BBC: "Car fumes 'raise heart attack risk for six-hour window' "

Link to BBC web site

"Breathing in heavy traffic fumes can trigger a heart attack, say UK experts. Heart attack risk is raised for about six hours post-exposure, and goes down again after that, researchers found.

"They say in the British Medical Journal that pollution probably hastens rather than directly cause attacks. But repeated exposure is still bad for health, they say, substantially shortening life expectancy, and so the advice to people remains the same - avoid as far as is possible."