Impact of aerosols and reactive trace gases concentrations in India

ABSTRACT

The concentration of reactive trace gases in the atmosphere affects the human health differently. This study presents the changes of aerosol and reactive gases load in the atmosphere from the recent past with the help of Copernicus Atmosphere Monitoring Service (CAMS) data in Indian domain. The EAC4 (ECMWF Atmospheric Composition Reanalysis 4) data sets were used to examine spatially the load of ambient trace gases (NO2, O3, SO2 & CO) and aerosol present in the atmosphere as aerosol optical depth(AOD). The four weekly phases of the study are for April, 2020 (01-07, 08-14, 15-21 & 22-30). It has been observed during the above said phases that the concentration of aerosols, chemically reactive gases and greenhouse gases shows appreciable reduction up to ~60-70 % from CAMS Long Period Average (LPA) 17 years (2003-2019) data over the entire Indian sub-continent, except few pockets of Central (Durg, Indore, Bilaspuretc.) and South West (Kolhapur, Gujaratetc.) India. These slightly higher values in 2nd and 3rd week of April-2020 are due to pre-monsoon dust storm activity and well captured in vertical air flow Omega at 850/NCAR reanalysis. Concentrations of reactive gases from 12 different Central Pollution Control Board (CPCB) stations of India with CAMS, LPA data of April-2019 & 2020 has been compared and show that aerosol load in terms of PM-2.5 & PM-10 is appreciably drop down (60-70 %) over IGP and 25-30 % in other parts of India. The concentration of other reactive gases (NO2, SO2 & CO) with actual data from the month of April, 2019 &2020 also decreases ~ 32 %, 7 %, 17 % over IGP and 16 %, 8 %, 9 % in other parts of India respectively. The concentration of Ozone shows slightly positive behaviour over IGP and negative at other parts of India. This study is further brought out a message for future that we should use the natural resources judiciously as their long term exposure can cause severe health problems and a psychological burden or stress globally during this COVID-19 spread period. © 2022, India Meteorological Department. All rights reserved.