PM10 in Canada

Annual mean PM10 concentrations in Canadian cities are between five and eight times estimated background levels. Federal and Provincial agencies in Canada are currently reviewing particulate standards, and considering replacing current total suspended particulate (TSP) standards with standards to regulate PM10 (thoracic particles) because epidemiological research suggests that this size fraction is active in the production of adverse health impacts. This paper documents the spatial and temporal variability of current particulate levels in Canada, and compares them with TSP standards presently implemented in Canada and PM10 standards as applied by the US EPA, state of California and the World Health Organization (WHO). Twenty-four-hour averaged PM10 data from the 52 sites described here exceed the standard as applied in California on up to 35% of monitoring days. The threshold suggested by the WHO for 24-h averaged concentrations in passed at the majority of the sites on approximately 5% of monitoring days.