Public health professor Richard Edwards from The Otago University conducted a study to find that 23 per cent of 14 and 15-year-olds were victims of second-hand smoke in vehicles during a given week.
"Kids exposed to second-hand smoke are at higher risk of various diseases," he said.
Second-hand smoke in cars could expose kids to a whole lot of diseases like pneumonia and chest infections. The risk of asthma attacks is also high for such kids.
Prof Edwards said, "Moreover, in-vehicle second-hand smoke exposure is consistently and significantly associated with susceptibility to initiation and more frequent smoking.''
He also warned tobacco addicts to avoid smoking while the windows were down as this is also harmful to children in the car.
This research supports a ban on smoking in cars.