Chemical characterization of particulate matter at Sinhagad, a high altitude station in Pune, India

Abstract

PM₁₀ and PM_2.5 samples were collected at Sinhagad, a rural high altitude location, nearby Pune, India, during Nov. 2008 to April 2009. The average concentrations of PM_10, PM_2.5 and PM_10-2.5 at Sinhagad were 35.8, 14.1 and 21.7 µg m^-3, respectively. The average ratio of PM_2.5/PM₁₀ (0.39) suggested that PM₁₀ at study area is dominated by primary particulate emissions by natural activities. In PM₁₀, anions and cations were contributed 33% and 67% whereas in PM_2.5 these were 43% and 57%. In both PM₁₀ and PM_2.5, contribution of marine components viz. Na⁺, Cl^- and Mg²⁺ were found to be 58% and 49%, respectively, reflecting Arabian sea is the major source of these components.  All the ionic components in PM₁₀ showed higher concentration in summer whereas in PM_2.5, secondary particles (SO₄^2-, NO₃^- and NH₄⁺) showed higher concentration in winter. The order of neutralization factor was found to be Ca²⁺ > Mg²⁺ > NH₄⁺ > K⁺ for PM₁₀ and Ca²⁺ > NH₄⁺ >Mg²⁺ > K⁺ for PM_2.5. During the sampling period, major contribution from marine sources was observed (43% for PM_2.5 and 53% for PM₁₀) followed by crustal sources (PM_2.5: 25% and PM₁₀: 30%) and anthropogenic sources (PM_2.5: 32% and PM₁₀:17%).