Abstract：Continuous online VOCs observation was carried out at urban sites in Shenzhen during the active photochemical reaction season from June to August 2022 (summer). The photochemical loss VOCs were evaluated based on the measured VOCs concentration using the photochemical age parametric method to obtain the initial VOCs concentration. The sources of initial VOCs were identified by the characteristic species ratio analysis method and Positive matrix factor model (PMF). The concentrations of photochemical consumption VOCs accounted for total VOCs (TVOCs) concentrations as follows: olefin (53.5%), oxygenated volatile organic compounds (OVOCs)(30.8%), alkane (10.9%), aromatic hydrocarbon (4.7%), acetylene (0.2%). Alkanes are dominant compounds in both initial and measured TVOCs concentration, but their photochemical loss ozone generating potential (OFP) is only 1.2×10-9, which is much lower than that of olefin (47.8×10-9), OVOCs(15.8×10-9) and aromatic hydrocarbons (4.7×10-9), suggesting that olefin is a key species for ozone pollution control. In this study, six major emission sources were obtained by PMF based on measured and initial VOCs concentrations respectively(Initial-PMF, Measured-PMF): industrial processes (0.91×10-9, 0.87×10-9), solvent use (2.75×10-9, 1.84×10-9), vehicle exhaust (3.49×10-9, 2.01×10-9), gasoline volatile (3.2×10-9, 2.62×10-9), natural source (0.74×10-9, 0.56×10-9), combustion source (2.35×10-9,1.16×10-9). It is suggested that PMF results are significantly affected by photochemical reactions, and the initial value of VOCs rather than the measured value should be considered in source apportionment, otherwise the exhaust gas and natural sources dominated by olefin will be significantly underestimated.
[1] Xue W H, Zhang J, Zhong C, et al. Satellite-derived spatiotemporal PM2.5 concentrations and variations from 2006 to 2017 in China [J]. Science of the Total Environment, 2020,712:134577. [2] Han X K, Guo Q J, Lang Y C, et al. Seasonal and long-term trends of sulfate, nitrate, and ammonium in PM2.5in Beijing: Implication for air pollution control [J]. Environmental Science and Pollution Research International, 2020,27(19):23730-23741. [3] Mirowsky J E, Carraway M S, Dhingra R, et al. Ozone exposure is associated with acute changes in inflammation, fibrinolysis, and endothelial cell function in coronary artery disease patients [J]. Environ Health, 2017,16(1):126. [4] 列淦文,叶龙华,薛立.臭氧胁迫对植物主要生理功能的影响[J]. 生态学报, 2014,34(2):294-306. Lie G W, Ye L H, Xue L. Effects of ozone stress on major plant physiological functions [J]. Acta Ecologica Sinica, 2014,34(2):294- 306. [5] Shao M, Zhang Y, Zeng L, et al. Ground-level ozone in the Pearl River Delta and the roles of VOC and NOx in its production [J]. Journal of Environmental Management, 2009,90(1):512-518. [6] Sun W, Shao M, Granier C, et al. Long-term trends of anthropogenic SO2, NOx, CO, and NMVOCs emissions in China [J]. Earth's Future, 2018,6(8):1112-1133. [7] 李佳佳.典型工业园挥发性有机物的三维空间分布特征及其健康风险评估研究[D]. 广州:广东工业大学, 2022. Li J J. Study on the three-dimensional spatial distribution characteristics and health risk assessment of volatile organic compounds in typical industrial parks [D]. Guangzhou: Guangdong University of Technology, 2022. [8] 张月,夏士勇,魏成波,等.深圳工业区夏秋季大气挥发性有机物来源研究[J]. 中国环境科学, 2023,43(8):3857-3866. Zhang Y, Xia S Y, Wei C B, et al. Source apportionment of atmospheric volatile organic compounds in summer and autumn in Shenzhen industrial area [J]. China Environmental Science, 2023, 43(8):3857-3866. [9] Xia L, Cai C, Zhu B, et al. Source apportionment of VOCs in a suburb of Nanjing, China, in autumn and winter [J]. Journal of Atmospheric Chemistry, 2014,71:175-193. [10] 李悦,邵敏,陆思华.城市大气中挥发性有机化合物监测技术进展[J]. 