After exposure to dilute diesel exhaust, men with coronary disease had increased exercise-induced myocardial ischemia, along with depressed fibrinolytic function. The data reported suggest possible mechanisms for the detrimental effect of air pollution from traffic in patients with coronary disease. After exposure to dilute diesel exhaust, men with coronary disease had increased exercise-induced myocardial ischemia, along with depressed fibrinolytic function. The World Health Organization (WHO) estimates that air pollution is responsible for 800,000 premature deaths worldwide each year. 1 Short-term exposure to air pollution has been associated with increases in cardiovascular morbidity and mortality, with deaths due to ischemia, arrhythmia, and heart failure. 2 In a large cohort study from the United States, Miller et al. recently reported that long-term exposure to air pollution increases the risk of death from cardiovascular disease by 76%. 3 These associations are strongest for fine particulate air pollutants (particulate matter of less than 2.5 μm in aerodynamic diameter PM 2.5 ), of which the combustion-derived nanoparticulate in . . .