Masterton’s air pollution rises

Masterton’s air pollution has exceeded World Health Organisation [WHO] guidelines five times in the past week.

WHO guidelines specify a daily average limit of 15 micrograms per cubic metre of small airborne pollutants [PM2.5].

But Masterton’s air quality monitoring site has recorded daily measurements of more than this several times in the past week.

PM2.5 are pollutants that are most commonly caused by the combustion of wood and fossil fuels such as home heating and traffic.

Other natural sources include dust, pollen, and sea spray.

These airborne particles are small enough to be breathed in and penetrate into human lungs, causing negative health effects for people’s respiratory and cardiovascular systems.

Last year, there were 55 days where Masterton’s air pollution of PM2.5 exceeded WHO guidelines.

The year before, there were 44 exceedances and in 2021, there were 75.

Greater Wellington Regional Council’s [GWRC] land air and climate knowledge team leader Douglas Gordon said Masterton’s poor winter air quality is attributed to wood smoke from older fireplaces and the burning of wet or damp wood, leading to high levels of fine particle air pollution.

“The hotter wood burns, the better it is for our health and environment,” Gordon said.

“We encourage everyone to use dry, untreated wood.

“Try to give your fire enough air – avoid letting it smoulder or burn low overnight – and remember to get your firebox checked and chimney cleaned every year.”

There were previously two sites that measured air quality in Masterton; one on the west side and one on the east side.

GWRC decommissioned the Masterton East site last year because it wasn’t meeting the new National Environmental Monitoring Standards, and ongoing technical issues meant the council wasn’t collecting enough high-quality data.

“In the past, the Masterton East site had detected higher PM levels than the Masterton West site due to the way pollution travelled through the air,” Gordon said.

“However, in recent years the data from the two sites were very similar – enough for us to confidently collect data using the one site.”