By Sean Semple

08 June 2018 - 13:18

Smoke against a dark background
'Second hand smoke lingers in the air for up to five hours after a smoker extinguishes a cigarette.' Photo ©

Paul Wong used under licence and adapted from the original.

Dr Sean Semple, Associate Professor at University of Stirling, describes the effects of second-hand smoke and what some researchers are doing to reduce it. 

How many people are exposed to second-hand smoke in their home?

Forty per cent of children globally are exposed to second-hand smoke at home, according to the Global Adult Tobacco Survey 2016. Some countries have particularly high rates: Indonesia (79 per cent), China (67 per cent), Bangladesh (57 per cent), the Philippines (57 per cent) and India (45 per cent). In these five countries, over 400 million children are exposed to second-hand smoke.

Recent evidence from the Scottish Health Survey showed that one in four non-smoking adults had detectable levels of cotinine – a marker of second-hand smoke exposure.

What are the risks of second-hand smoke exposure?

Smoking leads to concentrations of air pollutants in the home that are much higher than those in the most polluted cities.

The World Health Organisation estimates that nearly 900,000 deaths per year are attributable to second-hand smoke. Asthma, glue ear and chronic obstructive pulmonary disease are caused or made worse by second-hand smoke exposure.

How can we protect children from second-hand smoke in their homes?

We can all protect children from second-hand smoke by not smoking around them. But to achieve this, researchers and clinicians need to effectively encourage adults to make the home a smoke-free environment.

For example, mass media (TV, radio and online) adverts coupled with a government target has helped reduce the proportion of children exposed to second-hand smoke in their own home in Scotland from 12 per cent to six per cent between 2012 and 2016.

You received a Newton Fund grant to organise a research workshop on smoke-free homes in Malaysia. What are the particular challenges for Malaysia?

In Malaysia, nearly 48 per cent of men smoke, compared to less than two per cent of women. The challenge is involving men in understanding the harm caused to other members of their family from smoking at home. This is a big research gap. We need to carry out initial qualitative work to better understand why men smoke at home, and the barriers and facilitators to making a change.

By contrast, in the UK, researchers have focused on smoking mothers. They tend to be the primary caregivers for children, and so the main source of children’s exposure to second-hand smoke.

What are the roles of family and wider society?

Smoke-free home interventions must involve the whole family – a whole household approach – to succeed.

In the past, researchers in the UK and USA have supported women in talking with their partners and visitors about smoke-free rules in the home. In other countries, including Malaysia, men are the crucial group to stop smoking in the home.

Religion can also play a role. Ramadan or Lent, for example, can be an opportunity to quit smoking. Laws governing smoke-free public spaces can influence societal views about smoking within the home. There is also evidence, collected by Dr Eva Monson and Nicole Arsenault, that in countries with strong smoke-free laws, more smokers voluntarily have smoke-free homes.

How can research help to tackle the issue and increase the number of smoke-free homes?

I’ve been measuring second-hand smoke in homes for ten year, using low-cost air pollution monitors. I use those measurements to show smoking parents the levels of air pollutants within their home.

Many smokers think that opening a window, lighting candles or switching on a fan, mean that their smoking is not so bad for the non-smokers they live with. However, smoking indoors leads to high concentrations of pollutants in the home. Second-hand smoke lingers in the air for up to five hours after a smoker extinguishes a cigarette.

Our approach can help smokers understand that. We are now using low-cost instruments to provide daily feedback by SMS, email and telephone so that smokers can see their progress towards a safe, smoke-free home. The feedback contains a graph, daily messages about average levels of second-hand smoke and simple measures to help take smoking outside the home.

My colleague Professor Kamran Siddiqi is leading a project called MCLASS II – Muslim Communities Learning About Second-hand Smoke in Bangladesh. This project is developing and testing the effectiveness and cost-effectiveness of a community-based intervention called 'Muslims for better health', in reducing exposure to second-hand smoke in homes in Dhaka. Our partners in Bangladesh, the ARK Foundation, have recruited over 1,800 homes to the study. We’re hoping that this project will be a cost-effective and simple way to encourage smokers in Bangladesh to make their homes smoke-free.

Dr Sean Semple received a Newton Fund grant to organise a research workshop on smoke-free homes in Malaysia. You can apply for Newton Fund funding, grants and opportunities until 11 June 2018.

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