Statistical evaluation of PM2.5 and dissemination of PM2.5, SO2 and NO2 during Diwali at Chennai, India

The aim of this study is to evaluate the pollution caused by fireworks on the day of what is known as Diwali festival which is celebrated every year in October–November. The increase in particle pollutants such as the particulate matter 2.5 (PM 2.5 ) over a time period around the festival days is noted for a year of 2017 in the city of Chennai, South India, and this increase in pollutant levels is correlated with the increase in health issues present among public during this festival time. It was observed that PM 2.5 varied from 30.06 ± 1.5 to 146.82 ± 7.3 µg/m 3 with an average of 68.18 ± 26.84 µg/m 3 , and the mean concentration for three consecutive years (2015–2017) was lower than National Ambient Air Quality Standards. All the important pollutants such as sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ) and PM 2.5 have been measured during pre-Diwali, Diwali day and after Diwali at Choolaimedu (CM) and Chinmayanagar (CN) areas. Due to dense population, these areas are expected to have high levels of firework activity and are typical for the study. The gaseous pollutants SO 2 and NO 2 correlated with wind speed, wind direction, temperature and relative humidity. PM 2.5 had good correlation with SO 2 . Eye irritation was found to be the most common health issue, which affected 44.3% of the total surveyed residents during these festival days.