中国环境监测, 2015,31(4):1-7. Li Y, Shao M, Lu S H. Review on Technologies of ambient volatile organic compounds measurement [J]. Environmental Monitoring in China, 2015,31(4):1-7. [11] Atkinson R. Gas-phase tropospheric chemistry of organic compounds: a review [J]. Atmospheric Environment, 2003,37(2):197-219. [12] Gao Y, Li M, Wan X, et al. Important contributions of alkenes and aromatics to VOCs emissions, chemistry and secondary pollutants formation at an industrial site of central eastern China [J]. Atmospheric Environment. 2021,244:117927. [13] Zhan J, Feng Z, Liu P, et al. Ozone and SOA formation potential based on photochemical loss of VOCs during the Beijing summer [J]. Environment Pollution, 2021,285:117-444. [14] Mckeen S A, Liu S C. Hydrocarbon ratios and photochemical history of air masses [J]. Geophysical Research Letters. 1993,20(21):2363- 2366. [15] Liu B, Yang Y, Yang T, et al. Effect of photochemical losses of ambient volatile organic compounds on their source apportionment [J]. Environment International. 2023,172:107766. [16] Wu Y, Fan X, Liu Y, et al. Source apportionment of VOCs based on photochemical loss in summer at a suburban site in Beijing [J]. Atmospheric Environment. 2023,293:119459. [17] Zheng B, Tong D, Li M, et al. Trends in China's anthropogenic emissions since 2010 as the consequence of clean air actions [J]. Atmospheric Chemistry and Physics, 2018,18(19):14095-14111. [18] Yang Y, Liu B, Hua J, et al. Global review of source apportionment of volatile organic compounds based on highly time-resolved data from 2015 to 2021[J]. Environment International. 2022,165:107330. [19] Stroud C A, Roberts J M, Goldan P D, et al. Isoprene and its oxidation products, methacrolein and methylvinyl ketone, at an urban forested site during the 1999 Southern Oxidants Study [J]. Journal of Geophysical Research. 2001,106(D8):8035-8046. [20] Carter W. Reactivity estimates for selected consumer product compounds [R]. California: Air Resources Board, 2008. [21] Tian Y, Zhang Y, Liang Y, et al. PM2.5 source apportionment during severe haze episodes in a Chinese megacity based on a 5-month period by using hourly species measurements: Explore how to better conduct PMF during haze episodes [J]. Atmospheric Environment, 2020,224:117364. [22] Wang G, Cheng S, Wei W, et al. Characteristics and source apportionment of VOCs in the suburban area of Beijing, China [J]. Atmospheric Pollution Research, 2016,7(4):711-724. [23] Liu, Y, Song, M, Liu, X, et al. Characterization and sources of volatile organic compounds (VOCs) and their related changes during ozone pollution days in 2016 in Beijing, China [J]. Environment Pollution, 2020,257:113-599. [24] Hang Q, Wang Y H, Zhang R X, et al. Chemical production of oxygenated volatile organic compounds strongly enhances boundary-layer oxidation chemistry and ozone production [J]. Environmental Science & Technology, 2021,55:13718-13727. [25] Huang X F, Wang C, Zhu B, et al. Exploration of sources of OVOCs in various atmospheres in southern China [J]. Environment Pollution, 2019,249:831-842. [26] Qu H, Wang Y, Zhang R, et al. Chemical production of oxygenated volatile organic compounds strongly enhances boundary-layer oxidation chemistry and ozone production [J]. Environmental Science & Technology, 2021,55(20):13718-13727. [27] Yuan B, Chen W, Shao M, et al. Measurements of ambient hydrocarbons and carbonyls in the Pearl River Delta (PRD), China [J]. Atmospheric Research. 2012,116:93-104. [28] Sun J, Wu F, Hu B, et al. VOC characteristics, emissions and contributions to SOA formation during hazy episodes [J]. Atmospheric Environment. 2016,141:560-570. [29] Stroud C A, Roberts J M, Goldan P D, et al. Isoprene and its oxidation products, methacrolein and methylvinyl ketone, at an urban forested site during the 1999 Southern Oxidants Study [J]. Journal of Geophysical Research. 2001,106(D8):8035-8046. [30] Wu Y, Fan X, Liu Y, et al. Source apportionment of VOCs based on photochemical loss in summer at a suburban site in Beijing [J]. Atmospheric Environment. 