Our study with NIWA, performed in consultation with VTAG, helped us understand more about classroom ventilation and verify our COVID-19 ventilation strategy for New Zealand schools.

The study involved looking at ventilation levels in typical classrooms being used as they normally are during the day. This was done by monitoring CO2 levels, which indicates how much fresh air flow there is, in 18 different classrooms across three schools.

The study verified that good ventilation can be achieved in most naturally ventilated classrooms by opening windows and doors. The study highlighted the added benefits of opening windows and doors on different sides of the room, of introducing short breaks to periodically purge the room of stale air, and of supplementary assisted natural ventilation systems (e.g. fixed extract/exhaust fans).

It also identified other areas for further research including classroom ventilation in cold weather, and the effective use of portable air cleaners and other supplementary measures.
 

As a follow-on to the classroom ventilation study, this study assessed how the ventilation was impacted by different opening areas, differing indoor versus outdoor temperatures, and by supplementary measures such as portable air cleaners and fans.

The aim of this literature review was to review the available literature on the impact of natural ventilation during winter on thermal comfort.

This literature review summarises the current (at time of writing) research on the performance of portable air cleaners used in naturally ventilated classrooms for the purpose of COVID-19 mitigation.

From May 2022 the ventilation programme initiated a temporary monitoring study through the winter season of CO2, temperature and humidity in 169 spaces at 43 schools nationwide.  This study analysed the data with a focus on investigating how preheating rooms and taking refresh breaks (i.e. deliberate opening of multiple doors and windows, preferably while vacating the room) impacted CO2 and temperature levels. 

The findings generally showed that for most of the monitored teaching time, the CO2 levels were largely less than 800 ppm (67% of the time) and were within the temperature range of 18-25 °C (70% of the time). While the indoor air temperatures were similar in all Climate Zones, CO2 levels were higher in colder climates. 

A warmer temperature when teaching started in the morning may have played a positive role in lowering CO2 levels throughout the day, and indoor air temperature drop was likely to be limited when breaks and refresh breaks occurred.

In August 2022, the ventilation programme initiated a ventilation monitoring initiative which involved continuous monitoring of carbon dioxide (CO2), temperature and humidity levels in five ECEs spread across the country. This report is based on the data collected, which evaluated the ventilation performance of naturally ventilated ECEs to inform proactive ventilation management and improvement guidelines.