Scotland introduced a comprehensive smoke-free public places law in 2006. This law was widely regarded as a success and a model for legislation in other countries, including England and Wales. However, the 2006 law included several exceptions, including allowing prisoners to continue smoking in cells. Prison staff were therefore one of the few remaining groups exposed to secondhand smoke (SHS) indoors at work. Concern for the wellbeing of staff led the Scottish Government to introduce a smoke-free prisons policy in November 2018. The introduction of smoke-free prison policies has been marked by scepticism, with some commentators suggesting that smoking in prisons could not be restricted without major disruption.
We conducted a programme of static and task-based particulate air quality monitoring using the low-cost Dylos DC1700 sensor in 2016 (pre-ban), 2018 (as the ban was coming into force) and 2019 (six months post-ban). Static monitoring took place over six days in residential halls in all 15 Scottish prisons at each time point. Additionally, task-based monitoring of activities that may have resulted in exposure to SHS (such as cell checks) took place in 2016 and 2019.
In static monitoring, pre-ban particulate concentrations were high (median 31.7µg/m3), suggesting high levels of smoking in the prisons. The 2018 data showed that this had declined by the introduction of the ban, with 2019 post-ban data showing a median concentration of 3.0µg/m3 (lower than outdoor air). Significant declines were also seen in task-based monitoring across a range of activities.
The introduction of a smoke-free policy across Scotland’s prison estate was successful, according to objective air quality monitoring data. This, combined with the lack of major disruption associated with the introduction of the policy, will have implications for other prison systems wishing to protect staff and prisoners from the harmful effects of SHS.