Abstract: IntroductionA Cochrane systematic review was undertaken to answer the question: "does legislation to ban or restrict tobacco smoking reduce exposure to secondhand smoke and smoking behaviour?"Relevance for nursingSmoking bans are environmental, population-focused approaches that aim to rReducetion in both tobacco smoking behaviours and secondhand smoke exposure. through smoking bans impact the environment and hence population health. Often bans are accompanied by education regarding the need for the ban and support services thato help smokers use the opportunity to quit or reduce their tobacco consumption. Therefore, smoking bans can be associated with the 'settings approach' to health promotion derived from the World Health Organisation's Ottawa Charter (1986). Thise Charter supports population and individual health through integrated, coordinated and multi-dimensional interventions.Study characteristicsAThis was a Cochrane systematic review was undertaken thatwhich produced a 'narrative only' synthesis of 50 studies. Studies (with reported numbers of participants) had samples ranging from of 24 to 10413 subjects. No randomised controlled trials were identified that met review inclusion criteria., Nonethelesshowever, 13 non-randomised controlled studies (quasi-experimental designs) were included; of these 7, were located in a general or workplace setting and 6six related to hospital admissions. A further 37 studies which lacked a control group but recorded data from participants pre and post intervention were also included in the review. In total, In 16 16 of reviewed studies used random sampling was used to select participants from a target population, 11 employed convenience sampling, 5five used randomly selected clusters of bars/public houses; 5five sampling methods were unclear and 2two studies utilised mixed sampling methods.No age, gender or geographic limits were placed on study samples included in the review. ReviewedIncluded studies followed participants for a minimum of six months following the ban (except for 8 studies which measured exposure to second hand smoke). Eight study authors identified that small sample size or low statistical power limited the generalisability of their research findings. No age, gender or geographic limit was placed on participants in reviewed studies. A risk of bias summary table was not included in the review; however, the reviewers note that one source of bias (blinding participants to receipt of the intervention) was not possible in any study, due to the nature of the ban interventions. Eight study authors identified that small sample size or low statistical power was a limitation to the generalisability of their research findings.The most commonly reviewed intervention was a comprehensive legislative ban on indoor smoking that was comprehensive within indoor sites (a total ban in 40 studies). An additional 10Ten ?restriction' intervention studies were also included ; these permitted which the reviewers classified as 'restrictions' as they allowed smoking within a designated area. Twenty two of the reviewed studies were conducted in workplaces, most of these (19) targeted the health of hospitality workers in bars or restaurants. The reviewed studies included bans in 13 countries, mostly the USA (17) or Scotland (8). Exposure to secondhand smoke was collectedmeasured by participants' self-report recordingof either the 'duration of exposure' or 'percentage sample exposed'. Some researchers (mostly those conducting large population studies) also took biochemical samples e.g. of saliva, to validate self-reports. Measures such as: smoking prevalence, tobacco consumption, smoking cessation, and respiratory, cardiac or sensory health outcomes were also considered by the reviewers. …