Particulate matter (PM) pollutants are caused by sources such as fires and are monitored by the regional council.
Particulate matter (PM) pollutants are caused by sources such as fires and are monitored by the regional council.
Air pollution levels have been “underestimated” at a key Hawke’s Bay air monitoring site for a matter of years, according to new technology.
Hawke’s Bay Regional Council (HBRC) said while the discovery is “disappointing” it is also “reassuring that we have found this discrepancy”.
A recent study in Hastings revealedthe council’s current air monitoring technology has been “under-reading” air pollution levels by about 30%.
That led to HBRC notifying the public this month of nine air pollution breaches in Hastings, between June 2022 and July 2023, which were picked up by new technology in the study, but were not identified by existing monitoring equipment that has long been in use.
There are usually only one or zero breaches reported per year in Hastings.
The existing technology, called beta attenuation monitors (BAM), are coming to the end of their life and have been used for 20 years at sites in Hastings and Napier to monitor air pollution levels in those urban areas.
As such, the regional council began a study in 2022 to compare them with newer, and less time-consuming, technology.
The year-long study trialled new equipment alongside the old BAM monitors at the St John’s College monitoring site in Hastings.
The conclusion was Fidas monitors were more accurate and should be adopted in place of BAM monitors, the latter of which “have been underestimating” particulate matter (PM).
A Hawke's Bay Regional Council staff member using a new Fidas monitor to monitor air pollution. Photo / HBRC
“The results of the equivalence testing reveal that the BAM measuring PM10 is under-reading 24-hour average concentrations by around 30%,” council papers stated.
“The Fidas [monitoring technology] provides a more accurate representation of PM10 concentrations than the BAM.
“These results of the equivalence testing indicate that the Fidas is the most appropriate instrument to be using for [National Environmental Standards] reporting.”
The council has bought the new technology for its monitoring sites in Hastings, Napier and Awatoto, council papers stated.
PM cannot be seen by the naked eye but is easily inhaled and can lodge deep within the lungs, causing negative health effects, and is therefore closely monitored by the regional council.
Sources of PM include fires (including domestic fires), industrial processes, motor vehicles, and wind-blown dust.
The air pollution breaches which have been reported in Hastings as a result of testing with new technology. Photo / HBRC
The council monitors PM10 and PM2.5 concentrations and uses that information to record air pollution breaches, which is when PM levels go past a certain threshold and most commonly occur in colder months.
HBRC air quality scientist Jeremy Kidd said it was good to have discovered the “discrepancy”.
“Whilst this is obviously disappointing, it is reassuring that we have found this discrepancy and will be able to ensure the more accurate measurement of the PM10 particles into the future,” he said.
“Despite the additional exceedances, the long-term trend still shows a decrease in PM10 concentrations [in Hawke’s Bay].”
HBRC has been monitoring PM10 in the Napier and Hastings airsheds (the urban area around Napier and Hastings) since 2005.
During that time, monitoring has helped bring down the number of air pollution breaches.
The new technology for better monitoring air pollution will likely result in tighter regulations for future resource consents, to reduce the number of exceedances.
“Typically, industrial activities require resource consents for their air discharges. These matters will be addressed in the ongoing development of the Kotahi Plan,” council papers read.
Gary Hamilton-Irvine is a Hawke’s Bay-based reporter who covers a range of news topics including business, councils, breaking news and cyclone recovery. He formerly worked at News Corp Australia.
