Air pollution is an important modifiable risk factor for cardiovascular disease. Acute exposure has been linked to a range of cardiovascular events including acute myocardial infarction and death. We have demonstrated that exposure to dilute diesel exhaust causes detrimental vascular and thrombotic effects that promote atherogenesis and myocardial ischaemia. These effects appear to be mediated through adverse effects on nitric oxide bioavailability. The epidemiology, pathophysiology and potential aetiology of the adverse cardiovascular effects of air pollution on the nitric oxide system will be discussed.