Sulphur dioxide (SO2) is one of the main atmospheric pollutants in central
Taiwan. This article analyses the SO2 concentration seasonal variations and
spatial distribution using data obtained from ten air quality monitoring s
tations and the Taiwan Weather Bureau. It reveals that SO2 concentration is
high in winter and low in summer and that high concentration centers are l
ocated south of the Taichung coal-fired power plant, the main source of SO2
emissions in the region. The location of high concentration centers change
s with different prevailing winds. SO2 variations due to wind direction are
not unique. During short periods, when meteorological conditions are const
ant, variation in the pollution sources cause variations in the spatial dis
tribution. This has been deduced by appreciation of `Intervention analysis'
to time series of hourly data.