Issue No. 16

White House Gives ‘Disinfection’ Equal Billing as a Way to
Clear Indoor Air of SARS-CoV-2

“Let’s Clear the Air on COVID” was the title of a March 23 blog by Alondra Nelson, the head of the White House Office of Science and Technology Policy and formerly a chair of the School of Social Science at the Institute for Advanced Study at Princeton.

The pun was common, but the blog itself was unusual. It is part of what the Washington Post on March 29 called a “pivot” by the Administration, which will follow up the blog and a Fact Sheet with a virtual summit on “evidence for action” on the afternoon of April 7. Post reporter Dan Diamond wrote that the White House action is “a move scientists say is long overdue and will help stave off future outbreaks.”

Not only did the Nelson blog emphasize the importance of clean and safe air in the fight against the SARS-CoV-2 virus, it gave “air disinfection” equal billing with ventilation and filtration as part of a “set of simple but powerful actions we can use to bring clean air into the rooms we’re in and clean the air already in the room.” (The boldface is Dr. Nelson’s.)  

The science chief is quick to note that the “Biden Administration identified improved indoor air quality as an important tool to fight the spread of airborne diseases in the American Pandemic Preparedness Plan last September – and the National COVID-19 Preparedness Plan prioritized it again earlier this month.”

In fact, a thorough reading of the September plan finds improved air quality cited exactly once, in a section on personal protective equipment, and nowhere are specifics, even about ventilation, discussed. The plan emphasizes vaccines, therapeutics, diagnostics and early-warning systems. Air quality doesn’t even merit a mention in the summary of 12 goals.

Nor can the March plan can hardly be said to “prioritize” cleansing indoor air. It does, however, pledge that the Administration will work with Congress to “secure the necessary funding to give schools and businesses guidance, tests, and supplies to stay open, including tools to improve ventilation and air filtration.”

The truth is that government has been slow to recognize the value of clean and safe indoor air in stopping the spread of COVID. And even with earlier recognition, policy makers stressed ventilation and filtration, which certainly have their place but which alone are rarely a solution.

That has now changed, as evidenced by the latest White House activity. Schools and businesses will have to take notice – and act.

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A Change That’s Been Too Long in Coming

The Administration even says it will “foster ways to recognize steps taken by buildings to improve indoor air quality and protect their communities,” adding:
 
Similar to how programs like LEED, Fitwel, and WELL recognize buildings for their environmental and health impacts, this new effort between the federal government and external experts will develop ways to recognize steps taken by building owners for the health and safety of their communities and their achievements in improving air filtration and ventilation systems to protect and promote public health.
 
In other words, buildings with safe air will get a government seal of approval for clean and safe air. We will see how that process develops, but what’s clear is that policy makers are beginning to understand that unsafe indoor air is at least as dangerous as unsafe water.
 
The change has been long in coming. In the early days of the pandemic, public health institutions, including at the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), resisted the notion that COVID could be spread in tiny aerosols that can remain suspended in the air for minutes or even hours. Instead, as we noted in Issue No. 5 of this newsletter, CDC and WHO guidance stated that the SARS-CoV-2 virus was contained in droplets, which would fall harmlessly to the ground of their own weight within a few feet. More worrisome was supposed to be spread from surfaces or hand-to-hand.

But in July 2020, an article by Lidia Morawska of the Queensland University of Technology in Australia and Donald Milton of the University of Maryland School of Public Health, titled, “It’s Time to Address Airborne Transmission of Coronavirus 2019,” drew the support of 237 scientists in an open letter. The authors wrote:

There is significant potential for inhalation exposure to viruses in microscopic respiratory drop- lets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission.

In November of that year, Kimberly Prather of the Scripps Institute of Oceanography, an expert on aerosols, and several colleagues wrote a letter to Science magazine, explaining that aerosols were the problem:

Individuals with COVID-19, many of whom have no symptoms, release thousands of virus-laden aerosols and far fewer droplets when breathing and talking. Thus, one is far more likely to inhale aerosols than be sprayed by a droplet, and so the balance of attention must be shifted to protecting against airborne transmission.

Then, a little over a year ago, a group of 13 U.S. public health experts, including such members of President Biden’s own COVID task force as Rick Bright, the former director of the Biomedical Advanced Research and Development Authority, and Michael Osterholm, a highly regarded epidemiologist at the University of Minnesota, called for “immediate action to strengthen measures to limit inhalation exposure to SARS-CoV-2.”

