To investigate the causes and sources of atmospheric fine particulate matter (PM_2.5) pollution in the core area of the Ili River Valley in winter, environmental air particles were collected at 6 sampling sites in the core area, including Yining City and its surrounding counties from December 27, 2021 to January 12, 2022. A total of 58 components, including inorganic elements, water-soluble ions, and carbon components, were analyzed, and positive matrix factorization (PMF) was employed for source apportionment. The results showed that the mean concentration of PM_2.5 during the sampling period was 83±35 μg/m³. Three monitoring sites in Yining City showed the highest pollution levels, followed by Huocheng County. The concentration of SO₄²⁻ in PM_2.5 was the highest (14.1 μg/m³), followed by NO₃⁻ (10.5 μg/m³), NH₄⁺ (8.2 μg/m³), and Cl⁻ (1.6 μg/m³), indicating that coal combustion contributed significantly to pollution in winter. The concentrations of SO₄²⁻ (16.5 μg/m³), NO₃⁻ (11.8 μg/m³), and NH₄⁺ (9.5 μg/m³) reported by Yining City's Ecological Environment Bureau were significantly higher than those at other sites. Sulfur oxidation rate (SOR) and nitrogen oxidation rate (NOR) during air pollution were significantly higher than those in clean days, indicating a strong secondary transformation process. The source apportionment results showed that secondary particles had the highest contribution rate (40%), followed by biomass burning (24%), dust sources (14%), coal combustion (11%), industrial sources (6%), and vehicle sources (4%). Compared to clean days, the contribution rate of secondary particles significantly increased during air pollution, with a 27% increase in the contribution rate, mainly due to the accumulation of precursor concentrations in polluted weather conditions and the favorable conditions for the formation of secondary particles in high humidity. The contribution rate of secondary particles to PM_2.5 in the core area of the Ili River Valley was slightly higher than that in other Chinese cities. The contribution rate of biomass burning sources was higher. Therefore, local control measures are needed to strengthen regulation of local coal combustion, vehicle sources, and biomass burning sources.

为研究伊犁河谷核心区冬季大气细颗粒物PM_2.5污染成因和来源, 于2021年12月27 日—2022年1月12日在伊犁河谷核心区布设6个采样点, 采集环境空气颗粒物, 对无机元素、水溶性离子和碳组分等58种组分进行分析, 并使用正定矩阵因子分解模型PMF进行来源解析。结果表明, 采样期间PM_2.5的浓度均值为83±35 μg/m³, 其中伊宁市3个站点污染较重, 其次是霍城县。PM_2.5中以 SO₄²⁻的质量浓度为最高(14.1 μg/m³), 其次为NO₃⁻ (10.5 μg/m³)和NH₄⁺ (8.2 μg/m³), Cl⁻浓度也相对较高(1.6 μg/m³), 反映冬季燃煤源的重要贡献。伊宁市生态环境局站点SO₄²⁻ (16.5 μg/m³)、NO₃⁻ (11.8 μg/m³)和NH₄⁺ (9.5 μg/m³)的浓度高于其他站点。污染天硫氧化率(SOR)和氮氧化率(NOR)明显高于清洁天, 表明污染天二次转化作用明显增强。来源解析结果表明, 二次颗粒物的分担率最高(40%), 其次是生物质燃烧源(24%), 再次为扬尘源(14%)和燃煤源(11%), 工业源(6%)和机动车尾气源(4%)的分担率相对较低。与清洁天相比, 污染天二次颗粒物的贡献明显增加(增加 27%), 主要与污染天气态前体物浓度累积以及高湿条件有利于二次颗粒物生成有关。伊犁河谷核心区二次颗粒物对PM_2.5的分担率稍高于国内其他城市, 且生物质燃烧源的分担率较高, 需要加强当地电力行业、民用散煤以及生物质燃烧源的管控。