Expert: Employers, government face airborne COVID dangers

Andriy Onufriyenko / Getty Images

With feds returning to offices, Nathan Abse interviews William P. Bahnfleth, Penn State University engineer and government advisor on how to beat back the threat of COVID in the workplace.

Two years after the coronavirus pandemic began, and with hospitalizations and deaths due to the virus at a much lower level than at their peak, federal agencies are well along in returning to traditional workplaces large numbers of employees and contractors who had been working remotely. Most recently, the Social Security Administration and the Office of Personnel Management, among others, have been in the news for controversies that have erupted over safety concerns about the health risks still posed by traditional worksites. This week, Nathan Abse interviews indoor air safety expert, Pennsylvania State University’s William Bahnfleth. Bahnfleth is a Fellow with the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) and is among a key group of architects, engineers, scientists and medical professionals who—beginning with the early days of the disease—warned about the potential dangers of airborne spread of the infection. Bahnfleth—a mechanical engineer by training—testified to Congress on the issue beginning just as the epidemic took hold in 2020, and has continued providing analysis and advice on the issue to industry and government since.

Q&A William Bahnfleth

In 2020, you emphasized improved ventilation and filtration to cut airborne COVID risks. Two years on, have most employers endorsed such measures—and that COVID can infect as an aerosol?

Bahnfleth: Many employers are taking the issue seriously and are acting on some of these measures—improved ventilation, filtration and other means. But you know, it's hard to make blanket statements. I think many employers have tried to do many things to make their indoor air safer. They've done more inspections of their heating and air conditioning systems. They’ve increased the outdoor air in the mix. They’ve made more—and sometimes used better—filter replacements in their buildings. Some have also added portable air cleaners with HEPA filters, or germicidal systems that use, for instance, ultraviolet light. So, certainly, [expert and government] guidance on this hasn't been totally ignored. Having said that, we haven't seen a very aggressive approach to the indoor COVID problem from a lot of employers.

What are some workplaces that have shown the most improvement?

Bahnfleth: Again, many have taken at least some steps. Lately, I've been hearing more about efforts at schools than I have at businesses or other employers. There’s just been a lot of attention on schools, not just in the US, but in Canada as well. And in my work, I’ve been asked to speak on schools—and we’ve trying to get schools to take on more of these steps. Having said that, some have been reluctant to do much.

But, two years into COVID, do most businesses and government employers understand that COVID travels by air? Have the facts finally taken hold?

Bahnfleth: The evidence has only accumulated that airborne transmission is very, very likely—and in fact that often perhaps it’s the most significant exposure responsible for spreading the illness. At the same time, over the last two years we've seen almost no evidence that contaminated surfaces have been a major issue at all. What that means, of course, is that a lot of money was wasted on cleaning products and hand sanitizer type of stuff. And that businesses and government buildings often were shut down for days—needlessly—to be deep cleaned, if anyone in them was found to be infected.

OK, so you see deep cleaning surfaces against COVID as mostly folly?

Bahnfleth: Yes. I mean, to be fair, before most people knew much about COVID, doing that made some sense. But now, when scientists don't find much evidence of that particular mode of transmission, from surfaces, maybe that’s just not happening much. All I can say is that—for those of us who came from the aerosol science background and understanding of how fine particles can be transported—from the outset of COVID, we've been very concerned about airborne transmission. And it’s taken two years to succeed in getting understanding of this to sink in. But the World Health Organization and the CDC gradually have come around to support this position, too. Ironically, though—maybe between widespread vaccination and so many already having had the virus—now the knowledge and acceptance [of airborne COVID] may come just in time for the pandemic to settle down. Or at least to appear as “endemicity,” just becoming endemic.

So, that’s a new conundrum? Finally, will to combat airborne COVID, but acceptance it’s “endemic”—implying a sense that it’s maybe less threatening, despite continuing deaths and hospitalizations?

Bahnfleth: I can't know what's in people's minds, of course. But we can look at behavior. Unfortunately, I do think that a lot of people responsible for indoor workplaces just kept waiting—delaying, basically—for the pandemic to go away. That way they didn't have to do anything much about the problem. It’s important: many people deferred decisions and hoped COVID would just all go away. And I think that's probably been a factor—with respect to the point in your question. But it has not “gone away.”

Why is that important, that many people dithered?

