Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China
<p>A record-breaking severe ozone (<span class="inline-formula">O<sub>3</sub></span>) pollution episode occurred in the Pearl River Delta (PRD) in early autumn 2019 when the PRD was under the influence of a Pacific subtropical high followed by Typhoon Mitag. I...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/10751/2022/acp-22-10751-2022.pdf |
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| author | S. Ouyang S. Ouyang T. Deng R. Liu R. Liu J. Chen G. He G. He J. C.-H. Leung N. Wang S. C. Liu S. C. Liu |
| author_facet | S. Ouyang S. Ouyang T. Deng R. Liu R. Liu J. Chen G. He G. He J. C.-H. Leung N. Wang S. C. Liu S. C. Liu |
| author_sort | S. Ouyang |
| collection | DOAJ |
| description | <p>A record-breaking severe ozone (<span class="inline-formula">O<sub>3</sub></span>) pollution episode occurred in the Pearl River Delta (PRD) in early autumn 2019 when the PRD was under the influence of a Pacific subtropical high followed by Typhoon Mitag. In this study, we analyzed the effects of meteorological and photochemical processes on the <span class="inline-formula">O<sub>3</sub></span> concentration in the PRD during this episode by carrying out the Weather Research Forecast–Community Multiscale Air Quality (WRF-CMAQ) model simulations. Results showed that low relative humidity, high boundary layer height, weak northerly surface wind, and strong downdrafts were the main meteorological factors contributing to <span class="inline-formula">O<sub>3</sub></span> pollution. Moreover, delayed sea breezes that lasted into the night would transport <span class="inline-formula">O<sub>3</sub></span> from the sea back to the land and resulted in secondary <span class="inline-formula">O<sub>3</sub></span> maxima at night. In addition, <span class="inline-formula">O<sub>3</sub></span> and its precursors stored in the residual layer above the surface layer at night can be mixed down to the surface in the next morning, further enhancing the daytime ground-level <span class="inline-formula">O<sub>3</sub></span> concentration on the following day. Photochemical production of <span class="inline-formula">O<sub>3</sub></span>, with a daytime average production rate of about 7.2 <span class="inline-formula">ppb h<sup>−1</sup></span> (parts per billion), is found to be the predominate positive contributor to the <span class="inline-formula">O<sub>3</sub></span> budget of the boundary layer (0–1260 m) during the entire <span class="inline-formula">O<sub>3</sub></span> episode, while the
horizontal and vertical transport fluxes are the dominant negative contributors. This <span class="inline-formula">O<sub>3</sub></span> episode accounted for 10 out of the yearly total of 51 d when the maximum daily 8 h average (MDA8) <span class="inline-formula">O<sub>3</sub></span> concentration exceeded the national standard of 75 ppb in the PRD in 2019. Based on these results, we propose that the enhanced photochemical production of <span class="inline-formula">O<sub>3</sub></span> during the episode is a major cause of the most severe <span class="inline-formula">O<sub>3</sub></span> pollution year since the official <span class="inline-formula">O<sub>3</sub></span> observation started in the PRD in 2006. Moreover, since this <span class="inline-formula">O<sub>3</sub></span> episode is a synoptic-scale phenomenon covering the entire eastern China, we also suggest that the enhanced photochemical production of <span class="inline-formula">O<sub>3</sub></span> in this <span class="inline-formula">O<sub>3</sub></span> episode is a major cause of the extraordinarily high <span class="inline-formula">O<sub>3</sub></span> concentrations observed in eastern China in 2019.</p> |
| first_indexed | 2024-04-13T03:09:43Z |
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| id | doaj.art-6348fc1a29844c1a90aec6d0ad90bfbc |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-13T03:09:43Z |
| publishDate | 2022-08-01 |
| publisher | Copernicus Publications |
