Emissions and pollution enforcement
Methane appears in TROPOMI, not in the annual report.
Methane is invisible. Shortwave infrared is not.Methane point-source attribution from orbit
Satellite spectrometers now detect discrete methane plumes from oil and gas infrastructure, landfills, and coal mines. Resolution and detection floors vary sharply between sensors, and choosing the wrong one produces false assurance.
Sentinel-5P TROPOMIGHGSat-D/C seriesEMIT (ISS-mounted imaging spectrometer, Carbon Mapper heritage)
Flares cannot hide their heat. Satellites read the bill.Routine gas flaring volume quantification
Satellites detect gas flares by their infrared signature and convert radiant power to estimated gas volumes. The method is independent of operator self-reporting, works globally every night, and is honest about its uncertainty floor.
VIIRS Nightfire (Suomi NPP / NOAA-20)Landsat 8 / 9 OLI + TIRSSentinel-3 SLSTR
Stacks emit. Satellites count. The numbers rarely match permits.NO2 column mapping over industrial facilities
Tropospheric NO2 columns retrieved from TROPOMI and OMI can fingerprint persistent emission enhancements above named power stations, smelters, and industrial clusters. Multi-year composites resolve facility-level signals at 3.5 × 5.5 km, with honest caveats on cloud screening and air-mass factor uncertainty.
Sentinel-5P TROPOMIAura OMIGEMS (GEO-KOMPSAT-2B)
Stacks can be capped on paper. The atmosphere keeps its own ledger.SO2 emissions monitoring at smelters and cement plants
UV backscatter satellites detect sulphur dioxide columns above smelters and cement kilns independently of any reported figure. TROPOMI resolves facility-scale plumes daily, and wind-field integration converts those columns into source-rate estimates regulators can act on.
Sentinel-5P TROPOMIAura OMIGOME-2 (MetOp-A, -B, -C)
Three sensors disagree. The fusion is where the truth lives.Coal power plant activity inference from multi-signal fusion
No single satellite band confirms a coal plant's output. Combining TROPOMI NO2 columns, VIIRS thermal anomalies, and Sentinel-2 plume opacity builds a probabilistic activity index that is honest about its own gaps.
Sentinel-5P TROPOMIVIIRS M-band and I-band thermalSentinel-2 MSI
Oil dampens waves. That silence is visible from orbit.Oil spill detection and extent mapping with SAR
Synthetic aperture radar detects surface oil by the backscatter suppression it causes on centimetre-scale ocean waves. Sentinel-1 is the operational standard, but false positives from biogenic films and wind shadows demand careful contextual analysis.
Sentinel-1 (C-band SAR)RADARSAT-2 (C-band SAR)COSMO-SkyMed (X-band SAR)
The colour of oil tells you more than its outline does.Oil spill thickness and type estimation from optical sensors
SAR finds the spill; optical hyperspectral data tells you what kind of oil it is and, within limits, how thick. PRISMA and DESIS can separate crude, weathered oil, and water-in-oil emulsions that look identical in broadband imagery.
PRISMA (ASI)DESIS (DLR / Teledyne Brown Engineering)Sentinel-2 MSI
Landfills vent when pressure drops. Satellites can now catch them.Fugitive methane detection at municipal landfills
Municipal landfills are among the most variable methane sources on Earth, with emissions spiking episodically and mixing point-source leaks with diffuse surface flux. Satellite retrievals must overcome heterogeneous waste-surface emissivity before a plume rate means anything.
GHGSat-C seriesSentinel-5P TROPOMIEMIT (ISS-mounted imaging spectrometer)
Ships file false manifests. Exhaust plumes over the Channel do not.NO2 and SO2 attribution to international shipping corridors
Tropospheric column retrievals from TROPOMI and OMI make shipping-lane pollution visible as persistent linear enhancements. Multi-month composites resolve major corridors and the 2020 IMO sulphur cap left a measurable SO2 signature in the satellite record.
Sentinel-5P TROPOMIAura OMIGOME-2 (MetOp-A/B/C)
Plastic absorbs near 1,215 nm. Open ocean does not. The gap is narrow.Floating plastic and marine debris detection from orbit
Satellite sensors can detect dense floating debris aggregations using spectral indices derived from Sentinel-2 and hyperspectral data, but reliable discrimination from Sargassum, foam, and pumice at the pixel level remains an open research problem.
