Local and regional contributions to fine particulate matter in the 18 cities of Sichuan Basin, southwestern China
<p>The Sichuan Basin (SCB) is one of the regions suffering from severe air pollution in China, but fewer studies have been conducted for this region than for the more developed regions in eastern and northern China. In this study, a source-oriented version of the Community Multiscale Air Quali...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/5791/2019/acp-19-5791-2019.pdf |
| Summary: | <p>The Sichuan Basin (SCB) is one of the regions suffering from severe air
pollution in China, but fewer studies have been conducted for this region
than for the more developed regions in eastern and northern China. In this study,
a source-oriented version of the Community Multiscale Air Quality (CMAQ)
model was used to quantify contributions from nine regions to PM<span class="inline-formula"><sub>2.5</sub></span>
(i.e., particulate matter, PM, with an aerodynamic diameter less than 2.5 <span class="inline-formula">µ</span>m) and its components in the 18 cities within the SCB in the winter
(December 2014 to February 2015) and summer (June to August 2015). In the
winter, citywide average PM<span class="inline-formula"><sub>2.5</sub></span> concentrations are 45–126 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>, with 21 %–51 % and
39 %–66 % being
due to local and nonlocal emissions, respectively. In the summer,
15 %–45 % and 25 %–52 % of citywide average
PM<span class="inline-formula"><sub>2.5</sub></span> (14–31 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>) are due to local and
nonlocal emissions, respectively. Compared to primary PM (PPM), the
inter-region transport of secondary inorganic aerosols (SIA), including
ammonia, nitrate, and sulfate ions (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="9641cdd414b305565815b5b604dabf23"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-5791-2019-ie00001.svg" width="24pt" height="15pt" src="acp-19-5791-2019-ie00001.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="dd23f13eb24280cbe650be4567ce8571"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-5791-2019-ie00002.svg" width="25pt" height="16pt" src="acp-19-5791-2019-ie00002.png"/></svg:svg></span></span>, and
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="815783a157bc15e547bdd7a24388d96b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-5791-2019-ie00003.svg" width="29pt" height="17pt" src="acp-19-5791-2019-ie00003.png"/></svg:svg></span></span>, respectively), and their gas-phase precursors are greater.
The region to the east of SCB (R7, including central and eastern China
and others) is the largest contributor outside the SCB, and it can
contribute approximately 80 % of PM<span class="inline-formula"><sub>2.5</sub></span> in the eastern, northeastern,
and southeastern rims of the SCB but only 10 % in other SCB regions in
both seasons. Under favorable transport conditions, regional transport of
air pollutants from R7 could account for up to 35–100 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> of PM<span class="inline-formula"><sub>2.5</sub></span> in each of the SCB cities in the winter. This
study demonstrates that it is important to have joint emission control
efforts among cities within the SCB and regions to the east in order to
reduce PM<span class="inline-formula"><sub>2.5</sub></span> concentrations and prevent high PM<span class="inline-formula"><sub>2.5</sub></span> days for the
entire basin.</p> |
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| ISSN: | 1680-7316 1680-7324 |