January 7, 2021

New CDC Page Focuses on COVID-19 Building Ventilation Strategies

A new webpage published by CDC provides information on ventilation interventions for building owners, managers, and health and safety professionals intended to help reduce the concentration and spread of SARS-CoV-2 in their facilities. According to the agency, protective ventilation practices can reduce the airborne concentration of SARS-CoV-2 viral particles indoors. In outdoor settings, even a very light wind rapidly lowers the concentrations of airborne viral particles in an area, reducing individuals’ overall viral doses. Indoors, the lack of wind can be offset through ventilation strategies described by CDC as “tools in the mitigation toolbox.”

CDC’s list of ventilation tools is intended to apply across indoor environments, but the practicality of implementation varies across building types, occupancies, intended activities, and environmental and seasonal changes. Considerations to improve ventilation include opening windows and doors to increase fresh outdoor air; using fans to increase the effectiveness of open doors and windows, such as by placing a fan in a window to exhaust room air outdoors; increasing outdoor ventilation when possible and decreasing occupancy in areas where it is not; turning off demand-controlled ventilation features that reduce air supply based on occupancy or temperature; increasing air filtration as much as possible and inspecting filters and their housings for correct installation; ensuring that restroom exhaust fans operate at full capacity while a building is occupied; and introducing portable high-efficiency particulate air systems.

The webpage also recommends that interested parties consult with heating, ventilation, and air conditioning professionals and refer to recommendations by ASHRAE when determining ventilation practices for their facilities. CDC’s page also includes an FAQ addressing common concerns about building ventilation and COVID-19.

CDC recommends a “layered strategy” that includes practices such as social distancing, wearing face masks, and hand hygiene in addition to ventilation to reduce exposures to SARS-CoV-2. According to the agency, mitigation strategies are more effective when several are implemented together.