关键词: 灰霾, PM_2.5, 消光系数, 混合层高度

Abstract:

Based on data from the environmental monitoring system, meteorological stations and Lidar stations in Chengdu from January 14 to 28, 2017, the evolution mechanism of a hazing process was analyzed.The results show that the hazing process is closely related to the weather situation.The change in meteorological factors plays an important role in particle diffusion.The correlation coefficients of PM_2.5 mass concentration with wind speed, temperature, and relative humidity are -0.36, 0.45 and 0.20, respectively.During the hazing process, the average height of the mixing layer is about 378 m, and it is high in the daytime and low at the night.Trough the correlation analysis between the mixing layer height and the particle mass concentration at the ground in about two hour interval, it shows that the mixing layer height can play a significant role in the diffusion of ground particles.The correlation coefficient increases from -0.47 to -0.63 during the two hour period.This can to some extent indicate the evolution trend of particle mass concentration in the next few hours.In summary, the results obtained in this study can provide a theoretical basis and research reference for the early warning, prediction of local haze process, and pollution prevention and control.

Key words: Haze, PM_2.5, Extinction coefficient, Mixing layer height