Contribution of Secondary Particles to Wintertime PM2.5 During 2015-2018 in a Major Urban Area of the Sichuan Basin, Southwest China
Contribution of Secondary Particles to Wintertime PM2.5 During 2015-2018 in a Major Urban Area of the Sichuan Basin, Southwest China
复制标题
2015-2018年四川盆地主要城区二次颗粒物对冬季PM2.5的贡献
DOI：
10.1029/2020ea001194
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Tan Q. W.
中科院分区：
文献类型：
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作者：
Du X. X.;Shi G. M.;Zhao T. L.;Yang F. M.;Zheng X. B.;Zhang Y. J.;Tan Q. W.
提出了一种基于空气质量监测数据估算二次PM2.5浓度的新方法——近似包络法（AEM）。这种方法使得仅使用常规观测就能获得二次PM2.5的长期特征成为可能。以四川盆地主要城市成都为研究对象，分析了2015 - 2018年冬季不同PM2.5污染水平下的次生PM（2.5）浓度及其变化特征。结果表明，在轻度、中度和重度污染状态下，二次PM2.5浓度范围为52.3 ~ 122.8 μ g·m(-3)，分别占PM2.5总量的56.3%、63.6%和67.4%。2015 - 2018年，二次PM（2.5）浓度呈逐年上升趋势，一次PM（2.5）浓度呈显著下降趋势。一次和二次PM2.5的日变化均呈显著的单峰型，但分别在早晨和中午最大。高（低）相对湿度和温度（风速和气压）等特定气象条件加重了成都冬季二次颗粒物污染，反映了西南四川盆地区域气候变化对城市大气污染的影响。
A novel method, noted as approximate envelope method (AEM), was developed to estimate the secondary PM2.5 concentrations based on the air quality monitoring data. This approach made it possible to obtain the long-term characteristics of the secondary PM2.5 using only conventional observations. The secondary PM(2.5 )concentrations and their variation characteristics under different PM2.5 pollution levels during wintertime of 2015 to 2018 in Chengdu, a major urban area of Sichuan Basin over Southwest China, were analyzed. The results showed that the secondary PM2.5 concentrations ranged from 52.3 to 122.8 mu g.m(-3) and accounted for 56.3%, 63.6%, and 67.4% of the total PM2.5 in slight, moderate, and heavy pollution status, respectively. Additionally, the concentrations of secondary PM(2.5 )increased year by year, while the concentrations of primary PM2.5 performed significant decreasing trends from 2015 to 2018. The diurnal variations of primary and secondary PM2.5 presented a significantly unimodal patterns but with maximum at morning and noon, respectively. Specific meteorological conditions such as high (low) relative humidity and temperature (wind speed and air pressure) aggravated the secondary particulate pollution in wintertime of Chengdu, reflecting an influence of regional climate change over the Sichuan Basin of Southwest China on the urban air pollution.