Sentinel-2 MSIPRISMA (ASI)Landsat 8/9 OLI
Smoke is visible. Proving who made it is not.Aerosol optical depth attribution to industrial sources
Satellite sensors retrieve columnar aerosol loading daily over industrial clusters, but attributing persistent AOD anomalies to specific facilities requires multi-angle retrieval, wind-field analysis, and honest acknowledgement of what AOD alone cannot tell you about particle type.
MODIS MAIAC (Terra and Aqua)MISR (Terra)Sentinel-5P TROPOMI AER AI
Fires leave a thermal signature. Hiding the smoke changes nothing.Illegal waste burning and field-fire detection via thermal anomaly
Mid-infrared brightness temperature exceedances betray unauthorised combustion events from orbit, but separating illegal waste fires from permitted agricultural burns demands land-cover context that spectral data alone cannot supply.
VIIRS 375 m Active Fire (Suomi-NPP / NOAA-20)Sentinel-3 SLSTRMODIS MOD14 / MYD14
A refinery burns. The plume crosses a border before the inquiry opens.Carbon monoxide plume tracking from industrial fires and accidents
Tropospheric CO columns retrieved from TROPOMI, IASI and MOPITT let analysts trace pollution plumes from industrial fires and chemical accidents across hundreds of kilometres within 24 to 48 hours. This page explains the physics, the sensors, and the honest limits of what orbit can and cannot see.
Sentinel-5P TROPOMIMOPITT (Terra)IASI (MetOp-A/B/C)
Tailings ponds hide their chemistry. Shortwave infrared does not.Mine tailings and acid rock drainage mapping from spectral data
Iron-sulphate and iron-hydroxide minerals produced by acid mine drainage carry diagnostic spectral signatures that satellite sensors can read from orbit. Hyperspectral instruments resolve individual mineral species; multispectral sensors map gross contamination zones. Neither replaces field sampling, but both catch what ground inspection misses.
PRISMA (ASI)EMIT (NASA/JPL, ISS)Sentinel-2 MSI
Satellites see the whole city. Streets still need explaining.Traffic-related NO2 hotspot mapping in urban corridors
TROPOMI's tropospheric NO2 columns are too coarse to name a junction, but multi-year temporal averaging and land-use regression can push actionable hotspot maps below one kilometre. Here is what the method can and cannot promise.
Sentinel-5P TROPOMIAura OMIGEMS (GEO-KOMPSAT-2B)
The signal is real. Separating it from the noise is not simple.XCO2 anomaly detection above fossil fuel facilities
Detecting CO2 plumes from power stations and industrial sites via satellite is possible but genuinely difficult: a 1,000 MW coal plant lifts the local column by perhaps 1–3 ppm against a 420 ppm background, demanding sub-ppm retrieval precision and careful error budgeting.
OCO-2 (NASA)OCO-3 (ISS-mounted)GOSAT-2 (JAXA)
Ammonia is invisible from the road. It is not invisible from 817 km.Ammonia point-source detection above livestock and fertiliser facilities
Thermal infrared hyperspectral sounders can resolve concentrated NH3 plumes above intensive farms and urea-application events. This page explains what IASI, CrIS, TROPOMI and EMIT actually measure, where the method breaks down, and what a regulator can do with the output.
IASI (MetOp-A/B/C, EUMETSAT)CrIS (Suomi-NPP and NOAA-20, NOAA/NASA)Sentinel-5P TROPOMI (ESA/Copernicus)
Refineries vent VOCs invisibly. Formaldehyde columns remember every leak.Volatile organic compound plume mapping at petroleum refineries
TROPOMI and OMI HCHO column retrievals expose VOC emission intensity above refinery complexes, but biogenic background and coarse pixels demand careful interpretation. Wind-field integration converts column anomalies into flux estimates regulators can act on.
Sentinel-5P TROPOMIAura OMIGEMS (GEO-KOMPSAT-2B)
Benzene is invisible. Its absorption fingerprint in the SWIR is not.Benzene column retrieval above petrochemical and coking facilities
Benzene is a Group 1 carcinogen regulated under most national air-quality frameworks, yet routine satellite monitoring remains constrained by signal-to-noise limits. This page covers what TROPOMI, EMIT and airborne sensors can and cannot currently resolve.
