Impact of water vapor content on visibility: Fog-haze conversion and its implications to pollution control

Abstract

Abstract Atmospheric water vapor content, which reflects the total change of water vapor in the whole atmosphere, has an important effect on the atmospheric visibility (VIS). To investigate the variation of the VIS in Beijing during the past decades and to address the key factors affecting the VIS, the relationships of the VIS with the PM2.5 concentrations, the relative humidity (RH) and the total column water vapor (TCWV) have been explored in this study. The evolution characteristics of these factors in the fog-haze conversion process during the low-visibility (LVIS, VIS \u202fRH\u202f>\u202f40%), the VIS is more influenced by TCWV and RH. Under high RH and extremely low visibility conditions (RH\u202f>\u202f86% and VIS