Aims: This study evaluated the possible impact of national smoke-free work-place legislation on employee exposure to environmental tobacco smoke (ETS), employee smoking habits and attitudes on work-place smoking regulations.
Design: Repeated cross-sectional questionnaire surveys and indoor air nicotine measurements were carried out before, and 1 and 3 years after the law had come into effect.
Setting: Industrial, service sector and office work-places from the Helsinki metropolitan area, Finland.
Participants: A total of 880, 940 and 659 employees (response rates 70%, 75% and 75%) in eight work-places selected from a register kept by the Uusimaa Regional Institute of Occupational Health to represent various sectors of public and private work-places.
Measurements: Reported exposure to ETS, smoking habits, attitudes on smoking at work and measurements of indoor air nicotine concentration.
Findings: Employee exposure to ETS for at least 1 hour daily decreased steadily during the 4-year follow-up, from 51% in 1994 to 17% in 1995 and 12% in 1998. Respondents' daily smoking prevalence and tobacco consumption diminished 1 year after the enforcement of legislation from 30% to 25%, and remained at 25% in the last survey 3 years later. Long-term reduction in smoking was confined to men. Both smokers' and non-smokers' attitudes shifted gradually towards favouring a total ban on smoking at work. Median indoor airborne nicotine concentrations decreased from 0.9 micro g/m3 in 1994-95 to 0.1 micro g/m3 in 1995-96 and 1998.
Conclusions: This is the first follow-up study on a nationally implemented smoke-free work-place law. We found that such legislation is associated with steadily reducing ETS exposure at work, particularly at work-places, where the voluntary smoking regulations have failed to reduce exposure. The implementation of the law also seemed to encourage smokers to accept a non-smoking work-place as the norm.