Source apportionment studies on particulate matter (PM_(10) and PM_(2.5)) in ambient air of urban Mangalore, India

摘要

Particulate matter (PM10and PM2.5) samples were collected from six sites in urban Mangalore and the mass concentrations for PM10and PM2.5were measured using gravimetric technique. The measurements were found to exceed the national ambient air quality standards (NAAQS) limits, with the highest concentration of 231.5 μg/m3for PM10particles at Town hall and 120.3 μg/m3for PM2.5particles at KMC Attavar. The elemental analysis using inductively coupled plasma optical emission spectrophotometer (ICPOES) revealed twelve different elements (As, Ba, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sr and Zn) for PM10particles and nine different elements (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) for PM2.5particles. Similarly, ionic composition of these samples measured by ion chromatography (IC) divulged nine different ions (F−, Cl−, NO3−, PO43−, SO42−, Na+, K+, Mg2+and Ca2+) for PM10particles and ten different ions (F−, Cl−, NO3−, PO43−, SO42−, Na+, NH4+, K+, Mg2+and Ca2+) for PM2.5particles. The source apportionment study of PM10and PM2.5for urban Mangalore in accordance with these six sample sites using chemical mass balance model (CMBv8.2) revealed nine and twelve predominant contributors for both PM10and PM2.5, respectively. The highest contributor of PM10was found to be paved road dust followed by diesel and gasoline vehicle emissions. Correspondingly, PM2.5was found to be contributed mainly from two-wheeler vehicle emissions followed by four-wheeler and heavy vehicle emissions (diesel vehicles). The current study depicts that the PM10and PM2.5in ambient air of Mangalore region has 70% of its contribution from vehicular emissions (both exhaust and non-exhaust).