Sentinel-5P TROPOMIEMIT (ISS-mounted imaging spectrometer)AVIRIS-NG (airborne)
EtO absorbs mid-infrared light. Current satellites barely see it.Ethylene oxide emission detection at sterilisation and chemical plants
Ethylene oxide is a regulated carcinogen with a clear infrared spectral signature, yet space-based detection remains at the frontier of what published sounder science can demonstrate. This page explains what IASI and CrIS can and cannot do, and what future sensors would need to achieve facility-scale compliance monitoring.
IASI (MetOp-A/B/C, EUMETSAT)CrIS (Suomi-NPP and NOAA-20, NOAA/NASA)EMIT (ISS, NASA JPL)
PAN travels thousands of kilometres. Its origin does not.Secondary pollution mapping via peroxyacetyl nitrate column retrieval
Peroxyacetyl nitrate forms when NOx and VOCs react in sunlight, then drifts far downwind before decomposing into ozone precursors. Thermal infrared sounders can retrieve PAN columns globally, linking distant ozone episodes to specific industrial corridors.
IASI (MetOp-A, -B, -C)MOPITT (Terra)CrIS (Suomi-NPP, NOAA-20)
Ozone is never emitted. Its parents are, and they leave a record.Ground-level ozone precursor attribution to industrial emission clusters
Tropospheric ozone forms from NOx and VOC reactions, not direct emission. Attributing surface ozone episodes to specific industrial clusters requires combining TROPOMI NO2 and HCHO column retrievals with air-mass trajectory modelling, and the method has real resolution limits worth understanding before commissioning work.
Sentinel-5P TROPOMIAura OMIGEMS (GEO-KOMPSAT-2B)
H2S is invisible and lethal. Detection from orbit is barely possible today.Hydrogen sulphide detection above wastewater treatment and industrial lagoons
Thermal infrared sounders can detect large H2S plumes from industrial accidents, but the detection floor sits far above routine facility emissions. This page explains the retrieval physics, current limits, and what next-generation hyperspectral sensors may change.
IASI (MetOp-A/B/C)CrIS (Suomi-NPP, NOAA-20)EMIT (ISS)
Soot absorbs light. Dust scatters it. That difference is enforceable.Black carbon and soot plume mapping from industrial combustion sources
Black carbon from coking plants, steel mills and open industrial fires carries a distinct absorbing-aerosol signature that satellite retrievals can separate from scattering dust, turning a physics difference into an attribution tool for regulators.
Sentinel-5P TROPOMIPOLDER/PARASOL (CNES)MISR (Terra)
Mercury is invisible from orbit. Its companions are not.Mercury emission proxy mapping at coal and chlor-alkali facilities
No operational satellite retrieves atmospheric mercury directly, but TROPOMI's daily SO2 and NO2 columns expose the combustion and process activity that drives mercury release at coal plants and chlor-alkali facilities.
Sentinel-5P TROPOMIAura OMILandsat-8/9 OLI and TIRS
Dust disperses. Aerosol physics leaves a record that does not.Fugitive dust emission mapping at open-pit mines and quarries
Open-pit mines generate fugitive dust plumes detectable in multispectral and aerosol-retrieval data. This page explains how MODIS MAIAC AOD, Sentinel-2 surface reflectance, and TROPOMI aerosol index combine to map plume extent, frequency, and emission loading at active mine sites.
MODIS Terra and Aqua (MAIAC AOD product)Sentinel-2 MSISentinel-5P TROPOMI
Chlorine disperses in hours. Polar orbiters pass once a day.Chlorine gas plume detection from industrial accidents
IASI and CrIS sounders have retrieved Cl2 and HCl columns above large industrial chlorine releases, but rapid atmospheric dilution means the detection window is narrow and the minimum detectable mass is high. This page sets out what the public record shows, where the physics limits retrieval, and how geostationary infrared sounders could close the timing gap.
