Dirty buses to join pollution trial run

By MATHEW DEARNALEY

Some of Auckland's older and dirtier buses are likely to become test beds for pollution-control technology aided by a home-grown modelling system developed by university researchers.

The Auckland Regional Council hopes to import devices called diesel oxidation catalysts to reduce emissions in a trial of six to 10 buses, mostly built before 1988, after hearing from Australian and American technology suppliers at a workshop last week.

Although the catalysts are used widely overseas, the trial will depend for data assessment on know-how from the energy and fuels research unit at Auckland University.

Effective use of the catalysts will also rely on a Government-directed reduction in sulphur levels in diesel in August to 500 parts per million - from 1000ppm now allowed in Auckland and 2200ppm in the rest of New Zealand.

The university's contribution is a modelling tool which its researchers say could help cities around the world to reduce fuel emissions from buses.

They developed it primarily for the regional council, which is considering adding environmental "green ticks" when assessing tenders for subsidised bus services, but believe it could be adapted to score the performance of fleets everywhere.

Research unit manager Stephen Elder said it allowed users to key in bus models and weights, distances travelled and types of fuel used.

They could then assess the cost of reducing emissions from various options, such as fitting particle filters or changing fuels, against the price of replacing buses.

"The system provides an estimate of the cost involved with various strategies - this tool could be applied to any bus fleet in the world," Mr Elder said.

Fleet data allowing the researchers to devise the model was supplied by the Stagecoach bus company, but the regional council will also invite other operators to join the catalyst trial.

Council air quality scientist Gerda Kuschel said money was available for catalysts for six to 10 representative older buses from the region's 850-strong fleet, all of which would be tested for emissions in a parallel exercise in coming months.

Dr Kuschel said the catalysts were expected to cut health-endangering particulate emissions by up to 50 per cent, and carbon monoxide and hydrocarbons up to 60 per cent.

A Government report in 2002 estimated that almost 400 New Zealanders a year, including 253 in Auckland, die prematurely from motor vehicle pollution in an "invisible road toll".

Although buses contribute only 1 per cent to 2 per cent of almost 3000 tonnes of particulates spewed into the air each year from Auckland vehicles, those from diesel are considered more noxious than from petrol engines.

The council campaigned successfully in 2001 for a reduction in the sulphur content of diesel, to 1000ppm, but Dr Kuschel said a further halving of this figure in August would allow the most effective use of the catalysts.

Emission tests part-funded by the Niwa last year found well-maintained older vehicles could be environmentally cleaner than poorly kept new ones.

Poison fumes

* A Government report in 2002 estimated that almost 400 New Zealanders a year die prematurely from vehicle pollution.

* All vehicles will from late 2006 have to pass emission tests before having warrants or certificates of fitness renewed.