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COVID-19: Ventilation and Air Circulation · The SHEA Podcast

• 0:08
  SPEAKER_00: Welcome to the Rapid Response Podcast brought to you by the Society for Healthcare Epidemiology of America, SHA, promoting the prevention of healthcare associated infections and antibiotic resistance, and seeking to advance the field of healthcare epidemiology and antibiotic stewardship.
• 0:24
  SPEAKER_00: I'm Dr.
• 0:25
  SPEAKER_00: Chrissy Woods, hospital epidemiologist and medical director for infection prevention at Mount Sinai West, and I will serve as your moderator.
• 0:33
  SPEAKER_00: Discussion on the podcast does not reflect Shay's perspective, but facilitates communication of multiple perspectives and experiences as we go through this challenging time together.
• 0:43
  SPEAKER_00: Shay is excited to launch this episode of the podcast, COVID-19 updates, what we know now.
• 0:49
  SPEAKER_00: Today's discussion is entitled COVID-19 ventilation and air circulation.
• 0:55
  SPEAKER_00: Our speaker today is Dr.
• 0:56
  SPEAKER_00: Brett Singer, a staff scientist and principal investigator in the energy technologies area of Lawrence Berkeley National Laboratory.
• 1:04
  SPEAKER_00: Dr.
• 1:04
  SPEAKER_00: Singer is the head of Sustainable Energy and Environmental Systems Department and leader of the Indoor Environment Group Berkeley Lab.
• 1:12
  SPEAKER_00: Thank you for joining us today.
• 1:14
  SPEAKER_02: Thanks for having me.
• 1:16
  SPEAKER_00: Before we get started, I'd like to turn it over to Dr.
• 1:18
  SPEAKER_00: Christopher Cernish to get us started with a brief news and guidance update for this week.
• 1:23
  SPEAKER_01: Thank you, Dr.
• 1:24
  SPEAKER_01: Woods.
• 1:25
  SPEAKER_01: As of October 25th, there were a total of 244 million cases of COVID-19 and nearly 5 million COVID-19 related deaths reported worldwide.
• 1:36
  SPEAKER_01: In the United States, there have been 45.4 million cases and nearly 735,000 COVID-19 related deaths reported to date.
• 1:45
  SPEAKER_01: According to the CDC's COVID data track, daily COVID-19 cases have declined by 15% over the past seven days, and COVID-19 related hospitalization and deaths have dropped by 10 and nearly 4% over that same time frame, respectively.
• 2:00
  SPEAKER_01: Two weeks ago, the FDA authorized, and last week the CDC released recommendations for the Moderna and Johnson Johnson booster vaccinations.
• 2:08
  SPEAKER_01: The dose of the authorized Moderna booster vaccine contains half the concentration of mRNA contained in the primary vaccine series, and recommendations for administration merit those for the previously authorized Pfizer Biome test booster.
• 2:22
  SPEAKER_01: Specifically, persons who are more than six months beyond completion of their initial vaccine series and are over the age of 65 or aged 16 to 64 who have a high-risk medical condition or are employed in a setting that places an individual at elevated risk of COVID-19 exposure should receive the booster vaccine.
• 2:41
  SPEAKER_01: The CDC recommendations addressing the Johnson ⁇ Johnson booster vaccine are more broad.
• 2:46
  SPEAKER_01: Specifically, it's recommended that all individuals over the age of 18 who previously received a single dose of the Johnson ⁇ Johnson vaccine should receive a booster dose at least two months after receiving the primary vaccine series, while the CDC recommendations state a preference for individuals to receive a booster that matches the initial vaccines administered during a primary series.
• 3:07
  SPEAKER_01: Mixing of vaccine products is permitted based on product availability and risk profiles of the vaccines for that specific individual.
• 3:15
  SPEAKER_01: Data supporting the potential benefits of heterologous booster vaccine administrations was released by investigators at the National Institutes of Health on October 13th.
