Characteristics of air quality and sources affecting fine particulate matter (PM) levels in the City of Red Deer, Canada.

With concern about levels and exceedances of Canadian and provincial standards and objectives for fine particulate matter (PM) in recent years, an investigation of air quality characteristics and potential local and long-range sources influencing PM concentrations was undertaken in the City of Red Deer, Alberta. The study covered the period May 2009 to December 2015. Comparatively higher concentrations of PM were observed in winter (mean: 11.6 μg/m, median: 10 μg/m) than in summer (mean: 9.0 μg/m, median: 7.0 μg/m). Exceedances of the 1 h Alberta Ambient Air Quality objective (3-31 times per year > 80 μg/m) and the 24 h Canada-Wide Standard (2-11 times per year > 30 μg/m) were found at the Red Deer Riverside air monitoring station, particularly in 2010, 2011 and 2015. Positive matrix factorization (PMF) followed by multiple linear regression (MLR) analysis identified a mixed industry/agriculture factor as the dominant contributor to PM (39.3%), followed by an O-rich (biogenic) factor (26.4%), traffic (19.3%), biomass burning (10.5%) and a mixed urban factor (4.4%). In addition to local traffic, the mixed industry/agriculture factor - inferred as mostly upstream oil and gas emission sources surrounding Red Deer - was identified as another potentially important source contributing to wintertime high PM pollution days. These findings offer useful preliminary information about current PM sources and their potential contributions in Red Deer; and this information can support policy makers in the development of particulate matter control strategies if required.