CDC recommends a layered strategy to reduce exposures to SARS-CoV-2, the virus that causes COVID-19. This includes using multiple mitigation strategies with several layers of safeguards to reduce the spread of disease and lower the risk of exposure.In addition to ventilation, the layered approach includes efforts to improve social distancing, wearing face masks, and hand hygiene.
Ventilation improvements may include some or all of the following considerations:
Increase outdoor air ventilation, using caution in highly polluted areas.
When weather conditions allow, increase fresh outdoor air by opening windows and doors. Do not open windows and doors if doing so poses a safety or health risk (e.g., risk of falling, triggering asthma symptoms) to occupants in the building.
Use fans to increase the effectiveness of open windows. To safely achieve this, fan placement is important and will vary based on room configuration. One helpful strategy is to use a window fan, placed safely and securely in a window, to exhaust room air to the outdoors. This will help draw fresh air into room via other open windows and doors without generating strong room air currents.
Decrease occupancy in areas where outdoor ventilation cannot be increased.
Ensure ventilation systems operate properly and provide acceptable indoor air quality for the current occupancy level for each space.
Increase airflow to occupied spaces when possible.