The pandemic and recent wildfires have shown how unhealthy indoor air can be. But scientific and governmental inertia have slowed the necessary remedies.
By Apoorva Mandavilli; Published November 20, 2023
Other evidence for airborne transmission quickly piled up. There was a New York man who became infected simply by driving his neighbor to the hospital, the 712 infected passengers and crew members of the Diamond Princess cruise ship, a choir practice in Seattle, and diners at a restaurant in China.
Still, the erroneous distinction between large and small droplets remained entrenched, despite attempts from physicists and air quality experts to set the record straight.
“The resistance was thick. The walls of the silo were thick,” said Richard Corsi, dean of the College of Engineering at the University of California, Davis. “I’ll be blunt, it’s been frustrating as hell from the very start.”
Some scientists felt the health agencies were stonewalling because the consequences of indoor aerosol transmission — high-quality masks, air filtration, building closures — would require a herculean response.
William Bahnfleth, an architectural engineering expert at Penn State University, said he was shocked by “the paralysis of the public health community, the demand for more and more conclusive data.”
It took the C.D.C. until April 2020 to recommend masking and until October 2020 to acknowledge aerosol transmission of the coronavirus, and even then only obliquely. The World Health Organization was forced to review its stance in July 2020, after 239 experts issued a statement demanding it.
A watershed moment came in the spring of 2021, when three major medical journals published papers on airborne transmission of the coronavirus.
Still, the W.H.O. did not use the word “airborne” to describe the virus until December 2021, and the C.D.C. has yet to do so.
“I worked with them on editing the scientific brief on transmission, and it was clear that they did not want to use the word,” Dr. Marr said of the C.D.C. “It’s maddening.”
Respiratory viruses aren’t the only reason to clean the air indoors.
Indoor air pollution — from wildfire smoke that infiltrates homes, building materials like asbestos, gases like radon or even fumes from cleaning supplies — affects the heart, lungs and the brain, contributing to chronic illnesses like asthma and diabetes.
Elevated carbon dioxide in crowded rooms can cause drowsiness and loss of concentration, leading to poor academic performance. Improved air quality can reduce absenteeism, in schools and in offices.
“Improving indoor air quality pays for itself, in benefits to both the economy and to human health and happiness,” said Brian Fleck, an air quality expert at the University of Alberta in Canada. “It’s always surprising how things known for a very long time are still not acted upon.”
As the pandemic unfolded, some schools and businesses coped by simply opening windows. But with wildfires, soaring temperatures and rising air pollution, that will cease to be a practical option — indeed, it already has in many parts of the world.
The better solution is to clean the air already indoors.
Experts generally agree that the air in a room should be replaced six to eight times an hour. For an average-size room, air purifiers that cost a few hundred dollars can accomplish that goal.
Some schools have even successfully turned to homemade $100 contraptions of box fans that are taped to air filters. Ultraviolet light is an energy-efficient and powerful way to kill pathogens, and there are newer versions that are not harmful to people.
But a far-reaching campaign to clean America’s indoor air has not yet happened. In California, the minimum recommended standard is six changes per hour. But in one study, 93 percent of schools fell below that standard.
It’s not that there has been no discussion of fresh air.
The Biden administration’s pandemic preparedness plan, published in September 2021, included support of new technology to provide “pathogen protection within the built environment” and investments for retrofitting older buildings.
In March 2022, the Environmental Protection Agency announced the Clean Air in Buildings Challenge, which includes a checklist for better ventilation, to encourage building administrators to take air quality seriously. And in October 2022, the White House held a summit on indoor air quality, calling on business and school leaders to make improvements to mitigate the spread of Covid.
A life sciences team within the White House Office of Science and Technology Policy — the first under any administration — is coordinating efforts to improve indoor air quality with various arms of the government.
But none of these efforts has yet coalesced into anything like a rigorous national plan.
For once, money does not appear to be the barrier. The American Rescue Plan allotted $350 billion to state and local governments for Covid-related expenses, including measures to improve air quality. Schools can tap another $200 billion from various programs instituted during the pandemic.
For private businesses, even an investment of just $40 per employee could save about $7,000 per person per year, according to Joseph Allen, director of the Healthy Buildings program at the Harvard T.H. Chan School of Public Health.
But widespread change is unlikely unless a federal agency or official is tasked with establishing and enforcing standards, many scientists believe.
“The problem is there’s no regulatory authority to make this happen on the federal level,” said David Michaels, who led the Occupational Safety and Health Administration under President Barack Obama.
The E.P.A. has authority over outdoor air and specific pollutants like asbestos, lead and radon. OSHA has no rules on airborne infections, and an attempt in the 1990s to regulate air quality was quickly quashed by the tobacco industry.
The C.D.C. can offer recommendations on indoor air but not rules, and it does not venture far into ventilation practices and standards.
Still, the agency’s new guidelines may make it easier for people and businesses to recognize and demand better air quality. At least in theory, they may also enable OSHA to hold employers responsible for maintaining clean air, Dr. Michaels said.
“It helps OSHA if they want to directly address particular problems now, but it’s sort of a road map to future indoor air quality standards,” he said.
Dr. Allen noted that the move toward clean water came in fits and starts over decades, and changes to ventilation, too, may take a long time to unspool.
“The next pandemic, whatever it is, buildings will be part of the core response on Day 1,” he said. “I don’t have any doubt about that.”
is a reporter focused on science and global health. She was a part of the team that won the 2021 Pulitzer Prize for Public Service for coverage of the pandemic.