Abstract: This paper analyzed the watersoluble ionic components of TSP over Urumqi in 2009 based on the data of atmospheric total suspended particles (TSP) measured with ion chromatographers at 4 observation sites. The results are as follows: (1) The total ion concentration which was averaged with the values measured at three stations over Urumqi City was 151.28 μg/m³, and the total ion concentration at Baiyang Station was 40.83 μg/m³. The ratio of NO₃^-_/SO₄ ^2-at all the 4 stations was low, which revealed that the atmospheric pollution was mainly from the fixed pollution sources in Urumqi; (2) SO₄^2-, Ca²⁺, NO₃^- and NH₄⁺ levels were higher than the other ions of TSP in 2009. There were the significant seasonal variations of concentration of ions. All the concentrations of ions, especially that of SO₄^2-  and NO₃^-, were obviously increased in heating season; (3) Correlation analyses of all the ions were carried out, the results showed that the correlation coefficient between NH₄⁺ and SO₄^2-  was 0.828, and that between NH₄ ⁺and NO₃ ^-was 0.659, these revealed that ammonium compounds were dominated by ammonium sulfate and ammonium nitrate. The correlation coefficient between NO₃^- and SO₄^2-  was 0.973, which revealed that NO₃^- and SO₄^2- came mainly from sulfur dioxide and nitrogen oxides. There was a good correlation between crust elements Ca²⁺ and Mg²⁺, and their correlation coefficient was as high as 0.914, which revealed that the sources of these two crust elements were similar, and these elements came mainly from dust weather, road dust and construction dust.

Key words: atmospheric pollution, TSP, chemical composition, Urumqi