Measurement and Analysis of the Vertical Distribution Characteristic of the Atmospheric Particle Concentration in Beijing District

Abstract

In this paper, the vertical distributions of atmospheric particulate matter (PM2.5 and PM10) around residential building and in open space in Beijing district are measured and analyzed. The PM data in residential building environment is obtained by measuring it at each floor windows of the building, and the data in open space is obtained by measuring it at a rising hot-air balloon. The vertical distribution characteristics of PM concentration for different conditions of wind speed and direction are discussed. It is found that the distribution of PM concentration is in close association with the changing of wind for both residential building environment and open space. The results show that in breeze day, the highest atmospheric particle concentration around the residential building appears at a height about 20 m, and the coverage heights (defined by PM value less than 80 of that on ground) of PM2.5 and PM10 in free space are about 400 m and 100 m respectively; but for strong windy day, the distribution of atmospheric particles tends to be smooth along the residential building, and the coverage heights of PM2.5 and PM 10 in free space are all about 300 m. This paper also investigates the relationship between the vertical attenuation of PM concentration and the speed of wind at different heights. The natural accumulation phenomenon of atmospheric PM under the effect of microgravity is observed.