Is My Car Offgassing VOCs?

Will you please send information about automobiles' volatile organic compound (VOC) ratings: a study was made in Australia a year or so ago; did the detailed study say which automobiles had the lowest VOC's ?

Sincerely
Verna Rowe

Unfortunately, there haven't been any systematic studies of volatile organic compounds (VOCs) in the full range of new cars, though one might be welcome. Readers may better relate to the question if we relate it to what's popularly known as "new car smell"—that perfume-like aroma that serves as a cue that one's automobile was recently purchased.

VOCs that include alkanes, benzenes, adehydes and ketones are emitted (or "offgassed") by interior fabrics and plastics held together by sealers and adhesives. Chemical and Engineering News refers to this as "a dilute sea of VOCs floating about in the passenger compartment." Carmakers have standards for total VOCs, but there are no existing government standards for cars as a whole (automobile paint VOCs are regulated).

Dr. David Ozonoff, director of the Program in Public Health Preparedness for the School of Public Health and the principal investigator for the Superfund Basic Research Center at Boston University, believes that "new car smell" is largely caused by chemical phthalates released by automobile plastic. More than half of the plastic in new cars is in the interior, replacing such traditional materials as cloth, leather, metal and wood. Among the chemicals "offgassing" from this plastic are benzene (a known carcinogen); acetone (a nose irritant); cyclohexanone (a possible carcinogen); xylene isomers (toxic to developing babies); and ethylbenzene (a "systematic toxic agent").

Jeff Gearhart of the Michigan-based Clean Car Campaign says the new findings support the group's call for a phaseout of polyvinyl chloride (PVC) plastic in car interiors. "What you're seeing and what they're testing is outgassing from the vinyl, also sealers and adhesives, sound-deadening materials and trim components," he says. General Motors and Volvo have both responded to the call with PVC reductions and phaseouts.

Is "new car smell" harmful to car owners? Existing studies provide somewhat conflicting information. The Journal of Exposure Analysis and Environmental Epidemiology reported in January 2003 on a study of VOC concentrations in a variety of sedans, both parked and in motion using air conditioners. The vehicles tested included "three rental sedans less than 6 months old (two 1997 Ford Taurus and one 1997 Chevrolet Lumina) and two used sedans (1993 Toyota Camry and 1993 Ford Taurus) that were well maintained and in good operating condition." The conclusion was that levels of "VOC compounds varied considerably according to vehicle brand, age and interior temperature." In general, "relatively high concentrations of certain VOCs" build up when a car sits in the sun, but air conditioning (even when set in recirculation mode) quickly dissipates it.

In the Australian study cited, presented at the 15th International Clean Air and Environment Conference in Sydney, three (unidentified) cars were studied (one built in Korea, two in Australia). High VOC levels "associated with sensory irritation and impairment of performance and memory" were found when the Australian-built cars were brand new, but that these levels decreased approximately seven-fold in the first month. The Korean car (which because it had been imported was actually several weeks older) had much lower VOC levels.

A 1995 study of a Lincoln Continental by Santford V. Overton and John J. Manura found more than 100 volatile organics, including lubricants, solvents, adhesives and gasoline. As with the other studies, the concentrations increased with heat level, and dissipated over time. "After two months, the concentrations of VOCs in the Lincoln Continental were significantly decreased," the study said.

The conclusion seems to be that car buyers would do well to leave their new vehicles parked in the driveway for a few weeks before driving them. Government limits for daily VOC emissions in cars would be worth considering, but are unlikely to be enacted.