Clearing the Air: Assessing real-world ventilation practices in New Zealand

Most New Zealand’s buildings are ‘naturally’ ventilated, meaning they rely on the opening of windows (and/or doors) by occupants. Ventilation habits are often inefficient, probably because we have a relatively poor innate sense of when a room is under-ventilated. Most members of the public under-estimate how effective windows can be in improving ventilation and air quality.

With increased recognition following the COVID-19 pandemic of the role of ventilation in reducing the risk of spreading illness, National Institute of Water and Atmospheric Research (NIWA) were commissioned by the Ministry of Health to:

• assess the state of ventilation (inferred from measurements of carbon dioxide) in a sample of mostly naturally ventilated buildings occupied by people more vulnerable to the acute health effects of COVID-19 infection
• explore the potential for improving ventilation through changes in ventilation behaviour
• explore the potential for using carbon dioxide monitoring data to promote pro-ventilation behaviour change.

This research helped to inform updated ventilation guidance on the Health Information and Services website.