Measurement of NH₃, NO, NO₂ and related particulates at urban sites of Indo Gangetic Plain (IGP) of India

Abstract

This study presents variability and concentration of ambient NH₃, NO and NO₂ along with particulate matter (PM₁₀) at urban sites of Chandigarh and Delhi of IGP of India (Dec 2010 - Mar 2011). Concentration of NH₃ was found as follows: Chandigarh, 0.72 - 22.81 (av 5.17 ± 0.92 μg m^-3); and Delhi, av 8.54 ± 0.72 μg m^-3. Concentration of ambient NO (av 13.13 ± 1.50 μg m^-3) and NO₂ (av 5.92 ± 0.38 μg m^-3) were recorded over Chandigarh. NH₄ + concentration were found as follows: Chandigarh, 2.60 - 4.39 (av 3.41 ± 0.78 μg m^-3); and Delhi, 6.61 - 14.6 (av 9.91 ± 3.77 μg m^-3). Concentration of NH₃ was significantly

correlated with NH₄ + at both of the locations (<i>r²</i>= 0.87 and <i>r² </i>= 0.96). NH₃/ NH₄ + ratios were: Delhi, 0.59 - 1.75 (av 0.86); and

Chandigarh, 0.28 - 5.19. A good correlation of SO₄ ^2- and NO₃ ^- with NH₄ ⁺ over Delhi indicates formation of aerosol. Similar correlations were recorded over Chandigarh.