IASI (MetOp-A/B/C)CrIS (Suomi-NPP / NOAA-20)SEVIRI (Meteosat-9/10/11)
The water looks normal. The heat it carries does not.Thermal discharge plume mapping from power plant cooling water
Once-through cooling systems return water 3–10 °C above ambient, leaving a thermal signature that satellite infrared sensors can track across time. Multi-temporal stacking of Landsat TIRS and MODIS data distinguishes chronic discharge from seasonal variation and quantifies plume extent with honest resolution limits.
Landsat 8/9 TIRSMODIS (Terra and Aqua)Sentinel-3 SLSTR
Kilns run at night. Dust settles on the record.Cement plant fugitive dust and kiln plume mapping from optical data
Cement production leaves optical fingerprints: kiln plumes alter aerosol columns, and fugitive dust changes surface reflectance around plant perimeters. Sentinel-2, Landsat 8/9 and MODIS MAIAC together make those fingerprints legible, within honest resolution limits.
Sentinel-2 MSILandsat 8/9 OLIMODIS MAIAC AOD
The pond looks inert. The methane column above it does not.Methane detection above produced-water evaporation ponds in oil fields
Produced-water evaporation ponds degas dissolved methane continuously yet rarely appear in facility emission inventories. GHGSat high-resolution SWIR retrievals and TROPOMI column enhancements can identify active ponds, though co-located tank and compressor sources complicate attribution.
GHGSat-C series (Claire, Luca, Oliver and successors)Sentinel-5P TROPOMISentinel-2 MSI
Shafts vent continuously. The question is whether the sensor is looking.Coal mine methane detection from ventilation shaft emissions
Underground coal mines emit methane through surface ventilation shafts around the clock, making them tractable point sources for spaceborne SWIR spectrometers. Detection is real but constrained by shaft arrays that dilute flux below single-pass thresholds.
GHGSat-C seriesSentinel-5P TROPOMIEMIT (ISS-mounted)
Paddies flood on a schedule. Methane does not wait for permission.Seasonal methane flux mapping over rice paddy agriculture
Flooded rice paddies produce methane through anaerobic decomposition, with emissions peaking mid-season. Combining Sentinel-1 inundation maps with TROPOMI column retrievals lets analysts track the seasonal flux cycle, though separating paddy signal from co-located wetlands and livestock remains genuinely hard.
Sentinel-5P TROPOMISentinel-1 SAR (C-band, 5.405 GHz)MODIS Terra/Aqua
Wetlands breathe methane invisibly. Satellites can now read the breath.Natural wetland methane flux estimation via atmospheric inversion
Natural wetlands emit more methane than all fossil fuel sources combined, yet their fluxes remain poorly constrained. Top-down atmospheric inversion using GOSAT and TROPOMI column data, anchored by Sentinel-1 inundation mapping, is closing that gap.
GOSAT / GOSAT-2Sentinel-5P TROPOMISentinel-1 SAR (C-band)
Same gases, different fires: the chemistry tells them apart.Trace gas attribution to biomass burning versus industrial combustion
CO, NO2, and aerosols pour from both burning forests and industrial stacks, but their ratios, spatial patterns, and co-emitted tracers differ enough to separate the sources when you read the data carefully.
Sentinel-5P TROPOMIVIIRS (Suomi-NPP and NOAA-20)MOPITT (Terra)
Ships leave no footprints. Their soot lands on ice for decades.Black carbon deposition risk mapping from Arctic shipping routes
Heavy fuel oil combustion deposits black carbon on Arctic sea ice, cutting albedo and accelerating melt. TROPOMI aerosol data correlated with AIS vessel tracks can map emission density and model downwind deposition risk, though bright ice surfaces make retrieval genuinely hard.
Sentinel-5P TROPOMIMODIS Terra and AquaVIIRS DNB (Suomi-NPP and NOAA-20)
HFCs are invisible. Their infrared fingerprints are not.Hydrofluorocarbon refrigerant leak detection from atmospheric column retrievals
High-spectral-resolution thermal infrared sounders can detect column enhancements of HFC-134a and HFC-23 above individual industrial facilities, turning atmospheric physics into an enforcement tool for the Kigali Amendment.
