Mass, composition, and sources of particulate matter in residential and traffic sites of an urban environment.

Present study aims to assess the mass, composition, and sources of PM and PM (particulate matter having aerodynamic diameter less than or equal to 10 and 2.5 µm aerodynamic diameter, respectively) in Vellore city. Seasonal samples collected in traffic and residential sites were analyzed for ions, elements, organic carbon (OC), and elemental carbon (EC). Source apportionment of PM and PM is carried out using Chemical Mass Balance, Unmix, Positive Matrix Factorization and Principal Component Analysis receptor models. Results showed that traffic site had higher annual concentration (PM = 62 ± 32 and PM = 112 ± 23 µg m) when compared to residential site (PM = 54 ± 22 and PM = 98 ± 20 µg m). Al, Ca, Fe, K, and Mg known to have crustal origin dominated the element composition irrespective of PM size and sampling site. Among ions, SO accounted highest in both sites with an average of 70 and 60% to PM and PM ionic mass. Elemental carbon contribution to PM mass was found highest in traffic site (PM = 17 to 23% and PM = 8 to 10%) than residential site (PM = 9 to 17% and PM = 4 to 8%). Elements, ions, OC, and EC accounted 12, 28, 34, and 16% of PM mass and 12, 21, 20, and 8% of PM mass, respectively. Different sources identified by the receptor models are resuspended road dust, crustal material, secondary aerosol, traffic, non-exhaust vehicular emissions, secondary nitrate, construction, cooking, and biomass burning. Since Vellore is aspiring to be a smart city, this study can help the policymakers in effectively curbing PM.