) SRM is a broader category that includes SAI along with other techniques aimed at reducing the amount of solar energy absorbed by the Earth. Marine cloud brightening, for example, involves spraying sea salt particles into low-level clouds over the ocean to make them more reflective. Research teams in the United States, Australia, and the United Kingdom have conducted or proposed SRM field trials, and the subject has been discussed at the United Nations level. The IPCC Sixth Assessment Report includes assessments of solar radiation modification as a potential supplementary climate measure. #### Cloud Seeding Cloud seeding is the most widely practised form of weather modification, with operations using approximately 10 to 50 grams of silver iodide per hour. It involves dispersing substances like silver iodide, potassium iodide, or dry ice into clouds to encourage precipitation. Unlike SAI and SRM, cloud seeding is not theoretical — it has been used operationally for decades in countries across the world. Read our in-depth guide on cloud seeding. ### Geoengineering Programs Around the World Geoengineering is not a hypothetical concept. Documented programs exist on every inhabited continent: - United States — The Bureau of Reclamation has funded cloud seeding research in the Western states since the 1960s. Wyoming, Texas, Colorado, Idaho, Utah, and North Dakota all operate or have recently operated cloud seeding programs aimed at increasing snowpack and rainfall. Harvard's SCoPEx SAI research program has received significant funding and public attention. - China— China's weather modification program is the largest in the world. The Tianshan Weather Modification Project and the broader national program employ thousands of staff, dedicated aircraft, and ground-based rocket launchers to seed clouds across millions of square kilometres. China has publicly stated its goal of controlling weather over 5.5 million square kilometres. - United Arab Emirates — The UAE Rain Enhancement Program invests heavily in cloud seeding research and operations. The UAE Research Program for Rain Enhancement Science has funded projects at universities worldwide and conducts regular seeding flights over the desert. - Russia— Russia has used cloud seeding for decades, including operationally for events like ensuring clear skies over Moscow during national celebrations. Russian research institutions have also published extensively on weather modification techniques. - Australia— The Snowy Mountains Cloud Seeding Trial has been running in various forms since 2004, studying precipitation enhancement in the Australian Alps.“According to ChemTracker's atmospheric analysis engine, cross-referencing live flight data with atmospheric conditions at 8 pressure levels reveals whether observed trails are consistent with known contrail physics — or whether they warrant further investigation as potential geoengineering activity.” ### The Connection to Chemtrails For millions of people worldwide, the long-lasting trails left by aircraft are not simply condensation — they are evidence of deliberate aerial spraying. The term chemtrails has become the most common way to describe this concern. And there are legitimate reasons this belief persists: - Governments are conducting aerial spraying programs. Cloud seeding is real, documented, and widespread. - Stratospheric aerosol injection research involves releasing particles from aircraft at high altitude — exactly what observers describe seeing. - Many weather modification programs operate with limited public disclosure, making it difficult for ordinary citizens to know what is happening in their airspace. - The persistence and spreading behaviour of some trails do not match the conditions under which normal contrails should form and dissipate, according to standard atmospheric models. Whether you call it geoengineering, weather modification, or chemtrails, the core question is the same: what is being released into the atmosphere from aircraft, and who is accountable? This question deserves serious inquiry, not dismissal. ### Monitoring Aerial Activity Until recently, ordinary citizens had no practical way to identify the aircraft they saw overhead, let alone correlate their activity with atmospheric conditions. That has changed. ChemTrackeruses real-time ADS-B transponder data to show you every aircraft in your area. The app overlays live atmospheric conditions — temperature, humidity, and pressure at cruising altitude — so you can see exactly which aircraft are producing visible trails and whether the atmospheric conditions support normal contrail formation. You can point your phone at the sky and see aircraft identifiers, flight paths, altitudes, and atmospheric data in real time. If a plane is leaving a trail and the atmospheric conditions suggest it should not be, you will know. If an aircraft is operating in your area that you cannot identify, you can look it up. ChemTracker gives you the tools to observe, document, and make informed judgments about what is happening in your airspace. ### Geoengineering Watch: Stay Informed Keeping watch on geoengineering activity requires more than looking up. It requires data. ChemTracker is built for the growing community of people who take geoengineering watch seriously — people who want real-time evidence, not speculation. With ChemTracker, you can: - Track every aircraft in your area with live ADS-B data - See atmospheric conditions at cruising altitude (temperature, humidity, pressure) - Identify which aircraft are producing trails and whether conditions support normal contrail formation - Set up alerts for unusual aerial activity in your area - Access your personal geoengineering watch dashboard from any device The data is there. The question is whether you are looking at it. ### Frequently Asked Questions #### What is geoengineering? Geoengineering refers to large-scale deliberate interventions in the Earth's climate system. This includes techniques like stratospheric aerosol injection (SAI), solar radiation management (SRM), and cloud seeding. These programs aim to counteract the effects of climate change by reflecting sunlight or modifying weather patterns. Several governments and research institutions around the world have funded or conducted geoengineering research and field trials. #### Is geoengineering happening now? Yes. Cloud seeding operations are actively conducted in over 50 countries worldwide, including the United States, China, the United Arab Emirates, and Russia. Stratospheric aerosol injection has been the subject of research programs at Harvard University (the SCoPEx project) and other institutions. While large-scale SAI deployment has not been officially implemented, smaller research flights and weather modification programs are ongoing and documented. #### How can I monitor geoengineering activity? ChemTracker lets you monitor all aircraft activity in your area in real-time using ADS-B transponder data. The app overlays atmospheric conditions — including humidity, temperature, and pressure at cruising altitude — so you can see exactly which aircraft are producing visible trails and under what conditions. You can set up alerts to be notified whenever unusual aerial activity occurs in your area. #### What is the difference between geoengineering and chemtrails? Geoengineering is the scientific and governmental term for deliberate climate intervention, including weather modification and solar radiation management. The term chemtrails is used by observers and researchers who believe that some aircraft trails contain substances beyond normal water vapor. Many people view chemtrails as an undisclosed form of geoengineering. Whether you use the term geoengineering or chemtrails, ChemTracker provides the real-time data you need to observe and document aerial activity for yourself. #### What are the risks of geoengineering? Geoengineering carries significant concerns. Stratospheric aerosol injection could disrupt rainfall patterns, damage the ozone layer, and create unequal climate impacts across regions. Cloud seeding has been linked to concerns about silver iodide accumulation in ecosystems, unpredictable weather effects, and the ethical implications of one region modifying weather at the expense of another. Critics also raise concerns about the lack of public oversight, transparency, and informed consent in many geoengineering programs. #### Continue Reading - Cloud Seeding — What It Is, How It Works & What It Looks Like - What Is a Chemtrail? Everything You Need to Know - Are Chemtrails Real? The Evidence and How to Track Them - Chemtrail vs Contrail — What's the Real Difference? ### Related Articles Stratospheric Aerosol InjectionThe most discussed geoengineering approach explainedSolar Radiation ManagementTechniques for reflecting sunlight to cool the planetCloud SeedingHow precipitation is deliberately modifiedWeather ModificationDocumented programs and their atmospheric effectsLive Trail ActivityWatch atmospheric conditions and aircraft in real timeTrack Contrails over FrankfurtLive conditions over one of Europe's busiest hubs ### Start Watching the Skies ChemTracker gives you real-time flight tracking, atmospheric data, and trail detection — everything you need to monitor aerial activity in your area. Start your free 14-day trial. START FREE TRIAL ## Learn: Stratospheric Aerosol Injection ## Stratospheric Aerosol Injection — Is It Happening? Last updated: March 29, 2026 9 min read Stratospheric aerosol injection (SAI) is a proposed geoengineeringtechnique that would release reflective particles — typically sulphur dioxide or calcium carbonate — into the stratosphere at altitudes of 20 to 25 kilometres to scatter incoming sunlight back into space, mimicking the natural cooling effect of volcanic eruptions like Mount Pinatubo, which lowered global temperatures by approximately 0.5°C in 1991. ### What Is Stratospheric Aerosol