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Montana 



During 1990, the Montana Department of Health and Environmental Sciences, 

 Air Quality Bureau (AQB) operated five sulfation plate sampling sites in 

 the Scobey, Montana area. These were: (1) Richardson Residence; (2) 

 Flaxville; (3) TV Tower Hill; (4) Scobey Downtown; and (5) Four Buttes. 

 The sites were chosen to monitor potential sulfation level increases in 

 the area due to the Sask Power generating plant near Coronach, Saskatche- 

 wan. Table 10 summarizes 1990 sulfation plate data. 



Table 10 . --Sul fation rates for five Montana sites operated during 1990. Values of 



sulfation rate are in mg/100 cm* /day 



Site Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. 



Richardson 0.00 0.00 0.02 0.04 0.00 0.00 0.02 0.00 *N.D. N.D. N.D. 0.02 



Flaxville 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.02 



TV Tower 0.00 0.04 0.10 0.00 0.00 0.00 0.03 0.00 0.00 0.03 0.01 0.01 



Scobey 0.00 0.00 0.03 0.00 N.D. N.D. 0.00 N.D. 0.00 0.00 N.D. 0.00 



Four Buttes 0.00 0.00 0.04 0.02 0.00 N.D. 0.01 N.D. 0.00 0.00 N.D. 0.00 



'Indicates no data available. 



There are no federal or state standards for sulfation rate, but readings 

 greater than 0.5 mg/100 cm 2 /day indicate potential sulfation problems. 

 Since the highest reading experienced during 1990 was only 0.1 mg/100 

 cm 2 /day during March (TV Tower site), sulfation rates during the entire 

 year were obviously well below the potential problem rate. In light of 

 the low sulfation rates experienced over the decade-long sampling period, 

 it was decided by the AQB to terminate the sulfation plate sampling net- 

 work after December, 1990. 



