Repeated exposures are more dangerous, and can worsen your cholesterol, increase the odds of plaque building in arteries, and raise the risk of chest pain, weakness, or heart attack.
Health officials say there’s no reason to think that can’t happen from breathing in smoke outdoors.
“There’s no risk-free level of secondhand smoke,” said Brian King, an expert on secondhand smoke with the Centers for Disease Control and Prevention.
However, it’s hard to pin down the health effects of outdoor smoke. There have been some studies — fewer than a dozen — that tried to measure how much secondhand smoke can be found outdoors. Some have found levels that rival what people may breathe indoors, depending on which way the wind is blowing or whether there’s an overhang or sheltered area that can trap smoke.
One study detected significant fumes as far as 44 feet away from a smoker.
“If you can smell it, it’s obviously there,” said James Repace, a Maryland-based scientist-consultant who’s done some of the outdoor studies.
Two small studies tested about two dozen nonsmokers at a smoky outdoor dining area in Athens, Ga. The saliva tests detected significant jumps in cotinine, a substance produced when the body metabolizes nicotine.
That doesn’t mean it’s causing chronic illness, though. Repace thinks only two kinds of people may face a serious health risk outdoors — those with severe asthma and staff at outdoor cafes where smoking is allowed.
Indeed, health advocates in some places have focused on sites like sidewalk cafes, feeling they can’t make the case for beaches or open-air parks.