* Cigarette smoking is the single most preventable cause of morbidity and mortality
* Secondhand smoke is the third leading preventable cause of death in the U.S.
* Secondhand smoke is a major source of indoor air pollution, containing a complex mixture of more than 4,000 chemicals, more than 50 of which are cancer-causing.
* It is a cause of cardiovascular disease, respiratory illness, and lung cancer, among both smokers and nonsmokers.
* About one-third of the U.S. population is protected by a local or state smoke-free indoor air law.
* As of July 1, 2006, 2,282 U.S. municipalities had local smoke-free laws, 474 of which provided 100 percent smoke-free protection.
* The authors assessed the impacts of two different smoke-free laws on indoor air quality.
* They specifically wanted to evaluate the impact of the laws on indoor particulate matter with an aerodynamic diameter of 2.5 [micro]m or smaller ([PM.sub.2.5]).
* They compared the indoor air quality of 10 hospitality venues each in Lexington and Louisville, Kentucky, before and after the smoke-free laws went into effect.
* The Lexington law, which went into effect April 27, 2004, prohibits smoking in most public places.
* The Louisville law, by contrast, allows smoking if
-- establishments derive 25 percent or more of their sales from alcohol or
-- have a bar area that can be physically separated from a dining area by walls, a separate ventilation system, or both.
* The average indoor [PM.sub.2.5] concentrations in the nine Lexington venues decreased 91 percent, from 199 to 18 [micro]g/[m.sup.3].
* The average indoor [PM.sub.2.5] concentrations in the 10 Louisville venues, however, increased slightly, from 304 to 338 [micro]g/[m.sup.3].
* Among nine Lexington locations, average indoor [PM.sub.25] concentrations varied from 21 to 422 [micro]g/[m.sup.3] with a mean of 199 [micro]g/[m.sup.3] before the law went into effect.
* Smoking density was 2.29 ([+ or -]1.92) bc/100 [m.sup.3].
* After the smoke-free law was implemented, when smoking density was 0, the average indoor [PM.sub.2.5] concentration in the same Lexington locations was 18 [micro]g/[m.sup.3], representing 9 percent of the mean before the law went into effect.
* When 10 Louisville locations were measured before the law went into effect, average indoor [PM.sub.2.5] concentrations varied from 29 to 1,110 [micro]g/[m.sup.3], with a mean of 304 [micro]g/[m.sup.3].
* Smoking density was 0.73 ([+ or -].49) bc/100 [m.sup.3].