Air Pollution

[pib] Satellites to Assess Pollution Status


From UPSC perspective, the following things are important :

Prelims level : Aerosol Optical Depth (AOD)

Mains level : Combating urban air pollution in India

ISRO’s INSAT-3D & 3DR satellites are being used for assessment of air pollution.

Aerosol Optical Depth (AOD)

  • Aerosol Optical Depth (AOD) is a quantitative estimate of the amount of aerosol present in the atmosphere, and it can be used as a proxy for surface Particulate Matter PM2.5 (particles smaller than 2.5 µm median diameter).
  • AOD measures the extinction of a ray of light as it passes through the atmosphere.

How is AOD calculated?

  • Using medium resolution Indian Remote Sensing (IRS) satellite data, stubble burned area maps are generated at the end of stubble burning activity in Kharif season.
  • ISRO has been carrying out monitoring of stubble burning since 2015. The products generated are comparable to the NASA products.
  • The Imager payload on-board ISRO’s INSAT-3D & 3DR satellites are used to monitor Aerosol Optical Depth (AOD).

Significance of AOD

  • It is found that AOD, PM2.5 and PM10 concentrations are higher over Indo-Gangetic Plain covering parts of Delhi, Uttar Pradesh and Bihar during October and November.
  • High concentration of these pollutants is seen originating from parts of Punjab and Haryana during stubble burning.
  • Climatological study of satellite based fire occurrences and associated pollutant parameters reveal that fire occurrences increased by 4% over Punjab and Haryana region during Oct-Nov between 2003 and 2017.
  • The model based analysis suggests that there is a high probability of transportation of smoke aerosols from Punjab & Haryana, towards down-wind regions of Delhi, Uttar Pradesh and Bihar.
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