There is significant controversy about the level of fine particulate matter (FPM) that elevates risk of cardiovascular disease (CVD). Epidemiologists studied prospective data during a follow-up study of more than a million adults and found that CVD mortality risk increased by 64% in those who smoked three or fewer cigarettes per day and doubled in those who smoked a pack or more per day. Even those who were exposed to relatively low levels of FPM from second hand smoke or air pollution had substantially higher CVD mortality risk. Recent estimates in urban areas of China and India show FPM levels in excess of 100 mmg/m3 which is comparable to an active smoker's exposure of FPM (compare this to US urban levels of 10-24 mmg/m3).
PositiveTip: Minimize your exposure to FPM by living in the country when possible and exercising in the early morning when levels are the lowest.