Sunlight can heat car interiors to lethal temperatures in just 30 minutes, even if the weather is relatively cool, a new US study has found. The researchers strongly urge parents not to leave children alone in parked cars, no matter how mild the weather.
鈥淓ven on relatively mild-temperature days, the internal temperature of a vehicle left in the sun quickly gets very warm 鈥� the average rise in one hour is 22掳C,鈥� says lead author Catherine McLaren at Stanford University in Palo Alto, California. 鈥淢y guess is that parents would be surprised that leaving children in the car is very much like leaving them in a sauna.鈥�
In 2004, 35 children died of heat stroke in the US after being left unattended in a parked car. Previous research has shown that when ambient temperatures rise above 35掳C, sealed cars reach a suffocating 65掳C in just 15 minutes.
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But research on car heating has all been conducted on hot days 鈥� never less than 28掳C. So McLaren and her colleagues wanted to test how hot cars could get on cooler days, when the dangers of enclosed vehicles might not be as obvious to parents.
Open windows
On 16 cloud-free days in Northern California, the team measured a car鈥檚 inside temperature at 5 minute intervals for one hour post-parking. Ambient temperatures on the study days ranged from 22掳C to 35掳C.
They found that, regardless of outside air temperature, the car heated up at a similar rate 鈥� gaining 80% of its final temperature within 30 minutes. Cars that started out comfortable 22掳C, for example, rocketed to over 47掳C after 60 minutes in the sun. And keeping the windows open a crack hardly slowed the rise at all.
Young children and infants are much more susceptible to heat illnesses than adults, write the authors, meaning that such temperatures could prove dangerous. Toddlers鈥� body temperatures rise faster and they lose proportionally more water than adults in hot weather, for example.
The team suggest that laws against leaving kids in cars could help to raise awareness of the danger. But they note that because these heat-related deaths are mostly unintentional, additional public education is probably the best way to decrease the number of these preventable tragedies.
Journal Reference: Pediatrics (vol 116 p 109)
