Three decades of monitoring provides clear picture
Over 30 years of air quality monitoring has been drawn together in a report providing the most comprehensive picture of how smoke affects Coast towns.
The WCRC report combines long-running records from Reefton - monitored continuously since 2006 - together with historic data back to the 1990s. It also includes more recent investigative monitoring at Westport, Greymouth, Hokitika and nearby townships since 2022.
Group Manager Environmental Science Shanti Morgan says it represents years of fieldwork by staff including installing and maintaining monitoring instruments, running surveys across each town, and commissioning specialist analysis to identify pollution sources.
"It’s a significant achievement by the team to pull all this work together. Now we’ve established a clearer regional picture we can target future monitoring much more effectively focusing on where it can provide the most useful information.”
The report confirms domestic home heating as the main source of fine particle pollution in every town monitored. Concentrations rise sharply on cold winter mornings and evenings when fires are stoked.
Every town monitored, including those by the sea, recorded levels of PM2.5 above World Health Organisation guidelines. PM2.5 refers to very small particles in the air - including those produced by burning wood and other fuels - which can be breathed deep into the lungs. Larger particles, known as PM10, include smoke, dust and natural sea salt.
“We’ve found a big share of the PM10 measured in coastal towns was from natural sea salt rather than sources that can be managed,” says Shanti Morgan.
“This makes PM2.5 the more meaningful measure of the pollution communities can actually influence.”
Reefton will remain the priority for long-term monitoring, she says.,
“Work in other towns will focus on understanding local differences and confirming where fine particle pollution is highest.”
WCRC will continue to build its PM2.5 monitoring capability, reflecting the growing importance of this measure as most relevant to community health and most able to be influenced by changes in home heating.