IASI (MetOp-A/B/C, EUMETSAT)CrIS (Suomi-NPP / JPSS-1, NOAA/NASA)AIRS (Aqua, NASA)
Leachate ponds change colour. Satellites notice before inspectors do.Landfill leachate pond extent and contamination mapping from multispectral data
Multispectral and SAR data can map leachate pond extent, track post-rainfall expansion, and flag subsurface migration at active and closed landfills, giving regulators a timestamped record that ground visits alone cannot provide.
Sentinel-2 MSILandsat 8/9 OLI-TIRSSentinel-1 SAR (C-band)
SF6 is invisible. Its infrared fingerprint is not.SF6 emission detection at high-voltage electrical substations
Sulphur hexafluoride leaks from high-voltage switchgear carry a global warming potential ~23,500× CO2. Thermal infrared sounders can detect SF6 column enhancements at the district scale, though single-facility attribution remains beyond current thresholds.
IASI (MetOp-A, -B, -C)CrIS (Suomi-NPP, NOAA-20/JPSS-1)AIRS (Aqua)
Blast furnaces cannot hide their chemistry from orbit.Iron and steel plant emission fingerprinting via co-emitted NO2 and CO columns
Blast furnace and basic oxygen furnace operations produce a co-emission ratio of NO2 to CO that is physically distinct from power stations or traffic. TROPOMI and MOPITT column retrievals, cross-checked against Sentinel-2 facility imagery, can fingerprint integrated steelworks and separate them from electric arc furnace plants.
Sentinel-5P TROPOMIMOPITT (Terra)Sentinel-2 MSI
No flame, no flare record. The atmosphere still remembers.Unlit methane venting detection at offshore oil and gas platforms
Routine unlit venting leaves no thermal signal, hiding it from flaring inventories. Combining TROPOMI methane columns, Sentinel-1 platform catalogues, and ERA5 wind fields exposes it.
Sentinel-5P TROPOMISentinel-1 SAR (C-band, IW mode)VIIRS DNB / Nightfire
Peat burns without flames. Satellites still see the chemistry.Smouldering peat fire trace gas mapping from thermal and atmospheric sensors
Smouldering peat emits CO and CH4 at ratios that betray its origin, yet MODIS and VIIRS active-fire counts routinely miss it. TROPOMI and Sentinel-3 SLSTR close that gap, with caveats.
Sentinel-5P TROPOMISentinel-3 SLSTRMODIS (Terra/Aqua)
CF4 lasts 50,000 years. Smelters still release it unaccounted.Perfluorocarbon emission detection at aluminium smelters
Anode effects in aluminium electrolysis cells emit CF4 and C2F6, gases with atmospheric lifetimes exceeding 10,000 years. Thermal infrared sounders aboard MetOp and Aqua can detect column enhancements above the largest smelter clusters, though only at the upper end of the emission scale.
IASI (MetOp-A, -B, -C)CrIS (Suomi-NPP, JPSS-1/NOAA-20)AIRS (Aqua)
Fertiliser goes down. The atmosphere remembers for weeks.Nitrous oxide flux mapping above fertilised agricultural fields
Soil nitrification and denitrification after synthetic nitrogen application produce N2O pulses detectable in TROPOMI column retrievals. Regional flux anomalies can be correlated with fertiliser calendars derived from Sentinel-2 crop-stage mapping, though field-level attribution remains beyond current instrument precision.
Sentinel-5P TROPOMIIASI (MetOp-A/B/C)GOSAT-2
A plume you can see is a load you can measure.Industrial cooling tower water vapour plume mapping for facility activity inference
Wet cooling towers at power stations emit visible water vapour plumes whose size and persistence betray thermal load and generation output. High-resolution optical imagery, normalised against meteorological reanalysis, turns those plumes into an activity signal even when thermal infrared retrievals fail under cloud.
Planet SuperDoveSentinel-2 MSILandsat 8/9 OLI-TIRS
Ships move SO2 compliance from air to sea. Satellites notice.Open-loop scrubber washwater discharge plume detection in coastal waters
Open-loop scrubbers clean exhaust by flooding it with seawater, then discharge that acidic, PAH-laden washwater overboard. Sentinel-2 coastal and blue bands, fused with AIS tracks, can detect and attribute the resulting plumes in ports and restricted zones.
Sentinel-2 MSILandsat 9 OLISentinel-3 OLCI