Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals
<p>Particulate matter (PM<span class="inline-formula"><sub>2.5</sub></span>) concentrations in China have decreased significantly in recent years, but surface ozone (O<span class="inline-formula"><sub>3</sub></span>) concentra...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/15035/2022/acp-22-15035-2022.pdf |
| _version_ | 1811304863940739072 |
|---|---|
| author | J. Ren F. Guo S. Xie |
| author_facet | J. Ren F. Guo S. Xie |
| author_sort | J. Ren |
| collection | DOAJ |
| description | <p>Particulate matter (PM<span class="inline-formula"><sub>2.5</sub></span>) concentrations in China
have decreased significantly in recent years, but surface ozone (O<span class="inline-formula"><sub>3</sub></span>)
concentrations showed upward trends at more than 71 % of air quality
monitoring stations from 2015 to 2021. To reveal the causes of O<span class="inline-formula"><sub>3</sub></span>
increases, O<span class="inline-formula"><sub>3</sub></span> production sensitivity is accurately diagnosed by
deriving regional threshold values of the satellite tropospheric
formaldehyde-to-NO<span class="inline-formula"><sub>2</sub></span> ratio (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">HCHO</mi><mo>/</mo><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="61pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="506bea995009780c42447cfa36baaaf2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15035-2022-ie00001.svg" width="61pt" height="14pt" src="acp-22-15035-2022-ie00001.png"/></svg:svg></span></span>), and O<span class="inline-formula"><sub>3</sub></span> responses to
precursor changes are evaluated by tracking volatile organic compounds
(VOCs) and NO<span class="inline-formula"><sub><i>x</i></sub></span> with satellite HCHO and NO<span class="inline-formula"><sub>2</sub></span>. Results showed that
the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">HCHO</mi><mo>/</mo><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="61pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5c251b8d60f8c0d496f98a0b18355fd4"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15035-2022-ie00002.svg" width="61pt" height="14pt" src="acp-22-15035-2022-ie00002.png"/></svg:svg></span></span> ranges of transition from VOC-limited to NO<span class="inline-formula"><sub><i>x</i></sub></span>-limited
regimes apparently vary among Chinese regions. VOC-limited regimes are found widely over megacity clusters (North China Plain, Yangtze River
Delta and Pearl River Delta) and concentrated in developed cities (such as
Chengdu, Chongqing, Xi'an and Wuhan). NO<span class="inline-formula"><sub><i>x</i></sub></span>-limited regimes dominate
most of the remaining areas. From 2013 to 2021, satellite NO<span class="inline-formula"><sub>2</sub></span> and HCHO
columns showed an annual decrease of 3.0 % and 0.3 %, respectively,
indicating an effective reduction in NO<span class="inline-formula"><sub><i>x</i></sub></span> emissions but a failure to
reduce VOC emissions. This finding further shows that O<span class="inline-formula"><sub>3</sub></span>
increases in major cities occur because the Clean Air Action Plan only
reduces NO<span class="inline-formula"><sub><i>x</i></sub></span> emissions without effective VOC control. Based on the
O<span class="inline-formula"><sub>3</sub></span>–NO<span class="inline-formula"><sub><i>x</i></sub></span>–VOC relationship by satellite NO<span class="inline-formula"><sub>2</sub></span> and HCHO in
Beijing, Chengdu and Guangzhou, the ozone concentration can be
substantially reduced if the reduction ratio of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M22" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">VOCs</mi><mo>/</mo><msub><mi mathvariant="normal">NO</mi><mi>x</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="58pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="ee4f98adffe14f4cf5e60c7ba8f3ac56"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15035-2022-ie00003.svg" width="58pt" height="14pt" src="acp-22-15035-2022-ie00003.png"/></svg:svg></span></span> is between <span class="inline-formula">2:1</span>
and <span class="inline-formula">4:1</span>.</p> |
| first_indexed | 2024-04-13T08:14:55Z |
| format | Article |
| id | doaj.art-9038dcd63a80485e9dfa7d009eec3650 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-13T08:14:55Z |
