石家庄南郊黑碳气溶胶污染特征与来源分析

Pollution characteristics and source apportionment of black carbon aerosol in the south suburb of Shijiazhuang City

利用十波段黑碳仪实时监测石家庄南郊2018年9月-2019年7月大气中黑碳(Black Carbon,BC)质量浓度,并与同期CO、NO2、SO2质量浓度进行相关性分析,结合后向轨迹模型研究了该地区的BC质量浓度变化特征及潜在来源.结果表明,观测期间BC平均质量浓度为(4.35±3.59)μg·m-3,最大频数浓度法估算的BC本底质量浓度为1.0μg·m-3,不同季节BC平均质量浓度变化趋势为:冬季>秋季>春季>夏季.BC质量浓度日变化具有双峰特征,高峰时段为6:00-9:00和19:00-22:00.BC气溶胶■ngstr9m指数α的分析及BC与CO、NO2、SO2相关性分析表明,以化石燃料为能源的工业源和交通源对石家庄南郊BC的贡献占主导地位.后向轨迹分析表明,石家庄南郊各季节BC主要受东向、东南向河北省内气团(占比35.46%~48.40%)和西向、西北向途经内蒙古、陕西北部、山西中部气团(占比15.60%~23.19%)的影响.浓度权重轨迹分析表明,BC潜在源区主要集中在河北南部、山西中部和河南北部.

The Aethalometer with ten wavelengths was used to monitor the mass concentrations of atmospheric black carbon(BC) in real time in the south suburb of Shijiazhuang City from September 2018 to July 2019. The correlations between BC mass concentration and that of other pollutants(CO, NO2, and SO2) were analyzed. Combined with correlations results and HYSPLIT model in the same period, pollution characteristics and potential sources of BC were also investigated. The main results were as follows: the average mass concentration of BC during observation period was(4.35±3.59) μg·m-3, and the BC background concentration of 1.0 μg·m-3 was estimated by maximum frequency concentration method. The average mass concentration of BC in different seasons decreased as follows: winter> autumn> spring> summer. The diurnal variation of BC mass concentration had the characteristics of double peaks, which were observed at 6:00-9:00 and 19:00-22:00, respectively. According to ■ngstr9m index α and the correlations results, the contributions of industrial sources and transportation sources that use fossil fuels as energy sources to BC in the south suburb of Shijiazhuang City were dominant. Backward trajectory analysis showed that BC in each season was mainly affected by air masses from east and southeast of Hebei Province(accounting for 35.46%~48.40%) and air masses from west and northwest of Inner Mongolia, north Shaanxi and central Shanxi Province(accounting for 15.60%~23.19%). The concentration weighted trajectory(CWT) analysis revealed that the potential source areas of BC were mainly concentrated in the south of Hebei, central Shanxi and the north of Henan.