To investigate the temporal and spatial variation characteristics of VOCs during fog and haze events,a comprehensive 58-day field observation experiment was conducted at the Donghai National Meteorological Observing Station in Jiangsu Province from November 19,2020,to January 15,2021.This study utilized a self-developed multi-rotor UAV observation system to observe two radiation fog events and two haze events,resulting in over 100 atmospheric boundary layer profiles,including air temperature,pressure,relative humidity (RH),wind direction,wind speed,VOCs,and O₃.The results show the following:In terms of time,the volume concentration of VOCs during nighttime in the haze process (0.225-0.253 ppm) (parts per million,ppm;1 ppm=10^-6) was significantly higher than during the daytime (0.191-0.205 ppm).Moreover,the volume concentration before fog formation (0.121-0.239 ppm) was significantly higher than during the fog process (0.056-0.209 ppm).During the fog process,VOCs' volume concentration exhibited an opposite trend to fog intensity.The height of the fog layer closely correlated with the sharp change in VOCs' volume concentration.In the fog layer (below 200 m),the VOC volume concentration (0.172-0.178 ppm) significantly decreased,being notably lower than pre-fog events (0.195-0.240 ppm).Above the fog layer (200-700 m),VOCs' volume concentrations underwent significant changes,which persisted for up to 1hour after fog dissipation.The stable high-humidity environment within the fog layer had a scavenging effect on water-soluble pollutants trapped within the temperature inversion layer,resulting in decreased concentrations of VOCs and O₃.