From the first of October this year, smoking while having children present in the car will be banned in England and Wales.
This law was passed last year but while most agree that the intentions are good, some question the need for a law.
Children face higher risk
Drivers who flout the new law will face an on-the-spot fine of £50.
The legislation is the result of pressure from campaigners who say that second-hand smoke is more dangerous to children than to adults because of their smaller lungs and faster breathing.
Passive smoking in a confined space like a car is thought to increase the health risks further.
Dr Penny Woods, chief executive of the British Lung Foundation, said:
"Having campaigned on this issue for many years, we’re absolutely delighted that MPs have overwhelmingly backed the ban on smoking in cars carrying children.
"MPs from across the parties have come together to support this ground-breaking measure."
The British Lung Foundation says that roughly 185,000 children between the ages of 11 and 15 are exposed to smoke in their families’ cars on most days of a typical week.
Professor Dame Sally Davies, Chief Medical Officer, said: "The passing of regulations to make smoking in cars carrying under-18s illegal is a significant victory."
"Smoking just a single cigarette in a car exposes children to high levels of air pollutants and cancer-causing chemicals like arsenic, formaldehyde and tar.
"Children are least equipped to speak out to protest against secondhand smoke, so I welcome this legislation to end smoking in cars when they are present."
In England, the law was originally added by Labour to the Children and Families Bill at the start of 2014.
Politicians in Cardiff, meanwhile, had been running an educational campaign to warn drivers of the potential dangers of second-hand smoke for youngsters.
'A step too far'
But it was felt that this had not been sufficiently effective in reducing the number of motorists who smoked while transporting their children and that stronger measures were necessary.
Smokers’ rights group Forest, however, said the ban was a step too far.
Director Simon Clark said: "The overwhelming majority of smokers know it's inconsiderate to smoke in a car with children and they don't do it."
"They don't need the state micro-managing their lives."
Clark added that a further problem was that the police would be unable to enforce the law effectively.
"The government will need a small army of snoopers to report people," he said.
Can a child car smoking ban be enforced?
Jeanette Miller, a motoring lawyer and managing director at Geoffrey Miller Solicitors, said that innocent drivers could find it more difficult to clear their names.
"It's not like with a mobile phone, where you can get records to prove if a phone was in use," she explains.
"Many prosecutions for smoking with a child in the car will be dependent on the officer's evidence of what they saw.
"Challenging this may be a struggle if you genuinely were not smoking."