• 3:23
  SPEAKER_01: In this phase 1-2 study of 458 individuals, the COVID-19 serum binding antibody levels prior to receipt of a booster vaccine dose were 15 times lower among the study participants who had previously received the J and J amovirus vector vaccine as compared to participants who received the Moderna or Pfizer-biointed mRNA vaccines.
• 3:44
  SPEAKER_01: All individuals, regardless of whether they received a homologous or heterologist booster, experienced a significant increase in serum binding and neutralization antibody levels.
• 3:53
  SPEAKER_01: However, the geometric mean of neutralizing antibody titers 15 days after a booster among individuals who initially received the JNJ vaccine were 20 times higher if they were boosted with the Moderna vaccine as compared to a JJ booster.
• 4:08
  SPEAKER_01: A technical briefing released by the United Kingdom Health Security Agency on October 22nd contained some concerning news on the spread of the AY4-2 Delta subvariant.
• 4:19
  SPEAKER_01: The so-called Delta Plus variant, which is now listed as a variant under investigation, accounts for nearly 10% of newly identified cases in the United Kingdom.
• 4:27
  SPEAKER_01: The sublineage has now been documented in 33 other countries, including the United States.
• 4:33
  SPEAKER_01: At this point, it's too early to determine if Delta Plus is more transmissible than its current lineage, and there is limited information to determine if there is an increased risk of immune escape with this particular sublineage.
• 4:45
  SPEAKER_01: However, continued monitoring of studies are warned.
• 4:48
  SPEAKER_01: Finally, a modeling study conducted by an international group of investigators just published in Nature suggests that SARS-CoV-2, the agent of COVID-19, was likely introduced into the United States as early as December through introductions from China as well as Europe, and that community transmission was occurring as early as January.
• 5:06
  SPEAKER_01: Moreover, limited access to reliable laboratory testing significantly hampered the effectiveness of surveillance systems that were put in place by March.
• 5:15
  SPEAKER_01: According to this study, it is likely that U.S.
• 5:17
  SPEAKER_01: surveillance systems that were employed at the beginning of the U.S.
• 5:20
  SPEAKER_01: pandemic were only identifying one to three in 100 SARS-CoV-2 infections.
• 5:26
  SPEAKER_01: The results of this study, as well as those of others, will provide a strong argument for greater investments in future U.S.
• 5:32
  SPEAKER_01: and international biosurveillance infrastructure.
• 5:35
  SPEAKER_01: And this concludes today's weekly news update.
• 5:38
  SPEAKER_01: Back to you, Dr.
• 5:39
  SPEAKER_01: Woods.
• 5:40
  SPEAKER_00: Thank you, Dr.
• 5:40
  SPEAKER_00: Sernich.
• 5:41
  SPEAKER_00: I will now move into the discussion with our speaker.
• 5:43
  SPEAKER_00: Dr.
• 5:43
  SPEAKER_00: Singer, can you tell us about your background around ventilation and indoor air quality and COVID-19?
• 5:49
  SPEAKER_02: Sure.
• 5:50
  SPEAKER_02: So I've been working in indoor air quality for 20 plus years, 23 years.
• 5:56
  SPEAKER_02: Most of the work I had done prior to February of 2020 was actually on chemical air pollutants and chemical contaminants, looking at exposures and ways to use engineering controls to reduce our exposures.
• 6:08
  SPEAKER_02: Obviously, like many people in February 2020, grew increasingly aware of this virus that was circulating and spreading around the world.
• 6:17
  SPEAKER_02: And I became fairly obvious early on that indoor transmission was going to be an important part of that.
• 6:22
  SPEAKER_02: So I started doing reading and educating myself more on the infectious disease part of endo air quality, which was both very interesting and sort of somewhat troubling.
• 6:32
  SPEAKER_02: It came pretty clear relatively early on that transmissions were happening at what you would call longer range or airborne.
• 6:39
  SPEAKER_02: And aerosols were the simplest explanation, even back then.
• 6:43
  SPEAKER_02: There had been already some literature, quite a bit of literature, looking at airborne infectious disease being transmitted through respiratory and other aerosols, including through wastewater.
