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

Abstract

Particulate matter, PM₁₀and PM_2.5, samples were collected at Sinhagad, a high altitude location, near Pune, India during November 2008 - April 2009. <span style="mso-bidi-font-size: 11.0pt" lang="EN-GB">The average concentrations of PM₁₀, 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 contributed 33% and 67%, whereas in PM_2.5, these were 43% and 57%. <span style="mso-bidi-font-size:11.0pt" lang="EN-GB">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. Source categorization, i.e. marine, crustal and anthropogenic of chemical components of PM has been done. Sea salt and crustal fractions have been calculated by assuming entire Na and Ca from Sea and crust, respectively. The fraction of the chemical component, which remains after deducting the sea and crust fractions, has been considered as of anthropogenic origin. Major contribution observed was from marine sources [PM_2.5 (43%) and PM₁₀(53%)]; followed by crustal sources [<span style="mso-bidi-font-size:11.0pt" lang="EN-GB">PM_2.5 (25%) and PM₁₀ (30%)]; and then anthropogenic sources [(PM_2.5 (32%) and PM₁₀(17%)].

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