This study has focused on cardio-respiratory illnesses caused by the principal components of smog, namely ozone and air-borne particulate matter. 2 Smog consists of a complex “soup” of pollutants, some of which may cause human health problems directly and others which may be precursors to causal contaminants or which are closely correlated with causal contaminants and hence act as “markers” for human health risks. The complexities associated with the cause/effect relationships between this soup of pollutants and human health are explored in this report. The focus of this analysis is Ontario. The basic concept and structure of the methodology and analyses are applicable to any.
