BENGALURU: A joint study by the Indian Space Research Organisation (Isro) and National Aeronautics and Space Administration (Nasa) of the US, which had commenced after satellite images showed the presence of an aerosol layer over the Asia region, has confirmed the same and has also found the presence of nitrate, which is a new finding.
Aerosol, the sub-micron size particles suspended in air are produced from a variety of man-made and natural processes such as vehicle exhaust, waste-burning, wind blown dust, volcanic eruptions et al, are mostly restricted to the first few kilometers from the surface of Earth’s atmosphere—Upper Troposphere and Lower Stratosphere (UTLS).
According to Isro, measurements by the joint team has “confirmed the presence of aerosol layer seen in satellite measurements over the Asian region and it also shows a sharp increase of aerosol concentration near 16.5-18.5 km (from Earth’s surface).”
This layer, Isro says, has distinct size distribution as opposed to that from background mineral aerosol dust that is naturally present in the atmosphere. “This layer contains particles of size less than 0.25 micron and are 90 per cent volatile. It appears the aerosol is formed from precursor pollutant gases which are transported via convection from the ground,” Isro has said.
