Studies in humans and animals suggest that both short-term and long-term exposure to elevated traffic levels can adversely affect pulmonary and cardiovascular function. Although several studies have examined associations between blood pressure and air pollution, few have examined pulse pressure or measures of systemic inflammation. Rioux et al. studied residential traffic exposure with C-reactive protein (CRP), a measure of inflammation, and pulse pressure in 1,017 U.S. Puerto Ricans 45