Fresh scientific scrutiny for Arrowtown air

NIWA scientists have set up air quality sensors every 100 metres across Arrowtown in what is believed to be the world’s densest air monitoring network.

NIWA scientists have set up air quality sensors every 100 metres across Arrowtown in what is believed to be the world’s densest air monitoring network.

The monitors will be in place for the rest of winter to give scientists a much more detailed picture of smoke patterns first detected in the town last year.

Arrowtown suffers from poor air quality due to wood burning, cooking and calm conditions that prevent smoke dispersing. Since mid-May the town has exceeded the 24-hour National Environmental Standard for air quality nine times compared to just one for the same period last year. This included over five consecutive days from the Friday of Queen’s Birthday Weekend. The rate could double if a proposal to introduce a new National Environmental Standard for air quality goes ahead.

Students studying local air quality

Last year NIWA air quality scientist Dr Ian Longley launched the Arrowtown project that included some outdoor monitoring and indoor air quality monitoring by people in their homes. Scientists also worked with Arrowtown School students to analyse, visualise and communicate air quality data collected during winter.

Twenty-two ODINs were distributed across the town between June and mid-August, with more installed in August and September, reaching a maximum of 48. Results showed that air quality varied hugely across the town. It was excellent everywhere in early afternoons but persistently poor on cold winter nights.

Intense monitoring effort reveals localised smoke patterns

Following that research, scientists this year planned to work with a group of community volunteers in April and May to install 70 ODINs, or Outdoor Dust Information Nodes that measure particulate matter every few minutes. Dr Longley believes this may be the world’s densest air quality monitoring project.

However, COVID-19 restrictions meant a delay to the start of the programme and the monitors were instead set up by NIWA staff last week.

Dr Longley says this year’s monitoring will enable researchers to see the smoke patterns in unprecedented detail and get a better understanding of where it’s coming and where it’s going to.

“We know the Queenstown-Lakes area has been hit hard because of lockdown. Impacts may include more time spent at home and more home heating, but also less heating in households that can’t afford it.

“There is also growing evidence from overseas that death rates and severity of illness from COVID-19 has been worse in areas with poor air quality. This has provided a chance to reassess the importance of healthy homes and how we manage risk in our communities,” Dr Longley says.

Empowering the community to develop solutions to air pollution

Domestic wood burners are a major source of air pollutants during winter but until recently little scientific evidence has been gathered to show how smoke levels in New Zealand towns are influenced by weather, topography, buildings and home heating behaviour.

This year animations of the last 24 hours’ data will be posted to the Arrowtown 2020 webpage at 6am each day.

Arrowtown households are also invited to host indoor air quality monitors for about two to three weeks to help build a better understanding of how indoor air varies between homes. Priority will be given to those who have recently, or are planning to install a new heater, ventilation system or air cleaner, and are willing to be involved in an experiment to assess their effectiveness.

The Arrowtown project is part of the Community Networks for Air (CONA) programme that empowers communities to assess their air quality, then develop and evaluate solutions. Plans are under way to extend this project to other towns.

See more information: Air quality issues in New Zealand towns

Results from Arrowtown in 2019, including final report about outdoor air quality.

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