• 6:53
  SPEAKER_02: And then as the evidence grew, the importance of the airborne route, it was clear that knowledge of how air and aerosols moved around buildings and could be removed using engineering controls was going to be relevant to the general approach of layered controls, right?
• 7:06
  SPEAKER_02: I think by now everyone knows staying home, masking, et cetera, those primary controls are paramount.
• 7:12
  SPEAKER_02: And now we have thankfully the vaccines.
• 7:14
  SPEAKER_02: But beyond those controls and under kind of normal circumstances of building operations, the way you operate the building actually can have a big impact on how much airborne infectious disease transmission occurs.
• 7:24
  SPEAKER_00: Absolutely.
• 7:25
  SPEAKER_00: And I think we've also learned that all those primary controls can only happen for limited amounts of time and sometimes in limited applications.
• 7:31
  SPEAKER_00: And then we need to do, we do need to look for other things that we can do to help our defenses against this virus and against others that may potentially spread similarly.
• 7:39
  SPEAKER_00: So your team's research around air circulation and contaminants was released last month.
• 7:44
  SPEAKER_00: Can you provide us some insight into what the data told you?
• 7:47
  SPEAKER_00: What should healthcare professionals take away from it, and how can we apply it to real world settings?
• 7:52
  SPEAKER_02: Sure.
• 7:53
  SPEAKER_02: Thank you.
• 7:53
  SPEAKER_02: So the direct finding of the study that you're referring to, which by the way looked at scenarios where people are gathering at distance in meeting rooms or classrooms, so kind of common scenarios, and trying to understand how the provision of heating and cooling with ceiling diffusers, which is a very common way.
• 8:13
  SPEAKER_02: If you're if you're in a community or commercial building now, you look up a lot of times that's where the air is going to, the heating and cooling is going to be distributed and the ventilation as well.
• 8:24
  SPEAKER_02: So there's a feature of that that we've known for some time, which is that when you are heating, providing heating, the hot air will stay at the top of the room.
• 8:33
  SPEAKER_02: So as you increase your ventilation, you're not necessarily getting all the benefit you think, because you're basically providing that extra outdoor air to the top of the room that you're heating and then removing it from the top of the room.
• 8:47
  SPEAKER_02: And it doesn't always mix down to where the people are.
• 8:49
  SPEAKER_02: So we were we were looking at some scenarios.
• 8:52
  SPEAKER_02: We have this facility at Berkeley Lab called the Flex Lab.
• 8:55
  SPEAKER_02: And it's really a marvelous facility because it is very representative of common systems that are in buildings, and we can control it.
• 9:04
  SPEAKER_02: So we can look very carefully at what happens in real buildings, but in a controlled fashion.
• 9:08
  SPEAKER_02: And what we were able to do is to document kind of and quantify how much of an impact this physical process has on exposures down where the people are in the room.
• 9:19
  SPEAKER_02: And unsurprisingly, but somewhat unhelpfully, we found that when you have this process of providing heat at the top, you can have much higher exposures down in the room, even for people who are at distance.
• 9:31
  SPEAKER_02: Luckily, there's a very simple solution to this, which is if you have this kind of system, it really relies on air mixing in the room.
• 9:38
  SPEAKER_02: So we did a test where we used these portable air cleaners.
• 9:42
  SPEAKER_02: They were actually kind of sized for residential, but the kind that many classrooms would have, for example, one or two of these portable air cleaners.
• 9:48
  SPEAKER_02: And even one of these portable air cleaners, when operating on high, that pulls air from the bottom of the room and pushes it up, pushes it, pulls it through a filter and pushes it up.
• 9:56
  SPEAKER_02: Obviously, that also has the benefit of filtering, which is good, but it also mixes the room really well.
• 10:01
  SPEAKER_02: So just the people in the room, we had mannequins, the heated mannequins, the simulated people in the room, that they were enough to provide mixing, but the mechanical system of that portable air cleaner was enough to mix the room really well.
