State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Nanjing Intelligent Environmental Science and Technology Co., Ltd., Nanjing, 211800, China.
Chemosphere. 2021 Feb;265:129072. doi: 10.1016/j.chemosphere.2020.129072. Epub 2020 Nov 21.
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) 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 pollution episodes, alkanes comprised the highest proportion to TVOC concentrations, while alkenes contributed the most to ozone formation potential (OFP). In addition, O episode days were mainly caused by enhanced emissions of precursors and meteorological conditions favorable to O production. Based on Empirical Kinetic Modelling Approach (EKMA), the O 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 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 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 and evidence for regional O reduction strategies.
本研究于 2019 年 7 月 19 日至 9 月 19 日在关中东部渭南市连续测量了 105 种挥发性有机化合物 (VOC)。根据中国环境空气质量标准，确定了臭氧 (O) 爆发和非爆发日，总定量 VOC (TVOC) 浓度分别为 33.43 ± 13.64 ppbv 和 29.13 ± 14.31 ppbv。在不同的 O 污染期间，烷烃占 TVOC 浓度的比例最高，而烯烃对臭氧形成潜力 (OFP) 的贡献最大。此外，O 爆发日主要是由于前体排放增强和有利于 O 生成的气象条件造成的。基于经验动力学建模方法 (EKMA)，发现渭南市的 O 形成处于过渡区，在该区域，协同减少 VOC 和氮氧化物 (NOx) 将更有效地减少 O。通过正定矩阵分解 (PMF) 模型确定了 8 个来源，天然气 (NG)/液化石油气 (LPG) 的使用是 VOC 浓度的最主要贡献源，其次是车辆尾气、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、溶剂使用、燃料蒸发和车辆尾气是形成 O 的最重要来源。基于条件双变量概率函数 (CBPF)，车辆尾气、燃料蒸发和溶剂使用主要是本地排放，而其他来源主要受区域传输的影响。本研究为大气光化学 O 形成的研究提供了有用的参考，并为区域 O 减排策略提供了证据。