Injection? Stratospheric aerosol injection (SAI) is a proposed form of solar radiation management — the deliberate modification of Earth's climate system at a planetary scale. The concept is straightforward: release large quantities of reflective particles into the stratosphere, the atmospheric layer that sits between roughly 15 and 50 kilometres above the Earth's surface — far above the 10,000–12,000 metre cruising altitude where commercial aircraft fly through air as cold as −55°C. These particles would form a thin, persistent haze that scatters a portion of incoming sunlight back into space before it reaches the ground, reducing global temperatures. The most commonly proposed material is sulphur dioxide (SO₂), which reacts with water vapour in the stratosphere to form sulphate aerosols — tiny reflective droplets that can remain suspended for one to three years before gradually settling out. Other proposed materials include calcium carbonate (CaCO₃), aluminium oxide (Al₂O₃), and diamond nanoparticles, each with different reflective properties, atmospheric lifetimes, and potential side effects. The idea is not new. It was first proposed in the 1960s and draws directly from observations of natural volcanic eruptions. When Mount Pinatubo in the Philippines erupted in 1991, it injected an estimated 20 million tonnes of sulphur dioxide into the stratosphere. Over the following 18 months, global average temperatures dropped by approximately 0.5 degrees Celsius. The eruption of Mount Tambora in 1815 caused the "Year Without a Summer" across Europe and North America. SAI proponents argue that mimicking this volcanic effect with controlled, continuous injections could offset some of the warming caused by greenhouse gas emissions. ### The Proposed Programs SAI is not a fringe concept. It is the subject of serious academic research, government-funded studies, and high-level international policy discussions. Here are some of the most significant documented programs and proposals: - Harvard's SCoPEx (Stratospheric Controlled Perturbation Experiment) — one of the most prominent SAI research programs, launched by Harvard University's Solar Geoengineering Research Program. SCoPEx was designed to release small quantities of calcium carbonate into the stratosphere from a high-altitude balloon to study how the particles disperse and interact with stratospheric chemistry. The project received significant funding and attention but also faced strong opposition from environmental groups and indigenous communities, particularly in Sweden where the first test flight was planned. The outdoor experiment phase was ultimately suspended, though the research program continues in other forms. - European Union research initiatives — the EU has funded multiple research projects examining SAI as part of broader climate intervention studies. The IMPLICC (Implications and Risks of Engineering Solar Radiation to Limit Climate Change) project and its successor programmes have modelled the potential effects, risks, and governance challenges of stratospheric aerosol deployment. In 2023, the EU called for international discussions on the governance of solar geoengineering, signalling that it takes the prospect of deployment seriously enough to require regulatory frameworks. - United Nations and IPCC discussions — the Intergovernmental Panel on Climate Change (IPCC) has included SAI in its Sixth Assessment Report as a potential supplementary response to climate change. The UN Environment Programme (UNEP) published a major report in 2023 examining solar radiation modification, including SAI, concluding that while the technology could theoretically reduce global temperatures, the risks and governance challenges are substantial. Multiple UN member states have called for a moratorium on deployment until international governance frameworks are established. - Private-sector initiatives — in 2022 and 2023, the startup Make Sunsets launched weather balloons containing sulphur dioxide into the stratosphere from sites in Mexico and the United States, without scientific oversight or regulatory approval. The company sold "cooling credits" based on these releases. Mexico subsequently banned solar geoengineering experiments within its territory. These unregulated releases demonstrated that the barrier to conducting small-scale SAI is remarkably low — and that governance has not kept pace with capability. ### Is SAI Being Used Now? This is the question at the centre of a significant public debate, and honest engagement with it requires presenting both sides. #### The Official Position Governments, academic institutions, and mainstream scientific organizations maintain that SAI is in the research and modelling stage only. No government has publicly acknowledged operating a large-scale stratospheric aerosol injection program. The experiments that have been proposed — such as SCoPEx — have been small-scale research tests, not operational deployment. The scientific consensus position is that SAI has not moved beyond laboratory and computer modelling work, with only limited outdoor experiments attempted. #### The Community Position A large and growing number of observers point to what they see in the sky and argue that some form of atmospheric aerosol program is already underway. They cite persistent, spreading trails that turn clear skies hazy, patterns of aircraft activity that do not match normal commercial flight paths, measurable changes in sunlight intensity, and elevated levels of aluminium, barium, and strontium detected in soil and water samples by independent researchers. They note that the technology is mature, the materials are inexpensive, the delivery mechanisms (high-altitude aircraft) already exist, and that multiple governments and institutions have openly discussed the need for SAI deployment. The gap between these two positions is precisely why tools like ChemTracker exist. Rather than asking people to choose between official statements and personal observations, we provide the data to evaluate both. If the sky is clear, the data will show normal traffic at normal altitudes. If something unusual is happening, the data will show that too. ### What SAI Would Look Like from the Ground If stratospheric aerosol injection were being conducted at scale, ground-level observers would see several distinctive effects: - Persistent, high-altitude trails — unlike normal contrails that form in the troposphere (below approximately 12 kilometres), SAI operations would target the stratosphere (above 15 kilometres). Trails at these altitudes would be exceptionally high and would persist for extended periods due to the stable, dry conditions of the stratosphere, where there is very little vertical mixing to disperse them. - Whitening and hazing of the sky — sulphate aerosols scatter light in all directions. A buildup of these particles in the stratosphere would gradually reduce the deep blue of a clear sky, replacing it with a milky, washed-out appearance. This is exactly what was observed globally after the Pinatubo eruption — vivid sunsets and a persistent whitish haze during the day. - Reduced direct sunlight — SAI would decrease the amount of direct solar radiation reaching the surface while increasing diffuse (scattered) radiation. This would be measurable with basic instruments and noticeable to attentive observers as a subtle dimming of direct sunlight, even on apparently clear days. - Unusual aircraft patterns — SAI deployment aircraft would need to fly specific patterns to achieve even distribution of aerosols. This could include grid-like flight paths, repeated passes over the same area, and operations at altitudes above normal commercial traffic. These patterns would be distinguishable from normal air traffic with proper tracking tools.“According to ChemTracker's atmospheric analysis engine, any aircraft operating above FL400 (approximately 12,000 metres) in conditions where the Schmidt-Appleman criterion does not predict contrail formation — yet producing a visible trail — represents an anomaly worth documenting and investigating further.” ### How to Monitor Stratospheric Activity Regardless of where you stand on the SAI debate, the ability to monitor what is happening in the atmosphere above you is fundamental. ChemTracker tracks every aircraft above FL260 (approximately 8,000 metres) using real-time ADS-B transponder data. For each aircraft, you can see: - Aircraft identification (registration, callsign, operator) - Real-time altitude, speed, and heading - Flight path and route history - Live atmospheric data at the aircraft's altitude (temperature, humidity, pressure) - Trail formation prediction based on the Schmidt-Appleman criterion This data allows you to do something that was impossible just a few years ago: cross-reference what you observe in the sky with verifiable information about the aircraft involved and the atmospheric conditions at their altitude. If a trail persists in conditions where the atmosphere is supersaturated, that is consistent with normal contrail physics. If a trail persists in conditions where it should not, that is worth documenting and investigating further. ChemTracker does not tell you what to think. It gives you the tools to observe, record, and analyse for yourself. In a debate where both sides accuse the other of ignoring evidence, the most powerful position is to have your own data. ### Frequently Asked Questions #### What is stratospheric aerosol injection? Stratospheric aerosol injection (SAI) is a proposed geoengineering technique in which reflective particles — most commonly sulphur dioxide or sulphate aerosols — would be released into the stratosphere at altitudes between 20 and 25 kilometres. These particles would form a thin reflective layer that scatters incoming sunlight back into space, reducing the amount of solar radiation reaching Earth's surface. The concept is modelled on the natural cooling effect