Health implications of combustion engine exhaust

Abstract

The internal combustion engine is the primary power source in road traffic. Particulate matter, nitrogen oxides, hydrocarbons, and carbon monoxide engine emissions are regulated. New technology engines have much lower emissions of these exhaust components, but most vehicles currently on the road still rely on conventional engine technology. New biomass-based and non-petroleum synthetic components blended with conventional fuels may contribute to a reduction in exhaust emissions. Further reduction of regulated emissions is accomplished by exhaust after-treatment. However, even with these adaptations conventional engines produce exhaust fumes that have many toxic properties, and population-based studies show that exposure to emissions from road vehicles is associated with an increased burden of cardiovascular and respiratory disease and mortality, including lung cancer. Regarding the growing knowledge of toxicity mechanisms, additional markers and toxicity testing will be needed to evaluate the health impact of exhaust not only of improved and new engines concepts but also of retrofitted exhaust after-treatment and alternative fuels systems.