SPATIO-TEMPORAL DISTRIBUTION OF POLLUTANT TRACE GASES DURING DIWALI OVER INDIA

Abstract. People effected due to air pollution in India rose by almost 150% during 1990 to 2015. Diwali event is one of the major anthropogenic source contributing to the air pollution. The study focuses on spatial and temporal distribution of trace gases emitted during pre, on and post diwali days and identify areas with high concentration using station measured and satellite derived data during 2008-2017. The ground measured data shows that during diwali days, NO₂, SO₂, CO & O₃ concentration is almost 1.5 to 7 times the NAAQ safety limits over major cities particularly in northern, western and eastern India. Central and southern India experience low to moderate increase in pollution concentration. Spatial distribution over diwali days using satellite data reveal that NO₂ values over India are mostly below NAAQ standards, however high range are observed (27–48 μg/m³) over Delhi, Punjab, Haryana region (Northern zones), Western, central and Eastern Indo-Gangetic plain and this concentration is seen denser on diwali days compared to pre and post diwali. The observation reveal that SO₂ concentration is below safety levels over almost entire country except few cities like Delhi region, part of Gujarat, Tamil Nadu and Kolkata region. CO concentration is at higher level than NAAQ standards over Western, central and Eastern Indo-gangetic plain. The regression shows that the satellite derived values are in close agreement with the ground measured over the diwali days. The analysis conclude that the peak of the pollutants during diwali may not be increasing quite drastically over many parts of the cities but the overall spatial distribution of the pollutants is increasing from ‘moderate’ to ‘moderately high’ range.