2014年10月北京市一次空气重污染过程分析

ANALYSIS ABOUT THE CHARACTERISTICS AND FORMATION MECHANISM OF A SERIOUS POLLUTION EVENT IN OCTOBER 2014 IN BEIJING

采用轨迹模拟与观测资料相结合的方式,对北京市2014年10月6—12日1次典型空气重污染过程的大气环境背景、气象条件和形成原因进行分析。结果表明:京津冀区域稳定的气象条件是形成重污染的主要原因,重污染过程中大气层结稳定,平均逆温强度每100 m为3.42℃,平均风速为1.56 m/s,平均湿度为83.13%;重污染过程中10月8—11日污染最重,北京ρ(PM_(2.5))日均值平均为264μg/m^3,且京津冀约20×104km^2国土面积处于重度污染水平;模拟结果显示污染最重的8—11日区域输送对北京PM_(2.5)贡献率在61%~69%;区域输送对北京PM2.5浓度起着更为重要的作用。

In this paper,atmospheric environmental background,weather conditions and formation mechanism of one typical air pollution episodes in October 6th—12th 2014 in Beijing were investigated by combining observed data and numerical model CAMx. Results showed that the occurrences of heavy air pollution resulted mainly from stable atmospheric conditions regionally or locally. Observed heavy pollution episodes were characterized by a stagnant atmospheric structure with average wind speed of 1. 56 m/s,high humidity of 83. 13%,average inversion strongth was 3. 42 ℃ for 100 m. The air pollution in October 8th—11th was most serious with daily average PM_（2.5）concentration of 264 μg / m^3 in Beijing and heavily polluted land area in BeijingTianjin-and-Hebei region was about 20 × 104km^2. Model research showed that regional transmission contributions to the receptor sites in Beijing were between 61% ~ 69% during October 8 ~ 11 th and regional transportation played a more important role during this serious air pollution episode.