The Institute of Environmental Science and Research (ESR) has changed its name to the New Zealand Institute for Public Health and Forensic Science (PHF Science) as of 1 July 2025. The new website address is www.phfscience.nz. Visitors will automatically be redirected to the new address. Please check and update any links and bookmarks after this change.

Factsheet on WHO AQG - Health Effects of Short-Term Exposure to PM, NO2 & O3

Please note: As of 1 July 2025, the New Zealand Institute for Public Health and Forensic Science (PHF Science) is the new name for the Institute of Environmental Science and Research (ESR). Research and reports published prior to this date may reference the organisation’s former name.

Summary

In 2021, the World Health Organisation (WHO) published revised recommendations for ambient air quality (WHO 2021). To support this update, WHO published a review paper in 2020 evaluating all the available evidence on the effects of short-term exposure to particulate matter (PM) and nitrogen dioxide (NO2) (Orellano et al. 2020). Specifically, the research published updated quantified risk ratios for exposure to PM, NO2 and O3 on premature mortality (people dying earlier than they otherwise would have). They also assessed how this risk changed at different levels of exposure.

Download