Approaches to risk assessment of automotive engine exhausts

Contributions of alkenes to cancer risk from urban air pollution were estimated on the basis of radiation dose equivalent of target dose. The latter was inferred from the incremental carboxyhaemoglobin (COHb) level in urban areas, the ratio of epoxide-haemoglobin adducts to COHb levels in smokers and the alkenes/CO level ratios in cigarette smoke and urban air. This model predicts some 200 and 5 cancer cases annually in Sweden from ethene and propene, respectively. This indicates that the risk from alkenes is of the same order of magnitude as that from the particulate fraction of the pollution.