Investigation of the impact of the smoke-free legislation in Northern Ireland on second hand smoke exposure of adult non-smokers living with smokers:

On 30th April 2007 legislation was introduced in Northern Ireland to prevent smoking in enclosed public places and workplaces. A baseline study was carried out in five geographical areas in Northern Ireland before the introduction of the legislation on second hand smoke exposure for adult non-smokers who live with at least one smoker. Eligible participants were recruited through telephone surveys, stands in shopping centres and through workplaces. Participants completed a questionnaire or interview and, for a subset of the participants, residential airborne nicotine measurements were carried out using passive or active sampling monitors. In total, 604 participants took part in the study, with nicotine measurements carried out in 84 houses (14%). Smoking was allowed in 73% of the homes and participants were on average exposed for approximately 3 hours every day to residential second hand smoke. The majority of the participants were unhappy at being exposed to other people’s smoke at home (80%), in the same room (81%) or in their car (83%) and participants were overwhelmingly in favour of the smoking legislation (88%). However, almost half of the participants feared that smokers are more likely to smoke at home after introduction of the smoke-free legislation. The mean (and range) of the nicotine measurements using the active samplers was 12.7 μg/m3 (0.09-182.6 μg/m3) while for the passive sampler the mean (and range) was 2.3 μg/m3 (0.01-38.3 μg/m3). The reason for the difference between the results of the active and passive samplers were unknown as no true side-by-side measurements were carried out during this study. The nicotine levels increased with the number of cigarettes smoked. There also appeared to be a difference in nicotine levels for different type of houses, with higher levels found in semi-detached houses and flats compared to detached and terraced houses, even after taking into account the level of smoking. Similarly, houses with double glazing appeared to have higher nicotine levels than houses with single glazed windows. Overall the results of the nicotine measurements were comparable with nicotine levels observed in other studies. The questionnaire and nicotine results collected during this survey provide a good baseline database for investigating the impact of the smoke-free legislation in Northern Ireland.