Wintertime vertical profiles of air pollutants over a suburban area in central Taiwan

Using a tethered balloon, vertical air pollutant concentrations (CO, SO2, NO, NO2 and O3) were measured in central Taiwan during field campaigns in the winters of 1999 and 2001. Modified novel lightweight sampling equipment was used to take samples at heights of 1, 13, 100, 300, 500 and 1200 m. A balloon was launched every 3 h and in total there were 133 flights during the three campaigns. The data were collected in order to examine the temporal and vertical variations of pollutants. The average daytime profiles showed greater vertical convection mixing in unstable circumstances. The characteristics of shapes and time behavior of profiles are reported. Except for a slight decrease near the ground and strong photochemical reactions at clear daytime, titration of O3 by NO was observed at all altitudes in the atmospheric boundary layer during these campaigns. Ground level ozone may be contributed by downward mixing from above. A fair correlation appeared between the maximum ozone concentration at the surface during the daytime ( ) and average ozone concentration above the NBL ( ). A linear regression equation is shown as .