It could take 20 years for Masterton to meet international air quality guidelines, exposing vulnerable people to “unacceptably high levels of air pollution” for much of winter, a new report says.
By Emily Ireland of Local Democracy Reporting
The social cost of the pollution sits at more than $6000 per person in the area. This includes the direct medical costs associated with the health impacts of air pollution, such as reduced life expectancy, and broader societal costs such as lost income and time away from work or school.
Greater Wellington Regional Council’s Environment and Climate Committee would meet on Thursday to discuss the report prepared by council staff.
It outlined wood burners as a major culprit for the pollution, aggravated by “topographic conditions that limited the dispersion of wood smoke”.
In Featherston, 63% of dwellings used wood burners, 61% in Greytown, 58% in Carterton, and 52% in Masterton.
"Wood burning causes elevated levels of PM2.5 (small air pollutant) during the winter months," the report said.
"The impacts of this are not the same everywhere and are more significant where wood burners are more concentrated.
"The impacts are further amplified in areas of naturally poor dispersion, such as inland valleys where winter temperatures are colder and wind speeds are lower, leading to temperature inversions that trap air pollutants under clear sky conditions."
Wairarapa towns had the worst-case combination of both high emissions and poor dispersion in the Wellington region, meaning much higher emission cuts would be required to overcome this geographical disadvantage and achieve good air quality, the report said.
Wairarapa currently had one official air monitoring station – Masterton West – which on average recorded more than 50 high-pollution days per year since 2021, compared to the World Health Organisation (WHO) guidelines of no more than three per year.
High pollution days are defined as when the daily average of PM2.5 particles exceeds 15 micrograms per cubic metre.
So far this year, the air quality guideline for PM2.5 has been exceeded 29 times in Masterton.
The report said although air quality was improving, the rate of improvement was very slow.
"At the current pace, it could take Masterton around 20 years to meet the annual PM2.5 guideline."
Regional council Environment Committee chairman Quentin Duthie said progress to improve the region’s air quality was stalling and could be significantly improved.
"With our wind and spread-out urban areas we should be best in the world, but we still have preventable air pollution in places."
He said air pollution was a public health risk estimated to cause $1.29 billion in social cost and 3000 premature deaths nationally.
"This impacts on the health of locals, with an estimated social cost of over $6000 per Masterton resident for example."
He said pollution from fire-smoke could be reduced over time by pursuing cleaner home heating and better insulation, which also had wider health benefits.
"Toxins released from burning treated timber containing arsenic (cancer-causing) and timber with lead paint (neurotoxin) are also of concern. Past studies have found these toxins to be higher than recommended guidelines.
"Each winter, arsenic levels spike indicating that some households persist in burning treated timber, increasing cancer risk to their own household and the wider community.
"I urge households to ensure your fire burns bright not dull, use dry wood, and do not burn treated or painted timber – or manufactured wood products like MDF, particleboard, plywood or formica which contain nasty chemicals."
- LDR is local body journalism co-funded by RNZ and NZ On Air
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