• 武高峰,王丽丽,武志宏,赵雪,赵文吉.石家庄市采暖季PM2.5碳组分昼夜污染特征及来源分析[J].环境科学学报,2020,40(7):2356-2364

  • 石家庄市采暖季PM2.5碳组分昼夜污染特征及来源分析
  • Pollution diurnal variation and source analysis of PM2.5 carbon components in heating season in Shijiazhuang City
  • 基金项目:国家重点研发计划(No.2018YFC0706004)
  • 作者
  • 单位
  • 武高峰
  • 首都师范大学资源环境与旅游学院, 北京 100048
  • 王丽丽
  • 首都师范大学资源环境与旅游学院, 北京 100048
  • 武志宏
  • 首都师范大学资源环境与旅游学院, 北京 100048
  • 赵雪
  • 首都师范大学资源环境与旅游学院, 北京 100048
  • 赵文吉
  • 首都师范大学资源环境与旅游学院, 北京 100048
  • 摘要:为探究2017年石家庄市采暖季昼夜PM2.5中碳组分的污染及来源特征,选取2017年11月30日-2018年1月22日时间段分别采集石家庄白天(8:00-20:00)、夜晚(20:00-翌日8:00)的PM2.5样品,分析PM2.5组分中OC和EC昼夜间的浓度变化特征、来源特性,SOC的估算及影响因素,并对石家庄市碳质气溶胶进行源解析和区域传输分析.结果表明,①采样期间白天PM2.5、OC和EC的平均质量浓度分别为(110.6±71.6)、(39.9±20.4)和(9.3±3.6)μg·m-3,夜间平均质量浓度分别为(128.5±75.3)、(64.7±36.5)和(13.6±6.0)μg·m-3,PM2.5、OC和EC质量浓度均呈现出夜间质量浓度高于白天的特征.②燃煤和机动车尾气排放在增加了一次有机碳(POC)和元素碳(EC)的本底质量浓度的同时,产生的CO、NO2、SO2等气体污染物又促进了光化学反应,两者协同作用下促进了SOC质量浓度的生成和积累.根据估算,SOC、SOC/OC值在夜间高于白天,白天较强的太阳辐射和光化学活性是SOC转化的主导因素,夜间气态有机前体物浓度是SOC转化的主导因素.③采样期间昼夜间OC、EC的相关性较好,其来源具有较好的同源性.大气PM2.5碳质气溶胶主要来自燃煤、汽油车和柴油车尾气排放混合源,夜间柴油车污染源对碳质气溶胶的贡献率较白天更为明显.④后向轨迹结果表明,石家庄市严重污染期间颗粒污染物浓度变化主要受到低空东北方向气团的影响,PM2.5以及OC、EC质量浓度的变化和周边地区的污染物输送有关.
  • Abstract:In order to study the pollution and source characteristics of carbon components in PM2.5 during the heating season in Shijiazhuang, PM2.5 samples were collected from November 30, 2017 to January 22, 2018 in the daytime (8:00-20:00) and at night (20:00-8:00 the next day) in Shijiazhuang, respectively. The variations and source features of the organic carbon (OC) and the element carbon (EC) concentrations in PM2.5, and the estimation and influencing factors of the secondary organic carbon (SOC) in PM2.5 during the day and the night were analyzed. Then the source analysis and regional transport analysis of carbon aerosols in Shijiazhuang were carried out. The results are listed as follows:① The average mass concentrations of PM2.5, OC and EC during daytime are (110.6±71.6), (39.9±20.4), and (9.3±3.6) μg·m-3 respectively, and the nighttime average mass concentrations are (128.5±75.3), (64.7±36.5) and (13.6±6.0) μg·m-3. The PM2.5, OC and EC mass concentrations measured in the night are all higher than that during the day. ② The emission of coal burning and vehicle not only increases the background mass concentration of primary organic carbon (POC) and EC, but also generates some gaseous pollutants such as CO, NO2 and SO2 which promote the photochemical reaction. As a result, SOC is generated and accumulated due to the synergistic effect between POC and EC, and the gaseous pollutants. It is estimated that the SOC,SOC/OC value is greater at night than in the daytime. During the day, strong solar radiation and photochemical activity are the driving forces of SOC conversion, while at night SOC conversion is mainly controlled by the concentration of gaseous organic precursors. ③ Over the whole sampling period, the correlation between OC and EC is well, both in the daytime and at night, suggesting the sources of OC and EC are similar. It is concluded that the atmospheric PM2.5 carbon component of Shijiazhuang comes from a mixed set of sources including gasoline vehicles, diesel vehicles and coal burning. The diesel vehicle contributes more to the generation of carbon aerosol at night than in the daytime. Meanwhile. ④ The results of backward trajectory show that over the heavy pollution days, the change in the concentration of particulate pollutants in Shijiazhuang is mainly affected by the low level northeast air flow, and the change of PM2.5, OC and EC mass concentration is affected by the pollutant transport in the surrounding areas.

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