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  • Jul. 10, 2025

Arid Land Geography ›› 2025, Vol. 48 ›› Issue (4): 623-631.doi: 10.12118/j.issn.1000-6060.2024.358

• Climatology and Hydrology • Previous Articles     Next Articles

Characteristics and sources of water-soluble ion components in PM2.5 in the urban area of Urumqi City

WEI Jiang1(), ZHAO Caixin1, WANG Guohua2, ZHAO Lili2   

  1. 1. School of Public Administration, Xinjiang University of Finance and Economics, Urumqi 830012, Xinjiang, China
    2. Xinjiang Urumqi Ecological Environment Monitoring Station, Urumqi 830000, Xinjiang, China
  • Received:2024-06-07 Revised:2024-08-22 Online:2025-04-25 Published:2025-04-18

Abstract:

To investigate the water-soluble ion components and their sources in the major air pollutant PM2.5 in atmospheric environment of Urumqi City, Xinjiang, China, sampling points were established in the city center in 2023. A total of 164 samples were collected using membrane sampling, and the mass concentration of PM2.5 along with the concentration of various water-soluble ion components was measured following relevant testing standards. The sources of these components were also analyzed. The results indicate that: (1) The mass concentration of PM2.5 and the concentration of ion components are higher during the heating period than that in the non-heating period. (2) The total ion concentration during the heating period is 15 times of the non-heating period, accounting for 73.84% and 26.26% of the PM2.5 concentration, respectively. The anion-to-cation ratio (AE/CE) is 0.914 in the heating period and 0.600 in the non-heating period, indicating that the chemical properties of PM2.5 tend to be alkaline. (3) The annual average sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) are 0.43±0.30 and 0.15±0.13, respectively, suggesting a higher probability of secondary transformation pollution of gaseous precursors SO2 and NO2 during the heating period due to external meteorological conditions. NH+4 primarily exists as (NH4)2SO4 and NH4NO3 during the heating period, whereas in the non-heating period, it mainly exists as NH4NO3. (4) Principal component analysis indicates that during the heating period, the main sources of pollutants are secondary pollution, industrial production, and vehicle exhaust, followed by mineral dust and coal combustion, with a cumulative contribution rate of 80.24%. In the non-heating period, the primary sources are dust and industrial production, followed by secondary pollution and coal combustion, with a cumulative contribution rate of 86.34%. These findings demonstrate significant differences in the sources of water-soluble ions in PM2.5 between the heating and non-heating periods.

Key words: air pollution, ion concentration, vehicular exhaust emissions, principal component analysis