A research found that signs banning smoking may not have as much of an impact on secondhand smoke concentrations as the presence of ashtrays or ashtray equivalents. The research was published September 4 in the open access journal PLOS ONE by Constantine Vardavas from the Harvard School of Public Health and colleagues from other institutions.
The authors measured the success of a non-enforced, nationwide smoke-free legislation in Greece by testing levels of secondhand smoke before the ban and for two years afterward. Following the 2010 legislation, secondhand smoke concentrations dropped immediately, but gradually increased again in subsequent measurements. However, all measurements after the ban remained significantly lower than levels of secondhand smoke measured before the legislation.
They found that outdoor or indoor signs that banned smoking did not correlate with levels of secondhand smoke in areas where signs were posted. However, the presence of ashtrays, or ashtray equivalents, such as candleholders, was strongly associated with a higher concentration of secondhand smoke. Based on their results, the authors conclude "While the public may be supportive of smoke-free legislation, adherence may decline rapidly if enforcement is limited or non-existent. Moreover, enforcement agencies should also focus on the comprehensive removal of ashtray equivalents that could act as a cue for smoking within a venue."