Why our love for diesel cars is a fatal attraction

SPECIAL REPORT

Australians are buying diesel-powered cars in record numbers despite increasing concerns about the health impacts of diesel emissions. Sales of diesel-powered cars, utes and SUVs have tripled in the past 10 years; they used to represent 10 per cent of the market, they now represent 30 per cent (including 327,500 new deliveries last year alone).

Diesel cars were initially seen as an environmental saviour because they emit less CO2 per kilometre than petrol cars, and buyers appreciate not having to refuel as often. But it has since emerged diesel cars -- including the newer, so-called "clean diesels" -- are much worse for our health than first thought, leaving motorists with the unenviable choice of saving the planet or saving lives.

The International Agency for Research on Cancer (IARC) last year confirmed diesel emissions were carcinogenic but authorities in Australia are yet to react to the findings published more than a year ago.

The last time a Federal agency researched the health effects of diesel emissions was in 2005 -- based on data sourced in the early 2000s, more than 10 years ago. A spokesman from the department that published the 2005 report told News Corp "there are no current plans to update the study".

In 2005, the Bureau of Transport and Regional Services estimated diesel emissions were responsible for "between 900 and 2000" deaths and up to 4500 cardio vascular and respiratory diseases per year. The national death toll from car crashes last year was 1300.

The 2005 study did not distinguish the impact of diesel and unleaded emissions, however diesel is understood to be the larger contributor to air pollution given that diesel emits 56 times more oxides of nitrogen compared to unleaded fuel.

Diesel emissions have also been confirmed as "carginogenic to humans" whereas unleaded emissions are ranked third on the IARC warning list as "possibly carcinogenic".

IARC's Dr Dana Loomis, who will deliver new findings into air pollution at a conference in Geneva next week, told News Corp: "There is no doubt diesel emissions are more dangerous than most people realise."

In 2006, diesel was described as "the new asbestos" by Mark Curran, a retired plant physiologist from the University of Sydney, who now represents the action group Residents Against Polluting Stacks.

"Modern medical science has clearly shown … that diesel exhaust is one of the most dangerous and widespread of modern pollutants," said Curran. "Diesel exhaust is now known to be a carcinogen and particulate pollution has been fairly labeled as the 'new asbestos' for its ability to cause serious illness and death."

Despite their impressive fuel economy there is not one diesel-powered car in the top 400 vehicles listed on the Federal Government’s Green Vehicle Guide because a diesel car with the same consumption rating as a petrol vehicle produces 56 times more oxides of nitrogen.

Even the latest so-called “clean” diesels are not necessarily safe because the particles are so small they can bypass the lung’s natural defenses. But Australian experts are divided on the health risks of diesel fumes.

"Diesel can cause cancer but that doesn’t mean everyone who is exposed to diesel is going to get cancer because you might have a trivial level of exposure and you need quite a lot of it," said Professor Ian Olver, the CEO of Cancer Council Australia.

Professor Olver said while smaller particles from the tailpipes of so-called "clean diesel" cars may get into the lungs it was not yet clear if there would be enough to "trigger cancer".

People who work with diesel-powered machinery were at greater risk, he said. "Most of the data in the world relates to occupational exposure, such as diesel equipment in mines, or transport, particularly railway workers, exposed to diesel," said Professor Olver.

Dr Saiful Bari, program director, school of engineering, University of South Australia, an expert on diesel fuels, is more emphatic about the dangers of diesel emissions for the general public.

"Without any doubt, diesel particulates are harmful for humans," said Dr Bari. "Therefore, all particulates from diesel engines (are) harmful, even (from) clean diesels."

Dr Bari says diesel emissions are more dangerous when a car, truck or bus is idling. "(Diesel emissions) are dangerous at all loads. However, they emit more at idling due to lower (exhaust) temperature," said Dr Bari.

He warns diesel drivers "should switch off the engine if idling for a longer period" or "wear a mask while loading". Bus fumes were dangerous "especially for elderly people and infants", he said.

University of South Australia’s Shekh Nisar Hossain Rubaiyat, who has specialised in studying the effects of diesel emissions, said: "Contrary to perception diesel emissions are more dangerous when the engine is at low load, such as when an engine is idling.

"If you have a low load on the engine, the combustion of the diesel fuel is not complete, and that means more unburned hydrocarbons are emitted and that is really bad for your health."

Australia has been slow to embrace tighter emissions for diesel cars than Europe, where new limits have been in place since September 2009. That standard, labeled "Euro V", is not due to become mandatory in Australia until November 2016, more than seven years after Europe.

Meanwhile Europe is due to introduce even more stringent standards by September 2014 -- but the same standards will not be compulsory on all new cars sold in Australia until July 2018.

This reporter is on Twitter: @JoshuaDowling