Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze
<p>The Fenwei Plain, home to 50 million people in central China, is one of the most polluted regions in China. In 2018, the Fenwei Plain was designated as one of the three key regions for the “Blue Sky Protection Campaign”, along with the Beijing–Tianjin–Hebei (BTH) and Yangtze River Delta (YR...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/3595/2023/acp-23-3595-2023.pdf |
| _version_ | 1797861413511757824 |
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| author | C. Lin R.-J. Huang R.-J. Huang R.-J. Huang H. Zhong H. Zhong J. Duan Z. Wang Z. Wang W. Huang W. Xu |
| author_facet | C. Lin R.-J. Huang R.-J. Huang R.-J. Huang H. Zhong H. Zhong J. Duan Z. Wang Z. Wang W. Huang W. Xu |
| author_sort | C. Lin |
| collection | DOAJ |
| description | <p>The Fenwei Plain, home to 50 million people in
central China, is one of the most polluted regions in China. In 2018, the Fenwei
Plain was designated as one of the three key regions for the “Blue Sky
Protection Campaign”, along with the Beijing–Tianjin–Hebei (BTH) and
Yangtze River Delta (YRD) regions. However, compared to BTH and YRD, our
understanding of the current status of air pollution in the Fenwei Plain is
limited partly due to a lack of detailed analysis of the transformation from
precursor gases to secondary products including secondary organic aerosol
(SOA) and ozone. Through the analysis of 7 years (2015–2021) of surface
monitoring of the air pollutants in Xi'an, the largest city in the Fenwei
Plain, we show that roughly two-thirds of the days exceeded either the PM<span class="inline-formula"><sub>2.5</sub></span> or the O<span class="inline-formula"><sub>3</sub></span> level-1 air quality standard, highlighting the severity of
air pollution. Moreover, an increase in O<span class="inline-formula"><sub>3</sub></span> pollution in the winter
haze was also revealed, due to the constantly elevated reactive oxygenated
volatile organic compounds (OVOCs), in particular formaldehyde, with
an ozone formation potential of over 50 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>, in combination with
the reduced NO<span class="inline-formula"><sub>2</sub></span>. The abrupt decrease of NO<span class="inline-formula"><sub>2</sub></span>, as observed during
the lockdown in 2020, provided real-world evidence of the control measures,
targeting only NO<span class="inline-formula"><sub><i>x</i></sub></span> (70 % decrease on average), and were insufficient to
reduce ozone pollution because reactive OVOCs remained constantly high in a
volatile organic compound (VOC)-limited regime. Model simulation results showed that with NO<span class="inline-formula"><sub>2</sub></span>
reduction from 20 %–70 %, the self-reaction rate between peroxy radicals, a
pathway for SOA formation, was intensified by up to 75 %, while the
self-reaction rate was only reduced with a further reduction of VOCs of
<span class="inline-formula"><i>></i></span> 50 %. Therefore, a synergic reduction in PM<span class="inline-formula"><sub>2.5</sub></span> and
O<span class="inline-formula"><sub>3</sub></span> pollution can only be achieved through a more aggressive reduction
of their precursor gases. This study elucidates the status of ozone and
PM<span class="inline-formula"><sub>2.5</sub></span> pollution in one of the most polluted regions in China, revealing
a general trend of increasing secondary pollution, i.e., ozone and SOA in
winter haze. Controlling precursor gas emissions is anticipated to curb both
ozone and SOA formation, which will benefit not just the Fenwei Plain but
also other regions in China.</p> |
| first_indexed | 2024-04-09T22:03:18Z |
| format | Article |
| id | doaj.art-5401859bc47f49da865a7cc21155ede4 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-09T22:03:18Z |
