Banning smoking at workplaces and restaurants is widely recommended as a key intervention for protecting people from exposure to second hand smoke (SHS) [1–3]. Although the hospitality sector had been previously excluded from smoking bans, this omission has been amended in many countries over the past 10 years. Today, 28 countries have comprehensive policies banning smoking in all workplaces . This trend is in alignment with the recommendations from the World Health Organization’s Framework Convention for Tobacco Control (FCTC), stating in Article 8 that all workplaces in closed rooms should be protected from SHS . Although Switzerland signed the WHO Convention in 2004, it was never ratified.
There is no comprehensive smoking ban protecting hospitality staff from SHS in Switzerland. In May 2010, a national smoking ban based on a fairly unrestricted regulation which permitted certain exceptions was implemented . According to the national law, venues could allow smoking if they were less than 80 m2 in size or if smoking rooms did not exceed one third of the total venue size. Switzerland is divided into 26 administrative zones called cantons, and each was permitted to implement its own stricter legislation on top of the national law. This has resulted in a patchwork of different laws within a small geographical area.
It has been shown that a partial law can actually lead to an increase in SHS levels in venues that continue to allow smoking . In a global cross-sectional study measuring smoking and non-smoking Irish pubs, Connolly et al. found particulate matter less than 2.5 μm in diameter (PM2.5) to be 93% lower in smoke-free pubs . According to Villarroel et al., PM2.5 levels are five times higher in smoking venues than in non-smoking venues . Interestingly, several studies found that spatial separation of rooms where smoking is allowed does not prevent exposure to environmental tobacco smoke in nearby non-smoking areas. In 2004, Cains et al. found that spatially separated non-smoking rooms had only marginally reduced particulate matter less than 10 μm in diameter (PM10) and nicotine air levels when compared to a non- smoking area in direct confluence with a smoking area . A Swiss study showed that PM2.5 in non-smoking rooms of venues that allowed smoking elsewhere in the building was more than double the PM2.5 levels of completely smoke-free hospitality venues . Several longitudinal studies examined changes in SHS levels before and after introduction of smoking bans. While Semple et al. found an average PM2.5 reduction of 86% in Scottish pubs two months after implementation of the law, Lee et al. came up with a slight decrease resulting from a partial law compared to a large decrease from a comprehensive law [12, 13]. These effects were reproduced in other places such as Minnesota or Guatemala [14, 15].
The present study is part of COSIBAR (Cohort Study on Smoke-Free Interventions in Bars and Restaurants), a longitudinal quasi-experimental study examining exposure of hospitality workers who were non-smokers, and their health status at three different time points before and after implementation of the new law. There are several established methods to determine personal SHS exposure, all of which have their advantages and disadvantages. The most common and simple way is through a questionnaire . Other options include taking biological samples such as urine, saliva, blood or hair. While drawing blood is invasive, both urine and saliva sampling are simple and quick. Commonly the cotinine content is measured, as it is the most specific and sensitive biomarker . A hair sample provides cumulative exposure over time, with the last centimetre of hair usually corresponding to the previous month’s exposure , but this method needs to be further refined . In order to determine the SHS exposure within a room, PM2.5 levels in air are often used as proxies . In this study, SHS exposure of the participants was determined with three different methods. Firstly, by the MoNIC (Monitor of Nicotine) badge, a passive sampling device, secondly, by salivary samples and thirdly, by a personal interview relating to duration of SHS exposure at work and outside of working hours.
The aim of the present study was to analyse the effect of different smoking regulations on SHS exposure in bars, cafés and restaurants and of non-smoking hospitality workers employed therein. In addition, we aimed to evaluate the different methods of SHS exposure assessment and to determine the most accurate proxy for SHS exposure at work.