- 84 - 



storm. The remaining 25 violations cannot be attributed to the opera- 

 tions of the power plant and were likely caused by wind blown field 

 dusts. The provincial geometric mean of 70 H-crM 3 has not to date been 

 exceeded, with the highest mean of 48 ng' s occurring in 1981. Annual 

 down time for the monitor during the same period has ranged from a low of 

 10% to a high of 26%, for an 18% average. 



During 1990, ambient sulphur dioxide monitoring recorded no violations of 

 Saskatchewan Environment and Public Safety's hourly and 24-hour average 

 standards of 0.17 and 0.06 ppm, respectively. The highest recorded hour- 

 ly value of 0.085 ppm SO„ was recorded on July 16 at 1200 hours, as com- 

 pared to 0.112 ppm SO ? recorded in August of 1989. Weather information 

 obtained from the site indicated that winds at the time were blowing from 

 the southeast. As the power plant is located south of the monitoring 

 locations, it is the most probable source. The highest 24-hour average 

 reading of 0.010 ppm occurred on August 23, as compared to 1989' s highest 

 4-hour average reading of 0.017 ppm. Downtime for the monitor during the 

 12-month period was 1.8%, compared to 1989' s 2.2%. Figures 65 and 66 

 show in graphical form, maximum hourly and daily (24-hour) average 

 readings obtained at the monitoring station during the last five years. 



Suspended particulate concentrations obtained from the high volume 

 monitor at the same site for the 12-month period exceeded Saskatchewan 

 Environment and Public Safety's 24-hour average standard of 120 ng/m 3 /24 

 hrs on two occasions, October 2 and 26. Wind data for both dates 

 discount the plant as the source. The annual geometric mean of 35.4 

 |ig/m 3 is well below the provincial standard of 70.0 and is higher than 

 1989' s 20.8. Downtime for the monitor was 23% compared to 13% in 1989. 



