The interior of a brand-new vehicle could contain more than 30 times the acceptable level of volatile organic chemicals, known to cause symptoms of illnesses linked with sick building syndrome, according to a recent study by a public health researcher.
Toshiaki Yoshida, chief researcher at the Osaka Prefectural Institute of Public Health, said it takes over three years for the level to fall below that set by the state.
This form of air pollution remains little researched, although the Health, Labor and Welfare Ministry has set a provisional target limit for such chemical residues within vehicles in response to an increase in people suffering the syndrome.
Yoshida analyzed the air inside a brand-new Japanese minivan every week for the first two months and every month afterward. The car was driven daily and logged about 6,000 km a year.
One day after the dealer delivered the car, the examination found that its interior contained 113 kinds of volatile organic chemicals, mostly hydrocarbon-related, he said.
The density of such chemicals came to about 13,800 micrograms per cubic meter, or about 35 times the 400-microgram limit provisionally set by the ministry.
It took four months for the level to fall below the state level, but it shot far above it again in the hot summer months, even after two years. Yoshida estimates it takes 3.3 years for the level to remain below the state standard.
The chemicals detected include ethylbenzene, xylene and other chemicals used in paints, but also solutions used to prevent rubber from deteriorating, Yoshida said.
Xylene and other volatile organic chemicals, including formaldehyde and toluene, are contained in paints and adhesives and known to cause symptoms of sick building syndrome. Inhaled in high densities, they can affect the autonomic nervous system and cause headaches, dizziness and respiratory problems.
Yoshida took samples from just one vehicle, but Toyota Motor Corp., whose vehicles Yoshida did not use in the study, admitted that brand-new vehicles can be contaminated with chemicals attributed to sick building syndrome.
“Depending on temperature and ventilation, high densities of volatile organic chemicals could be detected,” a Toyota official said. “But we must accumulate more knowledge, and our company and industry have already begun research on it.”
Minoru Taniguchi, an official of the Japan Automobile Manufacturers Association, said: “Manufacturers began improving materials when the state standard was set two years ago. But the method for measuring the air inside vehicles has not yet been established.”
For those concerned about the chemicals, Yoshida recommends thorough ventilation, but added, “I want to ask manufacturers to develop materials that do not give off those chemicals.”