Linsey Marr: Air Quality—A Major Issue of Our Time
The war on bad air from raging wildfires to respiratory viruses, inside and outside
Linsey Marr, the Charles P. Lunsford Professor and University Distinguished Professor at Virginia Tech University, is a leading authority on airborne transmission of respiratory viruses and the interaction of nanomaterials and the atmosphere. She joined me in person on June 28th for this conversation.
Transcript
Eric Topol (00:00):
Well, hello, I'm Eric Topol and I'm really delighted to have with me in person, Professor Linsey Marr from Virginia Tech. And we're going to be discussing air quality. and I'm going to go back to a remarkable op-ed in the New York Times. Linsey that you published this month: “Air Quality Is The Issue of Our Time.” So can you give us a bit of background about this--we of course now, we're still in the midst of it, raging wildfires. And to start it off, the quote towards the intro of your piece was, “if the pandemic was whispering to us about air quality, the wildfires are screaming at us.”
Linsey Marr (00:40):
Yeah, thanks. It's great to be here. I, I wrote that because there were, there's these two things really staring at us in the face now, both the pandemic and thinking about the virus and being in the air and it being transmitted through shared air indoors almost entirely. That combined with the sudden wildfire smoke that the East coast is experiencing worse than it ever has before, where it's something that, and it's, that's different because it's outdoors, it's different types of particles, but still it's something that affects our health. And with the wildfire smoke, you know, I said it was screaming at us because you can see that, you can see the, the darkened sky and you can, you can smell it, you can almost taste it. and you, you know, that it, you viscerally just that it's not good to breathe this stuff. And so I, you know, I don't take credit for the title that's the, the [NYT] editors who choose the title of the op-ed, but certainly it seems like, you know, things, events and things are telling us that we, it's, it's time for us to really wake up and pay attention to our air quality and what we're breathing and putting into our bodies every day.
Eric Topol (01:49):
Well, here in late June, the wildfires are going strong in Canada and now seriously affecting throughout the Midwest and Northeast and good parts of this country. And here in California-- Northern California especially, we know are going to see yet another season of vicious wildfires. So this is a really big deal from public health standpoint. And in the piece, you get into the air pollution story also, which is I think a lot of people don't understand that the premature deaths almost 7 million a year the cancer, cardiovascular disease, the asthma they just don't understand the connection about air quality, both outside and what you just were also alluding to. We'll talk more about inside air quality. Why do you think the air pollution health risks have just not been adequately appreciated?
Linsey Marr (02:44):
That's a great question. you know, I think it was more of a problem in the US in the 1970s and eighties, especially around Southern California. and we've done actually done good job. This is a happy environmental story where we've had new regulations, new technologies, new laws that have really helped clean up our air. Another place where this has happened is if you think about steel mills around Pittsburgh, so it's also in the, you know, in the eastern US where the air quality was really terrible routinely several decades ago. But we've had a lot of success in cleaning up those emissions and improving our outdoor air quality. And so I think it's kind of fallen off the radar a little bit because of that, although it's sneaked back in over that period because at the same time we've made our buildings tighter, we've introduced more sources, more cleaning products, more personal care products, more funky types of materials in our carpets and furniture into our indoor air at the same time that we have made buildings tighter for energy savings. And so now we have all these different sources of emissions indoors that, that can get trapped in our poorly ventilated buildings.
Eric Topol (04:09):
That's the point about getting trapped, not letting indoor facilities be it schools, offices, work, homes, breathe. We got a real problem here. And it's interesting a very recent piece by Emily Anthes about a century ago, when there was a lot more respect for this. And over time somehow or other we've kind of set for ourselves for entrapment,
Linsey Marr (04:30):
I think part of it has to do with the history of medicine too, in that some of the, those feared diseases were really brought under control by antibiotics and vaccines. And so there was less concern about those things as our attention turned more towards chronic diseases like cancer and cardiovascular disease. Although we know of course that air pollution, contributes to those two chronic diseases.
