徐州市供暖期空气污染特征及来源分析

徐州市大气污染物浓度近年来下降明显，但供暖期的大气污染问题依然较为严重，研究供暖期空气污染特征及污染来源对于大气污染预警和防控具有重要作用。采用地面监测、遥感卫星监测、PM_2.5组分分析、潜在源贡献因子法(PSCF)以及浓度权重轨迹分析(CWT)等方法，对徐州市2016—2020年5个供暖期的空气污染特征进行了分析，并对供暖期PM_2.5来源进行了解析。结果表明：徐州市空气质量近年来有较大好转，但供暖期污染物浓度明显高于非供暖期。供暖对PM_2.5浓度影响较大，供暖期PM_2.5浓度较供暖前后升高40%~71%。供暖期Cl⁻、NO₃ ⁻、SO₄ ²⁻和NH₄ ⁺浓度明显高于供暖前后，说明供暖期NH₄ ⁺与NO₃ ⁻、SO₄ ²⁻、Cl⁻有高度相关性。PM_2.5来源中燃煤源、工业源贡献占比供暖期分别较供暖后高出9.9%和13.9%，供暖期间的SOR、NOR明显大于非供暖期，SO₂和NO_x的二次转化效率明显升高。轨迹分析表明，供暖期影响徐州市的潜在源区主要分布在徐州市周边及河北省，PM_2.5浓度大于75 μg/m³的主要贡献区集中在山东省、河南省、安徽省北部和河北省南部。

Characteristics and sources apportionment of air pollution during heating period in Xuzhou

The concentrations of air pollutants in Xuzhou have decreased significantly in recent years. However, the problem of air pollution during the heating periods is still serious. Studying the characteristics and sources of air pollution during the heating periods plays an important role in the early warning and prevention and control of air pollution. A set of approaches, such as ground monitoring, remote sensing satellite monitoring, PM2.5 composition analysis, potential source contribution factor method (PSCF) and concentration-weighted trajectory analysis (CWT), were comprehensively adopted. The air pollution characteristics of Xuzhou in five heating periods from 2016 to 2020 were analyzed, and the sources of PM2.5 in the heating periods were analyzed. The results showed that the air quality in Xuzhou had significantly improved in recent years, but the concentrations of most air pollutants during the heating periods were significantly higher than that in the non-heating periods. The heating had a great impact on the concentration of PM2.5, and during the heating periods, the concentration of PM2.5 increased by 40%-71% compared with those before and after the heating periods. The concentrations of Cl−, NO3 −, SO4 2−, and NH4 + in the heating periods were significantly higher than those before and after the heating periods, indicating that the concentration of NH4 + had a strong correlation with NO3 −, SO4 2− and Cl− during the heating periods. The contribution of coal combustion and industrial emission to PM2.5 during the heating periods was 9.9% and 13.9%, respectively, higher than that after the heating periods, the SOR and NOR during the heating periods were significantly higher than those in non-heating periods, and the secondary conversion efficiency of SO2 and NOx increased significantly. The trajectory analysis indicated that the potential source areas contributed to Xuzhou during the heating periods were mainly distributed in Hebei Province and the areas neighboring Xuzhou, and the main contributing areas with PM2.5 concentration higher than 75 µg/m3 were from Shandong, Henan, northern Anhui, and southern Hebei.