Variations in chemical composition of aerosol during Diwali over mega city Delhi, India

In the present study, we have investigated the spatio-temporal variation in concentrations of PM(2.5 a)nd its chemical constituents [organic carbon, elemental carbon, water-soluble organic carbon, levoglucosan, and water-soluble inorganic ions, organics] during pre-Diwali, Diwali, and post-Diwali days (13-30th October 2017) in Delhi. PM2.5 has been collected from seven strategic locations spread across the city. The massive burning of firecrackers during the Diwali festival give rise to remarkably high concentrations of ambient particulate matter (PM), organics, trace gases, and elements. Such undesirable mass loading of air pollutants over a short period degraded ambient air quality for several days after the festival, prompted us to investigate the impact of short-term air quality degradations events. The average concentration of PM2.5 over Delhi during pre-Diwali days, Diwali day and post-Diwali days have been recorded 169 +/- 51 mu g/m(3), 521 +/- 307 mu g/m(3) and 193 +/- 61 mu g/m(3), respectively with maximum observed at site 3 (903 mu g/m(3)) and minimum at site 7 (141 mu g/m(3)). The mass concentrations of the markers for biomass and firecrackers burning (OC, levoglucosan, WSOC, and K+, etc.) and mass ratios showed a significant increase in trend during the festive period.