In situ measurement of PM_1 organic aerosol in Beijing winter using a high-resolution aerosol mass spectrometer  

作　　者：LIU Quan SUN Yang HU Bo LIU ZiRui AKIO Shimono WANG YueSi 

机构地区：[1]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]Shoreline Science Research,Inc.,Tokyo 192-0045,Japan

出　　处：《Chinese Science Bulletin》2012年第7期819-826,共8页

摘　　要：Organic aerosol (OA) is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of submicron aerosols were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer in the winter of 2010, with a high time resolution of 5 min. During this study, the mean OA mass concentration was 20.9±25.3 μg/m3, varying between 1.9 and 284.6 μg/m3. Elemental analysis showed that the average H/C, O/C and N/C (molar ratio) were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.37. The average mass-based size distributions of OA present a promi- nent accumulation mode peaking at approximately 450 nm. The prominent presence of ultrafine particles (Dva < 100 nm) was mainly from the fresh emissions of combustion sources. A Positive Matrix Factorisation (PMF) analysis of the organic mass spectral dataset differentiated the OA into three components, including hydrocarbon-like (HOA), cooking-related (COA), and oxygenated (OOA) organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively, of the total organic mass. The HOA and COA likely corresponded to primary organic aerosol (POA) associated with combustion-related and cooking emissions, respectively, and the OOA components corresponded to aged secondary organic aerosol (SOA).Organic aerosol （OA） is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of submicron aerosols were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer in the winter of 2010, with a high time resolution of 5 rain. Dur- ing this study, the mean OA mass concentration was 20.9＋25.3 gg/m3, varying between 1.9 and 284.6 gg/m3. Elemental analysis showed that the average H/C, O/C and N/C （molar ratio） were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio （mass ratio of organic matter to organic carbon） of 1.37. The average mass-based size distributions of OA present a promi- nent accumulation mode peaking at approximately 450 nm. The prominent presence of ultrafine particles （Dva 〈 100 rim） was mainly from the fresh emissions of combustion sources. A Positive Matrix Factorisation （PMF） analysis of the organic mass spec- tral dataset differentiated the OA into three components, including hydrocarbon-like （HOA）, cooking-related （COA）, and oxygen- ated （OOA） organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively, of the total organic mass. The HOA and COA likely corresponded to primary organic aerosol （POA） associated with combustion-related and cooking emis- sions, respectively, and the OOA components corresponded to aged secondary organic aerosol （SOA）.

关 键 词：气溶胶飞行时间质谱仪 高分辨率 现场测量 北京 二次有机气溶胶 平均质量 天使 大气细颗粒物 

分 类 号：TQ316.334[化学工程—高聚物工业] X831[环境科学与工程—环境工程]