Particulate matter (PM) air pollution is one of the most prevalent involuntary exposures throughout the world with close to 100% of the population being exposed to levels of PM for which adverse health effects have been observed. Because humans primarily come into contact with PM via air, lung and airway diseases have been the main focus of health effects research in the past. More recent research has documented substantial long -term air pollution effects on the cardiovascular system. These fi ndings have shifted the research focus in air pollution epidemiology to cardiovascular disease (CVD).
CVD is the number one cause of morbidity and mortality in modern societies, accounting for approximately 48% of deaths in the developed world (Murray and Lopez, 1997 ). Atherosclerosis is the key underlying pathology of CVD and is caused by a multitude of known and unknown risk factors.
The combination of a very frequent disease and a highly prevalent exposure results in a large public health burden if PM air pollution exposure is actually causally related to atherosclerosis. There is already substantial evidence that short -term exposure to high levels of airborne PM leads to acute CVD events such as myocardial infarction, stroke, or death in people who have preexisting atherosclerotic disease. Only recently, results from animal studies have suggested that long -term exposure to PM air pollution can also induce atherogenesis. First evidence stems from rodents showing an accelerated development of atherosclerotic plaque under long -term exposure to concentrated ambient PM.