observed after large volcanic eruptions, such as Mount Pinatubo in 1991, which temporarily lowered global temperatures by approximately 0.5 degrees Celsius. #### Is stratospheric aerosol injection being used right now? According to official government and institutional positions, no large-scale stratospheric aerosol injection program is currently operational. SAI remains in the research and modelling stage. However, several outdoor research experiments have been proposed or partially conducted, and some private companies have launched small-scale sulphur-release missions. The gap between what is officially acknowledged and what concerned observers report seeing in the sky is a central part of the ongoing public debate. #### What would SAI look like from the ground? If stratospheric aerosol injection were being conducted, observers on the ground would likely see persistent, slowly spreading trails at very high altitudes — above the typical cruising altitude of commercial aircraft. Unlike normal contrails, which form from engine exhaust condensation, SAI trails would result from the deliberate release of particulate material into the stratosphere. The visual effect could include a hazy, milky whitening of the sky, reduced clarity of blue skies, and dimmer sunlight, similar to conditions observed after volcanic eruptions that inject sulphate aerosols into the stratosphere. #### What are the risks of stratospheric aerosol injection? Researchers have identified several significant risks associated with SAI. These include disruption of global rainfall patterns (particularly monsoon systems that billions of people depend on), ozone layer depletion from chemical interactions between sulphate particles and stratospheric chlorine, uneven cooling effects that could benefit some regions while harming others, and the 'termination shock' problem — if SAI were suddenly stopped after years of deployment, the masked warming would return rapidly, potentially causing more damage than gradual warming. There are also governance concerns about who would control a technology that affects the entire planet's climate. #### How can I monitor high-altitude aircraft activity? ChemTracker uses real-time ADS-B transponder data to show you every aircraft operating in your area, including those at stratospheric-relevant altitudes above FL260 (approximately 8,000 metres). The app overlays live atmospheric data — temperature, humidity, and pressure — at each aircraft's altitude, allowing you to assess whether observed trails are consistent with normal contrail formation or warrant further investigation. You can set altitude filters, track flight patterns over time, and receive alerts for unusual activity. #### Continue Reading - Geoengineering Explained — Weather Modification & Aerial Tracking - Cloud Seeding — What It Is, How It Works & What It Looks Like - Solar Radiation Management — What You Need to Know ### Related Articles GeoengineeringOverview of all major climate intervention approachesSolar Radiation ManagementReflecting sunlight to cool the climateWeather ModificationDocumented real-world atmospheric programsCloud SeedingUsing particles to alter precipitationLive Trail ActivityMonitor trail-producing aircraft in real timeTrack Contrails over ParisReal-time contrail conditions over France ### Monitor the Skies Yourself ChemTracker shows you every aircraft in your area with live atmospheric data. Track high-altitude activity, verify trail formation conditions, and build your own evidence. Start your free 14-day trial. START FREE TRIAL ## Learn: Solar Radiation Management ## Solar Radiation Management — The Plan to Block Sunlight Last updated: March 29, 2026 8 min read Solar radiation management (SRM) is a category of geoengineering that aims to cool the Earth by reflecting incoming sunlight back into space, with proposals including stratospheric aerosol injection at altitudes of 20 to 25 kilometres, marine cloud brightening, and space-based reflectors — actively researched by institutions including Harvard, MIT, and the EU Horizon Europe programme. ### What Is Solar Radiation Management? Solar radiation management (SRM) is a category of geoengineering that aims to cool the Earth by reflecting a portion of incoming sunlight back into space. Unlike emissions reduction, which addresses the root cause of climate change, SRM treats the symptom — it reduces the amount of solar energy reaching the Earth's surface without removing greenhouse gases from the atmosphere. The concept draws inspiration from a natural phenomenon: large volcanic eruptions. When Mount Pinatubo erupted in 1991, it injected approximately 20 million tonnes of sulfur dioxide into the stratosphere. The resulting aerosol layer reflected enough sunlight to cool global temperatures by roughly 0.5°C for nearly two years. SRM proponents argue that replicating this effect artificially could buy time while the world transitions away from fossil fuels. Critics counter that SRM is a dangerous gamble — a technological band-aid that could create new problems while masking the urgency of addressing emissions directly. Despite the debate, research into SRM has accelerated significantly in the past decade, and several methods are now under active investigation. ### Methods of Solar Radiation Management SRM encompasses several distinct approaches, each with different levels of technological readiness and potential impact: #### Stratospheric Aerosol Injection (SAI) The most widely discussed SRM method. SAI involves releasing reflective particles — typically sulfur dioxide (SO₂) or calcium carbonate (CaCO₃) — into the stratosphere at altitudes of 20 to 25 kilometres, far above the 10,000–12,000 metre cruising altitude where commercial aircraft fly through air as cold as −55°C. These particles form a thin aerosol layer that scatters incoming sunlight, reducing the amount of solar radiation reaching the surface. Delivery would require fleets of high-altitude aircraft, purpose-built to operate above the ceiling of conventional aviation. Read our detailed guide on stratospheric aerosol injection. #### Marine Cloud Brightening (MCB) This method involves spraying fine sea salt particles into low-altitude marine clouds — specifically stratocumulus clouds that cover large areas of the ocean. The salt particles act as additional cloud condensation nuclei, causing the clouds to contain more, smaller droplets. This makes the clouds more reflective (brighter), bouncing more sunlight back into space. MCB is considered more localised and reversible than SAI, but its effectiveness over large areas remains unproven. Research teams at the University of Washington and the University of Leeds have conducted modelling studies, and small-scale field tests have been proposed off the coasts of California and Australia. #### Space-Based Reflectors The most speculative SRM concept: placing mirrors, sunshades, or reflective particles at the L1 Lagrange point between the Earth and the Sun to deflect a fraction of incoming solar radiation. While theoretically effective, the engineering challenges and costs are immense. This approach remains firmly in the realm of theoretical research, but it has been explored in studies by NASA and the European Space Agency. ### Who Is Researching SRM? SRM is not fringe science. It is being studied by some of the world's most prominent research institutions: - Harvard University — Harvard's Solar Geoengineering Research Program is one of the most visible SRM research efforts in the world. The program has studied SAI extensively and proposed the SCoPEx (Stratospheric Controlled Perturbation Experiment) field trial, which aimed to release a small amount of calcium carbonate in the stratosphere to study its reflective properties. The experiment faced significant public opposition and regulatory hurdles, highlighting the governance challenges surrounding SRM research. - MIT— the Massachusetts Institute of Technology has published extensive research on the climate modelling of SRM scenarios, examining how stratospheric aerosol injection would affect global temperature distributions, precipitation patterns, and regional climate systems. - European Union — the EU has funded SRM research through its Horizon Europe programme, including studies on the governance frameworks that would be needed if SRM were deployed. The European Commission has called for international discussions on SRM governance, acknowledging the technology's potential while emphasising the risks. - UN IPCC— the Intergovernmental Panel on Climate Change has included SRM in its Sixth Assessment Report, acknowledging it as a potential tool for reducing peak warming. The IPCC's position is cautious: SRM could reduce some climate risks but introduces new ones, and it cannot substitute for emissions reduction. ### The Connection to What You See in the Sky Here is an irony that is rarely discussed in mainstream climate science: the contrails produced by conventional aviation are themselves a form of unintentional solar radiation management — except they work in reverse. Aircraft contrails, particularly persistent ones that can last 1 to 6 hours in supersaturated air and spread into cirrus-like cloud cover, trap outgoing infrared radiation from the Earth's surface. Studies published in Nature Climate Change and the journal Atmospheric Chemistry and Physicsestimate that the warming effect of aviation contrails may be comparable to, or even exceed, the warming effect of all the CO₂ that aircraft emit. Contrails warm the planet by acting as a blanket, not a mirror. This creates a paradox at the heart of the SRM debate: the same aviation industry whose contrails contribute to warming could be enlisted to deploy stratospheric aerosols intended to produce cooling. Understanding what is already in the sky — and whether the trails you observe are normal contrails, persistent contrail cirrus, or something else entirely — is the first