
Factsheet on WHO AQG - Health Effects of Short-Term Exposure to SO2
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 2021 evaluating the best available evidence on the effects of short-term exposure to sulphur dioxide (Orellano et al. 2021). Specifically, the research published updated quantified risk ratios for exposure to sulphur dioxide (SO2) on all-cause mortality (people dying earlier than they otherwise would have).