Exceeding the One-hour Objectives for Sulphur Dioxide

Map of monitoring stations

One-hour exceedances of the sulphur dioxide objective occur most often at the Redwater station and the oilsands stations, north of Fort McMurray. In 2007, there were 23 one-hour sulphur dioxide exceedances (13 at Redwater, 4 at Mannix, two at Millennium, and one at each of Lower Camp, Mildred Lake, Buffalo Viewpoint and Fort McKay). The one-hour average objective is 172 parts per billion (ppb). There were two exceedances of the 24-hour objective in 2007 (not shown), one at Redwater and one at Mannix. The 24-hour objective is 57 parts per billion.