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AIR QUALITY 



Saskatchewan 



As a result of construction at the water treatment plant, the 

 Coronach air quality monitoring station was dismantled in 

 September, 1986 and not relocated until the beginning of 1987. 

 Sulphur dioxide monitoring commenced once again on 

 February 5, 1987. Particulate monitoring began March 10, 1987. 

 Both instruments are presently located at a site approximately one 

 kilometre northeast of the previous location. 



Ambient sulphur dioxide monitoring began at Coronach in July 1979. 

 To date, a number of detectable concentrations have been recorded 

 at this site, however, violations of Saskatchewan's hourly or 

 24 hour standards (0.17 parts per million (ppra) and 0.06 ppm, 

 respectively) which could be attributed to power plant operations 

 have not occurred. The highest hourly value in 1987 was 0.071 ppm 

 which occurred on September 25 at 1400 hours. Weather information 

 for this day indicates winds blowing from the southern quadrants, 

 which suggests the power plant as the most probable source. The 

 highest 24 hour value of 0.009 ppm occurred on July 30. Weather 

 data indicates winds occurring from the southern quadrants 66% of 

 the time, again pointing to the power plant as the most probable 

 source. Figures 14 and 15 provide a summary of the maximum hourly 

 and daily SO concentrations measured during the past 5 years. 



Violations of Provincial sulphur dioxide standards have not 

 occurred at Saskatchewan Power Corporation's monitoring station 

 near the Montana border. This year's highest hourly value of 

 0.054 ppm occurred on February 28, 1987 at 1300 hours. Weather 

 information indicates winds blowing from the northwest which 

 suggests the power plant as the probable source. 



