Updated: Nov 25, 2020
Research shows that good ventilation plays a significant part in the management of COVID-19. As an airborne virus that is transmitted through aerosols (a suspension of fine solid particles or liquid droplets in the air), good ventilation is crucial to help reduce the risk of the virus being transmitted.
The Scientific Advisory Group for Emergencies (SAGE) has written a paper on the role of ventilation in controlling the transmission of COVID-19. The findings show that:
· Ventilation is an important factor in mitigating against the risk of far-field (>2m) aerosol transmission, but has no impact on other transmission routes (high confidence). The importance of far-field aerosol transmission is not yet known, but evidence suggests it is a risk in poorly ventilated spaces (medium confidence).
· Measurements of elevated CO2 levels in indoor air are an effective method of identifying poor ventilation in multi-occupant spaces.
· Ventilation should be considered as part of a hierarchy of risk controls approach.
The group have called for making ventilation in public buildings and workplaces integral to policy measures, highlighting risk in poorly ventilated spaces.
So how can you improve ventilation in your home or place of work?
1. Natural ventilation – an easy option for most homes, schools and small to mid-sized offices is to open the windows and doors to allow the air to flow through. The challenge arises during the winter as the temperature drops and trying to keep people warm. There is also a safety consideration around ease of access to a building if the windows and doors remain open. There may also be issues around energy usage, pollution and increased noise.
2. Temporary purge – Try opening doors and windows for a brief time or use of an extractor fan to ‘clear the air’. This option mitigates many of the issues around comfort, energy and noise but is less effective than continuous ventilation.
3. Breaks between occupants – For a room that is in continuous use leaving the room vacant to allow time for the virus to be diluted can be an effective method. Regular breaks reduce viral concentrations and limits build up over time, although this process may not be effective in small spaces. This can be completed in conjunction with a purge on the room for improved effectiveness.
4. Increasing the flow of outside air with mechanical systems – rather than recirculating the air within the room (e.g air conditioning), review the control settings and adjust them to provide more outdoor air into the room. An increase in outdoor air flow may
compromise thermal comfort and may also increase the energy consumption of the unit.
5. Extended mechanical operation such as extractor fans – where an extractor fan is installed to come on intermittently (e.g. those that operate with lights in bathrooms), see whether they can be amended to run for extended periods. The benefits are unlikely to be significant and noise could also become an issue where the systems are running for longer than normal.
6. Enhanced filtration/UVC within recirculating centralised HVAC systems – it may not be possible to upgrade the filters within these kind of systems without significant knock-on effects. It is also unlikely to be a considerable benefit unless the HVAC system is supplying an area that cannot be adjusted to accept fresh air from outdoors for operational reasons (e.g. chiller rooms).
7. Installation of new passive (louvres/air bricks) or mechanical (extract fans, new HVAC) systems – this kind of installation is a long-term solution and likely to be a significant financial investment. Solutions can be anything from simple vents and extractor fans through to new ventilation systems.
8. Use of local in-room HEPA or UVC air cleaning devices – This is a viable solution where it is difficult to provide good ventilation in a specific room or area. Before investing in a solution consider the choice of device in terms of size, flow rate, location, noise and any unintended effects on air quality. Some technologies can be hazardous to health if applied or operated incorrectly. Our AIRsteril solution uses germicidal UV light, dual UV operation, Photocatalytic Oxidation (PCO) and a purifying plasma of superoxide ions and optimal ozone technology to help control infection spread, combatting odours and improving overall air quality.