Chemical Characterization and Health Risk Assessment of Particulate Matter near National Highway at Urban and Semi- Urban location of Northern India

The current study was an attempt to measure ambient air quality in term of PM 2.5 and associated heavy metals at two different sites near very busy crossing on National Highway with the help of fine particulate dust sampler. The Average mass concentration for PM 2.5 was 77.59μg/m 3 and 72.86μg/m 3 at semi-urban and urban sites. From the outcomes it was determined that the influence of PM 2.5 concentrations was greater at the Semi-urban than urban site. Concentrations of PM 2.5 have been compared with WHO, NAAQS and USEPA standards and was found to be exceeded than prescribed limit. Among analyzed heavy metals, Ca (11.652 µg/m 3 ), showed the highest concentration due to various construction materials, such as cement, brick lime and concrete as well as road dust, accompanied by Al (1.397µg/m 3 ) and Fe (0.973µg/m 3 ). The concentration of metals followed the trend Ca > Al > Fe > K > Pb > Mn> Co > Cr > Cu > Ni and Ca > Al > Fe > K > Mn > Pb> Cr > Ni > Cu > Co at both the sites. The Enrichment factor (EF) values concluded that Al, K, Fe, and Mn as less enriched (EF100). Hazard Quotient (HQ) for Al, Cr, Mn, and Ni is lower than the safe level (HQ= 1) whereas Excess Lifetime Cancer Risk (ELCR) of Cr (VI) and Ni exceeded the respective safer limit ELCR≥ 10 -6 indicating long-term exposure to particulate-bound toxic metals via inhalation could lead to cancer in approximately one child and four adults per million.