The ‘two-way feedback mechanism’ between unfavorable meteorological conditions and cumulative PM2.5 mass existing in polluted areas south of Beijing

作者：Liangke Liu, Xiaoye Zhang, Junting Zhong, Jizhi Wang, Yuanqin Yang · 发表于：Atmospheric Environment · 年份：2019 · DOI：10.1016/j.atmosenv.2019.02.050 · 被引用次数：43 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric aerosols and clouds、Air Quality and Health Impacts

In winter, heavy aerosol pollution episodes (HPEs) occur frequently on the North China Plain (NCP) under unfavorable meteorological conditions. After the aerosol pollution with fine aerosol particles less than 2.5 μm (PM 2.5 ) accumulates to a certain extent in Beijing and its vicinity (BIV), boundary-layer (BL) meteorological conditions worsen due to radiative cooling effects of aerosols, which further facilitate PM 2.5 accumulation. This "two-way feedback mechanism" between unfavorable metrological conditions and cumulative PM 2.5 , particularly PM 2.5 explosive growth with mass concentration doubled in several to 10 h, has been found in BIV. To investigate whether the two-way feedback exists on the southern NCP, we selected four representative cities with radiosonde observations, which lie south of Beijing and used PM 2.5 data, radiation observations, and radiosonde data from December 2016 to the beginning of January 2017. We found that the two-way feedback existed in these four cities. In each city, HPEs included transport stages (TSs), during which relative strong winds transport pollutants into different regions, and cumulative stages (CSs), in which temperature inversions occur and became striking due to the radiative cooling effects of elevated aerosols under slight or calm winds. This would further cause an increase of PM 2.5 concentration. During the CSs, growth of PM 2.5 concentration was governed by the two-way feedback, which explained over 70% of the increase. D...