Characteristics and sources of volatile organic compounds during high ozone episodes: A case study at a site in the eastern Guanzhong Plain, China
Characteristics and sources of volatile organic compounds during high ozone episodes: A case study at a site in the eastern Guanzhong Plain, China
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DOI：
10.1016/j.chemosphere.2020.129072
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发表时间：
2021-02-01
期刊：
影响因子：
8.8
通讯作者：
Liu, Jiayuan
中科院分区：
文献类型：
--
作者：
Hui, Lirong;Ma, Tong;Liu, Jiayuan
本研究于2019年7月1日至9月19日在关中平原东部的渭南进行了105种挥发性有机物（VOCs）的连续测量。臭氧（O-3）发生日和非发生日分别为33.43 ± 13.64 ppbv和29.13 ± 14.31 ppbv。在不同的O-3污染事件中，烷烃组成的比例最高的TVOC浓度，而烯烃的贡献最大的臭氧生成潜能（OFP）。此外，O-3事件日数的增加主要是由于前体物排放增加和有利于O-3产生的气象条件。基于经验动力学模型（EKMA），发现渭南市大气中O-3的生成处于过渡阶段，此时VOCs和氮氧化物（NOx）的协同还原对O-3的还原更为有效。正矩阵分解（PMF）模型识别出8种污染源，其中天然气（NG）/液化石油气（LPG）的使用对VOC浓度的贡献最大，其次是机动车尾气、生物质燃烧、溶剂使用、燃料蒸发、橡胶/塑料工业排放、生物源和混合工业排放。此外，橡胶/塑料工业排放，溶剂的使用，燃料蒸发和汽车尾气是O-3形成的最重要来源。基于条件双变量概率函数（CBPF），汽车尾气、燃料蒸发和溶剂使用主要是本地排放，其他来源主要受区域交通影响。该研究为研究O3-的大气光化学形成提供了有益的参考，并为区域性的O3-减排策略提供了依据。(C)2020由Elsevier Ltd.出版
This study performed continuous measurements of 105 volatile organic compounds (VOCs) in Weinan in the eastern Guanzhong Plain from 1 July to September 19, 2019. Ozone (O-3) episode and non-episode days were identified according to China Ambient Air Quality Standard, and the concentrations of total quantified VOCs (TVOCs) were 33.43 +/- 13.64 ppbv and 29.13 +/- 14.31 ppbv, respectively. During different O-3 pollution episodes, alkanes comprised the highest proportion to TVOC concentrations, while alkenes contributed the most to ozone formation potential (OFP). In addition, O-3 episode days were mainly caused by enhanced emissions of precursors and meteorological conditions favorable to O-3 production. Based on Empirical Kinetic Modelling Approach (EKMA), the O-3 formation in Weinan was found in the transitional regime, in which the synergistic reduction of VOCs and nitrogen oxide (NOx) would be more effective for O-3 reduction. Eight sources were identified by positive matrix factorization (PMF) model, with natural gas (NG)/liquefied petroleum gas (LPG) usage as the most significant contributor to VOC concentration, followed by vehicle exhaust, biomass burning, solvent usage, fuel evaporation, rubber/plastic industrial emissions, biogenic source, and mixed industrial emissions. Furthermore, rubber/plastic industrial emissions, solvent usage, fuel evaporation, and vehicle exhaust were the most significant sources to O-3 formation. Based on conditional bivariate probability function (CBPF), vehicle exhaust, fuel evaporation, and solvent usage were mainly local emissions, while other sources were mainly affected by regional transport. This study provides useful reference for research on the atmospheric photochemical formation of O-3 and evidence for regional O-3 reduction strategies. (C) 2020 Published by Elsevier Ltd.