All data was stored on site and offloaded during regular servicings, at which time the air quality monitors were inspected and calibrated in accordance with methods described in the Code of Federal Regulations. The period of record at Breton extended from October 1994 through August 1998 and at Dauphin from March 1996 to May 1998. All data was quality controlled through calibration reports and station operator notes. The data was reduced and analyzed to determine significant characteristics of ambient air quality and meteorology affecting these locations. Hourly concentrations of SO 2 and NO 2 at both stations were less than 6 ppb for over half the study period.
Mean concentrations are generally higher in the fall and winter months at both stations.
No significant diurnal trends are evident. Maximums at Dauphin are mostly associated with winds from north-northeast. SO 2 maximums at Breton are primarily seen with northerly winds while NO 2 maximums are generally from south-southwest. On average, SO 2 concentrations are higher at Dauphin than Breton while NO 2 is nearly equivalent. Higher maximums are seen at Breton.