Delegates at a public health conference organised by the Chartered Institute of Environmental Health (CIEH) in Cardiff were informed of new research showing that smoking in cars is dangerous to children even after the cigarette is extinguished. 

The study also reveals that high levels of dangerous particulate matter (PM) from tobacco smoke is still present in cars up to two hours after lighting up, and that opening the car window does little to reduce the risk of harm to children. 

Smoking in cars is already banned in some U.S. states such as California and in parts of Australia and in Canada. 

The Public Health Conference – Public Health: Challenging Norms took place in Cardiff earlier this year. 

The study involved using cars belonging to a mother and two sets of grandparents who are smokers and who carry children in their cars. 

All of them said that they would not smoke while children were present in their cars, but would smoke before picking them up or when they were not present. The research establishes that even taking such a precaution is not enough to protect the health of children. 

The study shows that high levels of particulate matter peaked at 1,600 micrograms per cubic metre while a cigarette was being smoked. This level would decrease an hour later falling to 200 microgram per cubic metre – however the U.S. Environmental Protection Agency regards exposure to PM levels of over 40 in a 24-hour period as unhealthy and any figure more than 250 as hazardous to health. 

Julie Barratt, CIEH Director, who commissioned the research, said: 

“This pioneering piece of research comes at an opportune time as the Chief Medical Officer for Wales wants to start a debate about this very issue. We are happy that we can inform that debate with evidence. 

“While I am always hesitant about ‘banning’ people from engaging in what is technically a legal habit, the research provides a compelling case for responsible adults to not smoke in cars – even when children are not present. 

“We know that particulate levels in pubs dropped when the smoking ban was introduced in 2007 – cars are similar in that they are enclosed spaces. 

“What should give everyone considerable food for thought is that the negative effects of smoking are felt for hours after having a cigarette in a car – parents should know that the only way to protect children from the harmful effects of smoking in a car is to not smoke at all.” 

The CIEH is the UK’s leading provider of accredited food safety and health and safety qualifications. The CIEH’s 50 qualification training programmes are delivered through a network of over 10,000 registered trainers. The training is developed for the varied skill levels within organisations. They cater to different learning styles and preferences through a series of flexible structures. CIEH qualifications are OFQUAL (formerly QCA) accredited and are valued and recognised throughout the world. 

The CIEH is the professional voice for environmental health representing over 10,000 members working in the public, private and non-profit sectors. It ensures the highest standards of professional competence in its members, in the belief that through environmental health action people's health can be improved. 

For more information about the CIEH visit