As many as 3 million Australian cars may not conform to Australian standards for evaporative emissions.
“The results indicate that when vehicles are parked in warm conditions for an extended period (more than a day), the evaporative emission control systems may not be able to effectively control the build-up of evaporative hydrocarbons, as even the latest systems are only designed to provide effective control for a continuous 24-hour period,” the report said.
A 2003 Toyota Camry, for example, which emitted less than two grams of hydrocarbons after 24 hours, had emitted close to 30 grams over 72hours, according to Orbital, the company that did the testing.
Smog is linked to respiratory problems such as asthma. It also contributes to global warming.
“It means for the private individual who is doing the right thing and walking and catching public transport and not using their car, they’re actually causing emissions which they don’t want to do,” said Bruce Jeffreys, co-founder of car share company GoGet.
Mr Jeffreys said the federal government should adopt stricter standards to force vehicles to hold up to three days’ worth of hydrocarbons.
The study tested cars’ evaporative emissions one hour after they were driven and then during a stationary test, where vapours were measured from each vehicle over 24 hours.
One in four cars exceeded the test limit of two grams of hydrocarbons released.
Assuming this 25 per cent figure is representative of the wider vehicle population, almost 3 million cars on the road do not conform to Australian standards.
Mr Jeffreys said governments should stop turning a blind eye to the growing number of cars in Australia, while at the same time encouraging people to use them less. “We need to invest in public transport and a smaller number of cars that are better used,” he said.