| publishDate | 2023-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-5401859bc47f49da865a7cc21155ede42023-03-23T12:50:13ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-03-01233595360710.5194/acp-23-3595-2023Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter hazeC. Lin0R.-J. Huang1R.-J. Huang2R.-J. Huang3H. Zhong4H. Zhong5J. Duan6Z. Wang7Z. Wang8W. Huang9W. Xu10State Key Laboratory of Loess and Quaternary Geology (SKLLQG), Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaState Key Laboratory of Loess and Quaternary Geology (SKLLQG), Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaInstitute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaState Key Laboratory of Loess and Quaternary Geology (SKLLQG), Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaSchool of Advanced Materials Engineering, Jiaxing Nanhu University, Jiaxing 314001, ChinaState Key Laboratory of Loess and Quaternary Geology (SKLLQG), Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaState Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaState Key Laboratory of Loess and Quaternary Geology (SKLLQG), Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, ChinaState Key Laboratory of Loess and Quaternary Geology (SKLLQG), Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China<p>The Fenwei Plain, home to 50 million people in central China, is one of the most polluted regions in China. In 2018, the Fenwei Plain was designated as one of the three key regions for the “Blue Sky Protection Campaign”, along with the Beijing–Tianjin–Hebei (BTH) and Yangtze River Delta (YRD) regions. However, compared to BTH and YRD, our understanding of the current status of air pollution in the Fenwei Plain is limited partly due to a lack of detailed analysis of the transformation from precursor gases to secondary products including secondary organic aerosol (SOA) and ozone. Through the analysis of 7 years (2015–2021) of surface monitoring of the air pollutants in Xi'an, the largest city in the Fenwei Plain, we show that roughly two-thirds of the days exceeded either the PM<span class="inline-formula"><sub>2.5</sub></span> or the O<span class="inline-formula"><sub>3</sub></span> level-1 air quality standard, highlighting the severity of air pollution. Moreover, an increase in O<span class="inline-formula"><sub>3</sub></span> pollution in the winter haze was also revealed, due to the constantly elevated reactive oxygenated volatile organic compounds (OVOCs), in particular formaldehyde, with an ozone formation potential of over 50 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>, in combination with the reduced NO<span class="inline-formula"><sub>2</sub></span>. The abrupt decrease of NO<span class="inline-formula"><sub>2</sub></span>, as observed during the lockdown in 2020, provided real-world evidence of the control measures, targeting only NO<span class="inline-formula"><sub><i>x</i></sub></span> (70 % decrease on average), and were insufficient to reduce ozone pollution because reactive OVOCs remained constantly high in a volatile organic compound (VOC)-limited regime. Model simulation results showed that with NO<span class="inline-formula"><sub>2</sub></span> reduction from 20 %–70 %, the self-reaction rate between peroxy radicals, a pathway for SOA formation, was intensified by up to 75 %, while the self-reaction rate was only reduced with a further reduction of VOCs of <span class="inline-formula"><i>></i></span> 50 %. Therefore, a synergic reduction in PM<span class="inline-formula"><sub>2.5</sub></span> and O<span class="inline-formula"><sub>3</sub></span> pollution can only be achieved through a more aggressive reduction of their precursor gases. This study elucidates the status of ozone and PM<span class="inline-formula"><sub>2.5</sub></span> pollution in one of the most polluted regions in China, revealing a general trend of increasing secondary pollution, i.e., ozone and SOA in winter haze. Controlling precursor gas emissions is anticipated to curb both ozone and SOA formation, which will benefit not just the Fenwei Plain but also other regions in China.</p>https://acp.copernicus.org/articles/23/3595/2023/acp-23-3595-2023.pdf |
| spellingShingle | C. Lin R.-J. Huang R.-J. Huang R.-J. Huang H. Zhong H. Zhong J. Duan Z. Wang Z. Wang W. Huang W. Xu Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze Atmospheric Chemistry and Physics |
| title | Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze |
| title_full | Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze |
| title_fullStr | Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze |
| title_full_unstemmed | Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze |
| title_short | Elucidating ozone and PM<sub>2.5</sub> pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze |
| title_sort | elucidating ozone and pm sub 2 5 sub pollution in the fenwei plain reveals the co benefits of controlling precursor gas emissions in winter haze |
| url | https://acp.copernicus.org/articles/23/3595/2023/acp-23-3595-2023.pdf |
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