They wrote in a letter Feb. 16 to Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC); Administration COVID Coordinator Jeff Zients; and Anthony Fauci, director of NIH’s National Institute of Allergy and Infectious Diseases:
 
For many months it has been clear that transmission through inhalation of small aerosol particles is an important and significant mode of SARS-CoV-2 virus transmission… Numerous studies have demonstrated that aerosols produced through breathing, talking, and singing are concentrated close to the infected person, can remain in air and viable for long periods of time and travel long distances within a room and sometimes farther.
 
Linsey Marr, an expert on aerosols at Virginia Tech who also signed the Science letter, was quoted as saying:
 
It’s time to stop pussyfooting around the fact that the virus is transmitted mostly through the air. If we properly acknowledge this, and get the right recommendations and guidance into place, this is our chance to end the pandemic in the next six months. If we don’t do this, it could very well drag on.
 
The CDC and WHO finally changed their guidance at the end of April 2021, precipitating a long opinion piece on May 7 in the New York Times Zeynep Tufekci of the University of North Carolina with the headline, “Why Did It Take So Long to Accept the Facts About COVID?”

She said the updates were momentous, even though the two organizations seemed to try to bury them (“no news conference, no big announcement”) because of embarrassment: “These latest shifts challenge key infection control assumptions,…putting a lot of what went wrong last year in context. They may also signal one of the most important advancements in public health during this pandemic.”

Better late than never, she added:
 
If the importance of aerosol transmission had been accepted early, we would have been told from the beginning that it was much safer outdoors, where these small particles disperse more easily, as long as you avoid close, prolonged contact with others. We would have tried to make sure indoor spaces were well ventilated, with air filtered as necessary.

Instead of blanket rules on gatherings, we would have targeted conditions that can produce superspreading events: people in poorly ventilated indoor spaces, especially if engaged over time in activities that increase aerosol production…. And we would have been less obsessed with cleaning surfaces. Our mitigations would have been much more effective, sparing us a great deal of suffering and anxiety.

Unfortunately, the shifts by the CDC and WHO did not alter mitigation efforts, but perhaps the Biden Administration’s own shift will.

The Post on March 29 quoted David Michaels, a George Washington University professor who previously led the Occupational Safety and Health Administration and advised Biden’s transition team on the coronavirus pandemic, as saying that the new White House approach is “’a total rejection’ of earlier assumptions that the virus was spread through direct person-to-person contact. “
 
I think much of the world has been dragged kicking and screaming into this because the World Health Organization and the CDC both clung to the infectious-disease model,” said Michaels.

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Ventilation, Filtration and Disinfection

Let’s dig into the details of the Nelson blog.

It begins by saying, “While there are various strategies for avoiding breathing that air [i.e., air contaminated with SARS-CoV-2] – from remote work to masking – we can and should talk more about how to make indoor environments safer by filtering or cleaning air.”

Nelson writes that changing the air and filtering it can reduce COVID spread, “with studies showing that five air changes an hour reduce transmission risk by 50 percent.” She cites a study in July by Rothamer, et al., in Science and Technology for the Built Environment, and another by de Oliveria, et al., in Proceedings of the Royal Society.

Curiously, neither study is on point. The Rothamer research concerns the use of masks in ventilated environments, and the de Oliveria article describes a modeling exercise on the spread of aerosols and droplets.

If studies indeed show that an HVAC system that produces five air changes per hour reduces transmission risk by just 50%, that is hardly reassuring. There’s still a lot of risk.

The deficiencies of ventilation alone, or even with filtration, have been well documented. We previously cited an extensive article in HPAC Engineering in August 2020, in Gary and Ken Elovitz of Energy Economics in Newton Centre, Mass., write:
 
The biggest danger for COVID-19 infection is close-range contact with infected people who are talking loudly or are otherwise exhaling heavily for at least several minutes. The HVAC system does not have much effect on those conditions.
 
The Elovitzes’ main contribution is to deploy the Wells-Riley equation (also cited in the Rothamer study), which uses “infectious particle concentration, exposure time, and outside air ventilation” to come up with a prediction of the “likelihood that a person will be infected by a virus.” (Academic research shows that, if anything, Wells-Riley underestimates risk.)
 
After the authors plug in the numbers, they conclude:
 
No practical amount of ventilation can be relied on or expected to protect occupants over long exposure times like the 6 or 8 hours people might spend together in an office or school classroom. Similarly, ventilation is unlikely to succeed as the prime means of protection for people in close contact in a small space like a private office.

