The World Health Organization reduced acceptable limits for PM10 and PM2.5 when it updated their air quality guidelines in 2021. This reflects global research showing that particulate matter is more harmful at lower concentrations than previously thought. The Health and Air Pollution New Zealand (HAPINZ) update in 2022 provides detailed aspects of the health and social costs of air pollution in New Zealand. 

In Otago, the ORC worked with the Southern District Health Board (SDHB) in 2007 to show that in areas with more high pollution days for PM10. The SDHB recently refined this work in 2022 to show that higher PM10 concentrations increased the risk of acute respiratory infections, highlighting the risk of even short-term exposure to particulate matter. Areas with more wood burners have a higher risk. 

You can read more about particulate matter on the Ministry for the Environment website and see the modelled impact on health in New Zealand by district