Chemical investigation of polycyclic aromatic hydrocarbon sources and associated health risks in PM2.5 from Eastern India

Polycyclic aromatic hydrocarbons (PAHs) are hazardous air pollutants known for their carcinogenic and mutagenic properties. This study examines the concentrations, sources, and health risks of PM2.5-bound PAHs across four sites in two cities of eastern India, on the Indo-Gangetic Plain (IGP) from January to December 2023. Sampling locations included industrial (DI), commercial (DC), and residential (DR) sites in Durgapur, and an industrial site in Raniganj (RI), West Bengal. The highest annual mean PAHs concentrations were observed at RI (494.44 ± 315.80 ng m−3) and DI (416.15 ± 207.57 ng m−3), followed by DR (320.72 ± 170.71 ng m−3) and DC (185.62 ± 121.56 ng m−3). Among individual compounds, indeno[1,2,3-cd]pyrene (IcP), benzo[ghi]perylene (BgP), and benzo(b + k)fluoranthene (B(b + k)F) were predominant, while four-ring PAHs contributed the largest fraction (29.9–39.6%) of total PAHs. Diagnostic ratios and principal component analysis (PCA) indicated that combustion of biomass, coal, gasoline, diesel, wood, and vehicular emissions were the major sources. The toxic equivalent concentration (BaPₑq) was highest at RI (110.04 ng m−3, and ILCR values for adults (4.76 × 10−6–1.08 × 10−3) and children (3.03 × 10−6–6.87 × 10−4) were exceeded recommended safety thresholds at all sites. These findings highlight the need for targeted emission control strategies to reduce PAH exposure and protect public health.