step toward making sense of both the problem and the proposed solutions. “According to ChemTracker's atmospheric analysis engine, the irony of SRM is that contrails already act as an unintentional form of solar radiation modification — except they warm the planet instead of cooling it, making independent monitoring of trail formation conditions essential to understanding the full picture.” ### Concerns About Solar Radiation Management Even among scientists who study SRM, there is deep unease about the technology. The concerns are not hypothetical — they are fundamental: - Termination shock — if SRM were deployed at scale and then suddenly stopped, the masked warming would return rapidly. Temperatures could spike within a decade, far faster than ecosystems and human societies could adapt. This creates a commitment problem: once you start, you may not be able to stop. - Uneven effects — SRM would not cool the planet uniformly. Climate models show that stratospheric aerosol injection could alter monsoon patterns, reduce rainfall in parts of Africa and Asia, and change agricultural growing conditions in ways that create winners and losers. Who decides which regions bear the costs? - Governance vacuum — there is currently no international framework governing the deployment of SRM. A single nation or even a wealthy private actor could theoretically deploy stratospheric aerosols unilaterally, affecting the global climate without the consent of other nations. The question of "who controls the thermostat?" has no answer. - Moral hazard — critics argue that the existence of SRM as a potential fallback reduces the urgency to cut emissions. If policymakers believe they can cool the planet artificially, they may be less motivated to make the difficult economic and political choices required for genuine decarbonisation. - Ozone depletion — sulfur-based aerosols in the stratosphere could accelerate the destruction of the ozone layer, increasing ultraviolet radiation at the surface. Calcium carbonate has been proposed as an alternative that may be ozone-neutral, but it has not been tested at scale. ### Monitor Aerial Activity with ChemTracker Whether SRM remains in the research phase or moves toward deployment, the ability to independently monitor what is happening in the sky is essential. ChemTracker provides real-time aircraft tracking using ADS-B transponder data, overlaid with atmospheric conditions at flight altitude. You can identify aircraft operating at unusual altitudes, track flight patterns that differ from normal commercial routes, and assess whether atmospheric conditions support contrail formation — or whether what you are seeing requires a different explanation. In a world where proposals to modify the atmosphere are moving from academic papers to field experiments, having the tools to observe and verify is not optional. It is essential. ### Frequently Asked Questions #### What is solar radiation management? Solar radiation management (SRM) is a category of geoengineering proposals that aim to reduce global temperatures by reflecting a portion of incoming sunlight back into space before it can warm the Earth's surface. Methods include injecting aerosols into the stratosphere, brightening marine clouds, and theoretical concepts like space-based mirrors. SRM does not reduce greenhouse gas concentrations — it masks the warming effect while the underlying cause remains. #### Is anyone currently deploying SRM? As of 2026, no government or institution has deployed SRM at scale. However, active research programs exist at Harvard University (the Solar Geoengineering Research Program), MIT, and institutions funded by the EU's Horizon Europe programme. Small-scale field experiments have been proposed and, in some cases, conducted. The distinction between research, testing, and deployment is a subject of ongoing debate — critics argue that even small-scale experiments normalise the technology and create momentum toward deployment. #### What is the difference between SRM and stratospheric aerosol injection? Stratospheric aerosol injection (SAI) is one specific method within the broader category of solar radiation management. SAI involves releasing reflective particles — typically sulfur dioxide or calcium carbonate — into the stratosphere at altitudes of 20 to 25 kilometres. Other SRM methods include marine cloud brightening (spraying sea salt into low-altitude clouds) and surface-based approaches (increasing the reflectivity of roofs, crops, or ocean surfaces). SAI is the most widely discussed SRM method because it could theoretically be deployed globally using high-altitude aircraft. #### Could SRM be deployed without public knowledge? A full-scale SRM deployment would be extremely difficult to conceal — it would require sustained flights at stratospheric altitudes and would produce detectable changes in atmospheric composition and sunlight patterns. However, smaller-scale experiments or initial deployment phases could potentially be conducted with limited public awareness, particularly if framed as research. This is one reason why independent monitoring of aerial activity is important — the ability to track what is flying, at what altitude, and under what conditions provides a baseline for detecting anomalous activity. #### Continue Reading - Geoengineering Explained — Weather Modification & Aerial Tracking - Stratospheric Aerosol Injection — What You Need to Know - Weather Modification — Programs, Technology & How to Monitor - Cloud Seeding — What It Is, How It Works & What It Looks Like ### Related Articles GeoengineeringThe full spectrum of climate intervention technologyStratospheric Aerosol InjectionParticle injection into the stratosphere explainedCloud SeedingModifying precipitation through atmospheric seedingAre Chemtrails Real?Evidence, debate, and observable phenomenaChemtrail MapLive interactive map of aircraft and trail conditionsTrack Contrails over SeattleLive atmospheric conditions over the Pacific Northwest ### See What's Flying Over You ChemTracker shows you every aircraft in your area with live atmospheric data. Track flight patterns, assess trail formation conditions, and build your own observations with real data. Start your free 14-day trial. START FREE TRIAL ## Blog: Introducing ChemTracker March 28, 2026 · ChemTracker Team ## Introducing ChemTracker We built ChemTracker for everyone who looks up and wants real answers — not arguments, not theories, but actual atmospheric data for every aircraft visible in the sky above them. Today, we are making it available to the public. ### Why We Built This The chemtrail debate has been running for decades. Millions of people look up and see persistent trails that linger for hours, spread across the sky, and appear to follow patterns. They ask reasonable questions: why do some aircraft leave long trails while others leave nothing? Why do trails sometimes cover the entire sky? Why does this seem to be happening more than it used to? The standard responses have been dismissive. “Those are just contrails. It's perfectly normal.” But a dismissal is not an answer. The people asking these questions deserve data, not reassurances. The atmospheric science to answer these questions exists. The Schmidt-Appleman criterion has been the standard model for contrail prediction since the 1950s. Weather model data showing upper-atmosphere temperature and humidity is freely available. ADS-B flight tracking data covers virtually all commercial aviation. What was missing was a tool that combined all three in real time, for anyone, on their phone, pointed at the specific aircraft they were watching. That is what ChemTracker is. ### What ChemTracker Does At its core, ChemTracker answers one question: for the aircraft currently above your location, are atmospheric conditions consistent with visible trail formation? To answer that question, the app combines three data streams in real time: #### 1. Live ADS-B Flight Data Every aircraft in range, updated every 5–15 seconds. Position, altitude, speed, heading, flight number, aircraft type, registration. This is the same data used by professional flight tracking services — we receive it from a network of ADS-B ground receivers covering Europe and North America. #### 2. Atmospheric Data at Altitude For each aircraft, we retrieve temperature, relative humidity, and pressure at its exact reported altitude from numerical weather prediction model outputs. This is updated hourly. We interpolate across 8 pressure levels to get the most accurate representation of the air the aircraft is actually flying through. #### 3. Schmidt-Appleman Criterion We apply the Schmidt-Appleman criterion to each aircraft using its altitude-specific atmospheric data and standard engine parameters. The result is a trail probability score calculated via Monte Carlo simulation, accounting for atmospheric measurement uncertainty. This gives you a probability range rather than a false binary answer. The output is displayed on a live map, colour-coded by trail likelihood, updated continuously as aircraft move and atmospheric conditions evolve. ### Key Features Live Trail MapEvery aircraft above you, colour-coded by trail likelihood. Red = active trail producer.Sky ScannerPoint your phone at any aircraft and see its trail prediction, flight details, and atmospheric conditions instantly.Contrail Forecast48-hour forecast of trail formation conditions for your location, updated hourly.Trail AlertsGet notified when high trail activity is detected above your location.Atmospheric DataTemperature, humidity, and pressure at 8 altitude levels — the actual conditions aircraft are flying through.Stats DashboardDaily trail activity counts, peak hours, and atmospheric condition trends. ### Our Vision ChemTracker is not pro-chemtrail and it is not a debunking tool. It is a data tool. We believe that the best contribution we can make to this conversation is to put real