The authors say that “improved filtration can reduce the risk of transmission by reducing the concentration of infectious particles in the air.” But that reduction is by no means complete. They write that, on average, “MERV 13 filters might be 60% to 70% efficient at removing particles that contain viral material.”

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Higher-Capacity HVAC Systems Are Needed,
But They Produce Higher Emissions

The Elovitzes also warn that higher-efficiency filters “have higher pressure drop,” which means reduced air flow and heating and cooling capacity. Bringing an HVAC system back up to its pre-filter levels of air flow requires an increased “motor load” – that is, a bigger-capacity system, which will use more energy and pose a greater threat to the environment.

One would expect that, with its focus on climate change, the Biden Administration would show concern about the increased emissions from powering up an HVAC system to achieve more air changes per hour in addition to adding additional power to compensate for the pressure drop from stronger filters. But, so far at least, no one in the Administration has mentioned the danger to the environment of what it proposes.

“Using high-quality air filters like HEPA or MERV-13 – connected to capable HVAC systems or portable air purifiers – to remove virus particles from indoor air is also important,” writes Nelson. But there are deficiencies here as well in addition to the climate-change threat.

An article in the October issue of the ASHRAE Journal, a publication of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, acknowledged that HVAC systems are ineffective in fighting pathogens like SARS-CoV-2, even with the addition of powerful filters.

In analyzing a restaurant simulation, Zhiqiang Zhai, a professor of Civil, Environmental and Architectural Engineering at the University of Colorado at Boulder, and three colleagues write:
 
It is evident that if purely using the CA [that is, central air-conditioning with filtration], only a small fraction of the particles can be discharged through the ceiling exhausts. Most of the particles are spread out indoors and ultimately deposited on the occupants, tables, ground and walls.
 
The danger to occupants from HEPA [high-efficiency particulate air] filters placed on HVAC systems, write Zhai and his colleagues, is that some pathogens “do not get entrained into the return air vents and may float around in a given space.” In other words, this is hardly the solution to contaminated indoor air.
 
Adding eight air purifier units “can clean 28% of the particles.” A table purifier placed in the center of each table in the room – only a few feet away from each occupant -- “can handle almost 80% of the particles, while slightly increasing the deposition on the tables compared to floor units.” But, clearly, placing an air purifier in front of nearly every person in a room is impractical and expensive.

The problem is that for filters to work, pathogens need to find them. If they have to travel large distances, that connection is elusive.

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Nelson Opens the Door

To its credit, the Biden Administration has acknowledged that something else may be needed: “air disinfection.” Nelson writes, “By inactivating (‘killing’) airborne virus through methods like ultraviolet germicidal irradiation (UVGI) systems, we can add another layer of protection in indoor spaces.

She then spends the rest of the section discussing ultraviolet lights, citing a 2015 study by Matsie Mphaephlele of South Africa and colleagues that showed UVGI “about 80% effective against the spread of airborne tuberculosis, equivalent to replacing the air in an indoor room up to 24 times in an hour.” Ultraviolet disinfection also has the drawback of being dangerous to humans, which is why hospitals take great care in using UV in operating rooms, requiring special equipment or clearing the rooms entirely while disinfection occurs.

But Nelson has done a great service in opening the door to the use of other disinfection approaches – particularly active systems, as opposed to passive UV. For example, ActivePure, a Dallas-based company, has developed an Advanced Photocatalysis technology, cleared by the Food & Drug Administration, that is capable of safely suffusing an occupied indoor space with the same oxidative particles found to clean the atmosphere naturally.

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Rockefeller Report Also Stresses Safe and Clean Indoor Air

The rising White House interest in indoor air follows “Getting to and Sustaining the Next Normal,” a Rockefeller Foundation report issued in March by a distinguished group of epidemiologists and public health experts – including Bright, Michaels, Osterholm, and Ezekiel Emanuel of the University of Pennsylvania -- puts significant emphasis on safe and clean indoor air. It stated:

Indoor aerosol transmission in shared-room air, especially from people with few symptoms and who often don’t know they are infected, is a key reason Covid transmission has been so difficult to control.

The authors also noted that cleaner, safer air in the workplace and schools will reduce health care costs and absenteeism and “improve productivity, academic performance and cognitive function.”

The report urges “necessary investments in ventilation, filtration, and disinfection” and says, “Specific funds must be allocated to low-income communities to enable these investments

for small businesses, schools, and other public buildings.” Also proposed by the Rockefeller group are “income-linked subsidies” to households for upgrades to systems to fight COVID indoors.

