Experts are happy to see Masterton’s air quality improved this winter, despite still exceeding both national and international guidelines for healthy air.
Masterton’s air is notorious for exceeding air quality standards due to the low-lying town having insufficient airflow to defuse smoky winter air.
This year exceedances only slightly varied compared with the previous year, but most improved air quality went to the east side of town, according to the Greater Wellington Regional Council’s provisional figures.
Two types of coarse dust particles are measured in the air over Masterton – 2.5 micrometres in diameter (PM2.5) and 10 micrometres (PM10).
Masterton east exceeded the PM2.5 World Health Organisation guidelines of three days of exceedances per year by 26 days – but that is 17 days less than last year.
Masterton west recorded 25 days exceeding the guideline – three days less than last year.
Masterton east exceeded the PM10 National Environmental Standards [NES], of one day exceedance per year, by six days – that’s one less than last year.
Masterton west only recorded three days exceedance of the particles, the same as last year.
These airborne particles are too small for the human eye to see – in comparison, a grain of sand is around 90 micrometres in size.
But they can cause adverse health impacts ranging from irritation of the nasal tracts to respiratory and cardiac disease, and even premature death.
Masterton District Council’s strategic planning manager Tania Madden was pleased to see the town’s air quality had been improving.
As an example, she said, in 2016 the east side recorded 10 days of exceedances at the PM10 level compared with six this year.
“Although this year’s result is one day higher than 2017, the general trend is a reduction.”
Madden said the council had been working on ways to improve the air which included working with GWRC on the ‘Better Burning’ campaign.
A mobile air quality monitoring project was completed around the town which would offer more in-depth data, which was still being processed, on the air, she said.
The council’s 2018-28 Long Term Plan included a target to reduce the number of exceedances per year.
GWRC senior environment scientist of air quality Tamsin Mitchell said while there were reductions in this winter’s results, more were needed for healthy air.
“The biggest improvement is at the Masterton east site, which is very pleasing, but we still need to reduce PM2.5 further across the whole of Masterton,” she said.
Mitchell said the Census 2018 data, due next month, would offer a better picture on the number of households that use solid fuels.