杏吧原创

Air pollutants that generate 鈥渘ew car smell鈥� have been found at levels up to 10 times regulatory limits inside some models.

But new Chinese rules could put an end to the odour, which is generated by volatile organic compounds (VOCs), chemicals that are readily released as gases by the materials that make up dashboards, seat covers and other fittings.

China, Japan and South Korea regulate VOC levels, in part because many people in Asia have less of the enzyme that breaks down both alcohol and one of the key VOCs released by car interiors, acetaldehyde. While the odour is popular in the US and Europe, surveys in China have found more than one-tenth of car buyers complained about it.

Difficulties in measuring VOCs have hampered tests inside cars, but new instruments allowed UK-based testing firm Emissions Analytics to check three models.

During tests of a Hyundai i10,聽concentrations of methanol, a common solvent, rose from 18 micrograms per cubic metre (渭g/m3) to 935渭g/m3, a level that Emissions Analytics says could prove an irritant. Acetaldehyde also jumped between 4 and 6 minutes of testing, from 50 to 550渭g/m3, or 10 times the limit allowed in China and Japan.

For an unnamed Renault car and Peugeot model, the spikes weren鈥檛 as pronounced, but ethanol jumped to higher than expected levels. Acetaldehyde and methanol levels in the Peugeot were also higher after the 24-minute test finished.

鈥淭he message is still that research is at an early stage and needs further investigation, but clearly the cabin contains a cocktail of health hazards, which needs a common approach to understand and potentially regulate,鈥� says Nick Molden at Emissions Analytics.

While campaigners, regulators and the car industry have focused on the emissions from car exhausts after the dieselgate scandal, in which Volkswagen installed devices on its cars to fool emissions tests, scant attention has been paid to interior air quality.

Read more: Here鈥檚 how we can stop a mountain of electric car batteries piling up

Alastair Lewis at the University of York in the UK says the VOCs measured for this test aren鈥檛 unique to cars and are part of most modern environments, from homes to offices. But they are worth paying attention to because people respond in such wildly varying ways to them.

鈥淪ome people have very significant, genuinely debilitating sensitivities to certain VOCs even at low concentrations. Others actually rather like the smells and suffer no obvious acute effects. The new car smell is a good example. It makes some people physically ill in one part of the world, yet in the UK people seek it out as desirable,鈥� says Lewis.

Emissions Analytics says one idea for why the VOCs spike so much at the start of the car鈥檚 life is that the heating and ventilation system 鈥� which were run during the tests 鈥� act as a sink for the chemical compounds released by materials. Switching on the heating and ventilation potentially releases them into the car interior.

The rise of car ownership and China鈥檚 influence in global car markets mean there might not be a new car smell for much longer. In June, China鈥檚 environment ministry said it would be introducing tighter controls on VOCs in cars, to take effect from 2020. Due to the size of China鈥檚 car market, the new rules have the potential to act as de facto global regulations.

However, political wrangling in China means the rules may not take effect until later next year.

Hyundai said all of its cars are 鈥渢horoughly tested鈥� with regard to VOCs and interior air quality. A spokesperson for Renault said the company has 鈥渟et itself the objective of managing VOC emissions in order to minimise their impact on passenger health and comfort鈥�.

Groupe PSA, which owns Peugeot, says it has limits on VOCs. 鈥淭he air in the passenger compartment is checked for VOCs before the vehicle goes on the market [with international standards].鈥