Health and Safety Executive

Ventilation and air conditioning during the coronavirus (COVID-19) pandemic

The law says employers must make sure there’s an adequate supply of fresh air (ventilation) in enclosed areas of the workplace. This has not changed during the pandemic.

You should be maximising the fresh air in a space and this can be done by:

  • natural ventilation which relies on passive air flow through windows, doors and air vents that can be fully or partially opened
  • mechanical ventilation using fans and ducts to bring in fresh air from outside, or
  • a combination of natural and mechanical ventilation, for example where mechanical ventilation relies on natural ventilation to maximise fresh air

You should consider ventilation alongside other control measures needed to reduce risks of transmission as part of making your workplace COVID-secure, such as social distancing, keeping your workplace clean and frequent handwashing.

This guidance will apply in most workplaces – it will help you and your workers:

  • assess the risk from aerosol transmission in enclosed areas
  • identify poorly ventilated areas
  • decide on the steps you can take to improve ventilation

Why ventilation is important

Adequate ventilation reduces how much virus is in the air. It helps reduce the risk from aerosol transmission, when someone breathes in small particles (aerosols) in the air after a person with the virus has been in the same enclosed area.

The risk is greater in areas that are poorly ventilated.

Ventilation reduces the aerosol risk but has minimal impact on:

  • droplet transmission (where people are within 2 metres of each other)
  • contact transmission (touching surfaces)

Assessing the risk of aerosol transmission

Adequate ventilation can look different in different workplaces or settings.

You can reduce the risk of aerosol transmission by:

  • making sure infected workers (or any visitors with coronavirus symptoms) do not come into the workplace
  • providing adequate ventilation with fresh air
  • limiting the number of people in an area
  • thinking about activities that increase deeper breathing (including singing, physical exertion and shouting)
  • workers spending less time in occupied areas

Deciding what adequate ventilation looks like in your workplace should be considered as part of a risk assessment.

Read more: Ventilation