Canadian smog science assessment : Évaluation scientifique canadienne du smog : faits saillants et messages clés

You are asked to: • Exercise due diligence in ensuring the accuracy of the materials reproduced; •. Indicate both the complete title of the materials reproduced, as well as the author organization; and •. Indicate that the reproduction is a copy of an official work that is published by the Government of Canada and that the reproduction has not been produced in affiliation with or with the endorsem [...] This initiative is the most recent effort2 by the Government of Canada to assess the adverse effects of smog on Canadians and their environ- ment, quantify emissions of smog-forming pollutants, describe their behaviour in the atmosphere at a regional scale, and report on recent and projected levels of smog in the air we breathe. [...] The relative lack of data at low exposure levels, the potential for exposure misclassification, and the inherent heterogeneity of human populations imposes some limits on the interpretation of the form of the exposure-mortality relationship, especially at low concentrations. [...] Of particular importance is the confirmation of the impacts of long-term exposure to PM and the direction this gives to the adoption of an ambient target to reflect this relationship (i.e., an annual standard). [...] While ethical and logistical considerations limit the extent of controlled human exposure investigations, they have provided evidence of the presence of sensitive groups within the general population, the time-course of damage to the cardio-pulmonary systems, and the mechanisms by which O3 and PM could elicit effects (though the evidence is much less for PM).