Why are we still breathing dirty indoor air?

Why are we still breathing dirty indoor air?


In early 2020, the world scrubbed surfaces, washed hands and sneezed into their elbows to avoid infection with the new coronavirus. But the danger wasn’t really on countertops and door handles.

The virus was spreading in the air, in coughs and conversations, even in songs. The pandemic stretched on for six months before global health officials acknowledged that it was driven by an airborne pathogen.

That revelation also revealed something else: If indoor air quality had ever been a priority, the pandemic would have caused much less damage in the United States.

More than three years later, little has changed. Most Americans are still crammed into offices, classrooms, restaurants and shops with inadequate, often dilapidated ventilation systems, often in buildings with sealed windows.

Scientists agree that the next pandemic will almost certainly be caused by another airborne virus. But improving air quality doesn’t just mean fighting infectious diseases: indoor pollution Can damage Heart, lungs and the brain, being smaller life spread and reduce Feeling,

And wildfires, outdoor air pollution and climate change would quickly preclude Band-Aid solutions, such as simply opening windows or pulling more air in from outside.

Instead, the nation needs to start thinking about indoor air—in schools, restaurants, offices, trains, airports, movie theaters—as an environment that greatly impacts human health. Improvements will require money, scientific guidance on how clean the air should be, and, most importantly, political will for change.

“The push for clean water is recognized as one of the 10 greatest public health advances of the last century, and air should be no different,” said Lynsey Marr, an expert on airborne virus transmission at Virginia Tech.

Federal and state laws regulate the quality of water, food, and outdoor pollution, but there are no regulations for overall indoor air quality, only limited limits on certain pollutants. Nor does any single federal agency or official support it.

Without enforcing building codes or laws, efforts to address air quality have been weak so far. Some cities, school districts and businesses have moved forward on their own. But overall, Americans are still breathing the indoor air that set the stage for the pandemic.

“Everyone just does the bare minimum,” said Shelley Miller, an aerosol expert at the University of Colorado Boulder.

Experts in interviews said the real obstacle now is the lack of leadership — a federal agency or even a single agency — to implement the recommendations and set the country on a long-needed course to improve indoor air quality. There is lack of ventilation zar.

“To achieve real change that reaches broad segments of the population, we need to incorporate standards into building codes and laws at the state and federal level,” Dr. Marr said.

Two new sets of recommendations could initiate change. In May, the Centers for Disease Control and Prevention recommended five so-called air changes per hour in all buildings, including schools — the equivalent of changing all the air in a room.

An association of air quality experts, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, went further, Proposal More than eight air changes recommended.

Both sets of guidelines also provide clarity on air quality monitors and upgrading of air filters and ventilation systems.

“This is a huge leap forward,” Dr. Marr said, “because this is the first time, outside of hospitals and specialized workplaces, we have seen some kind of indoor air target that is based on health rather than just thermal comfort or energy considerations.” Is.”

Had the medical establishment not firmly believed that respiratory diseases like influenza spread exclusively through large respiratory droplets that are expelled when a person coughs or sneezes, indoor air quality would soon have deteriorated. Would have come at center stage.

This idea may have been strengthened by the observation that people who were closest to a sick person were at the highest risk of infection. This led medical experts to recommend hand washing and social distancing as the best ways to prevent respiratory viruses.

But scientists showed decades ago that larger droplets can evaporate and shrink as they exit, forming smaller aerosols that persist in the air. That is, a patient suffering from flu is not just expelling the virus in large droplets. According to Youguo Li, an air quality expert at the University of Hong Kong, the patient can exhale, cough or sneeze in any shape.

The smallest will float through the air and go straight into the lungs – a situation that requires precautions far different from wiping surfaces or washing hands.

For Dr. Lee and other air quality experts, it was clear from the beginning of the pandemic that the coronavirus came from above. The SARS coronavirus, a close relative that emerged in Asia in 2002, was air – Why would the new one be different?

In January 2020, Chinese researchers described a cluster of infections that included a 10-year-old child who had no symptoms but whose scans revealed “ground-glass lung opacity”, which may indicate infection with the new coronavirus. There was a sign of.

Dr. Donald K. of the University of Maryland. Milton, who has studied respiratory virus transmission for decades, knew what this meant: The coronavirus was entering the lungs.

“If this is happening in the lungs of an asymptomatic child, it will be very difficult to stop, because people without symptoms will be infectious,” Dr. Milton said, recalling his thinking when the Chinese reports came out.

