title: Characterization and source apportionment of volatile organic compounds based on 1-year of observational data in Tianjin, China.
abstract: From November 2014 to October 2015, the concentrations of volatile organic compounds (VOCs), O3and NOx were simultaneously monitored by using online instruments at the air monitoring station belonged to Tianjin Environmental Protection Bureau (TEPB). The results indicated that VOCs concentrations were higher in autumn and lower in spring, while O3concentrations were higher in summer, and lower in winter. The diurnal variations of VOCs and NOx (NO2plus NO) showed opposite tendency comparing to that of O3. The concentrations of alkanes were higher (the average of 18.2 ppbv) than that of aromatics (5.3 ppbv) and alkenes (5.2 ppbv), however, the alkenes and aromatics made larger contributions to ozone because of their high reactivity. Tianjin belonged to the VOC-limited region during most of seasons (except summer) according to the VOC/NOx ratios (the 8:1 threshold). The automobile exhaust, industrial emission, liquefied petroleum gas/natural gas (LPG/NG), combustion, gasoline evaporation, internal combustion engine emission and solvent usage were identified as major sources of VOCs by Positive Matrix Factorization (PMF) model in Tianjin, and the contributions to VOCs for the entire year were 23.1%, 19.9%, 18.6%, 10.6%, 8.7%, 5.4% and 4.7%, respectively. The conditional probability function (CPF) analysis indicated that the contributing directions of automobile exhaust and industrial emission were mainly affected by source distributions, and that of other sources might be mainly affected by wind direction. The backward trajectory analysis indicated that the trajectory of air mass originated from Mongolia, which reflected the features of large-scale and long-distance air transport, and that of beginning in Jiangsu, Shandong and Tianjin, which showed the features of small-scale and short-distance. Tianjin, Beijing, Hebei and Northwest of Shandong were identified as major potential source-areas of VOCs by using potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models.
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
authors: Baoshuang
authors: B
authors: Liu
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
authors: Danni
authors: D
authors: Liang
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
authors: Jiamei
authors: J
authors: Yang
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
authors: Qili
authors: Q
authors: Dai
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China. Electronic address: bixh@nankai.edu.cn.
authors: Xiaohui
authors: X
authors: Bi
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
authors: Yinchang
authors: Y
authors: Feng
authors: Tianjin Environmental Monitoring Center, Tianjin, 300191, China.
authors: Jie
authors: J
authors: Yuan
authors: Tianjin Environmental Monitoring Center, Tianjin, 300191, China.
authors: Zhimei
authors: Z
authors: Xiao
authors: State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
authors: Yufen
authors: Y
authors: Zhang
authors: Tianjin Environmental Monitoring Center, Tianjin, 300191, China.
authors: Hong
authors: H
authors: Xu
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000473:Alkanes / Q000032:analysis; D000475:Alkenes / Q000032:analysis; D002681:China; D004784:Environmental Monitoring / Q000379:methods*; D005579:Fossil Fuels; D006841:Hydrocarbons, Aromatic / Q000032:analysis; D007221:Industry; D008986:Mongolia; D009589:Nitrogen Oxides / Q000032:analysis; D010126:Ozone / Q000032:analysis*; D012621:Seasons; D012997:Solvents; D001335:Vehicle Emissions / Q000032:analysis; D055549:Volatile Organic Compounds / Q000032:analysis*; D014919:Wind
chemical_list: D000393:Air Pollutants; D000473:Alkanes; D000475:Alkenes; D005579:Fossil Fuels; D006841:Hydrocarbons, Aromatic; D009589:Nitrogen Oxides; D012997:Solvents; D001335:Vehicle Emissions; D055549:Volatile Organic Compounds; D010126:Ozone
keywords: Ozone; Potential source area; Source apportionment; VOCs