Characterization of Gaseous Pollutants and Water-Soluble Inorganic Ions in PM2.5 during Summer Time at an Urban Site of North India

Abstract

AbstractGaseous toxic air pollutants are normally associated with acute short-term and chronic long-term health effects, and hence measurement of these pollutants is essential on a daily basis to understand the science of their occurrences. In this study, gaseous O3, SO2, NO2, NH3, HNO2, HNO3, and HCl and water-soluble inorganic ions (Na+, K+, Ca2+, Mg2+, NH4+, NO3−, SO42−, and Cl−) in PM2.5 were measured during a summer in Kanpur, India, using an annular denuder technique on a time resolution of 12 h. The denuder technique revealed that evaporation losses of NH4+, Cl−, and NO3− from a Teflon filter and trapped in nylon filters were temperature sensitive. The evaporation losses were 17.8±8.7%, 29.5±19.3%, and 37.1±25.9% during daytime, and 10.2±6.4%, 17.7±10.1%, and 19.3±12.2% during nighttime for NH4+, Cl−, and NO3−, respectively. Overall, 24 h average concentrations of O3, SO2, NO2, NH3, HNO2, HNO3, and HCl were 49.6, 8.6, 34.2, 21.5, 3.6, 9.8, and 1.4 μgm−3, respectively; and 2.1, 1.5, 2.9, 1.1, 13.1,...