Stratospheric influence on surface ozone pollution in China.
Where this comes from
- Record sourced from PubMed, PMID 38744875.
- Also identified by DOI 10.1038/s41467-024-48406-x and PMC identifier 11093980.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Events of stratospheric intrusions to the surface (SITS) can lead to severe ozone (O<sub>3</sub>) pollution. Still, to what extent SITS events impact surface O<sub>3</sub> on a national scale over years remains a long-lasting question, mainly due to difficulty of resolving three key SITS metrics: frequency, duration and intensity. Here, we identify 27,616 SITS events over China during 2015-2022 based on spatiotemporally dense surface measurements of O<sub>3</sub> and carbon monoxide, two effective indicators of SITS. An overview of the three metrics is presented, illustrating large influences of SITS on surface O<sub>3</sub> in China. We find that SITS events occur preferentially in high-elevation regions, while those in plain regions are more intense. SITS enhances surface O<sub>3</sub> by 20 ppbv on average, contributing to 30-45% of O<sub>3</sub> during SITS periods. Nationally, SITS-induced O<sub>3</sub> peaks in spring and autumn, while over 70% of SITS events during the warm months exacerbate O<sub>3</sub> pollution. Over 2015-2022, SITS-induced O<sub>3</sub> shows a declining trend. Our observation-based results can have implications for O<sub>3</sub> mitigation policies in short and long terms.