Yet, despite efforts by physicists and air quality experts to clarify the record, the inaccurate distinction between large and small droplets persisted.

“The resistance was deep. 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 frank, it’s been very frustrating from the beginning.”

Some scientists felt that health agencies were creating barriers because the consequences of indoor aerosol transmission – high-quality masks, air filtration, building closures – would require a tough response.

William Banfleth, an architectural engineering expert at Penn State University, said he was surprised by “the paralysis of the public health community, demanding more and more conclusive data.”

It took until April 2020 for the CDC to recommend masking and until October 2020 to acknowledge aerosol transmission of the coronavirus, and even then only indirectly. The World Health Organization was forced to review its stance in July 2020, when 239 experts issued a statement demanding it.

A historic moment came in the spring of 2021, when three major medical journals published papers on air broadcasting Of Corona virus.

Nevertheless, the WHO did not use the term “airborne” to describe the virus as of December 2021, and the CDC has not yet done so.

“I worked with them on editing the scientific brief on transmission, and it was clear that they did not want to use the term,” Dr. Marr said of the CDC. “It’s troubling.”

Respiratory viruses aren’t the only reason to clean indoor air.

Indoor air pollution — from wildfire smoke that seeps into homes, building materials like asbestos, gases like radon or even fumes from cleaning supplies — affects the heart, lungs and brain, causing Contributes to chronic diseases like asthma and diabetes.

The increased carbon dioxide in crowded rooms can cause drowsiness and loss of concentration, which can lead to poor academic performance. Better air quality can reduce absenteeism in schools and offices.

“Improving indoor air quality benefits both the economy and human health and happiness,” said Brian Fleck, an air quality expert at the University of Alberta in Canada. “It’s always surprising how things that have been known for a very long time are still not acted upon.”

As the pandemic spread, some schools and businesses coped by simply opening windows. But with wildfires, rising temperatures and increasing air pollution, this will no longer be a practical option – in fact, it already is in many parts of the world.

A better solution is to clean the indoor air beforehand.

Experts generally agree that the air in a room should be changed six to eight times an hour. For an average-sized room, air purifiers costing a few hundred dollars can accomplish that goal.

Some schools have successfully begun using household box fans, which cost $100, and are attached to air filters. Ultraviolet light is an energy-efficient and powerful way to kill pathogens, and there are even new versions that are not harmful to people.

But no far-reaching campaign to clean America’s indoor air has been launched yet. In California, the minimum recommended standard is six changes per hour. But in one study, 93 percent of schools fell below that standard.

It is not that fresh air has not been discussed.

The Biden administration’s pandemic preparedness plan, published in September 2021, included support for new technology to provide “pathogen protection within the built environment” and investments for retrofitting older buildings.

In March 2022, the Environmental Protection Agency announced clean air challenge in buildingsWho Involved A checklist for improved ventilation to encourage building administrators to take air quality seriously. And in October 2022, the White House hosted a Summit on Indoor Air QualityCalled on business and school leaders to make improvements to slow the spread of COVID.

A life sciences team within the White House Office of Science and Technology Policy – ​​a first under any administration – is coordinating efforts to improve indoor air quality. various weapons Of the Government.

But none of these efforts have yet resulted in anything resembling a rigorous national plan.

For once, money doesn’t seem to be a hindrance. American Rescue Plan allocated $350 billion To state and local governments for COVID-related expenses, including measures to improve air quality. Schools could receive an additional $200 billion from various programs launched during the pandemic.

For private businesses, even an investment of just $40 per employee can save nearly $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 many scientists believe widespread change is unlikely unless a federal agency or official is tasked with setting and enforcing standards.

“The problem is there is no regulatory authority to do this at the federal level,” said David Michaels, who led the Occupational Safety and Health Administration under President Barack Obama.

The EPA has authority over outdoor air and specific pollutants such as asbestos, lead and radon. OSHA has no regulations on airborne infections, and an effort to regulate air quality was made in the 1990s quickly canceled By the tobacco industry.

The CDC can make recommendations but not regulations on indoor air, and it does not venture far into ventilation practices and standards.

Still, the agency’s new guidelines could make it easier for people and businesses to recognize and demand better air quality. At least in theory, they could 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 also like a road map for future indoor air quality standards,” he said.

Dr. Allen said the move toward clean water has taken decades to occur systematically, and changes in ventilation may also take a long time to achieve.

“The next pandemic, whatever it is, buildings will be part of the core response on day one,” he said. “I have no doubt about that.”



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