Secondhand smoke levels in Scottish bars 5 years on from the introduction of smoke-free legislation

ObjectiveTo determine current secondhand smoke (SHS) concentrations in bars previously assessed as part of an evaluation of Scottish smoke-free legislation 5 years ago.DesignComparison between SHS levels measured in 2006 and 2011 in 39 pubs in 2 Scottish cities.MethodsFine particulate matter (PM(2.5)) was measured discreetly for 30 min in each bar on one or two visits 5 years after the previous visit in May/June 2006. These 5-year follow-up visits were undertaken on the same day of the week and at approximately the same time of day.ResultsAverage PM(2.5) levels measured in a total of 51 bar visits in 2011 were 12 µg/m(3) (range 2-155 µg/m(3)) compared to 20 µg/m(3) (range 6-104 µg/m(3)) in the period immediately after the ban in 2006. Fine particulate concentrations in all but two visits in 2011 were comparable to PM(2.5) levels measured in outside ambient air on the same day, with 92% of visits (n=47) providing 30-min average PM(2.5) concentrations less than 25 µg/m(3).ConclusionsThese results are one of the longest follow-up of any national smoke-free legislation and indicate that, 5 years after introduction, compliance is high and that the legislation continues to provide bar workers and non-smoking customers protection from SHS.