Assessment of discrepancies in PM2.5 modeling and heavy metal associated health implications in Tier 2 and 3 non-attainment cities: EDGAR-driven WRF-Chem vs. field data in Alwar and Amritsar

The study investigates the discrepancies between WRF-Chem modelled and on-field measured water-soluble inorganic ions (WSIIs) and trace metals in under-researched non-attainment Tier 2 and Tier 3 Indian cities, Alwar and Amritsar. PMF-PSCF analysis concluded that in Alwar, sources included Secondary Inorganic Aerosols (SIA) and Coal Combustion (32 % in winter) and Crustal Emissions (27 % in summer), while in Amritsar, Brake and Tyre Abrasion (28 % in winter) and Crustal Emissions (68 % in summer) were predominant. A comprehensive health impact assessment using the U.S. EPA risk assessment model revealed that despite lower PM2.5 concentrations in Alwar compared to Amritsar, carcinogenic risks were notably higher, exceeding those observed in Tier 1 cities like Delhi. WRF-Chem model simulations, while insightful, underestimated concentrations of several ionic and metallic species. The limitations of these models highlight the need for more detailed and updated emission inventories, with finer temporal and spatial resolutions, to improve model accuracy in Tier 2 and Tier 3 Indian cities. © 2025 Elsevier Ltd