Bahnfleth: It is critical now that more people know what we should have done back then. If we know more about the airborne dangers involved, and more people accept that, we need to act on that. And it means we should be better prepared for the next virus or pandemic—for next time. Because there will be a “next time.”

What steps should governments and businesses take, acting on that knowledge?

Bahnfleth: We certainly know we do not want to be stuck with buildings that might contribute to our suffering all over again just as disruptive an experience as the one we've had the last two years, right? Besides, what we’ve learned about COVID in the air also ties directly into what we know about other troubling diseases that spread indoors—like influenza. We're still waiting for the next big influenza epidemic or pandemic. It is something that’s happened before, and no doubt will happen again someday.

Are there any other benefits beyond helping contain viruses to retrofitting buildings for cleaner air?

Bahnfleth: Absolutely. The whole issue of improving the indoor air quality of buildings is something we need to go further on anyway. There are a lot of other health implications to indoor air—and having better indoor air would reduce sick days and lost productivity from health issues unrelated to COVID. We need to focus on changing built environments and changing the way we operate buildings for better air, if we're going to maintain a commitment to having people come in and work in them. So there are both things to consider. The COVID pandemic was not just an isolated one-off horrible event that is now totally behind us—a dangerous virus can strike again, and it could be one that’s even worse. And, considering the need for cleaner air in buildings and changes we needed to make anyway, we should not go let ourselves slip back to the old normal.

Can you elaborate?  

Bahnfleth: At the very least, we need to get our buildings ready for the next airborne pandemic, because it could be the same or worse—and we certainly won't have the excuse of being blindsided.

Federal employee unions agree with you on this—and have pushed for better worksite and air safety. So, what about the government’s announcement in March on making indoor air safer. Is it satisfactory?

Bahnfleth: I’ve been talking with OSTP—the Office of Science and Technology Policy through the White House—about all this for several months now. To their credit, they’ve cast a very wide net, talking to all sorts of experts about what should be in their program to make workplaces and workplace air safer. I’ve been consulted as recently as last week on this. For now, I think it’s just a start—but it's a really significant one. Because, face it, when has the federal government ever made indoor air quality such a priority before? This is a crucial moment—we’re seeing the development of careful recommendations to improve indoor air quality.

So, you view the White House announcement on improving indoor air as just a beginning?

Bahnfleth: Yes. The bigger issue will be: Where are the resources to actually carry this out, to implement these aims? Much of that will have to be done through the EPA, and I’m pretty sure EPA’s budget hasn’t been boosted enough to support implementing this. To make it all happen, the government is also going to have to incentivize the updating of all kinds of [commercial and government] buildings, to get to significant improvements and system replacements. But you have to start somewhere. What I’ve seen so far and the White House initiative, it’s far better than nothing.

Well, at least you see it as a very promising start?

Bahnfleth: Yes. But as I said there is the obvious question whether the needed follow up will happen—to really make the needed impact. I have hope. I see good precedents. For example, starting back in the 1970s, the federal government pressed to improve the energy efficiency of buildings, during the oil shocks of that era. In response, we developed a national code-based energy standard—namely, "ASHRAE, standard 90,” now ASHRAE 90.1, with residential and non-residential standards. All done at the request of the federal government in a very short period of time, creating national standards. While there’s no real teeth for enforcement of these standards, every state is supposed to have a code on par with 90.1. Anyway, perhaps now we will develop strong standards for indoor air quality. I would like to see the government end up with a similar, at least recommended, minimum set of standards for states to follow. I think it would have a lot of impact. Remember, the energy standards were a success: with them, we now require that a compliant building must use less than half the regulated energy of a similar building back in 1975. I see in this example of energy use standards that if we start on the right path we can likewise get to where we need to be on clear minimum standards for indoor air.

Do you foresee any particularly tough problems in developing the new standards for indoor air?

Bahnfleth: One big problem is our starting point. That may be the biggest problem relative to COVID and indoor air. Our indoor air quality standards for non-healthcare buildings, right now, just don't address “infection control,” per se, at all. It’s not part of the definition of acceptable indoor air quality. So that's a big hurdle for our next set of standards to get past. Making it happen will need ongoing federal support.

Can you go into more detail on the existing standards, and why they are so inadequate?

