Interannual and Decadal Changes in Tropospheric Ozone in China and the Associated Chemistry-Climate Interactions: A Review

Abstract

China has been experiencing widespread air pollution due to rapid industrialization and urbanization in recent decades. The two major concerns of ambient air quality in China are particulate matter (PM) and tropospheric ozone (O₃). With the implementation of air pollution prevention and control actions in the last five years, the PM pollution in China has been substantially reduced. In contrast, under the conditions of the urban air pollution complex, the elevated O₃ levels in city clusters of eastern China, especially in warm seasons, have drawn increasing attention. Emissions of air pollutants and their precursors not only contribute to regional air quality, but also alter climate. Climate change in turn can change chemical processes, long-range transport, and local meteorology that influence air pollution. Compared to PM, less is known about O₃ pollution and its climate effects over China. Here, we present a review of the main findings from the literature over the period 2011–18 with regard to the characteristics of O₃ concentrations in China and the mechanisms that drive its interannual to decadal variations, aiming to identify robust conclusions that may guide decision-making for emissions control and to highlight critical knowledge gaps. We also review regional and global modeling studies that have investigated the impacts of tropospheric O₃ on climate, as well as the projections of future tropospheric O₃ owing to climate and/or emission changes.

摘 要

近几十年随着经济快速发展和工业化、城市化进程的加快, 中国的大气环境也因日益突出的空气污染问题而备受关注.自2013年大气污染防治行动计划的实施开展, 全国以细颗粒物(PM2.5)为首要污染物的空气质量总体得到了一定的改善, 但空气污染的形势依然严峻.在当前大气复合污染的背景下, 中国东部的城市群区域臭氧(O3)污染问题显现, 尤其在夏季, 对流层臭氧浓度呈升高态势, 屡屡成为继PM2.5之后的首要空气污染物.然而, 相比于颗粒物污染的研究, 我国在臭氧污染及其气候效应方面开展的研究相对较少.旨在科学认识中国臭氧污染变化规律及影响机制, 同时也为国家及地区制定合理的排放控制规划提供参考, 本文对2011-2018年期间中国地区取得的主要研究进展进行了回顾, 总结了中国对流层臭氧尤其是近地面臭氧污染的时空分布特征和变化趋势, 归纳了影响臭氧浓度年际、年代际变化的主要驱动因素及过程.此外, 概述了对流层臭氧对中国气候的影响及未来气候与排放变化对臭氧浓度的影响.最后, 本文还提出了在该领域未来需要进一步研究的科学问题和研究方向.