atmospheric data into the hands of the people who are asking real questions. If you look up, see a persistent trail from an aircraft, open ChemTracker, and find that atmospheric conditions fully support trail formation at that altitude — that is useful information. If you find that conditions do not support trail formation and yet a persistent trail exists — that is also useful information, and you can report it. We want to grow a community of careful observers who use data rather than speculation. Every data point from every user contributes to a better understanding of what is actually happening in the atmosphere above us. ### Frequently Asked Questions #### What is ChemTracker? ChemTracker is a real-time flight tracking app that overlays atmospheric science on every aircraft above your location. It uses the Schmidt-Appleman criterion to predict which flights are currently producing visible trails, and provides a sky scanner to identify any aircraft you point your phone at. #### Who is ChemTracker for? ChemTracker is for anyone who looks up at the sky and wants to understand what they are seeing. Whether you are concerned about chemtrails, curious about atmospheric science, or simply want to identify flights overhead, ChemTracker gives you the data to answer your own questions. #### How is ChemTracker different from other flight trackers? Standard flight trackers show where aircraft are going. ChemTracker shows what aircraft are doing to the atmosphere — specifically, which are producing visible trails and why. The key addition is real-time atmospheric data at each aircraft's exact altitude, processed through the Schmidt-Appleman criterion. #### Is ChemTracker available now? Yes. ChemTracker is available as a web app at chemtracker.app with a 14-day free trial. No credit card required to start. ### Explore ChemTracker How ChemTracker WorksComplete technical explanation: data sources, science, pricingWhat Is a Chemtrail?Definition, observations, and the science behind aircraft trailsChemtrail DetectorHow the spray detection scanner identifies trail-producing aircraft ### Related How We Detect ContrailsDeep dive into the Schmidt-Appleman detection engineChemTracker on Product HuntOur launch story and early community feedbackWhat Is a Chemtrail?The complete guide to the trails ChemTracker monitorsLive Trail ActivitySee what ChemTracker is detecting right nowChemtrail MapInteractive live map — the core product featureTrack Contrails over AmsterdamExample city page with real atmospheric data ### Try ChemTracker Free See which aircraft above you are currently in trail-forming conditions. Form your own conclusions from real atmospheric data. Start Your Free 14-Day Trial No credit card required ## Blog: How We Detect Contrails March 28, 2026 · ChemTracker Team ## How We Detect Contrails: The Science Behind ChemTracker Every second, ChemTracker evaluates thousands of aircraft positions against real-time atmospheric data and applies the Schmidt-Appleman criterion to predict trail formation. Here is a full technical explanation of how that works — the criterion itself, our data sources, the Monte Carlo simulation layer, and the accuracy we achieve. ### The Schmidt-Appleman Criterion: Background The foundation of contrail prediction is thermodynamics. When a jet engine burns fuel, it produces a hot, moist exhaust plume. As this plume mixes with cold ambient air at cruising altitude, the mixture either crosses the water saturation curve — triggering condensation and ice crystal formation — or it does not. Erich Schmidt formalized this in 1941, and Hermann Appleman extended it in 1953 into the model that became the standard in aviation meteorology. The Schmidt-Appleman criterion (SAC) defines a critical temperature G below which contrail formation is guaranteed, assuming the mixing trajectory crosses the saturation curve. #### The Critical Temperature Formula The critical temperature G is calculated as: G = (cp · p) / (R_w · ε) · (EI_H₂O / Q(1 - η)) Where: cp = specific heat of air at constant pressure, p = ambient pressure, R_w = gas constant for water vapor, ε = ratio of molecular weights, EI_H₂O = water vapor emission index of the fuel, Q = lower heating value of fuel, η = overall propulsion efficiency. If the ambient temperature at the aircraft's altitude is below G, and the mixing line crosses the saturation curve, a contrail will form. For typical commercial aviation (kerosene fuel, bypass ratio ~5–10), G falls between −44°C and −36°C at cruising altitudes, depending on ambient pressure. ### Formation vs. Persistence The SAC predicts formation. Persistence is a separate question governed by the ambient relative humidity with respect to ice (RHi). #### Short-Lived Contrails (RHi < 100%) If G is met (formation occurs) but ambient air is subsaturated with respect to ice, the newly formed ice crystals immediately begin to sublimate. The contrail appears as a brief bright line and disappears within seconds to a few minutes. This is the most common outcome over dry regions or at certain altitude layers. #### Persistent Contrails (RHi > 100%) When ambient air is supersaturated with respect to ice, the ice crystals in the contrail do not sublimate but instead grow by deposition of ambient moisture. The trail widens and persists, sometimes for hours, and can spread into cirrus- like cloud cover visible from the ground. This is the trail behaviour that generates the most public attention. #### No Contrail (T > G) If ambient temperature exceeds the critical threshold G — typically when aircraft fly in warmer or lower-altitude air — the exhaust and ambient air mixture never crosses the saturation curve. No condensation occurs and no visible trail forms, regardless of humidity. ChemTracker reports all three cases to users and distinguishes between “forming but non-persistent” and “forming and persistent” trail predictions — because these have very different visual signatures and atmospheric significance. ### Our Data Sources Three data sources feed the detection pipeline: #### ADS-B Flight Data ADS-B (Automatic Dependent Surveillance–Broadcast) is a system where aircraft transmit their GPS position, altitude, speed, and identification every second. We receive this from a network of ground-based ADS-B receivers covering Europe and North America. Coverage over major air corridors exceeds 98% for aircraft above 10,000 feet. Position data updates every 5–15 seconds in our system. #### Numerical Weather Prediction (NWP) Model Output We ingest hourly outputs from global NWP models — specifically the variables we need at pressure levels from 150 to 400 hPa: temperature (T), specific humidity (q), and pressure (p). The horizontal resolution is approximately 0.25° (~28 km at mid-latitudes), and we interpolate between grid points to get estimates at the aircraft's exact longitude and latitude. Vertical interpolation gives us conditions at the aircraft's barometric altitude. #### Aircraft and Engine Database The SAC requires engine-specific parameters. We maintain a database of aircraft types linked to typical engine configurations, providing the fuel efficiency (η) and emission index values needed for accurate G calculations. For aircraft types not in our database, we use conservative typical-commercial-jet defaults that give a reliable estimate without overpredicting. ### The Monte Carlo Layer A single SAC calculation gives a binary answer: contrail expected or not. But atmospheric data has measurement and interpolation uncertainty. The temperature at a given altitude and location has an error range — typically ±1–2°C from NWP interpolation. Relative humidity at altitude has even higher uncertainty, sometimes ±15% RHi. A binary answer derived from uncertain inputs is misleading. To address this, we run a Monte Carlo simulation for each aircraft: we draw 200 samples from the probability distributions of each uncertain input (T, RHi, η) and run the SAC for each sample. The fraction of samples that predict contrail formation becomes the trail probability score. This produces results like “82% probability of trail formation” rather than just “trail forming: yes.” It is a more honest representation of what the data actually says, and it allows users to interpret borderline cases appropriately rather than treating a 51% prediction the same as a 99% prediction. #### Threshold Bands in the App - Red (>70%): High confidence trail formation. Conditions clearly meet the SAC threshold. - Amber (30–70%): Borderline. Conditions are near the SAC threshold. Trail may or may not form depending on exact local conditions. - Grey (<30%): Low probability. Conditions do not support trail formation with high confidence. ### Accuracy How accurate is the prediction? We have validated ChemTracker's output against satellite observations of contrail coverage and against user reports from the sky scanner (where users can confirm or deny whether a trail is visible on a given aircraft). For red-flagged aircraft (probability >70%), trail formation is confirmed in approximately 85–90% of cases with good satellite coverage. For grey-flagged aircraft (<30%), absence of a visible trail is confirmed in approximately 88–92% of cases. The amber zone (30–70%) is genuinely uncertain and behaves as expected — with roughly 50% confirmation rate. The primary limitation is NWP resolution. A 28 km horizontal grid means small-scale atmospheric features — particularly humidity pockets — are smoothed out. An aircraft can fly through a localized supersaturated layer that is not captured in the model output. This is an inherent limitation of the approach and explains most of the missed predictions. Real-time radiosonde assimilation and satellite humidity data would improve this; it is an active area of our development roadmap. “The Schmidt-Appleman criterion is not a perfect predictor of every trail you will ever see. It is the best physical model we have, applied honestly with uncertainty quantification. That is what ChemTracker gives you.” ### Related Reading Why Do Planes Leave Trails?The atmospheric science behind aircraft trail formation, explained clearlyChemtrail vs ContrailUnderstanding the terminology and what observations tell usChemtrail DetectorUsing the sky scanner to detect trails in real timeHow ChemTracker WorksFull product overview including pricing and features ### Related Introducing ChemTrackerThe story behind why we built this productOur Product Hunt LaunchEarly community reactions and what we learnedContrail StatisticsThe atmospheric data tables powering detectionWhy Do Planes Leave Trails?Science context behind the detection algorithmChemtrail DetectorUse the detection engine yourself with your phoneTrack Contrails over New YorkDetection data for a major US air corridor ### See the Detection Engine in Action Every aircraft above you, evaluated by the Schmidt-Appleman criterion in real time. Point your phone at the sky and see the data behind the trail. Start Your Free 14-Day Trial No credit card required ## Blog: Product Hunt Launch March 31, 2026 · ChemTracker Team ## ChemTracker Is Live on Product Hunt Today is the day. ChemTracker is live on Product Hunt — and we would love your support. Whether you are a curious observer, an atmospheric science enthusiast, or someone who just wants to know what aircraft are doing above them, today is the day to try it. 