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COVID Surging, Leveling Off in Europe and Rising in Parts of the United States

Masks have come off all over the United States and kids are back in school, but the COVID pandemic is not over. A surge dominated by the Omicron variant began in November and peaked in mid-January with 805,000 cases. By April 3, the seven-day average daily case count had declined to 27,000, the lowest figure since July. But the slide seems to be at an end, with a national rate of 8 cases per 100,000. Some states, mainly in the Mid-Atlantic and New England regions -- are seeing sharp hikes, though their case rates remain below 20.

The increases – 51% in two weeks in New Jersey, for example -- seem to be the result of the new Omicron subvariant, BA.2, which now accounts for the majority of infections. According to a Yale Medicine report on March 30, the subvariant is “believed to be more contagious than any previous strain of the virus.” However, say the Yale experts, “the good news is that BA.2 does not appear to cause more severe illness than the original variant, and it has not caused a widespread rise in hospitalizations in Europe. But there is still much to learn about Omicron and BA.2.”
Europe has suffered a spike in cases as a result of BA.2. In the U.K., infections went from 28,000 on Feb. 27 to 85,000 on March 22; in France, from 53,000 on March 3 to 138,000 on April 3. But both countries are seeing cases level off, a phenomenon also seen in Germany, Italy and Japan. Still, with COVID, what happens in America first happens in Europe, so it is logical to expect that the rise in cases in a few states will spread.

But, meanwhile in the U.S., hospitalizations are continuing to drop sharply – down another 28% in the past two weeks to 21,000, the lowest level in more than a year. Deaths have fallen to 649 a day as a weekly average, down 41% in the last 14 days and at the lowest point since August.

The  broader message is that we can expect a surge – or sub-surge – of some sort this month and that the ups and downs of COVID-19 will persist.

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Protecting Vulnerable Employees in the Workplace

As COVID-19 cases decline in the U.S. and elsewhere, businesses are bringing workers back, but the work environment won’t be the same. As the New York Times put it recently:

Executives are entering the next zone of return-to-office planning with what psychologists call “stress-related growth.” They have endured a sustained period of tumult. They are emerging feeling hopeful, equipped with new insights about how to respond when Covid cases surge and how to keep workers safe while businesses are open.
 
One of these “new insights,” especially with the Omicron surge, is that certain groups are particularly vulnerable to COVID-19, especially to severe disease. The CDC provides a long list of conditions of vulnerability. They include: cancer; kidney, liver, heart, and lung conditions, diabetes; HIV/AIDS; immunocompromised states, either primary or brought on by taking medicines to weaken immune reactions after transplants, for example; mental health conditions such as mood disorders; overweight and obesity; and sickle cell disease.
 
Those over 65 are also far more vulnerable. CDC data, updated March 9, find that Americans aged 65 to 74 are just as likely as those aged 18 to 29 to become infected with COVID, but the older group is four times as likely to be hospitalized and 65 times as likely to die. (Some 11 million Americans over 65 are still in the workforce.)
 
Overall, a study found that 92 million Americans are at especially high risk of serious disease if they become infected. That is 37.6% of adults aged 18 and over.
 
Unfortunately, the Americans With Disabilities Act does not impose an affirmative obligation to take protective steps to a person who is for example, immunocompromised. If that person asks for a “reasonable accommodation” (which often benefit other workers as well), a covered employer has to take appropriate steps to comply.

That employer has a range of possible solutions, from remote work to improving ventilation or purchasing an air disinfection system. Remote work is a popular mitigation means, but it also isolates the worker, especially as the rest of the workforce returns, post-COVID. And a worker’s home environment without protection devices can be worse than the workplace.

The Occupational Safety and Health Administration (OSHA) does have requirements that create affirmative obligations, but not for all workers. OSHA has issued an Emergency Temporary Standard (ETS) for health care workers only. That ETS makes minimal demands on employers when it comes to clean and safe air. It requires only that “employer-owned or controlled HVAC system(s) are used in accordance with manufacturer’s instructions and the design specifications of the system(s) [and] air filters are rated Minimum Efficiency Reporting Value (MERV) 13 or higher if the system allows it.”

There is no mention of air disinfection, and, based on its new “pivot,” the White House may want to get OSHA to update the ETS.

Throughout the pandemic, private employers have been the vanguard of caring for their workers. The incentives are large. Healthier workers are more productive, and clean and safe air is an attraction for potential new workers at a time of low unemployment.