LAUSR

Based on the surface meteorological observation data collected by meteorological stations 57687 (Changsha), 57773 (Xiangtan) and 57780 (Zhuzhou) of Hunan province from January 14 to 20, in 2017, and the air monitoring data of Changsha City, Zhuzhou City and Xiangtan City provided by The National Environment Monitoring Station, this paper analyzed the stage characteristics of a continuous haze process in the Chang-Zhu-Tan Region of China and its influencing factors in late January of 2017. The results show that the haze process has stage characteristics with the fog and the haze alternating. Through correlation analysis, it is concluded that PM2.5 concentration, vapor pressure of water, dew point temperature and relative humidity are the four key factors determining visibility. Through analyzing main components, a meteorological factor consisting of vapor pressure of water, dew point temperature and relative humidity is established. A linear model featuring PM2.5 concentrations and visibility and a cubic curve model featuring the meteorological factor and visibility are set up. During the continuous haze process, the average concentration of PM2.5 is greater than 88 ug/m and is inversely related to the visibility. Accumulation of highly concentrated PM2.5 causes low visibility. With the changes of humidity and dew point temperature, fog and haze appear alternatively.