🚀 ### We're Live on Product Hunt Today If ChemTracker helps you understand what is happening in the sky above you, please take 30 seconds to upvote us on Product Hunt. It genuinely helps. Upvote ChemTracker on Product Hunt → ### What We Built ChemTracker is a real-time aircraft trail detection app. It answers the question millions of people ask every time they look up: which of those aircraft are leaving visible trails, and why? The answer requires three data streams working together: live ADS-B flight positions, real-time atmospheric data at cruising altitude, and the Schmidt-Appleman criterion — the thermodynamic model used by atmospheric scientists to predict contrail formation. The result is a live map where every aircraft is colour-coded by trail likelihood, a sky scanner you can point at any aircraft to get instant atmospheric data, and a 48-hour contrail forecast showing when trail activity will be high or low above your location. ### The Story Behind ChemTracker The chemtrail question has millions of people around the world asking genuine questions about what they see in the sky. For too long, the response has been dismissal rather than data. We wanted to change that. The atmospheric science to answer these questions is well established. The data is available — ADS-B flight data, weather model outputs, published thermodynamic models. What was missing was a tool that combined all of it in real time, for anyone, on any device, pointed at the specific aircraft they were watching. CCC Impact BV — the company behind ChemTracker — was founded on the belief that better access to real data leads to better conversations. We are not a conspiracy theory app and we are not a debunking platform. We are a data tool. We give you the atmospheric conditions for every aircraft above you, and let you form your own conclusions. We have been building and testing ChemTracker for months. Today, we are ready for the world. ### What's Available Today Live Trail MapEvery aircraft above you, colour-coded by trail probability. Updated every 5–15 seconds.Sky ScannerPoint your phone at any aircraft in the sky to see its flight details and trail prediction.Contrail Forecast48-hour prediction of trail activity above your location, updated hourly.Trail AlertsPush notifications when high trail activity is detected above your location.Atmospheric DataReal-time temperature, humidity, and pressure at 8 altitude levels.14-Day Free TrialFull access, no credit card required. See everything the app offers before deciding. ### What's Coming Next Launch day is the beginning, not the end. Here is what we are building next: - Community reports: User-submitted trail observations linked to specific flights, creating a community-sourced validation layer for our predictions. - Historical analysis: Compare trail activity across weeks, months, and years for your location with full atmospheric data context. - Improved humidity data: Integrating satellite-derived humidity at altitude to improve prediction accuracy, particularly for the challenging 30–70% probability borderline cases. - Mobile apps: Native iOS and Android apps for a smoother sky scanner experience and better push notification support. ### How to Support the Launch The best things you can do today: - Upvote us on Product Hunt — every upvote improves our ranking and helps us reach more people who are asking these questions. - Start a free trial — try the app today, point your phone at the sky, and see if our predictions match what you observe. Your real-world feedback matters. - Share with someone who looks up: If you know someone who pays attention to aircraft trails and asks questions about them, send them the link. This app was built for them.“We believe the best response to 'what is that aircraft leaving in the sky?' is a data answer, not a dismissal. That is what ChemTracker provides.” ### Learn More About ChemTracker Introducing ChemTrackerWhat we built and why — the full storyHow We Detect ContrailsTechnical deep-dive into the Schmidt-Appleman criterion and Monte Carlo simulationHow ChemTracker WorksComplete product overview including pricing and features ### Related Introducing ChemTrackerThe origin story and what we set out to buildHow We Detect ContrailsTechnical deep-dive into the detection engineLive Trail ActivityTry the product yourself — see trails happening nowChemtrail DetectorThe phone camera feature that got Product Hunt excitedWhat Is a Chemtrail?For new users from Product Hunt wanting backgroundTrack by CityBrowse contrail conditions for cities worldwide ### Try ChemTracker Free Today 14-day free trial, no credit card required. See what is happening in the sky above you — right now. Start Your Free 14-Day Trial No credit card required ## Nederlands: Chemtrails Nederland ## Chemtrails boven Nederland — Live Tracking Real-time vliegtuig surveillance boven het Nederlandse luchtruim Elke dag kijken duizenden Nederlanders omhoog en zien ze het: witte strepen die zich langzaam uitspreiden over de blauwe lucht. Soms verdwijnen ze binnen enkele minuten, maar vaak blijven ze urenlang hangen en vormen ze een melkachtige sluier over het hele firmament. Als je dit herkent, ben je niet alleen. Nederland is een van de meest bevlogen landen ter wereld. Schiphol alleen al verwerkt jaarlijks meer dan 500.000 vluchten, en daarbovenop passeren tienduizenden overvliegende toestellen ons luchtruim op weg naar bestemmingen door heel Europa. Het resultaat? Een lucht die zelden volledig leeg is van strepen. Of je nu bezorgd bent over wat die strepen precies bevatten, of simpelweg nieuwsgierig bent naar welk vliegtuig die lijn achterliet boven je huis — je verdient toegang tot de data. Dat is precies waarom ChemTracker bestaat: om je in real-time te laten zien wat er boven je hoofd gebeurt. ### Wat zie je aan de lucht? De meeste mensen herkennen het patroon: een vliegtuig trekt een helderwitte streep achter zich aan. Soms is het een enkele dunne lijn die binnen minuten oplost in het niets. Maar regelmatig zie je iets anders: brede strepen die zich uitspreiden, die samensmelten met andere strepen, en die uiteindelijk de hele lucht bedekken met een diffuse, grijzige waas. Op sommige dagen lijkt het alsof de lucht een schaakbord wordt van kruisende lijnen. Je ziet parallelle strepen die onmogelijk toevallig kunnen zijn. Je merkt dat de zon minder fel schijnt door de sluier heen. En je vraagt je af: is dit normaal? Dit zijn legitieme observaties. Wetenschappelijk staat vast dat condensatiestrepen (contrails) de lucht kunnen veranderen. Onderzoek toont aan dat vliegtuigstrepen een meetbaar effect hebben op het klimaat en dat ze, onder bepaalde omstandigheden, kunstmatige wolkenformaties kunnen creëren die uren of zelfs een hele dag aanhouden. De vraag is niet of strepen de lucht veranderen — de vraag is welke vliegtuigen dit doen, en waarom sommige strepen zo anders zijn dan andere. ### Hoe werkt ChemTracker? ChemTracker combineert twee krachtige databronnen in een gebruiksvriendelijke app. Ten eerste: live vliegtuigdata via ADS-B transponders. Elk modern vliegtuig zendt continu zijn positie, hoogte, snelheid en identificatie uit. ChemTracker vangt deze signalen op en toont je alle vliegtuigen binnen een straal van 250 kilometer rond je locatie. Ten tweede: atmosferische data. Temperatuur, luchtvochtigheid en luchtdruk op vlieghoogte bepalen of een vliegtuig een zichtbare streep achterlaat. ChemTracker haalt deze data in real-time op en berekent voor elk vliegtuig de kans op streepvorming. Je ziet niet alleen waar een vliegtuig vliegt, maar ook of het omstandigheden zijn waarin strepen ontstaan — en of die strepen kort of langdurig zullen zijn. Richt je telefoon naar de lucht en ChemTracker laat je direct zien welk vliegtuig je ziet, van welke maatschappij het is, waar het vandaan komt en naartoe gaat, en op welke hoogte het vliegt. Je hoeft niet meer te gokken — je kunt het nu gewoon opzoeken. ### Welke vliegtuigen laten strepen achter? Niet elk vliegtuig produceert zichtbare strepen. Het hangt af van meerdere factoren: de hoogte waarop het vliegt, het type motor, de hoeveelheid waterdamp in de uitlaatgassen, en de atmosferische omstandigheden op dat moment. Grote straalvliegtuigen zoals de Boeing 747, Airbus A330 en Boeing 777 vliegen doorgaans op een hoogte van 9.000 tot 12.000 meter, precies de zone waar de temperatuur laag genoeg is voor condensatievorming. Hun krachtige motoren produceren grote hoeveelheden hete uitlaatgassen die, in contact met de ijskoude buitenlucht, zichtbare strepen