Bahnfleth: Sure. So “ASHRAE Standard 170” is used in the design of most health care facilities in North America. It’s very specific about controlling pathogens—and in defining acceptable indoor air quality with respect to them. In contrast, the standards applied to non-healthcare buildings—ASHRAE Standard 62.1 and 62.2—specify some very important things, like that first there should be no known contaminants at harmful concentrations (as defined by specific authorities) and, second, that a “substantial majority” do not express dissatisfaction with the air. Let me clarify—the first part of that standard means to comply you can’t have too much formaldehyde or ozone or particulate matter, or etc., in the air. The second part, regarding “dissatisfaction,” that's specifying that occupants should not find the air smells so bad that it's unacceptable. These are important standards. But that’s all there is. So, my point is there is nothing in the non-healthcare building standards that speaks to infection control. And that is a major reason we've had to scramble for two years to figure out what we should recommend if we want people to be significantly safer than they are now in non-healthcare buildings. The standards just can’t be the same. In healthcare buildings, the existing standard can call for up to 20 air changes per hour all going through filters—but that is far beyond what’s needed in other types of buildings, and we don't need to go that far. So, setting the right standard [for airborne pathogens] for non-healthcare buildings is not a simple matter.

Since early 2020, have you and others in related fields learned a lot more about reducing the danger of airborne COVID, or airborne diseases in general, to help guide you in developing these standards?

Bahnfleth: We have learned a lot. But remember we had a lot of very incompletely solved problems before COVID started. One reason for that is that previously there was very low investment in some of the basic research into this area. Government just had not funded much research on how to make air quality better—and specifically how to control risk of infection spread in ordinary buildings. There are many complex things for us to ponder—we have looked into reducing the danger by reducing people’s exposure to COVID in the air by various means. But there are still a lot of details that are not crystal clear to the people who do research and write standards.

I know you’re an air conditioning specialist and Ph.D. scientist—not a medical doctor—but can you be a little more specific regarding pathogens in the air?

Bahnfleth: There are complex and different ways that pathogens in the air can infect people. For example, with microorganisms there’s an amount that it can take to cause an infection, and that often has implications for the seriousness of the disease. Beyond the amount we also know the kind and severity of illness can depend on exactly where the virus winds up infecting a person in the respiratory system, you know? With influenza virus, for example, it can take a much larger number of influenza [virus particles] in the nose and the sinuses to cause an infection than in the lungs. Also, in the case of some viruses if they end up in the right place in the lungs, that can cause a much worse kind of respiratory disease than you’d get if the infection is primarily in your nose. As for the danger of infection itself, that can depend on the cubic footage of the indoor space, the concentration of a pathogen in the air that is breathed and being emitted, as well as how much clean air you're putting in to dilute all of that. There are a lot of details, a lot of moving parts involved. For the most part, lower density of people in a building [and social distancing] reduces the likelihood that there's an infected person in a given space and it also reduces the number of cases that will result if there is one. In buildings, then, improving ventilation, filtration and reducing density of people in the space—these are all public health measures that may be appropriate to implement when a disease outbreak is really hot.

You have said that office environments can be made safer, but at times N95 masks or remote work will be required anyway, right?

Bahnfleth: Right. People don't like to hear it—but you know, if everybody wore good masks when they were indoors, especially at times of significant risk, it would likely have a very significant effect at reducing infection. We can improve and have great building systems, but there will be times when you need good—and I mean N95 or KN-95—masks. I use HEPA air cleaners at my house, room by room—they help too. They are low energy users. If we use these basic HEPA filter units, often we wouldn’t need any of the other very expensive technologies that there are out there. And again N95 or KN95 masks are what I wear when I go to work and when I travel. So, as long as you find yourself in a space and time in which there’s a serious concern [about airborne virus], sometimes masks are a part of what’s needed. Improving ventilation, upgrading filters, all of those are important—but then also I look to doing additional things like using portable air cleaners.

Research shows N95s help. But—speaking as a layperson—how can a small HEPA machine do much? The small amount of air it processes vs. the vast space in a house or, even more, an office?

Bahnfleth: This is all about reducing exposure, which is increasing the removal rate of the particles that contain viruses, right? So the more air we're putting through high efficiency filters, the more of a bad infectious aerosol that has gotten into the air that we're removing. The portable HEPA units really can help. What people have to understand is each piece helps—increasing ventilation, filtration, lowering the density of people, etc. (and you have to mask, depending). There is no one technology that will just “sterilize” your space and air completely. If we had something that powerful, it would “sterilize” you along with it!

NEXT STORY: FEVS: Feds less engaged

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