Composition, seasonal variation, and sources of PM₁₀ from world heritage site Taj Mahal, Agra

Abstract

Air samples for PM(10) (dp < 10 μm in aerodynamic diameter) were collected from March 2007 to February 2008 near Taj Mahal-a historically sensitive site in Agra. Each sample collected on 20.3 × 25.4-cm Whatman quartz microfiber filter using respirable dust sampler was analyzed gravimetrically for mass concentrations and chemically for elements such as Na, Mg, Al, Si, S, Ca, Sc, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Cd, Ba, and Pb by inductively coupled plasma atomic emission spectroscopy and inorganic ions such as NH (4) (+) , K(+), SO (4) (2-) , NO (3) (-) , F(-), and Cl(-) by ion chromatograph. Annual average of PM(10) 155.47 ± 77.97 μg/m(3) was three times high the annual average NAAQ standard of 50 μg/m(3) for sensitive area. PM(10) as well as K(+), Cl(-), As, and Pb were higher in winter while crust elements and secondary aerosols were higher in summer. The average equivalent ratio of NH (4) (+) to sum up of SO (4) (2-) and NO (3) (-) was greater than unity which indicates high source strength of ammonia and alkaline nature of aerosols in Agra. Source apportionment of PM(10) was carried out by factor analysis using principal component analysis (varimax rotated factor matrix method) of SPSS. Five sources contributing to PM(10) were identified as crust material, vehicular emissions, industrial emissions, coal and biomass burning, and secondary aerosols.