A comprehensive review of tropospheric background ozone: definitions, estimation methods, and meta-analysis of its spatiotemporal distribution in China

Le résumé fourni par la source

Background ozone (O 3 ) represents the baseline concentrations in the absence of local anthropogenic emissions and is critical for understanding and mitigating tropospheric O 3 pollution. Accurate estimation of background O 3 constrains the maximum achievable benefits of precursor emissions control and informs effective air quality management. This review synthesizes the definition and estimation methods for background O 3 , including in situ measurement, statistical analysis, numerical modeling, and integrated methods. A meta-analysis of background O 3 in China from 1994 to 2020 reveals pronounced spatial variability, with concentrations ranging from 33 ppb in the Northeast China to 48 ppb in the Northwest China, and a national mean of 41 ppb, accounting for 79 % of the tropospheric maximum daily 8 h average O 3 . Methodological discrepancies are evident for background O 3 : in situ and statistical methods yield higher estimates, whereas integrated approaches produce lower yet more consistent values. Placed in a global context, background O 3 levels in China are medium-to-high and exhibit an increasing trend. This review highlights the need for integrated estimation methods to improve accuracy, underscores the international collaboration to address long-range pollutant transport, and calls for further research on the interactions between background O 3 and climate change. By advancing the understanding of background O 3 dynamics, it provides critical insights for atmospheric chemistry and air pollution control in China and beyond.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.