Indoor air quality checklist

For community spaces

When a person has COVID-19, they release small particles that contain the virus when they breathe, talk, sing, cough or sneeze. These are often referred to as respiratory particles. Most of these small particles initially hover around an infected person’s face— that’s why keeping a distance can help reduce infections. But small particles can also move, like cigarette smoke. When someone develops COVID-19 by breathing in small particles that contain the virus, this is often referred to as airborne transmission or aerosol transmission. If a person who has COVID-19 is wearing a good, well-fitted respirator-type mask, such as an N95, this is called source control,because it helps prevent small particles that contain the virus from entering the room. 

Ventilation. In this document, we are using ventilation to refer to the process of bringing fresh air from outside into a building or a room while removing stale air from the same space. If a room feels stuffy or there are a lot of odours, this may be an indication that it is not well ventilated.