Department of Atmospheric and Oceanic Sciences, Fudan University, Shanghai 200433, China; State Key Laboratory of Severe Weather, Key Laboratory for Atmospheric Chemistry, Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
State Key Laboratory of Severe Weather, Key Laboratory for Atmospheric Chemistry, Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
Sci Total Environ. 2023 Feb 20;860:160520. doi: 10.1016/j.scitotenv.2022.160520. Epub 2022 Nov 25.
Significant upward trends in surface ozone (O) have been widely reported in China during recent years, especially during warm seasons in the North China Plain (NCP), exerting adverse environmental effects on human health and agriculture. Quantifying long-term O variations and their attributions helps to understand the causes of regional O pollution and to formulate according control strategy. In this study, we present long-term trends of O in the warm seasons (April-September) during 2006-2019 at an agricultural site in the NCP and investigate the relative contributions of meteorological and anthropogenic factors. Overall, the maximum daily 8-h average (MDA8) O exhibited a weak decreasing trend with large interannual variability. < 6 % of the observed trend could be explained by changes in meteorological conditions, while the remaining 94 % was attributed to anthropogenic impacts. However, the interannual variability of warm season MDA8 O was driven by both meteorology (36 ± 28 %) and anthropogenic factors (64 ± 27 %). Daily maximum temperature was the most essential factor affecting O variations, followed by ultraviolet radiation b (UVB) and boundary layer height (BLH), with rising temperature trends inducing O inclines throughout April to August, while UVB mainly influenced O during summer months. Under changes in emissions and air quality, warm season O production regime gradually shifted from dominantly VOCs-limited during 2006-2015 to NO-limited afterwards. Relatively steady HCHO and remarkably rising NO levels resulted in the fast decreasing MDA8 O (-2.87 ppb yr) during 2006-2012. Rapidly decreasing NO, flat or slightly increasing HCHO promoted O increases during 2012-2015 (9.76 ppb yr). While afterwards, slow increases in HCHO and downwards fluctuating NO led to decreases in MDA8 O (-4.97 ppb yr). Additionally, continuous warming trends might promote natural emissions of O precursors and magnify their impacts on agricultural O by inducing high variability, which would require even more anthropogenic reduction to compensate for.
近年来，中国的地表臭氧（O）浓度呈显著上升趋势，特别是在华北平原（NCP）的暖季，对人类健康和农业产生了不利的环境影响。量化 O 的长期变化及其归因有助于了解区域 O 污染的原因，并制定相应的控制策略。在这项研究中，我们展示了 NCP 农业站点在 2006-2019 年暖季（4 月-9 月）期间 O 的长期趋势，并调查了气象和人为因素的相对贡献。总的来说，最大日 8 小时平均（MDA8）O 表现出微弱的下降趋势，且年际变化较大。观测到的趋势中只有 <6%可以用气象条件的变化来解释，而其余的 94%归因于人为影响。然而，暖季 MDA8 O 的年际变化既受气象因素（36 ± 28%）也受人为因素（64 ± 27%）的驱动。日最高温度是影响 O 变化的最关键因素，其次是紫外线辐射 b（UVB）和边界层高度（BLH），随着温度上升趋势，O 在 4 月至 8 月期间呈上升趋势，而 UVB 主要影响夏季月份的 O。在排放和空气质量变化的情况下，暖季 O 生成机制逐渐从 2006-2015 年主要受 VOCs 限制转变为之后受 NO 限制。相对稳定的 HCHO 和明显上升的 NO 水平导致 MDA8 O 在 2006-2012 年期间快速下降（-2.87 ppb yr）。2012-2015 年期间，NO 快速下降，HCHO 持平或略有增加，促进了 O 的增加（9.76 ppb yr）。之后，HCHO 缓慢增加，NO 波动下降，导致 MDA8 O 下降（-4.97 ppb yr）。此外，持续的变暖趋势可能会促进 O 前体的自然排放，并通过诱导高变异性放大它们对农业 O 的影响，这将需要更多的人为减排来补偿。
