2014年京津冀地区PM_(2.5)浓度时空分布及来源模拟

采用模式(CAMx)模拟与污染物、气象观测资料相结合的方式,分析了2014年京津冀地区PM2.5时空分布及来源特征.结果表明:PM2.5具有较为明显的时间变化规律,呈秋冬高、春夏低的规律和双峰型分布的日变化特征;重污染日PM2.5高浓度(PM2.5150μg/m3)主要分布在太行山前的华北平原区,特别是北京、保定、石家庄一线,而太行山、燕山等西部及北部山区PM2.5浓度明显低于平原区;重污染日京津冀地区PM2.5平均浓度在150μg/m3以上的面积约占总面积的73%;重污染日北京、天津、石家庄市的PM2.5外来输送率分别为58%、54%、39%;2014年10月6~12日京津冀地区发生的一次重污染过程中污染物由南向北输送,区域输送对于各地区PM2.5浓度有着十分重要的影响.

Spatial and temporal distrubions and source simulation of PM2.5 in Beijing-Tianjin-Hebei region in 2014

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.