The 13th World Conference on Tobacco OR Health

Objective: What happens to secondhand smoke (SHS) outdoors?

Methods: Three experiments were conducted using real-time monitors for respirable particles (RSP) or particulate polycyclic aromatic hydrocarbon (PPAH) carcinogens to investigate the levels of secondhand smoke on two cruise ships in the Caribbean, in five outdoor cafes in Helsinki, Finland, and outdoors on a college campus.

Results: Smoking in outdoor areas of the cruiseship tripled the level of PPAH relative to indoor and outdoor areas in which smoking did not occur, despite the strong breezes and unlimited dispersion. Outdoor smoking areas were contaminated with PPAH to nearly the same extent as the ship's casino. A cigarette smoked in a well-ventilated 28 m3 stateroom increased PPAH levels 100-fold, emitting 21 micrograms of PPAH per gram of tobacco smoked. RSP levels in five outdoor cafes with smokers were 5 to 20 times higher than on the sidewalks along busy streets. Nonsmokers surrounded by a group of smokers are always downwind from the source. Point source cigarette RSP declines inversely with distance, and PPAH declines inversely as the square of distance. SHS outdoors increases the exposure of outdoor hospitality workers, such as waitstaff, bartenders, and musicians, as well as members of the public, to harmful fine particle air pollution and carcinogens. SHS outdoor air pollution is mediated by source strength, source geometry, plume rise, wind velocity, atmospheric stability, distance, and surrounding structures. These data have important implications for the regulation of outdoor air pollution from SHS under existing state or federal environmental statutes.