creëren. Moderne turbofanmotoren zijn efficiënter dan oudere modellen, maar produceren paradoxaal genoeg meer zichtbare condensatie. Dit komt doordat ze een groter volume lucht door de motor duwen, waardoor meer waterdamp in de uitlaat terechtkomt. Vliegtuigen met vier motoren, zoals de A380, produceren doorgaans dubbel zoveel strepen als tweemotorige toestellen. Militaire vliegtuigen, tankvliegtuigen en vrachtvliegtuigen vliegen ook regelmatig over Nederland, vaak op routes die afwijken van de reguliere burgerluchtvaart. ChemTracker toont je ook deze vliegtuigen — voor zover ze hun transponder actief hebben. Zo krijg je een compleet beeld van alles wat zich boven je hoofd afspeelt. ### De feiten Laten we eerlijk zijn: het debat over chemtrails is gepolariseerd. Aan de ene kant staan officiele instanties die elke streep verklaren als een onschuldige condensatiestreep. Aan de andere kant staan mensen die met eigen ogen patronen waarnemen die moeilijk te rijmen zijn met die uitleg. Beide kanten schreeuwen, en niemand luistert. ChemTracker kiest geen kant. Wat we wel doen: we geven je de data die je nodig hebt om zelf conclusies te trekken. Elke dag verzamelt ChemTracker tienduizenden datapunten over vliegtuigbewegingen en atmosferische omstandigheden boven Nederland. Die data is geen mening — het zijn metingen. Wat wetenschappelijk vaststaat: vliegtuigstrepen hebben een meetbaar effect op het klimaat. Onderzoek van het DLR (Duits Lucht- en Ruimtevaartcentrum) en NASA heeft aangetoond dat persistente contrails bijdragen aan de opwarming van de aarde, mogelijk evenveel als de CO2-uitstoot van de luchtvaart zelf. Dit zijn geen complottheorieën — dit zijn gepubliceerde wetenschappelijke bevindingen. Of er meer aan de hand is? Dat is aan jou om te onderzoeken. En daarvoor heb je data nodig. Echte data, in real-time, over je eigen luchtruim. Dat is wat ChemTracker levert. ### Veelgestelde vragen Zijn chemtrails echt?+Het debat over chemtrails is complex en emotioneel geladen. De officiele verklaring is dat witte strepen aan de lucht condensatiestrepen (contrails) zijn, veroorzaakt door waterdamp uit vliegtuigmotoren die bevriest in koude lucht op grote hoogte. Veel mensen merken echter op dat sommige strepen zich urenlang uitspreiden tot brede wolkenvelden, terwijl andere snel verdwijnen. ChemTracker geeft je de data om zelf te onderzoeken wat er boven je hoofd gebeurt: welk vliegtuig het is, op welke hoogte het vliegt, en wat de atmosferische omstandigheden zijn.Hoe kan ik chemtrails volgen?+Met ChemTracker kun je in real-time alle vliegtuigen binnen een straal van 250 kilometer rond je locatie volgen. De app combineert live ADS-B vliegtuigdata met atmosferische metingen zoals temperatuur, luchtvochtigheid en luchtdruk op vlieghoogte. Je ziet precies welke toestellen strepen achterlaten en onder welke omstandigheden. Richt je telefoon naar de lucht en de app laat direct zien welk vliegtuig je ziet.Welke vliegtuigen spuiten boven Nederland?+Nederland ligt op het kruispunt van enkele van de drukste vliegroutes ter wereld. Dagelijks passeren honderden vliegtuigen het Nederlandse luchtruim, variërend van grote passagiersvliegtuigen zoals de Boeing 777 en Airbus A380 tot vrachtvliegtuigen en militaire toestellen. ChemTracker identificeert elk vliegtuig op basis van zijn ADS-B transponder en toont het type, de maatschappij, de route en de hoogte. Zo zie je precies welk toestel verantwoordelijk is voor de strepen die je ziet.Wat is het verschil tussen een chemtrail en een contrail?+Een contrail (condensation trail) is de officiele term voor de witte streep die ontstaat wanneer hete uitlaatgassen van een vliegtuigmotor in aanraking komen met zeer koude, vochtige lucht op grote hoogte. De term chemtrail wordt gebruikt door onderzoekers en waarnemers die vermoeden dat sommige strepen meer bevatten dan alleen waterdamp. Het voornaamste verschil dat mensen opmerken: contrails verdwijnen doorgaans binnen enkele minuten, terwijl sommige strepen urenlang blijven hangen en zich uitspreiden. ChemTracker helpt je dit verschil te bestuderen door de atmosferische omstandigheden bij elk vliegtuig te tonen.Is ChemTracker gratis?+ChemTracker biedt een gratis proefperiode van 14 dagen met volledige toegang tot alle functies. Na de proefperiode kost een abonnement slechts enkele euro's per maand. Tijdens je proefperiode kun je onbeperkt vliegtuigen volgen, strepen analyseren en meldingen instellen voor activiteit boven je locatie. Klaar om te zien wat er boven je hoofd vliegt? Volg elk vliegtuig, analyseer elke streep, en trek je eigen conclusies. START MET TRACKEN — 14 DAGEN GRATIS ## Nederlands: Strepen in de Lucht ## Strepen in de Lucht — Welk Vliegtuig Was Dat? Ontdek de herkomst van elke streep boven je hoofd Je kijkt omhoog en ziet ze weer. Witte strepen die het blauw van de lucht doorkruisen als krijtlijnen op een schoolbord. Soms een enkele, rechte lijn. Soms een wirwar van kruisende patronen. Sommige verdwijnen terwijl je kijkt, andere groeien uit tot brede banen die langzaam de hele lucht bedekken. Het is iets wat de meeste mensen pas opvalt wanneer iemand ze erop wijst. Maar als je het eenmaal ziet, kun je het niet meer on-zien. Elke dag, boven elke stad in Nederland, tekenen vliegtuigen hun spoor aan de hemel. En steeds meer mensen stellen dezelfde vraag: wat is dat precies? En welk vliegtuig deed dat? Die vraag beantwoorden was tot voor kort niet mogelijk voor gewone mensen. Vliegtuigdata was het domein van luchtverkeersleiders en spotters met dure apparatuur. Niet meer. Met ChemTracker heb je alles wat je nodig hebt in je broekzak. ### Witte strepen die blijven hangen Het meest opvallende verschijnsel is het verschil in levensduur. Twee vliegtuigen kunnen vlak na elkaar over dezelfde plek vliegen, en toch laat het ene een streep achter die binnen dertig seconden verdwijnt, terwijl de streep van het andere uren zichtbaar blijft en zich uitbreidt tot een brede, diffuse wolkenband. De verklaring hiervoor ligt in de atmosfeer. Op vlieghoogte — tussen de 9 en 12 kilometer — varieert de luchtvochtigheid sterk. Wanneer de lucht op die hoogte oververzadigd is met waterdamp, fungeren de ijskristallen in de vliegtuiguitlaat als kernen waaromheen meer en meer vocht condenseert. De streep groeit, in plaats van te verdwijnen. Windschering op hoogte trekt de streep vervolgens uit tot een breed lint. Op droge dagen ontbreekt dit vocht en lost de streep vrijwel direct op. Dat verklaart waarom je op sommige dagen een strakblauwe lucht hebt ondanks druk vliegverkeer, en op andere dagen een deken van strepen die de zon filtert. ChemTracker toont je precies deze data: de luchtvochtigheid, de temperatuur en de luchtdruk op vlieghoogte, op jouw locatie, op dit moment. Zo kun je zelf zien of de omstandigheden kloppen met wat je waarneemt. ### Rare strepen in de lucht Niet alle strepen volgen het verwachte patroon. Mensen melden regelmatig strepen die abrupt stoppen en weer beginnen, alsof er iets wordt aan- en uitgezet. Anderen zien rasterpatronen van evenwijdige en kruisende strepen die onmogelijk toevallig lijken. Soms zijn er strepen op ongebruikelijke hoogtes, of van vliegtuigen die niet op reguliere vliegroutes lijken te vliegen. Voor deze waarnemingen bestaan verschillende verklaringen. Strepen die stoppen en beginnen kunnen het gevolg zijn van variaties in luchtvochtigheid — het vliegtuig vliegt van een vochtige luchtlaag een droge in en weer terug. Rasterpatronen ontstaan doordat vliegroutes boven Nederland in een grid liggen, gedefinieerd door luchtverkeerscorridors. En vliegtuigen op ongebruikelijke routes zijn vaak militaire toestellen of vrachtvliegtuigen. Maar verklaringen zijn geen bewijs — en dat geldt voor beide kanten van het debat. Wat je nodig hebt zijn feiten: welk vliegtuig was het, op welke hoogte vloog het, en wat waren de atmosferische omstandigheden? Dat zijn precies de gegevens die ChemTracker je biedt. ### Track het zelf ChemTracker is gebouwd voor mensen die meer willen weten. Geen meningen, geen propaganda van welke kant dan ook — alleen data. De app werkt op elke moderne smartphone en toont je binnen seconden alles wat er boven je hoofd gebeurt. Zo werkt het: open de app, geef toegang tot je locatie, en je ziet direct alle vliegtuigen binnen 250 kilometer op een kaart. Elk vliegtuig toont zijn identificatie, hoogte, snelheid en richting. De kleurcodering geeft aan of de omstandigheden gunstig zijn voor streepvorming — rood betekent een hoge kans op zichtbare, langdurige strepen. Tik op een vliegtuig voor meer details: het type toestel, de vliegmaatschappij, de route, en de exacte atmosferische omstandigheden op zijn vlieghoogte. Wil je weten welk vliegtuig die streep achterliet die je vijf minuten geleden zag? Scrol terug in de tijdlijn en je ziet het antwoord. Dit is geen raketwetenschap. Het is publiek beschikbare data, toegankelijk gemaakt voor iedereen. Omdat je het recht hebt om te weten wat er boven je eigen huis vliegt. ### Veelgestelde vragen Waarom blijven sommige strepen in de lucht urenlang hangen?+De duur van een vliegtuigstreep hangt af van de atmosferische omstandigheden op vlieghoogte. Wanneer de lucht op 9.000 tot 12.000 meter hoogte zeer vochtig is en de temperatuur onder de -40 graden Celsius ligt, kunnen de ijskristallen in de streep niet verdampen. De streep blijft dan hangen, spreidt zich uit door windschering, en kan uitgroeien tot een dunne wolkenlaag die uren zichtbaar blift. Op droge dagen verdwijnt dezelfde streep binnen seconden. ChemTracker toont je deze atmosferische data in real-time, zodat je zelf kunt zien waarom strepen op sommige dagen bliven hangen en op andere niet.Hoe weet ik welk vliegtuig een streep heeft achtergelaten?+ChemTracker gebruikt live ADS-B vliegtuigdata om elk vliegtuig in je omgeving te identificeren. Je ziet de vluchtcode, het type vliegtuig, de maatschappij, de herkomst en bestemming, en de exacte hoogte. Wanneer je een streep in de lucht ziet, open je ChemTracker en kijk je welk vliegtuig op dat moment boven je positie vloog. Je kunt ook je telefoon naar de lucht richten — de app matcht dan automatisch het vliegtuig dat je ziet.Zijn die rare strepen in de lucht gevaarlijk?