Eric Topol (04:58):
Yeah. In the piece you mentioned that, you know, we live 90% indoors and the indoor quality is generally --I don't even think you can use the word suboptimal --is poor. I mean, there's a lot of issues here and one of the ways we can deal with this is with air filtration beside besides just ventilation and, and HEPA [which stand for High Efficiency Particle Arresting] filters. I also wanted you to comment about, you know, this whole MERV that is for those who are not in it into it Minimum Efficiency, Reporting Value the different MERV categories and where are we with using better filtration and rating the MERV in our facilities.
Linsey Marr (05:48):
I'll, I'll start by saying where, where you started with that question, which is that our air quality indoors is often poor, and that's almost by design, by accident. because we've designed our buildings for thermal comfort and not for air quality. It's like you serve someone a glass of water and you make sure it's at the right temperature, but you don't really care about pay attention to what's in it. And so we do have there are good filters available out there, and I think the, the public is becoming more aware of those building managers are becoming more aware of those and the importance of that. There's filters all the way from HEPA high efficiency particulate air filtration units down to, and that would correspond to a, a very high MERV number. I think it's 14 or above, maybe 17, I'm not sure.
(06:35):
But then you go down the MERV scale and you get to lower quality filters. What we have in our homes is often around MERV four. so it's not really removing particles, it's really to protect the equipment and it removes the big things. but, and then as you go up to MERV eight, that might remove half of the particles we're concerned about, then you can get up to MERV 11 or 13 and 16, I think is what CDC is recommending now in HVAC systems, if your system can handle it and that can remove 90% or more of particles of the air that that flows through that filter. So now instead of just having this air trapped in indoors, if you're circulating it through this filter, you can actually remove some of the, a lot of the particles that are in the air,
Eric Topol (07:19):
Should people in their homes be doing things to have better filtration of air.
Linsey Marr (07:26):
Yeah. In your home. I think one thing you can do is use a higher MERV rating filter, but a lot of residential HVAC systems are probably not designed to handle like a MERV 13 type of filter. So alternatively, what you can do is buy a portable air cleaner. you can get a good one size for let's say a bedroom or even a larger area for two or $300 if you want something that can really handle a large open space, maybe you need to spend five or $600 to, to get something that can really pull the enough air through the filter. And those often have HEPA filters, like the best quality ones that remove over 99% of particles that pass through there. And so you, you're, you're looking for something that is not necessarily just HEPA, but also has a high flow rate, a high, what is called the clean air delivery rate, because you can have the best filter in the world, but if you're not actually moving the air through that, it's not helping.
Eric Topol (08:27):
So one of the things that comes up of course is that if you don't know where you're at, whether it's your office where you work or whether it's your home should you have, should you have a meter to monitor the quality? How, how do you find out how bad things are?
Linsey Marr (08:47):
That's a good question. I'm seeing more and more of these portable air cleaners that have a built-in sensor that can, that can tell you, and it's not perfect. It's not going to be the same quality reliability as the type of instrumentation that researchers use or that the EPA uses for outdoor air, but it still can give you a pretty good idea. and so I have one of these in our home, and if we see a number below, let's say 10-ish micrograms per cubic meter of air, that's a measure of the amount of particles in the air, then, then I'm happy. And then certainly when we've been impacted by wildfire smoke, we've seen that number go up into the thirties, forties. If we were in New York City, it would probably be in the hundreds.
Eric Topol (09:30):
Wow. Well, I think it's be really helpful to have that kind of monitoring.
Linsey Marr (09:35):
It's what's, what's interesting too is that you'll see it go up when you cook. Because cooking can produce a lot of particles too.
Eric Topol (09:42):
And that's not just gas stoves. Right.
Linsey Marr (09:44):
Not just gas stoves. Really, anytime you're heating up food, whether you're toasting bread or heating up oil to cook something, you can generate particles.
