RELATIONSHIPS BETWEEN SULPHUR DIOXIDE POLLUTION AND METEOROLOGICAL FACTORS IN MONTREAL.

SO2 concentrations measured at six sampling stations in the region of Montreal during the year 1975 are considered, together with some meteorological variables measured at one site for the same year. A descriptive analysis of these data indicates which of the available meteorological variables are most related to the SO2 level: wind speed, wind direction and temperature, mainly in winter. Some winds have a cleaning effect whereas others favor pollution. Increasing temperature results in a decreasing SO2 level in the urban area. Some regression models are built for each station and a more detailed analysis is made of the meteorological variables effects on the SO2 level. These effects can be evaluated locally at each station. Finally a principal component analysis of the stations is made in order to evaluate the same effects globally in the region of Montreal.