<qa>  What is the association between exposure to ambient air pollution and pulmonary disease?The association between exposure to ambient air pollution and pulmonary disease has been well established. Recent studies have attempted to investigate the effect of air pollution, specifically exposure to PM 2.5, on cardiovascular outcomes. Acute exposure to PM 2.5 is associated with increased heart rate, decreased heart rate variability, and increased incidence of cardiac arrhythmia. Population based research from the United States and Europe has demonstrated increased rates of emergency room visits, hospitalization and cardiovascular morbidity in association with increased daily concentrations of fine particulates. 