Indoor Air Quality - Ventilation and Filtration

Published on 7/16/24. Last updated on 9/6/24.

What is Ventilation and Filtration?

Ventilation and filtration can help to improve the indoor air quality in buildings, like homes, offices, and schools.

ventilation

Ventilation moves air into, out of, or within a room. There are two types of ventilation:

  • Natural ventilation is when air flows on its own from outdoor to indoor spaces. This can be through open windows or doors.

  • Mechanical ventilation moves outdoor air into a building. Most offices, schools, and other larger buildings have mechanical ventilation.

Upper-room ultraviolet germicidal irradiation (UVGI) can inactivate viral particles, like COVID-19, in the air. UVGI fixtures placed on walls or ceilings create a treatment zone of ultraviolet energy that is focused up and away from people. These fixtures treat air as it moves around a room from natural or mechanical ventilation.

filtration

Filtration traps particles on a filter to remove them from the air. Portable high-efficiency particulate air (HEPA) cleaners can be used to filter the air.

Both ventilation and filtration help prevent virus particles from “building up” in indoor air. Improving ventilation and filtration can protect you from viruses, like COVID-19. Virus particles spread between people more easily indoors than outdoors. So, it is important to have good ventilation and filtration systems in place to prevent this.

Benefits of Ventilation and Filtration

Good ventilation, along with other prevention actions, can help prevent you and others from getting and spreading COVID-19 and other respiratory viruses.

  • If you are sick with COVID-19, you can release virus particles into the air when you:
    • Breathe quietly
    • Speak
    • Sing
    • Exercise
    • Cough
    • Sneeze
  • These viral particles can “build up” in a poorly ventilated room. However, good ventilation and filtration can reduce the amount of virus particles in the air and lower your chances of getting sick.

Ways to Improve Ventilation and Filtration

Some ways to improve ventilation and filtration include:

  • Bringing in as much outdoor air as possible—for example, opening windows.
  • Increasing air filtration in your heating, ventilation, and air conditioning (HVAC) system. You can do this by changing filters often and using filters that fit and provide higher filtration.
  • Using portable HEPA cleaners.
  • Turning on exhaust fans and using other fans to improve air flow.
  • Turning your thermostat to the “ON” position instead of “AUTO.” Doing this helps your HVAC system provide continuous airflow and filtration.
  • Use fans to improve airflow.
  • Limit the number of visitors in your home and the time spent inside.

Resources

County of San Diego

California Department of Public Health (CDPH)

Centers for Disease Control and Prevention (CDC)

United States Environmental Protection Agency (EPA)