• 10:13
  SPEAKER_02: And then you get the benefit of the ventilation and any central filtration you have also.
• 10:18
  SPEAKER_02: So those central systems work really well in that case.
• 10:21
  SPEAKER_02: So you know, it's a problem that people should be aware of.
• 10:24
  SPEAKER_02: Luckily, there's a very, very, very simple solution.
• 10:27
  SPEAKER_02: And that is to mix in preferably with a portable air cleaner.
• 10:30
  SPEAKER_00: That certainly sounds like a really interesting kind of space to be able to kind of do these types of experiments in.
• 10:35
  SPEAKER_00: And I guess before we continue the conversation, do you think there are any basics around ventilation and the way that buildings work that you think might be important to understand as we continue the conversation?
• 10:46
  SPEAKER_02: Yeah, thanks for asking.
• 10:47
  SPEAKER_02: So we talked about layered controls.
• 10:49
  SPEAKER_02: Of course, I just want to point out for sure, minimizing sources, encouraging people with symptoms to stay home in public spaces, you know, the grocery stores, and and when when feasible having people wear masks, obviously those are great strategies and should be employed whenever possible, minimizing exposure to individual risk levels.
• 11:07
  SPEAKER_02: So you think about time and intensity.
• 11:09
  SPEAKER_02: This is the stuff that the medical community has been preaching for you know the whole time very helpfully.
• 11:14
  SPEAKER_02: But at the building scale, I think there are some things we we like to think about, particularly dilution and removal.
• 11:19
  SPEAKER_02: So when you think about your risk when you're in a room with somebody, the size of the room really does matter.
• 11:25
  SPEAKER_02: Now, the number of people matters too.
• 11:26
  SPEAKER_02: But in your mind, imagine being in a small office versus let's say a classroom or a gymnasium or a stadium, right?
• 11:34
  SPEAKER_02: The amount that you're exchanging air with the other people in that space is going to scale with the room size.
• 11:40
  SPEAKER_02: So if there's an infected person on the other side of, you know, a large stadium, you're not so worried about breathing in what they're breathing out, right?
• 11:48
  SPEAKER_02: Whereas if you're right next to the person, then that's an issue.
• 11:51
  SPEAKER_02: So keep the spacing is good.
• 11:53
  SPEAKER_02: And then once you're spacing, then it's a matter of how much dilution there is in the space that you are in, how much volume there is.
• 12:01
  SPEAKER_02: So bigger rooms are generally going to be less risky than smaller rooms.
• 12:05
  SPEAKER_02: And then removal.
• 12:06
  SPEAKER_02: So ventilation is exchanging air of the room and with the outside.
• 12:11
  SPEAKER_02: So that's one way that stuff that gets emitted inside the room gets removed.
• 12:15
  SPEAKER_02: And then filtration is another way of physically removing the respiratory aerosols that can carry the virus from an infected person.
• 12:23
  SPEAKER_02: And a third would be inactivation.
• 12:25
  SPEAKER_02: So an ultraviolet, especially a lot of healthcare array.
• 12:28
  SPEAKER_02: It's used in community centers, places like that, where you have at the top of the room, you'll set up a UV system so that will inactivate the airborne infectious agents, is another way of kind of removing them from harmfulness in the room.
• 12:42
  SPEAKER_02: So dilution and removal are really the keys.
• 12:44
  SPEAKER_02: And there are various ways to accomplish that.
• 12:47
  SPEAKER_00: Great.
• 12:48
  SPEAKER_00: Thank you for that.
• 12:49
  SPEAKER_00: So I think one of the things that we know is that hospitals have historically had to keep certain kinds of rooms at certain air exchange levels based on building codes.
• 12:58
  SPEAKER_00: And we're learning that non-healthcare settings would benefit from improved ventilation.
• 13:02
  SPEAKER_00: And what's happened now with COVID is that we've had a lot of non-healthcare settings turning to us for advice on what they can do to improve their situation.
