Assessment of Air Quality in Major Indian Cities

Abstract Description: With documented studies showing the causal relationship between ambient particulate exposure and various health endpoints, the detrimental effects of high values of fine particles (PM2.5), one of the main constituents of air pollutants, on health have long been known. Because of unchecked industry and urbanization, as well as the rapidly growing population in these metropolitan areas, the PM2.5 problem is particularly severe in developing countries like India. The primary sources of PM2.5 emissions vary from city to city, making it extremely difficult to establish air quality controls. This necessitates a greater understanding of the pollutant in question in order to create stricter regulations and more effective emission reduction plans. Consequently, a thorough evaluation of US embassy locations in Delhi, Kolkata, Chennai, Hyderabad and Mumbai was conducted for the six year period of 2017 through 2023.Over the years, the Delhi embassy recorded the highest 24-hour average readings, with 59% exceedances above the national standard of 60 µg/m3and annual average ranging from 93 to 111µg/m3. while Kolkata came in second with 43% exceedances above 60 µg/m3 and annual average ranging from 65 to 92µg/m3. Mumbai has lower daily average PM2.5 concentrations with36% exceedances over 60 µg/m3 and annual average of 41 to 74 µg/m3.Hyderabad demonstrated 34% exceedances above 60 ug/m3 with annual averages of 41 to 60 µg/m3. Chennai has lower annual average values of about 26 to 36µg/m3 with 10% exceedances of 60 µg/m3... For 24-hour averaged PM2.5 concentrations, the values at all five locations significantly surpass WHO guidelines of 15 µg/m3.Highest concentrations were observed in winter and post-monsoon as noted in previous studies. Back-trajectory analyses using HYSPLIT shows that some regional contribution is possible for high concentrations in Delhi and Kolkata other than local vehicular pollution. The study reveals the need for stringent measures to control PM2.5 concentrations in urban regions of India.