An important approach to lowering the concentrations of indoor air pollutants or contaminants including any viruses that may be in the air is to increase ventilation – the amount of outdoor air coming indoors. Ensuring proper ventilation with outside air can help reduce the concentration of airborne contaminants, including viruses, indoors. However, by itself, increasing ventilation is not enough to protect people from COVID-19. When used along with other best practices recommended by CDC and others, increasing ventilation can be part of a plan to protect people indoors.
In general, the greater the number of people in an indoor environment, the greater the need for ventilation with outdoor air. In other words, the ventilation rate should be based on the number of people that occupy an indoor space (and a few other factors). In fact, CDC has stated that “Indoor spaces are more risky than outdoor spaces where it might be harder to keep people apart and there’s less ventilation.” Give special consideration to increased ventilation when occupancy is high. Also, make sure high-traffic areas have additional ventilation. In addition to helping reduce risk from airborne transmission of viruses, improving ventilation also benefits indoor air quality by reducing exposure to products used for cleaning and disinfecting potentially contaminated surfaces.
Ventilation in Homes
Opening windows and doors (when the weather permits), operating window or attic fans, or running a window air conditioner with the vent control open increases the outdoor ventilation rate in a home. Do not open windows and doors if doing so poses a safety or health risk to children or other family members (e.g., risk of falling or triggering asthma symptoms). Local bathroom or kitchen fans that exhaust air outdoors and remove contaminants directly from the room where the fan is located also increase the outdoor air ventilation rate.