title: Spatial and seasonal variations of isoprene secondary organic aerosol in China: Significant impact of biomass burning during winter.
abstract: Isoprene is a substantial contributor to global secondary organic aerosol (SOA). The formation of isoprene SOA (SOAI) is highly influenced by anthropogenic emissions. Currently, there is rare information regarding SOAI in polluted regions. In this study, one-year concurrent observation of SOAI tracers was undertaken at 12 sites across China for the first time. The tracers formed from the HO2-channel exhibited higher concentrations at rural sites, while the tracer formed from the NO/NO2-channel showed higher levels at urban sites. 3-Methyltetrahydrofuran-3,4-diols exhibited linear correlations with their ring-opening products, C5-alkenetriols. And the slopes were steeper in the southern China than the northern China, indicating stronger ring-opening reactions there. The correlation analysis of SOAI tracers with the factor determining biogenic emission and the tracer of biomass burning (levoglucosan) implied that the high level of SOAI during summer was controlled by biogenic emission, while the unexpected increase of SOAI during winter was largely due to the elevated biomass burning emission. The estimated secondary organic carbon from isoprene (SOCI) exhibited the highest levels in Southwest China. The significant correlations of SOCI between paired sites implied the regional impact of SOAI in China. Our findings implicate that isoprene origins and SOAI formation are distinctive in polluted regions.
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors: Xiang
authors: X
authors: Ding
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors: Quan-Fu
authors: QF
authors: He
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors: Ru-Qin
authors: RQ
authors: Shen
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors: Qing-Qing
authors: QQ
authors: Yu
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors: Yu-Qing
authors: YQ
authors: Zhang
authors: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors: Jin-Yuan
authors: JY
authors: Xin
authors: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors: Tian-Xue
authors: TX
authors: Wen
authors: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors: Xin-Ming
authors: XM
authors: Wang
mesh_terms: D000336:Aerosols / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis*; D018533:Biomass; D002070:Butadienes / Q000032:analysis*; D002681:China; D004784:Environmental Monitoring; D045782:Hemiterpenes / Q000032:analysis*; D010420:Pentanes / Q000032:analysis*; D012621:Seasons
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene