Watchdog urges officials to improve monitoring of harmful tiny airborne particles from vehicles and fires.

New Zealand's monitoring of air pollution is lagging behind the rest of the developed world and needs to start picking up the tiniest, most harmful particles, Government's environmental watchdog says.

In a report released yesterday, Parliamentary Commissioner for the Environment Jan Wright said air quality in this country was generally good, and often "very good". But she warned there was "real evidence of harm" from the small airborne particles created by vehicle emissions or open fires, even when present in small amounts.

Dr Wright made the comments in a peer review of a government report card on air quality, published yesterday. The report cards on air, freshwater, oceans, land and climate, and the commissioner's analysis, would become mandatory under laws to be passed later this year.

While New Zealand's air quality was "an environmental good news story", Dr Wright said she held some concerns about the way it was monitored by authorities.

Advertisement

At present, officials measured airborne particles which had a diameter of less than 10 microns (PM10) - the size of a grain of sand.

The World Health Organisation said smaller particles were more likely to cause health problems because they could enter the bloodstream or penetrate deep into the lungs, potentially causing respiratory illness or cancer.

New Zealand also looked at short-term exposure to particles, while the WHO said long-term exposure was the most important measure.

"We are behind the rest of the developed world ... and it's time we caught up," Dr Wright said.