KEY POINTS:
A badly maintained diesel truck can be a worse air polluter than 1000 well run cars on New Zealand roads, says air quality expert Gavin Fisher.
As the Government prepares to outlaw older cars to reduce harmful emissions, Mr Fisher, an air quality scientist, told 60 Minutes last night that the benefits of buying 1000 new cars and running them properly were overwhelmed by one badly tuned diesel truck or bus.
Mr Fisher told the Herald that ordinary petrol cars, especially new ones, were quite clean.
"But diesel vehicles - especially those which are badly tuned - are quite dirty."
On average badly tuned vehicles cause as much damage as about 100 cars, he said.
Mr Fisher said in all about 70 per cent of the New Zealand's air pollution from vehicles came from about 30 per cent of the fleet, particularly diesel-run vehicles.
The Government could consider a cost-effective, directed approach in testing vehicle emissions that concentrated on diesel vehicles as the main culprits, he said.
Mr Fisher was an author of the Health and Air Pollution in New Zealand report released in July which found air pollution to be a billion-dollar killer claiming nearly 1100 lives each year.
Associate Minister of Transport Judith Tizard told the Herald last night the freight fleet was a problem but it was hard to get reliable emission tests that would stand up in court as the vehicle fleet in New Zealand was so varied.
New minimum vehicle emissions standards on new and used car imports were due to come into force in January 2008 to cut the rate of pollutants pumped out by used vehicles.
Used cars would be tested before they were allowed in and it would be illegal to modify any new or used vehicles' equipment that could cause their emissions to worsen.
David Crawford, the Ministry of Transport's general manager land transport and environment and safety, said testing for all road vehicles currently in the fleet was something the Government could still consider.
"We have it on our work program to have another look at how that might work." Mr Crawford said one option could be to test for heavy vehicles only.
David Vincent, of the Independent Motor Vehicle Dealers' Association, said the pollution problem was with the vehicles already in the fleet and heavy diesel vehicles contributed a disproportionate amount of particulate pollutants.
The association, which represented the importers and distributors of used cars, recently launched a nationwide campaign against the Government's vehicle emissions proposals, concerned they would severely restrict imports.
It urged the Government to develop a strategy including economic incentives to help ban older cars from roads.
The Auckland Regional Public Health Service yesterday welcomed the moves to cut vehicle emissions.
Professional and clinical director Dr Julia Peters said it would create healthier environments at a time when mounting evidence showed growing concerns about the risk to public health from rising vehicle emissions.
Dr Peters said children were particularly vulnerable to the health effects of air pollution with studies showing an association between poor air quality and impaired lung function. Concerns about children and air quality around early childhood education centres are emerging as an important issue in the Auckland region.
"With the trend towards locating centres away from residential and into commercial and light industrial areas children may be being exposed to more emissions from vehicles and industry, and this needs considered action."
