The COVID-19 pandemic has highlighted the importance of ventilation as a transmission mitigation strategy. However,
there was a widely held concern that a drop in outdoor temperatures during winter may impact thermal comfort in the
context of naturally ventilated classrooms. This concern has not been widely investigated by peer-reviewed empirical
studies (Sutherland et al., 2022b).
The aim of the Ministry’s ventilation monitoring initiative was to assess ventilation performance and thermal comfort
by continuously measuring indoor CO2 levels, air temperature, and relative humidity in classrooms during winter,
without obstructing teaching activities.
A total of 43 schools, which represent a broad mix of property attributes and located across the 6 Climate Zones in New
Zealand, were selected for the monitoring initiative. The CO2 monitors were deployed in about 4-6 pre-selected and
representative spaces in each school. Data was retrieved from 213 spaces; of these, 44 spaces were excluded, because
the initiative concentrated on teaching environments (classrooms) and those spaces were categorised as non-teaching
environments (e.g., staff rooms, meeting rooms, etc.).
From the 213 spaces, the data from 169 teaching spaces retrieved for the period 23 May to 26 August 2022 were
analysed to ascertain the impacts of inferred human behaviours considered to be able to improve natural ventilation
and detected from features of CO2 and temperature data. This analysis does not (and did not intend to) corroborate
independent observation of behaviours
