As the pandemic enters a new phase in the United States, marked by fewer precautions and the emergence of the even more transmissible Omicron subvariant BA.2, the Biden administration has begun to emphasize the importance of reducing the risk of indoor aerosol transfer, the main cause of the pandemic.
The Environmental Protection Agency recently provided expert guidance to building managers, contractors and business owners, with two pages of recommendations codifying best practices in ventilation, air filtration and air disinfection from academic experts and federal agencies over the past two years. The agency said implementation could be guaranteed with federal funds from the $1.9 trillion US bailout that President Biden signed into law a year ago.
dr. Alondra Nelson, chief of the White House Office of Science and Technology Policy, said last week that the guidance was part of an initiative called the Clean Air in Buildings Challenge. In a blog post titled “Let’s Clear the Air on Covid,” she quoted the guidance, saying: “Now we all need to work together to make our friends, family, neighbors and colleagues aware of what we can do or ask to get together in are safer.”
“For decades, Americans have demanded clean water from our taps and pollution limits placed on our chimneys and exhaust pipes,” she wrote in the post. “It is time for healthy and clean indoor air to become an expectation for all of us.”
The US federal health authorities were initially slow in identifying airborne transmission of the virus. It wasn’t until October 2020 that the Centers for Disease Control and Prevention recognized that the virus can sometimes be airborne, long after many infectious disease experts warned that the coronavirus was traveling in tiny airborne particles. Scientists have been arguing for a greater focus on addressing that risk for more than a year now.
The initiative is “really a big deal,” said William Bahnfleth, a professor of engineering at Penn State University and chief of the Epidemic Task Force at the American Society of Heating, Refrigerating and Air-Conditioning Engineers. “Making the start is often the hardest part.”
The association, whose roots date back to the dawn of the skyscraper in the late 1800s, is a global, nonprofit technical association that, among other things, develops the consensus standards for indoor air quality referenced in U.S. building codes.
The task force of Dr. Bahnfleth was established as the pandemic swept the world in March 2020, and the new federal recommendations are following closely with its guidance. He said the pandemic had spurred the long-awaited effort to improve the country’s “mediocre” air quality standards for buildings, noting that existing standards had failed to protect people from coronavirus infections.
Viruses can travel in different ways. At the start of the pandemic, health officials assumed that the coronavirus was mainly transmitted through droplets emitted during coughing or sneezing, as with the flu, or perhaps through contact with contaminated surfaces. But many scientists were noticing mounting evidence that the coronavirus was airborne, spreading in tiny particles adrift in interior spaces.
Similar to the rating system for high-performance masks, whose high-tech filter material captures at least 94 to 95 percent of the most hazardous particles (N95s, KN95s and KF94s), the filters used in building ventilation systems have a so-called MERV rating. The higher the rating, which ranges from 1 to 16, the better the filter can capture particles.
The new federal guidelines advise buildings to upgrade to at least a MERV 13 filter, which captures 85 percent or more of the high-risk particulates. Before the pandemic, many buildings used MERV 8 filters, which are not designed for infection control.
Long before the pandemic, studies showed that indoor air quality was affecting the health of students and employees. A Harvard study of more than 3,000 employees found that absenteeism rates among employees in poorly ventilated areas increased by 53 percent. Improved ventilation has also been associated with better test scores and less absenteeism from school.
“Improving indoor air has benefits beyond Covid-19,” wrote Dr. Nelson. “It reduces the risk of getting the flu, cold or other airborne illnesses, and leads to better overall health outcomes.”
March 27, 2022
Due to an editorial error, an earlier version of this article misrepresented the amount of the US bailout that President Biden signed last year. It was $1.9 trillion, not $1.9 billion.
