Temporal variations in atmospheric particulate matter (PM) were studied in Bhagwanpur-a data-deficient area located along the foothills of the Himalayas. The concentrations of respirable suspended particulate matter (RSPM) and PM 0.4-10 µm (categorized into eight size fractions) were measured during winter and summer of 2014-2015. The RSPM concentration over a 24-h period was found to be 259.6 ± 52.6 µg/m 3 , which is 2.6 times greater than the permissible limit set by the Indian National

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... t Air Quality Standards. A significant difference (p < 0.05, t test) in RSPM with seasons was observed with winter maximum (284.6 ± 48.6 µg/m 3 ) and summer minimum (234.5 ± 44.8 µg/m 3 ). Size fractionated PM measurements revealed maximum concentration (36.4 ± 5.2 µg/m 3 ) in PM 9.0-10.0 µm, while least concentration was observed in PM 2.1-3.3 µm (16.8 ± 2.3 µg/m 3 ). Further, on quantification of 13 chemical species associated with RSPM, it was observed that mass concentration followed the trend of Ca > K > Mg > Al > Zn > Fe > Mn > Cr > Co > Ni > Cu > Pb > C d. Source apportionment through principal component analysis revealed the sources such as industrial, vehicular, and crustal. The excess cancer risk for Cr was about 2.7 times higher than the tolerance level (10 −4 ), while only Pb was below the safe limit (10 −6 ). However, total ECR for Cr, Cd, Pb, and Ni was about 3 times higher than the tolerance level. Three-day air mass back trajectory analysis reveals that emissions from biomass burning over the neighbouring regions adversely affect the air quality at the study site. The results of this study can be utilized toward the effective implementation of environmental regulations at the study site.