Differential impacts of smoke-free laws on indoor air quality.

The authors assessed the impacts of two different smoke-free laws on indoor air quality. They compared the indoor air quality of 10 hospitality venues in Lexington and Louisville, Kentucky, before and after the smoke-free laws went into effect. Real-time measurements of particulate matter with aerodynamic diameter of 2.5 microm or smaller (PM2.5) were made. One Lexington establishment was excluded from the analysis of results because of apparent smoking violation after the law went into effect. The average indoor PM2.5 concentrations in the nine Lexington venues decreased 91 percent, from 199 to 18 microg/m3. The average indoor PM2.5 concentrations in the 10 Louisville venues, however, increased slightly, from 304 to 338 microg/m3. PM2.5 levels in the establishments decreased as numbers of burning cigarettes decreased. While the Louisville partial smoke-free law with exemptions did not reduce indoor air pollution in the selected venues, comprehensive and properly enforced smoke-free laws can be an effective means of reducing indoor air pollution.