title: Spatiotemporal distribution and source apportionment of low molecular weight organic acids in wet precipitation at a coastal city, China.
abstract: To investigate the characteristics and sources of low molecular weight (LMW) organic acids in wet precipitation at a coastal city, Xiamen, a total of 313 rainwater samples were collected at seven different functional areas from September 2012 to August 2013. Spatiotemporal characteristics of LMW organic acids as well as pH and electrical conductivity were analyzed. Meanwhile, air mass clusters in different seasons and the positive matrix factorization (PMF) source apportion model were comprehensively used to identify the sources of organic acids. In conclusion, the volume-weighted mean (VWM) concentration of formic (3.20 μmol/L), acetic (1.84 μmol/L), lactic (0.44 μmol/L), and oxalic acid (0.53 μmol/L) were obtained, which jointly contributed to 4.33% of the total free acidity (TFA). At the same time, the highest wet deposition flux of LMW organic acids and contribution of that to TFA were achieved at the forest protection area during growing season in Xiamen. In addition, biogenic emissions (77.12%), sea salts (13.77%), regional agriculture activities (3.92%), soil emissions (2.56%), biomass burning (1.47%), and secondary aerosols (1.15%) were determined as the source of LMW organic acids. Besides, the dominancy of biomass burning via long-range transport in non-growing season (NGS) and the contribution of biogenic emission in growing season (GS) were recognized. Finally, the considerable influence of sea salts on the LMW organic acids (13.77%) in Xiamen was quantified, especially for oxalic acid.
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.|University of Chinese Academy of Sciences, Beijing, 100086, People's Republic of China.
authors.forename: Wenjiao
authors.initials: W
authors.lastname: Du
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.|University of Chinese Academy of Sciences, Beijing, 100086, People's Republic of China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Hong
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.
authors.forename: Yanting
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Deng
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China. jschen@iue.ac.cn.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China. jschen@iue.ac.cn.
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Chen
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Xu
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.
authors.forename: Youwei
authors.initials: Y
authors.lastname: Hong
authors.affiliation: Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China.|Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, People's Republic of China.
authors.forename: Hang
authors.initials: H
authors.lastname: Xiao
mesh_terms: D015258:Acid Rain / Q000032:analysis*; D000336:Aerosols / Q000032:analysis; D018533:Biomass; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D008970:Molecular Weight; D012621:Seasons; D012987:Soil
chemical_list: D015258:Acid Rain; D000336:Aerosols; D012987:Soil
keywords: Biomass burning; Coastal city; Low molecular weight organic acids; Source apportionment; Wet precipitation