Today we review a description of a new national inventory of hazardous air pollutants that are rated according to the exposure of the population to various carcinogens present. Results indicate that of 21 pollutants, arsenic and benzene are found at the top of the list for each province with most (73%) of the emissions coming from agriculture, construction and transportation 15% from residential wood burning and forest fires and only 6% from industrial sources. Quebec was found to have the highest contributions from arsenic.
Key Quotes:
“long-term health risks (cancer and non-cancer) were estimated by calculating exposure (intake) and applying cancer risk factors or non-cancer hazard quotients to the resulting intake level. This process enables the ranking of air pollutants based on lifetime excess cancer risk or non-cancer hazard indices in each census tract[under the National-Scale Air Toxics Assessment (NATA) program ]”
“the CAREX Emissions Mapping Project (EMP) in Canada, a Google Earth-based data set that includes indicators based on emissions of 21 known and suspected carcinogens to air, as reported to the NPRI [National Pollutant Release Inventory (NPRI)] and from our own estimates of emissions from transportation and residential heating”
"in 2011, Environment Canada estimated emissions of fine particulates in Canada to be on the order of 1.18 million tonnes …Of that, 73 % was attributed to dust from agriculture, construction, and transportation; 9 % to residential wood burning; 6 % to forest fires; and only 6 % to industrial activities”
“between 94 and 99 % of Total TEQ [annual toxic equivalent emissions to air in kilograms for each substance], for each province or territory is contributed by only five substances, based on the associated TEQ ranks ... Arsenic was most frequently the top contributor to Total TEQ, followed by benzene, benzo[a]pyrene, 2, 3, 7, 8-tetrachlorodibenzo -p-dioxin (TCDD), 1,3-butadiene, lead and benzo[b]fluoranthene”
“in Quebec, arsenic emissions are the top contributor to Total TEQ”
“our results suggest that wood smoke from residential heating may be an important source of cancer-related pollutants, indicating a shift away from focusing on industrial activities may be warranted in some regions of Canada.”
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