The presence of multiple smokers in outdoor settings is likely to increase exposure substantially from the single-smoker case. Our data can be used to estimate exposures for situations with multiple smokers. Since it is reasonable to assume that average smoke levels increase in proportion to the number of outdoor smokers, we can then roughly estimate levels of particle exposure for different distances from groups of smokers.

Our results show that a nonsmoker, who is near a smoker at an outdoor pub, cafe, or restaurant, can potentially inhale toxic smoke produced from a cigar or cigarette at very high levels. Our research proves that drifting secondhand smoke can indeed pose a significant nuisance or health risk for nonsmokers sitting or standing near smokers on outdoor patios.

Yes. Concentrated streams of outdoor tobacco smoke can, at the very least, act as a respiratory or eye irritant. But outdoor tobacco smoke may also pose a serious health hazard for severe asthmatics even if the exposure is transient, since tobacco smoke may act as a trigger. Those with compromised cardiovascular systems may be at risk from even brief exposures. People spending time near outdoor smokers over multiple hours, such as waiters or dinner guests, can receive exposure that exceeds the current USEPA limit on fine particulate matter pollution.

Some have argued that exposure to toxic chemicals can result from being near campfires or barbeques (outdoor grilling) -- in addition to from cigarettes -- but that no one is talking about banning these sources. This argument is a red herring and irrelevant to the consideration of smoking bans. Other sources should be considered independently from tobacco. In fact, we are unaware of the ability of people to indiscriminately burn campfires or have BBQs at cafes and on city sidewalks.