Component Characteristics and Source Apportionment of Fine Particulate Matter (PM2.5) in Autumn and Winter in Shihezi City, China

Urumqi Meteorological Bureau, Urumqi Xinjiang Uygur Autonomous Region 830002, China

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Abstract

This study investigates the status of fine particulate matter (PM2.5) pollution in Shihezi City during the autumn and winter seasons of 2022 to 2023. Through thorough data analysis and rigorous research meth- odologies, it identifies the compositional characteristics and origins of PM2.5, with the intention of offering scientific backing for pollution management initiatives. The findings reveal that the primary components of environmental PM2.5 in Shihezi during these seasons include sulfate (SO4^2-) and nitrate (NO3-), with con- centrations measuring 31.31 µg/m3 and 28.69 µg/m3, respectively, which together make up 23.1% and 21.9% of the total particulate matter. Meanwhile, the concentration and share of ammonium (NH4+) are 19.62 µg/m3 and 15.14%, respectively, showing that they are somewhat lower than the measurements for SO4^2- and NO3-. This data indicates that the combined contributions from SO4^2-, NO3-, and NH4+ account for roughly 60%, emphasizing the notable role of secondary sources throughout the autumn and winter months. The pres- ence of SO4^2- is predominantly attributed to the secondary transformation of sulfur dioxide (SO2) arising from coal burning or from direct emissions associated with wet desulfurization techniques used in coal-fired boilers. The heightened levels of SO4^2- signify a substantial influence from coal combustion sources in Shihezi during these periods. Additionally, chloride (Cl-) concentrations attain 5.53 µg/m3, representing 4.25% of the overall PM2.5. The environmental NO3- principally originates from the secondary transfor- mation of nitrogen oxides (NOX) produced by industrial combustion, coal usage, and emissions from vehi- cles. The relatively high concentrations of NO3- observed in autumn and winter further highlight the im- portant role of coal burning and industrial practices within Shihezi. Moreover, the levels of aluminum (Al) and iron (Fe) significantly exceed those of other heavy metals, whereas the concentrations of zinc (Zn), arsenic (As), manganese (Mn), and copper (Cu) remain comparatively low.