Pellets could slash pollution

If every person in Rotorua with a wood fire switched to clean burning wood pellet burners, 322 tonnes of dust will disappear.

That's according to Crown Research Institute Scion, which has examined ways of reducing Rotorua's air pollution caused by heating.

The study showed that if all Rotorua homes used pellet stoves the total amount of dust particles produced from heating would be 28 tonnes annually.

This would be to a 92 per cent reduction. The city emits 350 tonnes of particles.

Rotorua's air pollution exceeds recommended health levels with domestic wood burning being the major cause of the city's air pollution. Poor air quality is reported to cause respiratory illnesses and 22 premature deaths a year in the city.

Environment Bay of Plenty has estimated that more than half of all Rotorua's winter PM10 emissions - dust particles in the air - are caused by burning firewood.

PM10 emissions are fine dust that can be breathed in causing heart and respiratory problems, especially in asthmatics, the elderly and children.

Dr Per Nielsen from Scion's bioenergy group is encouraging Rotorua homeowners to consider switching to cleaner burners before next winter.

However, while the regional council acknowledged that changing to pellet burners was part of the solution it wasn't the only answer to improve pollution, with cost being a factor.

The study found that using pellets rather than wood could significantly cut emissions, ultimately improving air quality because they were cleaner to burn and were more efficient in giving out heat than firewood.

Although Dr Nielsen acknowledged wood pellet burners would not solve the city's air quality problems, he said it was a simple and immediate step that would make a difference.

The study was carried out to offer an idea on how to improve air quality.

"I think we just wanted to illustrate the potential," Dr Nielsen said.

He said there were no plans to lobby local MPs about the issue and it had nothing to do with new regulations aimed at reducing pollution in the city to acceptable standards.

These regulations were presented to the Rotorua District Council by the regional council which said there were 7500 Rotorua people who would have to spend $2000 to $8000 to replace non-complying wood burners, wetback fires, pot belly stoves and open wood fires which don't meet new requirements.

The main problem was a combination of wet wood being used in an old fireplace. New fireplaces are designed so they burn hotter which in turn causes less pollution. Owners would have until 2013 to replace outdated wood burners.

Attention was drawn to Rotorua's pollution problem after new national air quality regulations were introduced in 2005. The city is a Local Air Management Area and the regional council wants pollution reduced to new standards by 2013.

Fully installed wood pellet fires generally cost between $4000-$5000. A 20kg bag of pellets costs around $10, amounting to an annual cost of between $400 and $600.

The regional council's environmental planner Karen Parcell said other options such as heat pumps, gas fires or compliant wood fires should also be considered. Although results would not be as good, they would still cut heating emissions by at least half.

Dr Nielsen acknowledged this and said other emission saving options included combining pellet heating with heat pumps, geothermal and solar heating.

He said if firewood had to be used, householders had to make sure it was dry.


Regional council environmental scientist Shane Iremonger encouraged people to look at alternative heating.

"[Wood pellets] are not the sole answer but we are supportive of moves to encourage people to consider newer heating technologies," he said.