One in ten children in Wales continues to be exposed to smoke in family cars, new research shows.
And one in five children with a parent who smokes say adults continue to light up in the family vehicle.
The study, commissioned by the Welsh Government and carried out by researchers at the DECIPHer centre, Cardiff University, has informed today's decision to introduce a ban on smoking in cars.
Despite the growing unacceptability of smoking in front of children, 9% of 10 and 11 year olds surveyed in 2014 said smoking was permitted in the family vehicle, compared to 18% in 2008.
Dr Graham Moore, lead researcher on the study, said: "We welcome the ban announced this morning by the Welsh Government. Smoking in cars and the home continue to decline, but a sizeable minority of children continue to be exposed to smoke in these places."
"There is evidence to show high levels of public support for a ban on smoking in cars carrying children. Our evidence points to a need for continued action to make smoking in front of children less socially acceptable, whether in the car or at home."
Dr Moore is a researcher at DECIPHer, the Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement, which investigates ways of improving health and well-being whilst reducing health inequalities.
His research also shows children who experiment with e-cigarettes have weaker anti-smoking intentions.
Some 15% of 10 and 11 year olds who had used an electronic cigarette said they might, or will, take up smoking in the next two years, compared to 2% of those who had not.
The figures show that in 2014, 6% reported having used an e-cigarette at least once; three times as many as had tried smoking tobacco (2%).
Dr Moore added: "E-cigarette use appears to represent a new form of childhood experimentation with nicotine, which is more prevalent among 10-11 year old children than smoking tobacco. E-cigarette use is more common among children whose parents smoke tobacco, and is associated with increased intentions to take up smoking."
Cardiff University began working with the Welsh Government on children's passive smoking in 2006. Wales was the first UK country to propose legislation against smoking in public places.
Specific powers inserted into the Heath Act 2006, by the Children and Families Act 2014, provide enabling powers for Welsh Ministers in Wales to introduce regulations to prohibit smoking in private vehicles carrying under 18s".
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