# Tropospheric column mapping (NO2/SO2)
*methodologies*

Maps tropospheric NO2 and SO2 column density from UV-VIS backscatter; good for urban air quality, shipping emissions, and volcanic SO2 tracking.

## Specifications
- **family**: Atmospheric spectroscopy
- **requirements envelope**: {"kind":"spectral","spectral_range_nm":{"min":310,"max":490},"bands_min":50,"calibration_tier_min":"radiometric","snr_min":150,"daylight_required":true,"cloud_tolerant":false}
- **entity type**: methodology
- **last verified date**: 2026-05-22
- **verified by**: sw
- **claim status**: unclaimed
- **attributes**: {"family":"Atmospheric spectroscopy","summary":"Maps tropospheric NO2 and SO2 column density from UV-VIS backscatter; good for urban air quality, shipping emissions, and volcanic SO2 tracking.","requirements_envelope":"{\"kind\":\"spectral\",\"spectral_range_nm\":{\"min\":310,\"max\":490},\"bands_min\":50,\"calibration_tier_min\":\"radiometric\",\"snr_min\":150,\"daylight_required\":true,\"cloud_tolerant\":false}"}
- **technology**: optical-spectral-sensing

## Editorial
DOAS retrieval over UV-VIS (~310-490 nm) exploiting differential absorption structures. TROPOMI/Sentinel-5P is the operational benchmark at 3.5 x 5.6 km nadir resolution. [Wikipedia: Differential optical absorption spectroscopy](https://en.wikipedia.org/wiki/Differential_optical_absorption_spectroscopy)

## Sources
- [wikipedia] | Wikipedia: Differential optical absorption spectroscopy | https://en.wikipedia.org/wiki/Differential_optical_absorption_spectroscopy | tier=community | accessed=2026-05-22

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Source: https://eo-atlas.org/methodologies/tropospheric-column-no2-so2
Maintainer: SpectraWorks B.V. (CC-BY 4.0)