Physicochemical Characterization of Ambient Air Particulate Matter in Tabriz,Iran

Atmospheric particulate matter (PM) was measured concurrently from September, 2012, to June, 2013, at two sites, urban and industrial suburban, in Tabriz, Iran. The annual average concentration of total suspended particulates (TSP), PM₁₀, PM_2.5, and PM₁ at the urban site were 142.2 ± 76.3, 85.3 ± 43.9, 39 ± 19.1, and 28.4 ± 14.9 µg/m³ (mean ± SD), respectively. A total of 11 inorganic water-soluble ions in the TSP and PM₁₀ were identified by ion chromatography. In the urban site, concentrations of total water-soluble ions in TSP and PM₁₀ were 20.3 ± 20.8 and 16.0 ± 14.1 µg/m³, respectively. In this sampling site, secondary inorganic aerosols (i.e., Σ $ {text{SO}}_{4}^{2 - } $ , $ {text{NO}}_{3}^{ - } $ , and $ {text{NH}}_{4}^{ + } $ concentrations) were the main measured water-soluble ions, which collectively accounted for 13.9 % of TSP mass and 17.7 % of PM₁₀ mass. Correlations between $ {text{NH}}_{4}^{ + } $ with $ {text{NO}}_{3}^{ - } $ and $ {text{SO}}_{4}^{2 - } $ indicated that the main source of these ions in PM was the combustion processes. Results of elemental analysis in the industrial suburban site showed that natural sources were the dominant source of PM in this area.