Eric Topol (09:54):
And what about, there's been a lot of concerns about gas stove and nitrogen dioxide. What do you have to say about that?
Linsey Marr (10:02):
It is a, a problem that's been around really forever, and that people are only starting to recognize now that when, whenever you have a flame, you are producing nitrogen dioxide, which causes respiratory irritation and exposure over long periods can, can lead to other symptoms, coughing, wheezing, and making it hard to breathe, exacerbating asthma. And so that's produced by combustion. So if you have a gas stove, you'll produce nitrogen dioxide. It's easy to handle that if you have a strong exhaust fan that actually vents outside that not don't, not just the exhaust back into the indoor air. But, you know, it's certainly something that people should pay attention to.
Eric Topol (10:51):
Yeah, I would think so. Now there was a historic thing that happened with the CDC which was they came out with their first ever recommendation for ACH--air changes per hour--that was five per hour. Can you tell us what that means and, and what it's all about?
Linsey Marr (11:14):
Yeah, this was really historic because we have not had any indoor air ventilation or quality air quality standards. There are some that exist for certain types of workplaces, but for the general public, there's been nothing. And so now CDC has issued this recommendation that buildings aim for at least five air changes per hour. What that means is that the air in inside your, your building or your room is replaced with outdoor air by at least five times every hour, at least every 12 minutes. And, you know, there's a good amount of research and evidence now that that reduces the risk of transmission of diseases, airborne diseases. And so that, you know, where are homes now? Homes, homes are typically maybe a half to one to two air changes per hour. Schools often aim to have three air changes per hour, but fall short of that. So if we can get those types of, of facilities, especially schools where lots of kids congregate, of course up to five air changes per hour, then, you know, I think we can really, we'd see a lot of benefit. And also, I should add for context, hospitals require six air changes per hour in patient rooms and then 12 air changes per hour in areas where procedures are taking place.
Eric Topol (12:38):
Yeah. Well that's impressive. If we can only get the schools to be on board. Now, they were apparently the White House put aside billions of dollars for buildings and schools, but they're not being deployed. Is that right?
Linsey Marr (12:50):
Yeah, I think there's the money is out there. I think it needs to be easier to access and people need to understand the importance of, of accessing that and improving your quality. I think just there's not a lot of appreciation is there's not as much appreciation for good air quality right now as there is for good water quality. Everybody knows you shouldn't drink water that's, that has bacteria or things in any because you could get sick. and I think we're starting on that journey now with air of, of helping people realize how important this is for their health. And I think once they do, then they'll be more motivated to access these funds. It's going to be a slow process. I don't know what can be done at this point. Maybe I think local school boards or state departments of education would need to take the lead to tell schools you must do this.
Eric Topol (13:50):
Connecting the dots there. you actually ended your op-ed in the New York Times. “We wouldn't accept a glass full of dirty water and we should no longer accept a lung full of dirty air.” And so apropo are schools where the the kids performance, cognitive performance testing takes a hit. I mean, it suffers from the poor air quality. I think that's something that can't be underscored enough now I want to try to connect the pandemic with the wildfires because as you alluded to, you've got the air coming in even though you're trying to stay from going outside because you, you, you can just see how bad things are, as you say, it's streaming, but then you're inside and the air's coming in now. the issue is how to protect. And one of the things of course you've mentioned is using N95 or KN95 masks. Can you tell us more about that?
Linsey Marr (14:51):
So during the pandemic, we were, you know, we were telling people move activities outdoors. Outdoors is safer than indoors. Now with the wildfires, we're telling people avoid outdoors stay indoors. So I can see the confusion. And so it's, it's because we have different sources with the pandemic. We're worried about people infected people as the source indoors with wildfire smoke, the source is mainly outdoors. Now, either way, if you are indoors, having good filtration will remove virus particles, smoke particles from the air and reduce your exposure. The other thing that will also reduce your exposure is if you wear a good quality, well-fitting mass such as an N95 or KN95, those are designed to filter out particles of all types. It doesn't matter whether it's a virus or a smoke particle or a particle generated by cooking the f filtration works as a physical process.
