Characterization of PM2.5-Bound Carcinogenic PAHs and Their Emission Sources on the Western Coast of India
JAMSON MASIH, Lorraine Tellis, Sachin Gupta, Chemistry Department, Wilson College
Abstract Number: 66
Working Group: Chemicals of Emerging Concern in Indoor and Outdoor Aerosol: Sources, Vectors, Reactivity, and Impacts
Abstract
Particulate matter (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) are critical components of air pollution due to their persistence in the atmosphere and harmful effects on human health. PM2.5 can penetrate deep into the lungs, facilitating the transport of toxic compounds such as PAHs. These organic pollutants are mainly produced by incomplete combustion of fossil fuels and biomass and are known for their carcinogenic, mutagenic, and teratogenic properties. Monitoring their concentration and identifying emission sources is essential for risk assessment and pollution control. This study presents a comparative investigation of PM2.5-bound PAHs in Mumbai, a densely populated urban center on the western coast of India. The study spans two periods 2018-2019 and 2022-2023. While the earlier study focused on six priority carcinogenic PAHs, the recent phase expanded the scope to include 22 PAHs, capturing both low and high molecular weight compounds. PM2.5 concentrations during the study ranged from 66.29 to 182.15 µg/m³, exceeding safe exposure limits. The cumulative concentration of the 22 PAHs in the recent study was 48.36 ng/m³. Major contributors included fluoranthene (5.47 ng/m³), benzo(b)fluoranthene (4.26 ng/m³), indeno(1,2,3-cd)pyrene (3.14 ng/m³), and chrysene (2.71 ng/m³). Source apportionment using diagnostic ratios and principal component analysis indicated that vehicular emissions-particularly from gasoline and diesel combustion—remain the dominant source over both periods. BaP-equivalent toxicities showed that despite the broader PAH profile, a few key compounds contributed disproportionately to overall carcinogenicity. The expansion in PAH analysis from 6 to 22 compounds has allowed a more comprehensive understanding of air toxicology and trends in pollutant sources. The results highlight the ongoing need for stringent vehicular emission control and continuous PAH monitoring in urban coastal regions.