EPA Updates Ventilation Guidance to Prevent Virus Spread
Updated guidance from EPA presents ventilation strategies for preventing the spread of respiratory viruses in homes, schools, offices, and commercial buildings. A news release from the agency says that the guidance incorporates the latest science on indoor air quality and recent recommendations from CDC.
The guidance recommends that schools, offices, and commercial buildings hire professionals knowledgeable about heating, ventilation, and air conditioning (HVAC) systems to ensure their systems are running optimally. If increasing the amount of outdoor air in a building is not possible, EPA’s guidance suggests upgrading HVAC filters to the highest MERV rating the system can accommodate and using portable air cleaners. It suggests targeting five air changes per hour (ACH) as a goal to reduce the number of viral particles in indoor spaces. It also recommends promoting remote work and reducing occupancy.
In addition to increasing outside-air ventilation where possible, EPA suggests adjusting or reconfiguring airflows in indoor spaces to prevent air from blowing directly from person to person and exhausting restrooms to the outdoors. Upper room ultraviolet germicidal irradiation, or UVGI, is recommended as a possible supplement to, but not a replacement for, ventilation and filtration. The guidance includes a warning to avoid the use of air cleaners that generate ozone, which is a lung irritant.
Readers can access EPA’s updated guidance on the agency’s website. For more information, the guidance points to ASHRAE standard 241, Control of Infectious Aerosols, ASHRAE’s building readiness guide (PDF), and CDC’s webpage on ventilation and respiratory viruses.
CDC expects a similar or lower number of hospitalizations for flu, COVID-19, and respiratory syncytial virus (RSV) during the 2024–2025 virus season as for last season. The agency’s preliminary estimates indicate that between Oct. 1, 2023, and April 30, 2024, there were between 380,000 and 900,000 hospitalizations for flu and between 17,000 and 100,000 flu deaths.