(15:46):
It doesn't care what type of particle it is. Size of the particle does affect filtration efficiency. And we know that N95 are designed to filter out at least 95% of particles of all sizes. Now, some people say that, oh, it only filters out 95% of particles down to a certain size, 0.3 microns and everything else gets through. That's absolutely not true. Particles smaller than 0.3 microns actually are filtered out with even better efficiency. And I realize this seems counterintuitive because we all think about seiving our pasta and the small things can get through that, those holes, but that's not how filtration works. Those tiny particles have a lot of random motion that causes them to move around in a way that they end up being trapped by the, the filter even more easily.
Eric Topol (16:39):
Yeah, and I think the, your point about the N95, would it be fair to say that if you have a tightly fitting KN 95, that's just as good?
Linsey Marr (16:49):
You know, from what I've seen, I think a big, a main difference between an N95 and a KN95 is that the N95 has straps that go around the back of your head and you're able to get a tighter fit with those. So I think on average, an N95 is going to do a little better than a KN95. But you can, if you're careful with a KN95, I think you still can get a good fit and a good seal to your face. One way you can test that is if you're wearing the KN 95, kind of cup your hands around the edges and hold it down while you're breathing through it and see if there's any difference when you do that and press it to your face versus when you don't. If you notice a difference, that means it's not well sealed to your face and you should try a different type of mask.
Eric Topol (17:35):
Yeah. And another thing regarding the mask is that if you've got wildfire smoke indoors you can detect that, but the mask is still protecting you.
Linsey Marr (17:47):
Right. The mask is still protecting you, whether you're indoors or outdoors from any type of particle in the air. It's filtering out at least 95% of it and reducing your exposure, whether it's viruses or cigarette or, or wildfire smoke or, or cooking smoke or anything in the air.
Eric Topol (18:03):
Yeah. Now, when we spoke before something that was immensely popular is what you described about one-way and two-way masking. And so we, we have a pretty tough situation right now because the virus hasn't gone away. That is SARS-COV-2, we have immunocompromised people who have no prophylaxis. That is the combined monoclonal antibodies don't work anymore against how the Omicron strain evolved. So they're left in the lurch where there's nothing to really prevent them. And they the ones who are severely immunocompromised, like for example, having had transplant or cancer therapies or various things that would make their immune system either dysfunctional, or afunctional, they're in a tough situation because they want to wear a mask, they want to protect themselves. But a lot of people have said, “Hey, we've just moved on. Can you get over it? “The difference between that is if we were to, we're around a person with who's known immunocompromised, what is the amplification or difference between two-way and one-way masking?
Linsey Marr (19:17):
Yeah, sure. I'd be happy to talk about that again. So, masks work in both directions. They filter out particles coming into the mask that you would breathe in. They also filter out particles that you might exhale. And so let's say that we have a hundred particles in the air that you might take in from the, from the air around you, if you're not wearing a mask, and if you have a mask that's 90% efficient and it fits well, then that's going to block 90 of those particles and you'll only breathe in 10 of them. So that's, that's a good reduction. Now, if we're talking about these particles being respiratory particles that came from someone else who might be infected, if they're wearing a mask, instead of those a hundred particles all being there, they're wearing a mask, it reduces what they emit by 90%. So now there's only 10 particles in the air, and, if I'm wearing a mask instead of breathing in all 10. If the mask removes 90% of those, it removes nine. Now I'm down to breathing in only one. So we've gone from a situation with one-way masking, where I'm breathing in 10 out of the 100 to two-way masking where I'm breathing in one out of the 100 particles. And so you get, you can see you get this, this multiplicative effect with two-way masking.
