The Otago Regional Council’s new central Dunedin air quality monitoring station now measures finer particles in the air.
The new station has also moved from its Albany St site after a major University of Otago construction project confounded readings in 2021.
Council air quality scientist Sarah Harrison said the new Clyde St station was able to measure particulate matter in the air only two and a-half microns or less in width (PM2.5).
The council was upgrading its air quality monitoring network, and the central Dunedin site now monitored PM2.5 as well as particulate matter in the air 10 microns or less in width (PM10), she said.
"We have monitored PM10 since 2006, which includes anthropogenic and natural sources, but the new site also monitors PM2.5, which are smaller particles emitted by combustion, and are more dangerous to human health," she said.
The council also monitored meteorological parameters at the upgraded site, such as temperature, wind and humidity.
New monitors for solar radiation and atmospheric pressure were also being added to this site.
"All of these parameters help us understand the air quality data.
"Central Dunedin has relatively good air quality, and the main particulate matter sources in the area are traffic, industry, home heating, with some natural sources such as sea salt as well."
In 2021, a single day’s Albany St reading of PM10 concentrations as high as 54mcg/cu m was treated as a significant outlier and investigated.
The reading was not included in the annual roundup and that year across Otago only Dunedin had no days where the air quality breached the standard of 50mcg/cu m, the annual air quality report for 2021 said.
Ms Harrison said the council had moved its monitoring station due to the former site’s proximity to the under-construction University of Otago Te Rangihiroa residential college in Albany St .
"We chose this location as it is very close to the previous location, and it meets air quality monitoring criteria of being away from buildings and trees, which can impact air quality readings," she said.
"We upgraded this site at the same time as relocating it.
"The instrument housing and some of the instruments are new.
"We will be installing a permanent fence, native plants and will be adding graphics and information to the sides of the shed to explain what it is for."
In a report to the council last year, Ms Harrison said the World Health Organisation had updated its guidelines such that clean air standards would drop from 50mcg/cu m to 45mcg/cu m for large particles (PM10) and for smaller particulate matter (PM2.5) the clean air standard was dropped from 25mcg/cu m to 15mcg/cu m.
The council website notes the changes support global research indicating particulate matter is more harmful at lower concentrations than previously thought.
