Typical processes of ozone (O-3) pollution in the lower atmosphere in Shang
hai are studied in the winter, summer, and autumn of 1994. Relationships be
tween O-3-NOx (nitrogen oxide) concentrations and meteorological parameters
are analyzed in order to find meteorological indices corresponding to high
O-3 concentration days. Meteorological conditions favorable for high O-3 c
oncentrations usually appear when Shanghai is dominated by a high-pressure
system in the lower atmosphere, while a northwestern current prevails over
this area in the upper atmosphere. High O-3 concentrations can occur when t
he wind speed is relatively high. O-3 could increase rapidly on fog days. T
emperatures influencing O-3 concentrations are not as obvious in summer as
in winter. Some possible mechanisms for the measurement results are suggest
ed in this paper.