Variations in summertime ozone in Nanjing between 2015 and 2020: roles of meteorology, radical chain length and ozone production efficiency

IF 6.1 2区环境科学与生态学 Q2 ENGINEERING, ENVIRONMENTAL

Frontiers of Environmental Science & Engineering Pub Date : 2024-09-06 DOI:10.1007/s11783-024-1897-z

Lin Li, Jingyi Li, Momei Qin, Xiaodong Xie, Jianlin Hu, Yuqiang Zhang

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Abstract

Changes in ozone (O₃) can be evaluated to inform policy effectiveness and develop reasonable emissions reduction measures. This study investigated the causes of summertime maximum daily 8-h average (MDA8) O₃ variation between 2015 and 2020 in Nanjing, China, a megacity in the Yangtze River Delta (YRD) region, from the perspective of meteorological conditions and anthropogenic emissions of O₃ precursors (VOCs and No_x). Compared with 2015, the observed MDA8 O₃ decreased by 19.1 µg/m³ in August 2020. The indirect and indirect impacts of meteorological conditions contributed 44% of the decline, with temperature, relative humidity, and wind playing important roles in the O₃ variation. The O₃ drop by 10.7 µg/m³ (56% of the total decrease) may have been due to the decreases in anthropogenic emissions of VOCs and NO_x by 7.8% and 11.7%, respectively. The longer hydroxyl (OH) radical chain length and higher ozone production efficiency (OPE) indicated that the reduction of anthropogenic emissions accelerated the RO_x (RO_x = OH + HO₂ + RO₂) and NO_x cycles in O₃ production, making O₃ more sensitive to NO_x. This corresponded to the O₃ formation shifting from a VOC-limited regime in 2015 to a transition regime in 2020 and O₃ decrease with anthropogenic emission reduction. Hence, the joint control of O₃ precursor emissions can effectively mitigate O₃ pollution in Nanjing.

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2015-2020 年间南京夏季臭氧的变化：气象、自由基链长度和臭氧生产效率的作用

通过评估臭氧（O3）的变化，可以了解政策的有效性，并制定合理的减排措施。本研究从气象条件和人为臭氧前体物（挥发性有机物和氮氧化物）排放的角度，研究了长三角地区特大城市中国南京 2015 年至 2020 年夏季最大日均 8 小时臭氧（MDA8）变化的原因。与 2015 年相比，2020 年 8 月观测到的 MDA8 O3 降低了 19.1 µg/m3 。气象条件的间接和间接影响占了降幅的 44%，其中温度、相对湿度和风在 O3 变化中发挥了重要作用。臭氧下降 10.7 微克/立方米（占总降幅的 56%）可能是由于人为排放的挥发性有机化合物和氮氧化物分别减少了 7.8% 和 11.7%。较长的羟基自由基链长度和较高的臭氧生成效率（OPE）表明，人为排放量的减少加速了 O3 生成过程中的 ROx（ROx = OH + HO2 + RO2）和 NOx 循环，使 O3 对 NOx 更为敏感。这与 O3 的形成从 2015 年的 VOC 限制机制向 2020 年的过渡机制转变以及 O3 随人为排放量减少而减少的情况相对应。因此，联合控制 O3 前体排放可有效缓解南京的 O3 污染。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Frontiers of Environmental Science & Engineering ENGINEERING, ENVIRONMENTAL-ENVIRONMENTAL SCIENCES

CiteScore

10.90

自引率

12.50%

发文量

988

审稿时长

6.1 months

期刊介绍： Frontiers of Environmental Science & Engineering (FESE) is an international journal for researchers interested in a wide range of environmental disciplines. The journal''s aim is to advance and disseminate knowledge in all main branches of environmental science & engineering. The journal emphasizes papers in developing fields, as well as papers showing the interaction between environmental disciplines and other disciplines. FESE is a bi-monthly journal. Its peer-reviewed contents consist of a broad blend of reviews, research papers, policy analyses, short communications, and opinions. Nonscheduled “special issue” and "hot topic", including a review article followed by a couple of related research articles, are organized to publish novel contributions and breaking results on all aspects of environmental field.