Article Text
Abstract
Objective To determine current secondhand smoke (SHS) concentrations in bars previously assessed as part of an evaluation of Scottish smoke-free legislation 5 years ago.
Design Comparison between SHS levels measured in 2006 and 2011 in 39 pubs in 2 Scottish cities.
Methods Fine particulate matter (PM2.5) 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.
Results Average PM2.5 levels measured in a total of 51 bar visits in 2011 were 12 μg/m3 (range 2–155 μg/m3) compared to 20 μg/m3 (range 6–104 μg/m3) in the period immediately after the ban in 2006. Fine particulate concentrations in all but two visits in 2011 were comparable to PM2.5 levels measured in outside ambient air on the same day, with 92% of visits (n=47) providing 30-min average PM2.5 concentrations less than 25 μg/m3.
Conclusions These 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.
- Environmental tobacco smoke
- inhalation exposure
- hospitality sector
- public health
- exposure assessment
- secondhand smoke
Statistics from Altmetric.com
- Environmental tobacco smoke
- inhalation exposure
- hospitality sector
- public health
- exposure assessment
- secondhand smoke
Introduction
Smoke-free legislation has been introduced across much of Europe in the past decade. The Smoking, Health and Social Care (Scotland) Act 2005 to ban smoking in substantially enclosed public places was implemented across Scotland on the 26 March 2006.1 Similar legislation was introduced in England, Wales and Northern Ireland in the spring and summer of 2007.
The effects of the Scottish restrictions on the hospitality industry have been subject to a comprehensive evaluation programme that has included measurement of changes in air quality in bars,2 ,3 assessment of bar workers' health4 and examination of changes in attitudes towards legislation.5 At a population level, changes in children and adults' exposure to secondhand smoke (SHS) has been shown to have reduced since the introduction of restrictions6 ,7 while studies on the frequency of cardiac events in the community8 and hospitalisations of patients experiencing severe asthmatic episodes9 have also demonstrated significant reductions in the time period since the smoke-free legislation came in to effect.
Previously, our group reported on SHS levels in Scottish bars immediately prior and immediately after the introduction of the ban in March 2006.2 Our data showed a clear and significant (median −86%) reduction in SHS levels as assessed by measuring particulate matter less than 2.5 microns in size (PM2.5) in a random selection of bars in the cities of Aberdeen and Edinburgh. The average concentration reduced from 246 to 20 μg/m3. Enforcement activity and compliance was clearly at a high level in the immediate aftermath of the introduction with over 3900 inspections across Scotland between March and May 2006 and a reported 99.4% compliance rate,10 but this level of inspection has not been maintained.
In order to determine if SHS levels in Scottish bars have remained at the low levels previously reported, a measurement campaign repeating the visits of May–June 2006 was carried out. This paper describes the levels of SHS measured 5 years after the introduction of smoke-free legislation in Scotland and compares the data using identical study methods to that generated in 2006. This 5-year follow-up represents one of the longest evaluations of any national smoke-free legislation.
Methods
A visit to all bars visited during the 2006 measurement study was attempted. This cohort of 41 bars had been selected randomly from all public houses in the central areas of Aberdeen and Edinburgh, from a search of internet local service directories (http://www.yell.com and http://www.thomsonlocal.com). The visit to each pub was scheduled for the same time of day (±30 min), on the same day of the week and within 10 days of the date of the visit that had been carried out during May–June 2006. Visits had previously been categorised as ‘busy’ when conducted on Thursday, Friday or Saturday evenings between 17:00 and 23:00 with the ‘quiet’ time visits carried out on Monday to Thursday before 17:00.
As previously described,2 we used PM2.5 as our marker for SHS concentrations. In brief we used a battery operated aerosol monitor (TSI SidePak AM510 Personal Aerosol Monitor; TSI Incorporated, Minnesota, USA) fitted with an impactor in order to sample the concentration of PM2.5. The monitor was placed in a small bag with a short length of Tygon tubing attached to the inlet and left protruding to the outside. Measurements were carried out discreetly. The researcher aimed to place the bag containing the monitor at seat or table level to ensure that sampling was as close to breathing zone as possible and also tried to ensure that they were not within 1 m of anyone smoking. Concentrations were logged every 1 min for a minimum of 30 min during each visit.
The number of patrons and the number of those smoking at three time points (entry, 15 min post entry and 30 min post entry) was recorded. In addition, the presence of no smoking signage as required by the legislation, and the number of people smoking outside the pub either at the door entrance or in designated outdoor facilities, at the time of the researcher's entry and exit were noted.
Outdoor measurements of PM2.5 using the same device were made for at least 30 min on each day of sampling in the city where the bars being measured on that date were located.
Data analysis
Data from each visit was downloaded to a PC using the TSI TrackPro v3.41 software. A calibration factor of 0.295 was applied to all measurements to correct for the properties of SHS particles.11 A time-weighted PM2.5 average concentration was calculated for each visit.
Descriptive statistics, including the geometric and arithmetic means, SD, minimum, maximum and median, were generated for the PM2.5 levels and subdivided by city and quiet or busy sampling time.
