Response of winter fine particulate matter concentrations to emission and meteorology changes in North China
The winter haze is a growing problem in North China, but the causes are not well understood. The chemistry version of the Weather Research and Forecasting model (WRF-Chem) was applied in North China to examine how PM<sub>2.5</sub> concentrations change in response to changes in emissio...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/11837/2016/acp-16-11837-2016.pdf |
| Summary: | The winter haze is a growing problem in North China, but the causes are not well understood. The chemistry version of the Weather Research and
Forecasting model (WRF-Chem) was applied in North China to examine how
PM<sub>2.5</sub> concentrations change in response to changes in emissions (sulfur
dioxide (SO<sub>2</sub>), black carbon (BC), organic carbon (OC), ammonia
(NH<sub>3</sub>), and nitrogen oxides (NO<sub><i>x</i></sub>)), as well as meteorology
(temperature, relative humidity (RH), and wind speeds) changes in winter.
From 1960 to 2010, the dramatic changes in emissions lead to +260 %
increases in sulfate, +320 % increases in nitrate, +300 %
increases in ammonium, +160 % increases in BC, and +50 % increases
in OC. The responses of PM<sub>2.5</sub> to individual emission species indicate
that the simultaneous increases in SO<sub>2</sub>, NH<sub>3</sub>, and NO<sub><i>x</i></sub> emissions
dominated the increases in PM<sub>2.5</sub> concentrations. PM<sub>2.5</sub> shows more
notable increases in response to changes in SO<sub>2</sub> and NH<sub>3</sub> as compared
to increases in response to changes in NO<sub><i>x</i></sub> emissions. In addition, OC
also accounts for a large fraction in PM<sub>2.5</sub> changes. These results
provide some implications for haze pollution control. The responses of
PM<sub>2.5</sub> concentrations to temperature increases are dominated by changes
in wind fields and mixing heights. PM<sub>2.5</sub> shows relatively smaller
changes in response to temperature increases and RH decreases compared to
changes in response to changes in wind speed and aerosol feedbacks. From 1960
to 2010, aerosol feedbacks have been significantly enhanced due to higher
aerosol loadings. The discussions in this study indicate that dramatic
changes in emissions are the main cause of increasing haze events in North
China, and long-term trends in atmospheric circulations may be another
important cause since PM<sub>2.5</sub> is shown to be substantially affected by
wind speed and aerosol feedbacks. More studies are necessary to get a better
understanding of the aerosol–circulation interactions. |
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| ISSN: | 1680-7316 1680-7324 |