Using ventilation to reduce COVID-19 exposure: CDC creates webpage

Washington — A new webpage published by the Centers for Disease Control and Prevention is intended to help employers and building managers improve the ventilation system in their facilities to reduce the spread of COVID-19.

CDC recommends ventilation as part of a “layered strategy” that includes physical distancing and use of facial coverings to help reduce the concentration of SARS-CoV-2 – the coronavirus that causes COVID-19 – in indoor air.

“The lower the concentration, the less likely some of those viral particles can be inhaled into your lungs; contact your eyes, nose and mouth; or fall out of the air to accumulate on surfaces,” the webpage states. “Protective ventilation practices and interventions can reduce the airborne concentration, which reduces the overall viral dose to occupants.”

The agency’s recommendations for improved ventilation include:

• Increasing outdoor air ventilation, but use caution if your facility is in a highly polluted area.
• Opening windows and doors to the outside, but only when weather conditions allow and doing so doesn’t create a safety or health risk (e.g., risk of falling or triggering asthma symptoms).
• Using fans to improve the effectiveness of open windows. However, don’t place fans in a configuration that could cause potentially contaminated air to flow from one person to another. One strategy is to use a fan that’s placed safely and securely in a window.
• Decreasing occupancy in areas where outdoor ventilation isn’t possible.
• Making sure restroom exhaust fans are working at full capacity when a building is occupied.
• Using a portable high-efficiency particulate air fan/filtration system to help enhance air cleaning, especially in high-risk areas such as a nurse’s office.

Additionally, CDC advises running HVAC systems at “maximum outside airflow” for two hours before and after a building is occupied. The agency’s webpage includes a set of strategies with corresponding estimated costs, as well as answers to list of frequently asked questions about building ventilation.