The WHO has recently stated that its outdoor air quality guidance for PM2.512 can be applied to indoor environments.13 This guidance recommends that 24-h PM2.5 concentrations should not exceed 25 μg/m3. Data were compared to this threshold although we note that our measurements were made over a 30-min period and are not 24-h time-weighted averages as used for the WHO guidance.
Results
A total of 51 visits were made to 39 pubs with a subset of 12 Edinburgh pubs visited on 2 occasions: once during a ‘quiet’ time and once during a ‘busy’ period. Visits were carried out between 12 May and 17 June 2011; 37 visits in Edinburgh and 14 in Aberdeen. In all, 18 of the visits were at quiet times and 33 during busy times. Four bars from the original cohort had closed down completely; for two of these we were able to select a nearby bar (<100 m) as a replacement. One other bar had changed to an establishment of a different nature and a nearby replacement was also found for this bar. Four other bars had changed their name but had essentially remained the same.
Table 1 provides detail on the location of the monitoring visits undertaken, the timing of visits and the levels of PM2.5 measured together with the average number of patrons per pub and the average number of people observed smoking. Summary data from the 2006 measurement campaign is also provided for comparison.
The PM2.5 levels recorded during the 51 visits carried out in 2011 averaged 12 μg/m3 (range 2–155 μg/m3). This compares with the measurements made in 2006 when average levels were 20 μg/m3 (range 6–104 μg/m3). In the present study 47 of the 51 bar visits (92%) recorded levels below the WHO 24-h PM2.5 air quality guidance level of 25 μg/m3. This compares to the 4% (n=2) of this cohort that complied with this guidance prior to legislation in March 2006, and the 77% (n=41) that were below this threshold post legislation in May–June 2006.
The average outdoor PM2.5 concentration measured on each sampling day was 5.3 μg/m3 (range 2.6–9.2 μg/m3). We compared the PM2.5 levels measured inside the bars to those measured outside and found that all but two bar visits had concentrations within 20 μg/m3 of the outdoor ambient PM2.5 concentration. Other sources of fine particulate matter such as candles, incense, cooking fume and resuspended dust generated from walking on carpets may be responsible for these increases over the outdoor level.
The average number of patrons recorded in each bar visit during this current study was 31 compared to 28 during the data collection in 2006 suggesting little change in the numbers of customers at the time of sampling in these establishments compared to 5 years previously.
Of the 39 bars visited, 27 (69%) displayed visible no smoking signage during our visits in 2011. This compared to 40 of the 41 pubs visited (98%) at the visits immediately post ban in 2006. In none of the 51 visits in 2011 was there evidence of smoking occurring within the premises and in none of the pubs was there any evidence that smoking was being permitted or assisted by the presence of ashtrays or cigarette ends/spent matches.
Discussion
These findings show that the dramatic reductions in indoor particle levels (as PM2.5) in pubs following smoking restrictions implemented in 2006 have been maintained. Average PM2.5 concentrations continue to be close to those measured in outdoor ambient air. Compliance appears to be high although we did observe a reduction in the number of bars with visible no smoking signage as required by law. This may indicate that customers are now so used to the principle of having to smoke outside that signs and active enforcement are deemed unnecessary by some bar owners. Smoking was observed outside the majority of bars and this generally took place at the doorway or at outdoor tables where smoking is permitted. Recent work in Australia has suggested that indoor concentrations of PM2.5 in bars with smoke-free restrictions were positively associated with concentrations in adjacent outdoor eating and drinking areas.14 It is likely that some of the PM2.5 measured in our study arises from outdoor SHS drifting indoors from outdoor smoking.
Other recent studies of SHS levels within the hospitality sector have examined concentrations measured around the time of legislation being implemented in various countries15 but this study reports the longest follow-up of a national ban that we know of. The study has a particular strength in using identical methodology to compare levels in the same locations, at the same time of day and same day of the week and similar date to data gathered 5 years previously.
Conclusions
Debate about the need for smoke-free legislation and the possibility of introducing exemptions for some establishments has continued over the past 5 years16 with some arguing for bars to be given the choice to be smoke free or to permit smoking. This paper presents evidence that the comprehensive Scottish legislation continues to be effective in protecting workers and non-smoking patrons of bars from exposure to SHS. These findings demonstrate the long-term effectiveness of indoor smoking restrictions and the continued benefits to those who were previously exposed to SHS. We believe this evidence will be useful to those in the tobacco control community in jurisdictions that are still debating or contemplating the development of indoor bans.
What this paper adds
This is the first long-term evaluation of changes in secondhand smoke (SHS) levels in bars as a result of the introduction of national smoke-free legislation.
Directly comparable data on over 50 bar visits carried out in 2006 and 2011 show that levels of fine particulate matter continue to remain low and are broadly comparable to those measured in outdoor air.
The study demonstrates the continued benefits of smoking restrictions 5 years on from implementation.
Footnotes
Funding This work was funded by a studentship grant from NHS Health Scotland.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.