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Staff in Scottish prisons inhale roughly the same amount of second-hand smoke at work as they would in the average smoking household (32μg of fine particulate matter per m3). Some activities, like inspecting a smoky prison cell, exposed staff to far higher levels (up to 753.6μg per m3).

Despite smoking bans in public spaces across the UK, around three-quarters of prisoners smoke. This poses health threats from second-hand smoke to staff and prisoners alike.

This NIHR study detailed the second-hand smoke exposure in all 15 prisons in Scotland using static and staff-wearable airborne particle and nicotine monitors. Pre- and post-shift salivary nicotine measurements corroborated these readings.

The Scottish Prison Service requires all Scottish Prisons to be smoke-free by 2018, citing this study as part of the reason to act. Stop Smoking Services are likely to play an important role in supporting this aim.

Why was this study needed?

The World Health Organisation says there is no safe level of exposure to second-hand smoke.

Scotland enforced a smoking ban in enclosed public spaces in 2006 and the rest of the UK followed suit in 2007. From 2007 until this year, prisons received a partial ban. Prisoners could smoke in their cells unless they share a room with a non-smoker.

A policy and guidance document from Public Health England In 2015 acknowledges that UK prisons were not smoke-free. This outlines a pathway to deliver a comprehensive nicotine dependence treatment to all smokers in the criminal justice service. This programme is being rolled out in stages.

Data suggests that nearly three-quarters of prisoners in Scotland smoke. A similar proportion smoke in English and Welsh prisons with about four times as many people in prisons, custody or probation smoking compared with the general population.

This NIHR-funded study sought to rigorously measure the second-hand smoking exposure of staff in all Scottish prisons to better inform pragmatic policies to protect prison staff.

What did this study do?

This study, part of a larger Tobacco In Prisons study, measured second-hand smoke exposure for 407 staff working in all 15 prisons in Scotland in autumn 2016.

Second-hand smoke exposure was measured in multiple ways. Fixed-position detectors recorded airborne nicotine and fine particulate matter (PM2.5) levels in prison landings or hallways over six days. Staff mobile detection devices recorded PM2.5 over 30 minute periods in specific locations or during particular activities. Non-smoking staff also had salivary cotinine (a product of nicotine metabolism) levels measured at the start and end of their shift.

The main limitation is that the average second-hand smoking readings will hide the variety of individual staff and prisoner exposure levels, which will depend on the prison, time-of-day and work activity.

What did it find?

  • The six-day average (median) fine particulate matter (PM2.5) concentration across the 15 prisons was 31.7μg per m3 (range 11 to 136μg per m3). Compared with other studies, this was the same as recorded in Scottish smokers’ homes (median 31μg per m3), 10-times higher than non-smoking Scottish households (mean 3.1μg per m3), but much lower than in Scottish pubs and bars before the smoking ban (mean 246μg per m3).
  • From the mobile detectors, the highest PM2.5 readings were during cell searches or inspections (max 753.6μg per m3), in residential corridors or landings (max 436.4μg per m3), and recreational areas (309.7μg per m3). These are places where inmates are allowed to smoke, or immediately adjacent.
  • There was second-hand smoke exposure for staff in staff offices (max 42.9μg per m3), with levels lower in teaching areas (15.5μg per m3), gyms (8.7μg per m3) and reception areas (4.1μg per m3).
  • One hundred and of 149 staff had signs of second-hand smoke exposure when comparing their pre-shift and post-shift salivary cotinine measurements. It was estimated that staff had been exposed to average PM2.5 concentrations of 24.8μg per m3, which correlates closely with the levels from the detectors.

What does current guidance say on this issue?

The Scottish Prison Service (SPS) intends all prisons in Scotland to be smoke-free by the end of 2018.

The deadline announcement made specific reference to the results of this study (Tobacco In Prisons study) in terms of a strong and detailed rationale to act.

Tobacco will stop being sold and the SPS will seek to make changes to the Prison Rules to make smoking in Scotland’s prisons illegal. SPS will seek to develop a range of support systems to help people in prison to quit.

From 2nd May 2016, all prisons in Wales became smoke-free. Prisons in England are also in the process of becoming smoke-free. The ban does not include electronic cigarettes.

What are the implications?

The detailed exposure data from this study provides evidence to support smoke-free prison policies to minimise staff and prisoner exposure to second-hand smoke.

The implementation of new smoke-free prison policies or legislation will likely increase the demand on local Stop Smoking Services.

The smoke-free policies will have pragmatic hurdles to overcome. Quitting may increase the risk of irritability and depression in a vulnerable prison population. The need to eliminate all second-hand smoke exposure needs to be balanced against maintaining prison order and safety within existing facility constraints. Local plans are being put in place to address these issues.

Citation and Funding

Semple S, Sweeting H, Demou E, et al. Characterising the Exposure of Prison Staff to Second-Hand Tobacco Smoke. Ann Work Expo Health. 2017;61(7):809-21.

This project was funded by the National Institute for Health Research Public Health Research Programme (15/55/44).


ASH Wales. Smokefree prisons. Cardiff: Action on Smoking and Health Wales; 2015.

PHE. Smoking in prisons: management of tobacco use and nicotine withdrawal. London; 2015

SPS. Creating a Smoke Free Prison Environment. Edinburgh: Scottish Prison Service; 2017.

The Guardian. Prison Smoking Ban Overturned By Court Appeal. London: The Guardian; 2016.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

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