基于SPAMS的天津市夏季环境受体中颗粒物的混合状态及来源

天津位于京津冀区域,近年来面临的颗粒物污染问题受到广泛关注,研究其大气环境中颗粒物的化学组成及来源具有重要意义.为明确天津市夏季环境受体中颗粒物的混合状态及可能来源,于2017年7月利用单颗粒气溶胶质谱仪(single particle aerosol mass spectrometer,SPAMS)在津南区采集到成功电离有粒径及完整质谱信息颗粒209 887个,利用ART-2a对有质谱数据的颗粒按照质谱特征的相似性进行聚类共获得369个颗粒物类别,随后按照类别的化学组成(质谱谱图)的相似性进行人工合并获得19个颗粒物类别,包括:K-EC(0.20%)、K-EC-Sec(0.18%)、K-NO_3-PO_3(12.00%)、K-NO_3-SiO_3(2.98%)、K-Sec(0.16%)、EC(39.60%)、EC-Sec(3.46%)、EC-HM-Sec(3.93%)、HEC(1.49%)、HEC-Sec(1.38%)、OC-Amine-Sec(3.58%)、OC-Sec(0.36%)、OCEC-Sec(0.71%)、Dust-HEC(21.35%)、Dust-Sec(0.72%)、Cl-EC-NO_3(1.22%)、Na-Cl-NO_3(3.20%)、HM-Sec(2.58%)和PAH-Sec(0.90%)颗粒.得到的各个颗粒类别可归因于气溶胶颗粒的不同来源及不同的传输和反应过程,综合分析采集到的颗粒贡献源主要包括机动车排放源、生物质燃烧源、工业排放源、扬尘源、燃煤源和二次源等.其中K-EC、EC、HEC和Dust-HEC等颗粒主要来自一次源直接排放,K-Sec、OC-Amine-Sec、OC-Sec、OCEC-Sec和Na-Cl-NO_3等颗粒大都是一次源排放颗粒经历了不同程度的老化或与二次组分进行了不同程度的混合.

Mixed State and Sources of Fine Particulate Matter in the Summer in Tianjin City Based on Single Particle Aerosol Mass Spectrometer (SPAMS)

Tianjin is located in the Beijing-Tianjin-Hebei region. Recently, particulate matter pollution has received wide attention; therefore, studying the chemical composition and sources of particulate matter in the atmospheric environment is of great significance. To clarify the mixed state and possible sources of particulate matter in the summer ambient air in Tianjin, this study used single particle aerosol mass spectrometer (SPAMS) to collect 209887 samples. Particle size and complete spectrometry information were collected in July 2017. A total of 369 particle classes were obtained with respect to clustering particles with similarities in mass spectrometry characteristics using ART-2a. Then, according to the similarity in the chemical composition (mass spectrometry) of the categories, 19 particulate matter categories were artificially merged: K-EC (0.20%), K-EC-Sec (0.18%), K-NO₃-PO₃(12.00%), K-NO₃-SiO₃(2.98%), K-Sec (0.16%), EC (39.60%), EC-Sec (3.46%), EC-HM-Sec (3.93%), HEC (1.49%), HEC-Sec (1.38%), OC-Amine-Sec (3.58%), OC-Sec (0.36%), OCEC-Sec (0.71%), Dust-HEC (21.35%), Dust-Sec (0.72%), Cl-EC-NO₃(1.22%), Na-Cl-NO₃(3.20%), HM-Sec (2.58%), and PAH-Sec (0.90%). The obtained particle classes can be attributed to different sources of aerosol particles and different transmission and reaction processes. According to comprehensive analysis, the collected particle contribution sources were found to mainly include motor vehicle emission sources, biomass combustion sources, process sources, dust sources, and secondary processes. Among them, K-EC, EC, HEC, and Dust-HEC particles were mainly from direct emissions of primary sources. K-Sec, OC-Amine-Sec, OC-Sec, OCEC-Sec, Na-Cl-NO₃, and PAH-Sec particles mainly undergo different degrees of aging or mixed with secondary components.