The Australian reports that children exposed to cigarette smoke in cars are more than twice as likely as other kids to develop asthma.

Some Australian officials would like to ban smoking in vehicles with children for this reason.

"Teenagers can escape their parents' smoke in the home by leaving the room, but in mum's taxi they are essentially trapped, regardless of whether the windows are down," says Peter Sly, from the Centre for Child Health Research at the University of Western Australia. "They're forced to inhale the smoke while they're being ferried about to and from school and, as we've found, the risk is great."