CDC Specifies New Air Ventilation Guidelines for COVID-19

The U.S. Centers for Disease Control and Prevention (CDC) has released updated ventilation guidelines for mitigating the spread of COVID-19 in indoor facilities that include specifics on how often air should be changed and what type of filter should be used.

The revised CDC guidance was developed in conjunction with a new standard from the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHARE) and provides detailed recommendations for how to make indoor air healthier. Among the updates is a target for how often rooms and buildings should be fully ventilated—five air changes per hour, CNN reports. The CDC also recommends using MERV-13 air filters in all HVAC systems and deploying portable or built-in high-efficiency particulate air (HEPA) fan/filtration systems.

“It’s a monumental shift,” Joseph Allen, director of the Harvard Healthy Buildings Program told CNN.  “We haven’t had this. We haven’t had health-based ventilation standards.”

In the May 2020 issue of the journal Science, Kimberly Prather, an atmospheric chemist at the University of California San Diego’s Scripps Institution of Oceanography, co-authored an article explaining the airborne spread of COVID-19. In CNN’s article, Prather points out that these specific recommendations were published after the pandemic emergency had been declared officially over by CDC.

“I am pleasantly surprised to see CDC add this guidance. I do find it ironic that they finally published ways to end the pandemic at the same time as declaring it is over,” Prather said. “If they had broadcast and implemented these changes at the beginning, there never would have been a pandemic.”

A complete listing of updated CDC guidelines can be found on the agency’s website.