Poor ventilation in public transport settings in Aotearoa NZ: New data for buses and trains
10 July 2023
Nick Wilson, Lucy Telfar Barnard, Julie Bennett, Amanda Kvalsvig, Caroline Halley, John Kerr, Jonathan Jarman
In this Briefing we report on carbon dioxide (CO2) levels in public transport settings in Aotearoa NZ as a proxy measure for poor ventilation and increased Covid-19 transmission risk. In buses and trains with more than 50% of seats occupied, ventilation was typically poor 94% and 77% of the time respectively (CO2 levels above 800 ppm). These and other NZ findings (eg, from a 2022 study of Wellington’s Metlink buses) are consistent with international research also showing poor ventilation in these settings. Fortunately, there are multiple actions that transport companies and central/local government can take to improve the situation – including adopting relevant standards. Such interventions may lower the risk of Covid-19 and other respiratory virus transmission and ensure staff occupational safety.