Inter annual variability of tropospheric NO2 and tropospheric ozone over Maharashtra (India) : the role of lightning

The seasonal and inter annual variability of Tropospheric Nitrogen dioxide (NO2), Ozone (O-3) and lightning activity over Maharashtra and adjoining part of states (15.5 degrees N-22.5 degrees N, 72.5 degrees E-81.5 degrees E) of India, is analyzed to study the role of lightning activity in the seasonal variation of NO2 and O-3. Satellite observations of Tropospheric NO2 and O-3 from Aura-Ozone Monitoring Instrument (OMI)/Microwave Limb Sounder (MLS) for the period 2005-2016 and lightning data of 2014-2016 from lightning detection network over Maharashtra are used for analysis. Analyses show that the seasonal variations of all the three quantities are closely related to each other. The scatter plot between monthly NO2 concentration verses monthly lightning activity for years 2014-2016 also show good correlation between these two parameters (r = 0.71, significant at 99.9%). Our analysis demonstrates that the seasonal and inter-annual variations in NO2 and O-3 are affecting by lightning activity over study region. However, biomass burning during April-May and increased air pollution during winter months (November-January) also play important role in the intra seasonal variations of NO2 and O-3 over this region.