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| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-6348fc1a29844c1a90aec6d0ad90bfbc2022-12-22T03:05:06ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-08-0122107511076710.5194/acp-22-10751-2022Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, ChinaS. Ouyang0S. Ouyang1T. Deng2R. Liu3R. Liu4J. Chen5G. He6G. He7J. C.-H. Leung8N. Wang9S. C. Liu10S. C. Liu11Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, ChinaGuangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510640, ChinaGuangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510640, ChinaInstitute for Environmental and Climate Research, Jinan University, Guangzhou 511443, ChinaGuangdong–Hong Kong–Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, ChinaGuangdong Ecological Meteorology Center (Pearl River Delta Center for Environmental Meteorology Prediction and Warning), Guangzhou 510640, ChinaGuangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510640, ChinaSchool of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, ChinaGuangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510640, ChinaGuangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510640, ChinaInstitute for Environmental and Climate Research, Jinan University, Guangzhou 511443, ChinaGuangdong–Hong Kong–Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China<p>A record-breaking severe ozone (<span class="inline-formula">O<sub>3</sub></span>) pollution episode occurred in the Pearl River Delta (PRD) in early autumn 2019 when the PRD was under the influence of a Pacific subtropical high followed by Typhoon Mitag. In this study, we analyzed the effects of meteorological and photochemical processes on the <span class="inline-formula">O<sub>3</sub></span> concentration in the PRD during this episode by carrying out the Weather Research Forecast–Community Multiscale Air Quality (WRF-CMAQ) model simulations. Results showed that low relative humidity, high boundary layer height, weak northerly surface wind, and strong downdrafts were the main meteorological factors contributing to <span class="inline-formula">O<sub>3</sub></span> pollution. Moreover, delayed sea breezes that lasted into the night would transport <span class="inline-formula">O<sub>3</sub></span> from the sea back to the land and resulted in secondary <span class="inline-formula">O<sub>3</sub></span> maxima at night. In addition, <span class="inline-formula">O<sub>3</sub></span> and its precursors stored in the residual layer above the surface layer at night can be mixed down to the surface in the next morning, further enhancing the daytime ground-level <span class="inline-formula">O<sub>3</sub></span> concentration on the following day. Photochemical production of <span class="inline-formula">O<sub>3</sub></span>, with a daytime average production rate of about 7.2 <span class="inline-formula">ppb h<sup>−1</sup></span> (parts per billion), is found to be the predominate positive contributor to the <span class="inline-formula">O<sub>3</sub></span> budget of the boundary layer (0–1260 m) during the entire <span class="inline-formula">O<sub>3</sub></span> episode, while the horizontal and vertical transport fluxes are the dominant negative contributors. This <span class="inline-formula">O<sub>3</sub></span> episode accounted for 10 out of the yearly total of 51 d when the maximum daily 8 h average (MDA8) <span class="inline-formula">O<sub>3</sub></span> concentration exceeded the national standard of 75 ppb in the PRD in 2019. Based on these results, we propose that the enhanced photochemical production of <span class="inline-formula">O<sub>3</sub></span> during the episode is a major cause of the most severe <span class="inline-formula">O<sub>3</sub></span> pollution year since the official <span class="inline-formula">O<sub>3</sub></span> observation started in the PRD in 2006. Moreover, since this <span class="inline-formula">O<sub>3</sub></span> episode is a synoptic-scale phenomenon covering the entire eastern China, we also suggest that the enhanced photochemical production of <span class="inline-formula">O<sub>3</sub></span> in this <span class="inline-formula">O<sub>3</sub></span> episode is a major cause of the extraordinarily high <span class="inline-formula">O<sub>3</sub></span> concentrations observed in eastern China in 2019.</p>https://acp.copernicus.org/articles/22/10751/2022/acp-22-10751-2022.pdf |
| spellingShingle | S. Ouyang S. Ouyang T. Deng R. Liu R. Liu J. Chen G. He G. He J. C.-H. Leung N. Wang S. C. Liu S. C. Liu Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China Atmospheric Chemistry and Physics |
| title | Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China |
| title_full | Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China |
| title_fullStr | Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China |
| title_full_unstemmed | Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China |
| title_short | Impact of a subtropical high and a typhoon on a severe ozone pollution episode in the Pearl River Delta, China |
| title_sort | impact of a subtropical high and a typhoon on a severe ozone pollution episode in the pearl river delta china |
| url | https://acp.copernicus.org/articles/22/10751/2022/acp-22-10751-2022.pdf |
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