Eric Topol (20:34):
Yeah. And I think this is an essential point because if we want to help the folks, and we're talking about could be 7 million Americans or more, no less immunocompromised people around the world, that we want to help them wearing a mask is a big deal. And you just described an order of magnitude difference in the particle exposure. So that I think is something, you know, just the pandemic is with us with respect to persistent virus. We could see, of course, evolution to another strain in the years ahead whereby it challenges our immunity. And this really comes into play, much more than for a lot of people in, in their minds right now. But right now, of course, the major thing that's occupying concerns are wildfire smoke and how this isn't going to go away. Our climate crisis is a true escalating crisis. And I think the question now would be this war, war against bad air. If you were to say, let's pull out all the stops. If you, if the budget wasn't a concern, what should people do of the things we've reviewed to protect themselves from bad air, particularly I think your, you know, the, the comments would be relevant to indoors. Have we touched on everything we could do? And would you prioritize these things?
Linsey Marr (22:06):
I would prioritize spaces that are crowded and tend to be poorly ventilated where people are vocalizing, talking. So I would think about places like restaurants, bars, meeting spaces, schools, wherever you have large numbers of people congregating together for long periods of time. That's where I would prioritize resources. And yeah, I would, I would upgrade the ventilation to, I would go beyond five air changes per hour in those types of situations. Let's hit the hospital grade, you know, 12 air changes per hour or better, and let's add high quality filtration to that air and that, you know, I think that's how we're going to, we could really make a, a big difference in terms of the number of people who are getting sick and, and spreading disease around to others.
Eric Topol (22:59):
That’s, I'm, I'm glad you pointed that out about, you know, where we can make our most improvements. Now, one of the things that's striking is that the pandemic, a silver lining, if you will, brought this all to fore. I mean, that before, the respect for importance of air quality just wasn't there like it was a century ago as we touched on. But perhaps now the awareness is starting and there are some resources, capitalization to do things. You and others have been leading the charge to try to get us to really think about this and take action. Are you optimistic or do you think this is going to be a slow-mo effort now that it's finally the awareness is starting to take hold?
Linsey Marr (23:48):
I'm a little bit of both. I would say optimistic and pessimistic. I'm optimistic in that we've, we've started the conversation about air quality and have come a lot farther than we've been. We've come before. I would say it's been the start of a revolution, but at the same time, it's not done because our buildings last for 60 years. And it, it's going to take a long time to upgrade all the buildings or for buildings to turn over so that everyone gets the benefit from this. But I think it will happen slowly. I'm a little bit, I guess, pessimistic, about our attention span being short and, you know, now that everyone seems to be past the pandemic, people aren't really thinking about this anymore. And we'll turn back to other concerns. but, but still, overall, I would say we've, we've come farther than I ever would've thought in a very short amount of time. And that progress was, you know, catalyzed by the pandemic. And I think it really sets us up so that we're in a better place the next time some respiratory virus like this emerges, could be flu, it could be another coronavirus, it could be something novel. but it, it's definitely going to happen.
Eric Topol (25:05):
Yeah. Well, I mean, I think if you try to pull together the things that change pretty radically during the pandemic, like for example genomic surveillance and wastewater surveillance and the attention to air quality, finally when you see the CDC and the White House and, and other actions that are taking place now, you sort of get the sense that well finally there's the attention is, is getting there, but as you put it so well will, it will be durable, whether it will, be self-sustaining. I guess we'll have to see. Well, I, in closing, Linsey you know, you are my “go-to” authority for this topic and I read everything you write about this and I, I just have learned so much from you and I know the public has as well. So thanks for, for being with me today and your visit to the region. And I hope you won't hold back and keeping us up to speed on what we should be doing to have a better protection from problems with air quality.
Linsey Marr (26:13):
Thanks so much. It's been a pleasure and I really want to thank you for getting this important message out to the public.
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