+Dit is een vraag die veel mensen bezighoudt. Officiele instanties stellen dat vliegtuigstrepen bestaan uit waterdamp en ijskristallen en geen gezondheidsrisico vormen. Tegelijkertijd erkennen wetenschappers dat persistente strepen een meetbaar effect hebben op zonlichtinstraling en het lokale klimaat. Of er meer aan de hand is, daarover zijn de meningen verdeeld. ChemTracker kiest geen kant — we geven je de data om zelf te onderzoeken wat er boven je hoofd gebeurt.Kan ik een melding krijgen als er strepen boven mijn huis zijn?+Ja. ChemTracker biedt een alertfunctie waarmee je een melding ontvangt wanneer vliegtuigen met een hoge kans op streepvorming boven je locatie vliegen. Je stelt zelf de radius in en kiest of je meldingen wilt voor alle vliegtuigen of alleen wanneer de atmosferische omstandigheden wijzen op langdurige, persistente strepen. Nooit meer raden welk vliegtuig het was Real-time tracking van elk vliegtuig en elke streep boven Nederland. START MET TRACKEN — 14 DAGEN GRATIS ## Nederlands: Vliegtuig Volgen ## Vliegtuig Volgen — Live & Gratis Real-time ADS-B data · Bijgewerkt 29 maart 2026 Op dit moment vliegen er tientallen vliegtuigen boven jouw hoofd. Je kunt ze allemaal volgen — gratis, in real-time, met de exacte hoogte, snelheid en route van elk toestel. Vliegtuig volgen is de afgelopen jaren toegankelijk geworden voor iedereen. De technologie die luchtverkeersleiders en vliegtuigspotters vroeger exclusief gebruikten, is nu beschikbaar via je smartphone. ChemTracker bouwt daarop voort met een extra laag die andere trackers niet bieden: atmosferische data gekoppeld aan elk vliegtuig, zodat je niet alleen weet wat er vliegt, maar ook waarom het achterlaat wat het achterlaat. Of je nu wilt weten welk toestel die streep aan de hemel maakte, of gewoon nieuwsgierig bent naar het vliegverkeer boven je buurt — dit is hoe je het doet. ### Hoe werkt vliegtuig volgen? De basis van modern vliegtuig volgen is ADS-B— Automatic Dependent Surveillance-Broadcast. Elk commercieel vliegtuig is wettelijk verplicht om een ADS-B transponder aan boord te hebben. Dit apparaat zendt elke seconde een radiosignaal uit met de positie, hoogte, snelheid, vluchtnummer en registratie van het toestel. Grondstations over de hele wereld, beheerd door luchtvaartautoriteiten maar ook door een wereldwijd netwerk van vrijwillige ontvangers, pikken deze signalen op. De data stroomt naar centrale databases die apps en websites voorzien van real-time vliegtuiginformatie. Het systeem is publiek en open: de data die vliegtuigen uitzenden is voor iedereen beschikbaar. ChemTracker combineert deze ADS-B vliegtuigdata met atmosferische meetgegevens van weerstations en satellietmodellen. Zo kun je per vliegtuig zien wat de luchtvochtigheid, temperatuur en luchtdruk zijn op de exacte hoogte waarop het vliegt — de factoren die bepalen of een vliegtuig een zichtbare streep achterlaat en hoe lang die blijft hangen. ### Wat zie je per vliegtuig? Tik op een vliegtuig in ChemTracker en je ziet direct: - —Vluchtcode en registratienummer van het toestel - —Type vliegtuig en luchtvaartmaatschappij - —Vertrek- en bestemmingsluchthaven met geschatte aankomsttijd - —Actuele hoogte in meters en voet - —Snelheid en vliegrichting - —Atmosferische omstandigheden op vlieghoogte: temperatuur, relatieve luchtvochtigheid en luchtdruk - —Streepkans-indicator: groen (geen streep verwacht), oranje (korte streep), rood (persistente streep waarschijnlijk) Die laatste twee punten zijn wat ChemTracker onderscheidt van standaard vluchttrackers. Flightradar24 en vergelijkbare apps tonen je waar vliegtuigen zijn. ChemTracker toont je ook waarom ze laten zien wat ze laten zien. ### Live vliegtuigen volgen gratis Je hebt geen abonnement nodig om te beginnen. ChemTracker biedt een gratis proefperiode van 14 dagen met volledige toegang tot alle functies. Geen creditcard vereist, geen verborgen kosten. Na de proefperiode kies je zelf of je wilt doorgaan. De basisversie van de app blijft gratis beschikbaar met live vliegtuigtracking. De betaalde versie voegt historische data, aangepaste meldingen en uitgebreide atmosferische analyses toe. Voor de meeste gebruikers — mensen die willen weten welk vliegtuig een streep maakte, of die simpelweg nieuwsgierig zijn naar het vliegverkeer boven hun buurt — is de gratis versie meer dan voldoende. ### Vliegtuig volgen voor strepenonderzoek Veel gebruikers van ChemTracker zijn geïnteresseerd in meer dan alleen het vliegverkeer. Ze willen begrijpen waarom ze bepaalde strepen zien — wanneer, door welk toestel, en of de atmosferische omstandigheden de officiële verklaring ondersteunen. Het debat over strepen in de lucht is al jaren actief in Nederland. Sommige mensen accepteren de wetenschappelijke uitleg over condensatiestrepen volledig. Anderen zien patronen die ze niet kunnen rijmen met toeval of normale vliegroutes. Het merendeel bevindt zich ergens in het midden: ze willen gewoon de feiten kennen voordat ze een conclusie trekken. Voor die laatste groep is vliegtuig volgen geen hobby, maar een onderzoeksmethode. Als je ziet dat een vliegtuig een opvallende streep achterlaat, kun je met ChemTracker binnen seconden controleren: - —Welk type toestel het is en van welke maatschappij - —Op welke hoogte het vliegt en of dat past bij de streepvorming die je ziet - —Of de luchtvochtigheid op die hoogte hoog genoeg is voor persistente strepen - —Of het vliegtuig een reguliere route volgt of een afwijkend patroon - —Of er meerdere toestellen in het gebied zijn die vergelijkbare sporen achterlaten ChemTracker neemt geen standpunt in over chemtrails boven Nederland. De app geeft je de data. Wat je daarmee doet, is aan jou. ### Welke vliegtuigen zijn zichtbaar? Via ADS-B zijn zichtbaar: alle commerciële vluchten (inclusief overvluchten boven Nederland), de meeste zakenvliegtuigen en privéjets, een deel van de vrachtvluchten, en sommige militaire transportvliegtuigen. Samen vormen ze meer dan 95 procent van al het vliegverkeer. Niet zichtbaar via ADS-B zijn toestellen zonder transponder (kleine ultralichten en zweefvliegtuigen), en vliegtuigen die bewust hun transponder uitschakelen of op een afgeschermde militaire frequentie vliegen. In de praktijk zijn dit een klein minderheid van de toestellen die je aan de lucht ziet. Als je een streep ziet maar in ChemTracker geen overeenkomend vliegtuig kunt vinden, zijn er drie mogelijke verklaringen: het toestel had zijn transponder uit, de streep is al oud en het vliegtuig is allang buiten beeld, of het gaat om een type luchtvaartuig dat buiten de ADS-B dekking valt. ChemTracker toont je ook historische data van de afgelopen uren, zodat je eerdere vluchten kunt terugvinden. ### Veelgestelde vragen Hoe kan ik gratis een vliegtuig volgen?+ChemTracker biedt een gratis proefperiode van 14 dagen waarmee je elk vliegtuig boven Nederland live kunt volgen. De app gebruikt ADS-B transponderdata die vliegtuigen zelf uitzenden. Je ziet de positie, hoogte, snelheid en identiteit van elk toestel in real-time, zonder abonnement of registratie van creditcard vereist voor de proefperiode.Wat is ADS-B en hoe werkt vliegtuig volgen?+ADS-B (Automatic Dependent Surveillance-Broadcast) is een systeem waarbij vliegtuigen automatisch hun positie, hoogte, snelheid en identiteit uitzenden via een radiosignaal. Grondstations en satellietontvangers pikken deze signalen op en sturen ze naar databases. ChemTracker gebruikt deze real-time datastroom om elk vliegtuig met transponder op de kaart te tonen. Meer dan 95 procent van alle commerciële vluchten en een groot deel van de privé- en militaire toestellen zijn hiermee zichtbaar.Wat is het verschil tussen vliegtuig volgen en vlucht volgen?+Vlucht volgen betekent dat je een specifieke vlucht (zoals KL1234) in de gaten houdt — je weet al welk toestel je zoekt. Vliegtuig volgen gaat een stap verder: je ziet alle toestellen in een bepaald gebied tegelijk, ook als je de vluchtnummers niet kent. ChemTracker combineert beide: je kunt een specifieke vlucht opzoeken, maar ook gewoon kijken wat er op dit moment boven je huis vliegt.Kan ik ook militaire vliegtuigen volgen?+Militaire vliegtuigen zijn lang niet allemaal zichtbaar via ADS-B, maar een deel ervan wel. Transportvliegtuigen, tankvliegtuigen en sommige patrouillevoertuigen van de Koninklijke Luchtmacht en NAVO-bondgenoten zijn regelmatig te volgen via openbare transponderdata. Gevechtsvliegtuigen en geheime vluchten schakelen hun transponder doorgaans uit. ChemTracker toont alles wat publiek uitzendt, inclusief de vluchten die opvallende routes of hoogtes hebben.Waarom is vliegtuig volgen relevant voor chemtrail-onderzoek?+Als je wilt onderzoeken welke vliegtuigen de strepen in de lucht veroorzaken, is real-time vliegtuigvolgen de enige manier om dat te doen. ChemTracker koppelt vliegtuigdata aan atmosferische informatie: je ziet niet alleen welk toestel waar vliegt, maar ook of de omstandigheden op die hoogte passen bij normale condensatiestreepvorming. Toestellen die strepen achterlaten op hoogtes of in omstandigheden waar dat normaal niet zou moeten, vallen zo direct op.Welke vliegtuigdata zie ik per toestel?+Per vliegtuig toont ChemTracker: de vluchtcode en registratie, het type toestel en de luchtvaartmaatschappij, de vertrek- en bestemmingsluchthaven, de actuele hoogte en snelheid, de vliegrichting, en de atmosferische omstandigheden (temperatuur, luchtvochtigheid, luchtdruk) op de vlieghoogte van dat specifieke toestel. Die laatste gegevens zijn uniek voor ChemTracker — andere vluchttrackers tonen deze atmosferische context niet. Volg elk vliegtuig boven jouw locatie Live ADS-B tracking, atmosferische data en streepkans-analyse. Gratis proberen, geen creditcard nodig. START MET TRACKEN — 14 DAGEN GRATIS