Only a quarter of New Zealand sites meet guidelines for most harmful air pollution, data shows

2:03 pm today

Smoke from a wood burner.

Photo: Dave Allen / NIWA CC BY-NC-ND 4.0

Only a quarter of sites across the country meet international guidelines for the most harmful type of air pollution, new data shows.

However, overall air pollution is improving in most places, with the majority of sites meeting national regulatory standards for overall particulate matter.

The data has been released by LAWA, the government partnership responsible for monitoring and reporting on New Zealand's air and water quality.

Recent University of Auckland research found that particulate matter and nitrogen dioxide created by vehicle traffic is responsible for 700 deaths in Auckland every year.

And an earlier report jointly published by government put nationwide deaths associated with human-created air pollution at 3300 a year - 40 percent from fine particulate matter.

Chief science advisor for regional government partnership Te Uru Kahika Chris Daughney said levels of fine particulate matter, known as PM2.5, were of concern.

There is no national standard for PM2.5, which is mostly created by burning wood, coal and diesel, but many councils still monitor it.

That monitoring showed that just nine out of 39 sites with data met World Health Organisation daily guidelines for PM2.5 levels.

However, most sites met the regulatory standard for PM10, which monitors levels of both coarse and fine particles in the air.

LAWA air quality science lead Teresa Aberkane said New Zealand had relatively good air quality by international standards.

The long-term trends, which showed improvements at 37 out of 50 sites, were encouraging, she said.

"But the data also shows where further improvement is needed, especially in winter," she said.

"Smoke from home heating is still an issue in many places, and fine particles from combustion can get deep into the lungs and have serious health impacts."

National direction, together with council action and household choices, could all help.

"Cleaner heating, burning only dry untreated wood, avoiding outdoor burning, and lower-emission transport options can all make a difference," Aberkane said.

Continuing to improve air quality would be a "win-win" for human health and the environment, Daughney said.

"When we reduce smoke from home heating, cut vehicle emissions, or move to cleaner energy, we can improve air quality today while also helping reduce emissions that affect the climate."

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