THERE has been a huge reduction on the amount of second-hand smoke inhaled by people in Scotland over the past two decades, according to research.

The work, led by the University of Stirling, found that the average amount of cotinine, a biomarker for exposure to tobacco, has reduced by more than 97 per cent in non-smokers’ saliva.

Dr Sean Semple, associate professor at the university’s Institute for Social Marketing, said the analysis showed Scotland has made “even greater progress” in protecting non-smokers than previously thought.

He added: “The paper also shows that the proportion of non-smokers who have no measurable evidence of cotinine in their saliva has increased at almost every survey year and now stands at more than four out of every five adults.

“However, that still means nearly one-fifth of non-smoking adults experience regular exposure to second-hand smoke.

“We recommend that policymakers use these two measures – the average amount of cotinine in non-smokers’ saliva, and the proportion of non-smokers with no detectable levels of cotinine – as targets to further drive progress to Scotland achieving a tobacco-free generation by 2034.”

The paper, titled Assessing progress in protecting non-smokers from second-hand smoke, was published in the BMJ journal Tobacco Control.

Collaborating with Dr Semple were scientists from the Institute of Occupational Medicine in Edinburgh, the University of Glasgow and Heriot-Watt University.

The research was partly funded by the Medical Research Council and Scottish Government Chief Scientist Office.

Sheila Duffy, chief executive of tobacco related harm reduction charity ASH Scotland, said: “It is established scientific fact that second-hand tobacco smoke is harmful to health and is associated with a range of illnesses.

“So, I am delighted to see the huge reductions in second-hand smoke exposure in Scotland, delivering a healthier living environment to nearly half the population of Scotland.

“This has not happened by accident but is the result of deliberate and sustained work by successive Scottish administrations and is a clear example of the benefits of public health campaigns.”

Dr Semple added: “The work shows just how far Scotland has come in tackling exposure to second-hand smoke in the past two decades.

“We’ve come a long way and these figures suggest that policies and changes in how we treat smoking mean that about 2.3million additional adults in Scotland are no longer breathing in second-hand smoke compared to the situation in 1998.

“While this is great news, we now need to work even harder on making sure that we protect the remaining 600,000 non-smokers in Scotland who continue to be exposed to second-hand smoke on a regular basis.”