Chemical Characterization and Health Risk Assessment of Particulate Matter Near National Highway at Urban and Semi-urban Locations of Northern India

Air pollution is one of the major concerns of India as it is the second leading risk factor, with pollutants being released faster than they can be absorbed and dispersed, contributing to one-quarter of the global disease burden. Both urban and semi-urban regions face pollution due to increased private transportation, resource exploration, industrial development, and improved living standards but studies have only focused on outdoor air pollution in urban areas, while the entire country of India is not merely urban, it also affects the nonurban areas just as much as the urban location. The current study was an attempt to measure ambient air quality in terms of PM2.5 and associated heavy metals (Al, Ca, Co, Cu, Cr, Fe, Mn, Pb, Ni, and K) collected from two different locations (semi-urban and urban) near very busy crossing on National Highway with the help of fine particulate dust sampler (APM-550) during the study period July and August 2020. From the outcomes, it was determined that the influence of PM2.5 concentrations was greater at the semi-urban than at urban sites. Concentrations of PM2.5 have been compared with World Health Organization, National Ambient Air Quality Standards, and United States Environmental Protection Agency (USEPA) standards and were found to be exceeded the prescribed limit. The correlation was done between the fine particulate concentrations and meteorological parameters which shows an inverse relation in both sites. Among analyzed heavy metals, Ca (11.65 µg/m3) showed the highest concentration due to various construction materials, such as cement, brick lime, and concrete as well as road dust, accompanied by Al (1.39 µg/m3) and Fe (0.97 µg/m3). The enrichment factor (EF) values concluded that Al, K, Fe, and Mn is less enriched (EF < 10), while Co and Pb had been classified as very highly enriched (EF > 100). Risk characterization for non-carcinogenic and carcinogenic effects was evaluated through ingestion, dermal contact, and inhalation pathway posed by heavy metals in fine particulate matter, the results showed that Co showed non-carcinogenic risk at both urban and semi-urban locations from different pathways (USEPA in Part A, Human health evaluation manual; Part E, Supplemental Guidance for dermal risk assessment; Part F, Supplemental Guidance for inhalation risk assessment 1. Part E Access available online—risk assessment guidance for superfund (RAGS): Part E|US EPA, Part F, Risk assessment guidance for superfund (RAGS): Part F|US EPA, 2011), whereas Ni from the different sites showed an insignificant health risk for both children and adults (HQ ≤ 1) while, Cr, Pb, and Co cause the highest carcinogenic as exceeding the benchmark limit of 1 × 10–6 as prescribed by USEPA (2011), but Ni was found to be safe at both locations.