2023,293:119459. [31] Chen W T, Shao M, Lu S H, et al. Understanding primary and secondary sources of ambient carbonyl compounds in Beijing using the PMF model [J]. Atmospheric Chemistry and Physics. 2014,14(6): 3047-3062. [32] Song C, Liu Y, Sun L, et al. Emissions of volatile organic compounds (VOCs) from gasoline- and liquified natural gas (LNG)-fueled vehicles in tunnel studies [J]. Atmospheric Environment, 2020,234: 117626. [33] Hong Z, Li M, Wang H, et al. Characteristics of atmospheric volatile organic compounds (VOCs) at a mountainous forest site and two urban sites in the southeast of China [J]. Science of the Total Environment, 2019,657:1491-1500. [34] Lai C H, Chang C C, Wang C H, et al. Emissions of liquefied petroleum gas (LPG) from motor vehicles [J]. Atmospheric Environment, 2009,43(7):1456-1463. [35] Huang A, Yin S, Yuan M, et al. Characteristics, source analysis and chemical reactivity of ambient VOCs in a heavily polluted city of central China [J]. Atmospheric Pollution Research, 2022,13(4): 101390. [36] Liu B, Liang D, Yang J, et al. Characterization and source apportionment of volatile organic compounds based on 1-year of observational data in Tianjin, China [J]. Environment Pollution, 2016, 218:757-769. [37] Hui L, Liu X, Tan Q, et al. VOC characteristics, chemical reactivity and sources in urban Wuhan, central China [J]. Atmospheric Environment, 2020,224:117340. [38] Hui L, Liu X, Tan Q, et al. Characteristics, source apportionment and contribution of VOCs to ozone formation in Wuhan, Central China [J]. Atmospheric Environment, 2018,192:55-71. [39] Barletta B, Meinardi S, Simpson I J, et al. Ambient mixing ratios of nonmethane hydrocarbons (NMHCs) in two major urban centers of the Pearl River Delta (PRD) region: Guangzhou and Dongguan [J]. Atmospheric Environment, 2008,42(18):4393-4408. [40] Yurdakul S, Civan M, Kuntasal Ö, et al. Temporal variations of VOC concentrations in Bursa atmosphere [J]. Atmospheric Pollution Research, 2018,9(2):189-206. [41] Zheng H, Kong S, Chen N, et al. Source apportionment of volatile organic compounds: Implications to reactivity, ozone formation, and secondary organic aerosol potential [J]. Atmospheric Research, 2021, 249:105344. [42] 于广河,朱乔,夏士勇,等.深圳市典型工业行业VOCs排放谱特征研究[J]. 环境科学与技术, 2018,41(S1):232-236. Yu G H, Zhu Q, Xia S Y, et al. Emission characteristics of Volatile Organic Compounds (VOCs) source profile from typical industries in Shenzhen [J]. Environmental Science & Technology, 2018,41(S1): 232-236. [43] 黄沛荣,朱波,张月,等.PM2.5与O3协同控制视角下深圳市工业VOCs源谱特征[J]. 中国环境科学, 2022,42(8):3473-3482. Huang P R, Zhu B, Zhang Y, et al. Source profile characteristics of industrial VOCs in Shenzhen from the perspective of PM2.5 and O3 synergistic control [J]. China Environmental Science, 2022,42(8): 3473-3482. [44] 林理量.深圳市不同功能区夏秋季挥发性有机物污染特征研究[D]. 北京:北京大学, 2021. Lin L L. Characteristics of volatile organic compounds in different functional areas of Shenzhen in Summer and Autumn [D]. Beijing: Peking University, 2021. [45] Zheng J Y, Yu Y F, Mo Z W, et al. Industrial sector-based volatile organic compound (VOC) source profiles measured in manufacturing facilities in the Pearl River Delta, China [J]. Science of the Total Environment, 2013,456-457:127-136. [46] Wu R R, Li J, Hao Y F, et al. Evolution process and sources of ambient volatile organic compounds during a severe haze event in Beijing, China [J]. The Science of the Total Environment, 2016,560-561: 62-72. [47] Kountouriotis A, Aleiferis P G, Charalambides A G. Numerical investigation of VOC levels in the area of petrol stations [J]. Science of the Total Environment, 2014,470-471:1205-1224. [48] 王怡然.基于光化学损失校正的挥发性有机化合物(VOCs)来源解析方法优化及应用[D]. 广州:华南理工大学, 2020. Wang Y R. Optimization and application of volatile organic compounds (VOCs) source apportionment based on correction of photochemical loss [D]. Guangzhou: South China University of Technology, 2020.
