2015世界互联网大会期间嘉兴市大气细颗粒物污染特征及来源研究——以单颗粒气溶胶质谱技术为例

基于单颗粒气溶胶质谱技术,于2015年12月12—23日互联网大会期间开展了嘉兴市细颗粒物污染特征和来源研究.结果显示,观测期间共捕捉到5次不同的污染过程,分别为:管控期的区域输送(P1)-清洁天(P2)-本地排放(P3)过程,以及管控后的污染反弹(P4)-重污染程(P5)过程.污染期间(P1、P5),硝酸盐含量及比例均有显著增加,并且增加的主要是老化的硝酸盐颗粒,表明硝酸盐的二次转化对长三角地区高浓度细颗粒物形成具有重要影响.受管控措施和南下的强冷空气影响,会议期间,除有机碳和生物质燃烧组分外,PM_(2.5)质量浓度及其它各组分浓度均有不同程度的下降.管控措施解除后(P5),受区域输送和本地污染物积累共同作用,颗粒物浓度开始反弹并持续升高,硝酸盐和EC组分均有明显增加,并且呈现出早、晚高峰值.源解析结果显示,P5期间颗粒物浓度反弹与机动车尾气排放密切相关.研究表明,实施管控措施对降低机动车尾气排放和PM_(2.5)质量浓度、改善环境空气质量等效果显著.

Pollution characteristics and source apportionment of fine particles in Jiaxing City during the period of the Second World Internet Conference: A case study by single-particle mass spectrometry

The Single Particle Aerosol Mass Spectrometry (SPAMS) was employed to analyze chemical components and source apportionment of fine particles during the period of the Second World Internet Conference (WIC) (12^th to 23^rd Dec., 2015)in Jiaxing City, Zhejiang Province. A five-stage episode, long range transport (P1)-cleaning day (P2)-local emission (P3)-pollution rising (P4)-heavy pollution (P5), was observed during this WIC observation. Aged nitrate concentration increased significantly during P1 and P5, indicating secondary chemical transformation made a great contribution to the formation of haze in the Yangtze River Delta (YRD). Due to the contingent pollution control policies and strong cold air invasion from the Northern China, chemical components concentration of fine particles except those of organic carbon (OC) and biomass burning decreased dramatically during the conference held. After the termination of contingent pollution control policies, concentration of fine particles dominated by nitrate and elemental carbon (EC) increased significantly with morning and evening peaks as a result of vehicle emissions. It was proven that implementation of pollution control policies were effective and critical for improving air quality in the YRD during the WIC.