New evidence strengthens the link between air pollution and heart disease. How strong is the data suggesting a causal relationship between the two? Dr. Sidney Smith, professor of medicine and director of the Center for Cardiovascular Science and Medicine at the University of North Carolina in Chapel Hill says there are two areas of interest in determining the effect of air pollution on the heart. One area being examined is whether air pollution can trigger acute cardiac events, and the other is whether chronic exposure to air pollution can cause the development of long-term cardiovascular disease. Which patients are most at risk for developing cardiovascular health problems from exposure to particulate matter, and how can patients limit their risk of adverse cardiovascular disease-related events from air pollution, even in urban areas? How does heavy air pollution in developing countries or during exercise impact the heart? Dr. Janet Wright hosts.