Study on chemical components and sources of PM2.5 during heavy air pollution periods at a suburban site in Beijing of China
| Autor: | Zheng Yang, Minghao Zhu, Xinxin Wang, Xuekui Qi, Shumiao Zhang, Qingyang Liu, Yanju Liu, Jingming Qu, Jia Kai |
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| Rok vydání: | 2021 |
| Předmět: |
Pollution
Atmospheric Science Gypsum 010504 meteorology & atmospheric sciences media_common.quotation_subject Air pollution chemistry.chemical_element 010501 environmental sciences engineering.material medicine.disease_cause 01 natural sciences chemistry.chemical_compound Beijing medicine Ammonium Waste Management and Disposal NOx 0105 earth and related environmental sciences media_common Seasonality medicine.disease chemistry Environmental chemistry engineering Environmental science Carbon |
| Zdroj: | Atmospheric Pollution Research. 12:188-199 |
| ISSN: | 1309-1042 |
| DOI: | 10.1016/j.apr.2021.03.006 |
| Popis: | PM2.5 and its main chemical components have been investigated during six air pollution periods across four seasons from Jun. 16, 2016 to Jun. 15, 2017 at a suburban site in Beijing, China. Daily PM2.5 mass concentrations were measured with associated ions, OC, EC, 16 PAHs and seven heavy metals. Mass closure analyses were conducted using measured and reconstructed chemical components. Chemical ratios were used to identify possible pollution sources, while principal component analysis (PCA) coupled with multiple linear regression (MLR) method was used to estimate the source contribution to PM2.5 mass. The annual mean PM2.5 concentration (96.7 μg m−3) is about 2.8 times the national level-2 standard limit, with apparent seasonal variation of daily exceedances as winter > spring > autumn > summer. Generally, higher levels are observed in winter and autumn than in spring and summer for NO3−, SO42−, NH4+, Cl−, K+, OC, EC, PAHs and metals Zn, As, Cu, Pb, along with higher concentrations of NOx, CO and SO2. Secondary ions and carbon fractions are most abundant over all seasons, except levels of dust related species Ca2+, Mg2+, Ca, Fe and Mn are also high in spring. The reconstructed results show that PM2.5 consists of mostly organic compounds (26–38%) and ammonium salts (NH4NO3 + (NH4)2SO4) (43–53%) in winter and autumn, while summer is dominated mainly by ammonium salts (81%). In spring, very high PM2.5 episodes are occasionally composed of large amount of soil/road dust and gypsum particles (23–55%) due to floating dust events with drier weather conditions and human activities. Fuel combustions and secondary sources are responsible for ~70% of PM2.5 mass while mobile source is mostly a regional origin. |
| Databáze: | OpenAIRE |
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