School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Environ Sci Technol. 2021 Dec 7;55(23):15625-15636. doi: 10.1021/acs.est.1c01567. Epub 2021 Nov 17.
Ozone (O) isopleths describe the nonlinear responses of O concentrations to changes in nitrogen oxides (NO) and volatile organic compounds (VOCs) and thus are pivotal to the determination of O control requirements. In this study, we innovatively use the Community Multiscale Air Quality model with the high-order decoupled direct method (CMAQ-HDDM) to simulate O pollution of China in 2017 and derive O isopleths for individual cities. Our simulation covering the entire China Mainland suggests severe O pollution as 97% of the residents experienced at least 1 day, in 2017, in excess of Chinese Level-II Ambient Air Quality Standards for O as 160 μg·m (81.5 ppbV equally). The O responses to emissions of precursors vary widely across individual cities. Densely populated metropolitan areas such as Jing-Jin-Ji, Yangtze River Delta, and Pearl River Delta are following NO-saturated regimes, where a small amount of NO reduction increases O. Ambient O pollution in the eastern region generally is limited by VOCs, while in the west by NO. The city-specific O isopleths generated in this study are instrumental in forming hybrid and differentiated strategies for O abatement in China.
臭氧（O）等浓度线描述了臭氧浓度对氮氧化物（NO）和挥发性有机化合物（VOC）变化的非线性响应，因此是确定臭氧控制要求的关键。在这项研究中，我们创新性地使用了带有高阶解耦直接方法的社区多尺度空气质量模型（CMAQ-HDDM），模拟了 2017 年中国的臭氧污染，并为各个城市推导了臭氧等浓度线。我们的模拟涵盖了整个中国大陆，结果表明，2017 年，97%的居民至少经历了 1 天的臭氧污染，超过了中国二级环境空气质量标准（臭氧浓度为 160μg·m³，等效值为 81.5 ppbV）。臭氧对前体物排放的响应在各个城市之间差异很大。人口密集的大都市区，如京津冀、长三角和珠三角，已经处于氮氧化物饱和状态，此时少量的氮氧化物减排会增加臭氧。东部地区的环境臭氧污染通常受到 VOCs 的限制，而西部地区则受到 NO 的限制。本研究生成的特定于城市的臭氧等浓度线有助于在中国形成混合和差异化的臭氧减排策略。
