Employers that provide workspaces for employees should be aware of the implications that COVID-19 has had on general ventilation and air conditioning. By law, employers must ensure an adequate supply of fresh air in the workplace.
Good ventilation can help reduce the risk of spreading COVID-19, so if you have staff returning to work you need to consider ways to help air flow within your working environment.
Where possible, open doors and windows to increase and maintain the supply of fresh air. Mechanical systems such as ceiling fans and desk fans can also be used – the risk of virus transmission through fans is extremely low providing there is good ventilation in the area. By using fans you are preventing pockets of stagnant air in occupied spaces1.
Just as with the use of mechanical fans, the risk of air conditioning spreading COVID-19 in the workplace is low as long as there is an adequate supply of fresh air and ventilation.
Without fresh air ventilation the airflow generated by air conditioning units may facilitate the spread of droplets excreted by infected people longer distances within indoor spaces.
If you use a centralised ventilation system that removes and circulates air to different rooms it is recommended that you turn off recirculation and use a fresh air supply. COVID-19 aerosols (small droplets and droplet nuclei) can spread through HVAC systems within a building or vehicle and stand-alone air conditioning units if the air is recirculated.
Air conditioning systems that mix some of the extracted air with fresh air and return it to the room are perfectly fine as this increases the fresh air ventilation rate. Likewise, systems in individual rooms or portable units can be used as normal as these operate on 100% recirculation.
Maintenance of the systems themselves should not be overlooked, especially if they have not been in regular use.