Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain
Enhanced ozone (O<sub>3</sub>) pollution has emerged as a pressing environmental concern in China, particularly for densely populated megacities and major city clusters. However, volatile organic compounds (VOCs), the key precursors to O<sub>3</sub> formation, have not been r...
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MDPI AG
2024-02-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/15/2/213 |
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| author | Saimei Hao Qiyue Du Xiaofeng Wei Huaizhong Yan Miao Zhang Youmin Sun Shijie Liu Lianhuan Fan Guiqin Zhang |
| author_facet | Saimei Hao Qiyue Du Xiaofeng Wei Huaizhong Yan Miao Zhang Youmin Sun Shijie Liu Lianhuan Fan Guiqin Zhang |
| author_sort | Saimei Hao |
| collection | DOAJ |
| description | Enhanced ozone (O<sub>3</sub>) pollution has emerged as a pressing environmental concern in China, particularly for densely populated megacities and major city clusters. However, volatile organic compounds (VOCs), the key precursors to O<sub>3</sub> formation, have not been routinely measured. In this study, we characterize the spatial and temporal patterns of VOCs and examine the role of VOCs in O<sub>3</sub> production in five cities (Dongying (DY), Rizhao (RZ), Yantai (YT), Weihai (WH), and Jinan (JN)) in the North China Plain (NCP) for two sampling periods (June and December) in 2021 through continuous field observations. Among various VOC categories, alkanes accounted for the largest proportion of VOCs in the cities. For VOCs, chemical reactivities, aromatic hydrocarbons, and alkenes were dominant contributors to O<sub>3</sub> formation potential (OFP). Unlike inland regions, the contribution to OFP from OVOCs increased greatly at high O<sub>3</sub> concentrations in coastal regions (especially YT). Model simulations during the O<sub>3</sub> episode show that the net O<sub>3</sub> production rates were 27.87, 10.24, and 10.37 ppbv/h in DY, RZ, and JN. The pathway of HO<sub>2</sub> + NO contributed the most to O<sub>3</sub> production in JN and RZ, while RO<sub>2</sub> + NO was the largest contributor to O<sub>3</sub> production in DY. The relative incremental reactivity (RIR) revealed that O<sub>3</sub> formation in DY was the transitional regime, while it was markedly the VOC-limited regime in JN and RZ. The O<sub>3</sub> production response is influenced by NOx concentration and has a clear daily variation pattern (the sensitivity is greater from 15:00 to 17:00). The most efficiencies in O<sub>3</sub> reduction could be achieved by reducing NOx when the NOx concentration is low (less than 20 ppbv in this study). This study reveals the importance of ambient VOCs in O<sub>3</sub> production over the NCP and demonstrates that a better grasp of VOC sources and profiles is critical for in-depth O<sub>3</sub> regulation in the NCP. |
| first_indexed | 2024-03-07T22:42:50Z |
| format | Article |
| id | doaj.art-9fdebfc0537248238ab5b2a009bcb805 |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-07T22:42:50Z |
| publishDate | 2024-02-01 |
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| series | Atmosphere |
| spelling | doaj.art-9fdebfc0537248238ab5b2a009bcb8052024-02-23T15:07:10ZengMDPI AGAtmosphere2073-44332024-02-0115221310.3390/atmos15020213Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China PlainSaimei Hao0Qiyue Du1Xiaofeng Wei2Huaizhong Yan3Miao Zhang4Youmin Sun5Shijie Liu6Lianhuan Fan7Guiqin Zhang8Qingdao Gemini Scientific Co., Ltd., Qingdao 266100, ChinaSchool of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266555, ChinaSchool of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, ChinaShandong Provincial Ecological Environment Monitoring Center, Jinan 250101, ChinaShandong Provincial Ecological Environment Monitoring Center, Jinan 250101, ChinaSchool of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, ChinaResource and Environment Innovation Institute, Shandong Jianzhu University, Jinan 250101, ChinaSchool of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, ChinaSchool of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, ChinaEnhanced ozone (O<sub>3</sub>) pollution has emerged as a pressing environmental concern in China, particularly for densely populated megacities and major city clusters. However, volatile organic compounds (VOCs), the key precursors to O<sub>3</sub> formation, have not been routinely measured. In this study, we characterize the spatial and temporal patterns of VOCs and examine the role of VOCs in O<sub>3</sub> production in five cities (Dongying (DY), Rizhao (RZ), Yantai (YT), Weihai (WH), and Jinan (JN)) in the North China Plain (NCP) for two sampling periods (June and December) in 2021 through continuous field observations. Among various VOC categories, alkanes accounted for the largest proportion of VOCs in the cities. For VOCs, chemical reactivities, aromatic hydrocarbons, and alkenes were dominant contributors to O<sub>3</sub> formation potential (OFP). Unlike inland regions, the contribution to OFP from OVOCs increased greatly at high O<sub>3</sub> concentrations in coastal regions (especially YT). Model simulations during the O<sub>3</sub> episode show that the net O<sub>3</sub> production rates were 27.87, 10.24, and 10.37 ppbv/h in DY, RZ, and JN. The pathway of HO<sub>2</sub> + NO contributed the most to O<sub>3</sub> production in JN and RZ, while RO<sub>2</sub> + NO was the largest contributor to O<sub>3</sub> production in DY. The relative incremental reactivity (RIR) revealed that O<sub>3</sub> formation in DY was the transitional regime, while it was markedly the VOC-limited regime in JN and RZ. The O<sub>3</sub> production response is influenced by NOx concentration and has a clear daily variation pattern (the sensitivity is greater from 15:00 to 17:00). The most efficiencies in O<sub>3</sub> reduction could be achieved by reducing NOx when the NOx concentration is low (less than 20 ppbv in this study). This study reveals the importance of ambient VOCs in O<sub>3</sub> production over the NCP and demonstrates that a better grasp of VOC sources and profiles is critical for in-depth O<sub>3</sub> regulation in the NCP.https://www.mdpi.com/2073-4433/15/2/213volatile organic compounds (VOCs)O<sub>3</sub> pollutionozone formation potential (OFP)observation-based model (OBM) |
| spellingShingle | Saimei Hao Qiyue Du Xiaofeng Wei Huaizhong Yan Miao Zhang Youmin Sun Shijie Liu Lianhuan Fan Guiqin Zhang Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain Atmosphere volatile organic compounds (VOCs) O<sub>3</sub> pollution ozone formation potential (OFP) observation-based model (OBM) |
| title | Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain |
| title_full | Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain |
| title_fullStr | Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain |
| title_full_unstemmed | Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain |
| title_short | Composition and Reactivity of Volatile Organic Compounds and the Implications for Ozone Formation in the North China Plain |
| title_sort | composition and reactivity of volatile organic compounds and the implications for ozone formation in the north china plain |
| topic | volatile organic compounds (VOCs) O<sub>3</sub> pollution ozone formation potential (OFP) observation-based model (OBM) |
| url | https://www.mdpi.com/2073-4433/15/2/213 |
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