An Otago Regional Council (ORC) report shows air quality in Otago has improved over the last ten years, but more work is still needed.

The amount of ‘particulate matter’ in the air in seven out of eight ORC monitoring areas still exceeds the national environmental standards for air quality.

Particulate matter is produced by sources including industrial activity, vehicle exhaust and solid fuel burning for home heating (which causes the majority of emissions in Otago), and can also be produced by vehicle movements or processes that create dust. 

ORC strategy, policy and science general manager Gwyneth Elsum said the report showed air quality was “gradually improving” at the majority of Otago sites.

“Winter air quality trend analysis showed improvements in Alexandra, Arrowtown, Clyde, Cromwell and Milton over the ten-year period,” she said. 

Wānaka is not one of the ORC’s monitoring sites but nearby Cromwell showed an improvement in air quality over the past ten years. PHOTO: Wānaka App

“These towns have the strictest air plan rules for wood burner emission rates and thermal efficiency, and are the areas where ORC has previously incentivised residents to replace older burners.”

Neither Wānaka nor Hāwea were being monitored, but testing in Mosgiel and central Dunedin was also “trending in a positive direction”.

Balclutha, where monitoring ceased in 2018, was the only site where the air quality trend was degrading over the long-term.

Gwyneth said the air quality picture is complicated in areas that are experiencing rapid urban growth.

“Different towns in Otago have different climates, geography, and changing population sizes, and these local factors all contribute to air quality.

“We also know that air quality can change spatially within towns, sometimes quite dramatically.”

The data in the report will inform policy making in the upcoming air plan review, Gwyneth said.

The ORC’s long-term plan includes a review of the current regional plan on air for Otago, starting in the next financial year, before notification in 2025 and implementation in the years to follow.