Source Apportionment of Atmospheric PM 10 in Kanpur,India

Abstract

Atmospheric particle characteristics and concentrations are critical in source apportionment analysis. Particulate matter (PM) levels (in Indian conditions) suggest significant seasonal variability. There could be several reasons for this variability, including the variable meteorology, wind-driven dust, and atmospheric chemistry, which is responsible for formation of secondary particles. To clearly establish the cause–effect relationship of particulate levels and sources, PM₁₀ (n = 100) samples were collected at Kanpur, India, during 2000 to 2001. The collected samples were analyzed for metals and water-soluble ions, and results were utilized for factor analysis and source apportionment estimations with specific focus on secondary particles of fine mode. In the three seasons studied, two important PM₁₀ sources were soil-road dust (15–47%) and inorganic secondary particles like (NH₄) 2SO₄ and NH₄NO₃ (21–26%). Winter and monsoon conditions were conductive for formation of secondary particles due to moderate temperatures and high relative humidity. The role of ambient ammonia was vital in overall atmospheric chemistry of secondary particulate formation. It is thus clear that control of PM will require control of primary precursor gases like SO₂ and NO_x, including NH₃.