New Car Smell Not Toxic

German scientists discover alluring aroma is really only hazardous to your wealth

April 2007:

Go ahead, fill your lungs with that new car smell. After exhaustive tests, researchers in Germany have concluded there's no evidence of any health harm.

The scientists didn't explain, however, why so many people derive such pleasure from inhaling alkanes, alkybenzenes and o,m,p-xylenes.

Collectively known as volatile organic compounds, those are the kinds of chemicals that impart the distinctive aroma of plastic, leather and newness to a car that's just rolled out of the showroom.

Collectively, the concentrations of these compounds were found to be nine times higher in new cars than old.

German researchers compared the air inside one such new car, with just 8 kilometres on the clock, to that from a three-year-old car of the same unspecified make, which had racked up more than 100,000 kilometres.

Both had metallic silver finishes and black leather interiors. They were placed under halogen lamps inside a lab so the interior temperature reached 65C, to simulate a car being parked in direct sunshine. The scientists called this a "worse-case scenario."

An intricate experimental set-up let the team at Munich's Technical University monitor the temperature and humidity inside the vehicles and suck air out for gas chromatography-mass spectrometry, which is the equivalent of Formula One racing when it comes to analysis of gaseous compounds.

In total, the research identified more than 40 chemical compounds that a driver and passenger would have inhaled in the super-hot air of a new car, sucking in 12 to 18 breaths a minute.

But none of the chemicals produced any evidence of toxicity when tested on the standard lab cell cultures made from humans, Chinese hamsters and mice, the scientists report in the current issue of Environmental Science & Technology, a research journal published by the American Chemical Society.

Lead researcher Jeroen Buters and colleagues also pointed out that concentrations of these chemicals would almost certainly be lower in real life, since passengers would open windows or turn on air conditioning after getting into a 65C car interior.

Concentrations of most of the chemical compounds plunged over the three years, but two kinds, called aldehydes and ketones, were still around at two-thirds of the levels initially measured in the new car. The researchers noted that both are found in cleaning agents and also in urban air pollution, so vehicle interior levels could have been replenished by either of those routes.

"Our investigations indicated no apparent health hazard of parked motor vehicle indoor air," the study concludes.