The White House has embraced a model of COVID-19 transmission that could help shift infection prevention efforts toward indoor air quality and industrial hygiene. A public webinar set for Tuesday, March 29 at 12:30 p.m., EST, will discuss this.

In a blog post released last week titled “Let’s Clear the Air on COVID,” a top science adviser to President Biden highlighted a commonly accepted theory of transmission. The SARS-CoV-2 virus is spread via tiny aerosolized particles that remain suspended in the indoor or outdoor air from minutes to hours after an infected person has been in the area, Alondra Nelson, M.D., wrote.

“Just as chemicals can build up in the air, viruses can as well,” wrote Nelson, head of the White House Office of Science and Technology Policy and deputy assistant to the president. “That requires different sorts of controls in the air, and different sorts of respiratory protection.”

HVAC measures reduce risk by 50%

In the White House blog post, Nelson generally encouraged readers to use evidence-based hygiene procedures ranging from opening windows and using portable air cleaning devices to installing built-in air purification technology. This includes constant indoor room air exchange using highly effective filters in heating, ventilation and air conditioning (HVAC) systems, she said.

All of this can cut the spread of COVID-19, with studies showing that five air changes an hour reduce transmission risk by 50%, she wrote.

“While there are various strategies for avoiding breathing that air – from remote work to masking – we can and should talk more about how to make indoor environments safer by filtering or cleaning air,” Nelson said.

The Tuesday White House webinar will include experts from public health, the social sciences, engineering and journalism. “It is time for a national conversation on how better indoor air quality can help us all live healthier lives,” Nelson wrote.

The official acknowledgment underscores the importance of clean air,” epidemiologist David Michaels, Ph.D., of the George Washington University School of Public Health, told CIDRAP News. “It parallels clean water and outdoor air quality. We expect clean water, and we demand pollution be eliminated to make outdoor air clean. Now people will demand clean indoor air quality.”

A White House first

This attention to air quality may be overdue, some experts said. 

“This is the first time the White House has formally acknowledged that aerosol transmission has been the primary driver of the COVID-19 pandemic,” according to a report from the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota.

The aerosol transmission model is currently “underplayed” by the Centers for Disease Control and Prevention, Lisa Brosseau, ScD, a research consultant at CIDRAP, told the organization’s news arm. But there’s been strong evidence since the early part of the pandemic of long-lasting airborne particles, and examples of viral RNA found in air filters and air exhaust pipes in COVID-19 patients’ rooms, Brosseau said. 

“If aerosol transmission is the dominant way the virus is spread, cloth and surgical masks are inefficient face coverings,” CIDRAP reported. Mitigation strategies should therefore focus on the most effective respiratory protection such as N95 respirators, and on ventilation and air quality,” Brosseau and other experts told CIDRAP News.