Sir David King said cars were “boxes collecting toxic gases” and children would be better off walking which would expose pupils to less nitrogen dioxide and help them keep fit.
Air is more polluted in the middle of the road and accumulates inside vehicles via air vents.
“Children sitting in the back seat of vehicles are likely to be exposed to dangerous levels of air pollution,” said Sir David, who works for the British Lung Foundation.
“You may be driving a cleaner vehicle but your children are sitting in a box collecting toxic gases from all the vehicles around you. The best thing for all our health is to leave our cars behind.
“It’s been shown that the health benefits of walking and cycling far outweigh the costs of breathing in pollution.
“If more drivers knew the damage they could be doing to their children, I think they’d think twice about getting in the car.”
Research has shown that children’s brains slow down when they are exposed to high levels of air pollution. Toxic air is linked to 40000 deaths a year, with diesel engines the leading culprits.
Their engines produce fewer greenhouse gases blamed for climate change but more particles harmful to health.
More than 85% of the population is exposed to illegal levels of air pollution over the course of a year, according to official figures.
Brussels has warned of fines if Britain continues to breach EU safety limits.
And ClientEarth, a pressure group that has issued legal challenges to the government’s anti-pollution plans, is calling for a further judicial review.
Sir David served as chief scientific adviser between 2000 and 2007, and as the UK permanent special representative for climate change between 2013 and this March.
The professor has previously admitted that it was wrong for the Labour government to cut fuel duty on diesel vehicles in 2001, a move that led to an upsurge in the number of diesel vehicles on our roads.
But he said the government had accepted assurances from car manufacturers that diesels were getting cleaner.
The World Health Organisation estimates that 92% of the world’s population live in areas where pollution exceeds safety guidelines.
Previous research has shown there to be no safe level of air pollution for humans, and long-term exposure is known to reduce life expectancy. - Daily Mail