| Author: | Li, Hongyi |
| Title: | Trends of summer PM₂.₅ and its components during 2013-2017 in China: the effects of meteorological changes and emission reductions |
| Degree: | M.Sc. |
| Year: | 2020 |
| Subject: | Air quality -- Standards -- China Air -- Pollution -- China Climatic changes Air -- Pollution -- Law and legislation -- China Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Civil and Environmental Engineering |
| Pages: | ix, 98 pages : color illustrations |
| Language: | English |
| Abstract: | Chinese government released the Air Pollution Prevention and Control Action Plan in 2013, summertime PM₂.₅ and its components concentration decreased significantly in the latter five years. Here, we utilized the latest regional chemical transportation model (WRF-CMAQ) to investigate the effects of meteorological changes and anthropogenic emission reductions on summertime PM₂.₅ and its components from 2013 to 2017. The anthropogenic emission reductions are the main elements that significantly reduced PM₂.₅ and its components concentration in summer. Nevertheless, meteorological changes also play a vital role in changes in PM₂.₅ and its components. The variations in summertime PM₂.₅ and its components caused by meteorological changes had obvious regional characteristics, which showed that summer PM₂.₅ concentration increased in Central, East and South China, while that in other regions declined. Changes in temperature and specific humidity caused a decline trend in summer PM₂.₅ and its components in Beijing-Tianjin-Hebei and Sichuan-Chongqing, while wind speed changes markedly increased summer PM₂.₅ and its components concentration in Yangtze River Delta. Variations in Planetary boundary layer height, cloud fraction and precipitation had little effect on summer PM₂.₅ and its components concentration. The influence of changes in biogenic emissions and boundary conditions on the summertime PM₂.₅ concentration was negligible during the five-year period. After the implementation of the emission control, in addition to the ascent in VOCS emissions, the emissions of particulate matter, EC, OC, CO, NOX, SO₂ and NH3 all decreased, with particulate matter and SO₂ emissions reducing the most. The reduction of SO₂ and particulate matter reduced the summertime PM₂.₅ and its components concentration considerably, especially in Beijing-Tianjin-Hebei, Yangtze River Delta and Sichuan-Chongqing. Compared with rural areas, the downward trend in urban areas was more obvious in summer. Our outcomes indicated that the role of meteorological changes on summertime PM₂.₅ concentration cannot be ignored and reducing SO₂ and PM₂.₅ emissions is an efficient measure to control PM₂.₅ pollution. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 5365.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 3.9 MB | Adobe PDF | View/Open |
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