This Advisory Note guides premises managers on how carbon dioxide (CO2
) monitoring can be used as a proxy for ventilation adequacy, so that premises managers can take timely mitigating measures when ventilation is poor (when CO2
levels are above 800ppm). Measures to improve ventilation in indoor spaces can be found in the Guidance Note on Improving Ventilation and Indoor Air Quality in Buildings amid the COVID-19 Situation
As Singapore transitions to COVID-19 endemicity, premises managers should take active steps to ensure good ventilation, especially in enclosed, air-conditioned indoor environments. Good ventilation reduces the amount of virus aerosols and other indoor air pollutants that could be present. This will help mitigate the risk of aerosol-based transmission to protect the health of occupants, workers and general public in these premises. Measures to improve ventilation will also enhance our resilience against new COVID-19 variants of concern and future airborne infectious disease threats.
Ensuring good ventilation is critical in premises with higher risk of aerosol transmission, due to risk factors such as mask-off or bioaerosol-generating activities, prolonged time duration spent by occupants within the space, and/or the presence of vulnerable populations. A list of such higher risk premises is shown below. Managers of such premises should proactively ensure that these premises are always well-ventilated. List of premises with higher risk of aerosol transmission and/or presence of vulnerable group
- Hospitals and clinics
- Eldercare facilities, including nursing homes and day activity centres
- Establishments with food and drinks served on-site*
- Gyms and fitness studios
*Include food establishments, event venues, function rooms, nightlife establishments, karaoke establishments etc.
CO2 monitoring can be used as a quick, easy-to-implement proxy for ventilation adequacy, and to identify pockets of under-ventilated spaces or overcrowding within the premises. High CO2 levels imply that there is insufficient outdoor air intake and/or overcrowding, and measures should be taken to improve ventilation or reduce occupancy. Managers of higher risk premises should carry out CO2 monitoring regularly and take prompt action to improve ventilation, where necessary.
For more information, please refer to appended Guide to Premises Managers on CO2 Monitoring.
(1) Recommended Specifications for CO2 Meters
✔️ Non-dispersive infrared (NDIR)
✔️ Able to measure between 300 to 3,000ppm or more
✔️ Logging frequency of at least once every minute
✔️ Accuracy of not more than ±50 ppm or ±5% (measured within the specified measurement range)
✔️ Resolution of 10ppm or less
✔️ Can be calibrated
✔️ [Good to have] Provide average readings based on selected measurement duration