Our goal is to estimate Canadians' potential exposures to the most common known or suspected carcinogens in community settings outside of work. This includes exposures via outdoor air, indoor air and dust at home, drinking water, and foods and beverages.
We use a risk-based approach to produce indicators of potential lifetime excess cancer risk circa 2011. This allows us to compare substances and exposure pathways, and supports priority setting for exposure reduction or elimination activities. The indicators typically show a national average and maximum lifetime excess cancer risk, based on actual measured data, for each substance and exposure pathway.
Potential lifetime excess cancer risk is calculated by multiplying intake (the amount inhaled or ingested) by a cancer potency factor or unit risk factor. For most substances, we estimated average and maximum intake using standard breathing and ingestion rates along with average and maximum measured levels in each exposure pathway (except food and beverages).
- The indicators are general estimates, and do not represent an actual risk for any specific Canadian. We assume that exposure occurs at the same level, 24 hours per day, for 70 years. This is rarely true for any single individual, but using a standard set of assumptions allows us to provide a relative ranking for known and suspected carcinogens across exposure pathways.
- At any one place, measured levels may change due to changes in source emissions.
- For any one person, intake may change over time, or as they move from place to place or change their eating habits.
We have also developed:
- eRISK, a tool that allows users to calculate lifetime excess cancer risk using local data or evaluate changes using different measured level scenarios.
- Highly detailed maps of known and suspected carcinogen concentrations in outdoor air across Canada, with estimates of the number of people exposed at levels above or below the national average.