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Abstract The spatial and temporal distributions of PM2.5, as well as the source characteristic were analyzed in Beijing-Tianjin-Hebei region by applying the combination of numerical model CAMx and the direct measurements. The results showed that PM2.5, which had bimodal daily distributions, was characterized with obvious seasonal pattern with higher concentrations in Winter and Autumn and lower concentrations in Spring and Summer. During the heavy polluted days, high concentrations of PM2.5 (>150μg/m3) was normally occurred in the North China Plain (NCP) locating beside the Tihang Mountain, especially to the internal cities of Beijing, Baoding, Shijiazhuang etc. However, mountain areas surrounded had lower PM2.5 concentrations in comparison with the former plain. Totally, 73% of the BTH region had PM2.5 concentration averaged above 150μg/m3, and the contributions from external transport to the particulate mass burden of Beijing, Tianjin and Shijiazhuang were 58%, 54% and 39%, respectively. It was found that regional transportation exerted a significant impact to the local PM2.5 loadings during a serious pollution weather induced by the southerly incoming pollutants transported via long distance on 6~12th October 2014.
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Received: 10 March 2015
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