| publishDate | 2022-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-9038dcd63a80485e9dfa7d009eec36502022-12-22T02:54:51ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-11-0122150351504710.5194/acp-22-15035-2022Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievalsJ. RenF. GuoS. Xie<p>Particulate matter (PM<span class="inline-formula"><sub>2.5</sub></span>) concentrations in China have decreased significantly in recent years, but surface ozone (O<span class="inline-formula"><sub>3</sub></span>) concentrations showed upward trends at more than 71 % of air quality monitoring stations from 2015 to 2021. To reveal the causes of O<span class="inline-formula"><sub>3</sub></span> increases, O<span class="inline-formula"><sub>3</sub></span> production sensitivity is accurately diagnosed by deriving regional threshold values of the satellite tropospheric formaldehyde-to-NO<span class="inline-formula"><sub>2</sub></span> ratio (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">HCHO</mi><mo>/</mo><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="61pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="506bea995009780c42447cfa36baaaf2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15035-2022-ie00001.svg" width="61pt" height="14pt" src="acp-22-15035-2022-ie00001.png"/></svg:svg></span></span>), and O<span class="inline-formula"><sub>3</sub></span> responses to precursor changes are evaluated by tracking volatile organic compounds (VOCs) and NO<span class="inline-formula"><sub><i>x</i></sub></span> with satellite HCHO and NO<span class="inline-formula"><sub>2</sub></span>. Results showed that the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">HCHO</mi><mo>/</mo><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="61pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5c251b8d60f8c0d496f98a0b18355fd4"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15035-2022-ie00002.svg" width="61pt" height="14pt" src="acp-22-15035-2022-ie00002.png"/></svg:svg></span></span> ranges of transition from VOC-limited to NO<span class="inline-formula"><sub><i>x</i></sub></span>-limited regimes apparently vary among Chinese regions. VOC-limited regimes are found widely over megacity clusters (North China Plain, Yangtze River Delta and Pearl River Delta) and concentrated in developed cities (such as Chengdu, Chongqing, Xi'an and Wuhan). NO<span class="inline-formula"><sub><i>x</i></sub></span>-limited regimes dominate most of the remaining areas. From 2013 to 2021, satellite NO<span class="inline-formula"><sub>2</sub></span> and HCHO columns showed an annual decrease of 3.0 % and 0.3 %, respectively, indicating an effective reduction in NO<span class="inline-formula"><sub><i>x</i></sub></span> emissions but a failure to reduce VOC emissions. This finding further shows that O<span class="inline-formula"><sub>3</sub></span> increases in major cities occur because the Clean Air Action Plan only reduces NO<span class="inline-formula"><sub><i>x</i></sub></span> emissions without effective VOC control. Based on the O<span class="inline-formula"><sub>3</sub></span>–NO<span class="inline-formula"><sub><i>x</i></sub></span>–VOC relationship by satellite NO<span class="inline-formula"><sub>2</sub></span> and HCHO in Beijing, Chengdu and Guangzhou, the ozone concentration can be substantially reduced if the reduction ratio of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M22" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">VOCs</mi><mo>/</mo><msub><mi mathvariant="normal">NO</mi><mi>x</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="58pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="ee4f98adffe14f4cf5e60c7ba8f3ac56"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15035-2022-ie00003.svg" width="58pt" height="14pt" src="acp-22-15035-2022-ie00003.png"/></svg:svg></span></span> is between <span class="inline-formula">2:1</span> and <span class="inline-formula">4:1</span>.</p>https://acp.copernicus.org/articles/22/15035/2022/acp-22-15035-2022.pdf |
| spellingShingle | J. Ren F. Guo S. Xie Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals Atmospheric Chemistry and Physics |
| title | Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals |
| title_full | Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals |
| title_fullStr | Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals |
| title_full_unstemmed | Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals |
| title_short | Diagnosing ozone–NO<sub><i>x</i></sub>–VOC sensitivity and revealing causes of ozone increases in China based on 2013–2021 satellite retrievals |
| title_sort | diagnosing ozone no sub i x i sub voc sensitivity and revealing causes of ozone increases in china based on 2013 2021 satellite retrievals |
| url | https://acp.copernicus.org/articles/22/15035/2022/acp-22-15035-2022.pdf |
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