• 13:11
  SPEAKER_00: And while many of us are pretty comfortable with understanding epidemiology and maybe how these things spread, we're certainly not as comfortable at being able to give the answers on ventilation.
• 13:21
  SPEAKER_00: So I'd like to ask you some questions that we get pretty commonly and see what your take would be on this.
• 13:26
  SPEAKER_00: And there are three of them, and I'll do them one at a time.
• 13:28
  SPEAKER_00: I think might be easier.
• 13:29
  SPEAKER_00: So, what can a school or a business do broadly to improve their ventilation?
• 13:34
  SPEAKER_00: And I know that's a very big question that could probably take up a lot of your time to answer.
• 13:38
  SPEAKER_02: Yeah, I I think the the first is just the simple answer to hopefully many of these places already have what we call mechanical ventilation, which distinguishes from natural ventilation.
• 13:48
  SPEAKER_02: So natural ventilation be opening windows or doors, which is great and you know, encourage when conditions are suitable outside to provide fresh air.
• 13:56
  SPEAKER_02: I think there's a lot of benefits to that.
• 13:58
  SPEAKER_02: But there's lots of situations where that doesn't work as well.
• 14:01
  SPEAKER_02: It could be polluted outside, it could be cold, it could be hot, it could be noisy.
• 14:05
  SPEAKER_02: So mechanical ventilation is a way of ensuring that there's a steady air supply through a mechanical system, fans, essentially.
• 14:12
  SPEAKER_02: And this organization called Ashray, formerly it was the American Society of Heating, Refrigerating, and Air Conditioning Engineers.
• 14:18
  SPEAKER_02: Now they just go by Ashray.
• 14:20
  SPEAKER_02: They have standards for different building types and how much ventilation is required for different building types and uses.
• 14:26
  SPEAKER_02: As you might imagine, a sports facility or you know, a workout room or something like that is going to need more ventilation.
• 14:32
  SPEAKER_02: A healthcare facility is going to need more ventilation than, let's say, an office.
• 14:36
  SPEAKER_02: A classroom is going to need more ventilation just because you have more people, more students in a smaller space.
• 14:41
  SPEAKER_02: So it goes with occupancy and activity.
• 14:43
  SPEAKER_02: So making sure that you have this mechanical ventilation and trying to check to see if it is up to current standards, especially with older buildings, that can be tougher.
• 14:52
  SPEAKER_02: But in some cases, you're able to verify that yourself.
• 14:55
  SPEAKER_02: In some cases, you might need to bring in an HVAC engineer to inspect your system and make sure it's providing enough ventilation and that the system is working properly.
• 15:05
  SPEAKER_02: Just you mentioned schools.
• 15:07
  SPEAKER_02: I'll just mention briefly the EPA has this great program called Tools for Schools with a lot of great information that schools can kind of use themselves to do some checking themselves before they have to call professional.
• 15:18
  SPEAKER_00: That's a really great resource.
• 15:20
  SPEAKER_00: Thank you.
• 15:20
  SPEAKER_00: And a lot of schools definitely don't always have the funding to be able to do that.
• 15:23
  SPEAKER_00: So it's nice that they have another resource to go to.
• 15:25
  SPEAKER_00: And you were talking about opening windows.
• 15:28
  SPEAKER_00: You know, do you think that opening windows is as good as improving filtration?
• 15:32
  SPEAKER_00: You know, that we've learned about different levels of filtration, the MERV 13s or higher or lower.
• 15:38
  SPEAKER_00: What are your thoughts on how those compare?
• 15:39
  SPEAKER_00: Or are they different?
• 15:40
  SPEAKER_02: Yeah, as I mentioned, opening windows is great and it has lots of benefits.
• 15:44
  SPEAKER_02: But as I noted, there are issues of comfort, potentially comfort noise, bringing in outdoor allergens or air pollution.
• 15:51
  SPEAKER_02: And so you really do want to have mechanical ventilation.
• 15:54
  SPEAKER_02: Another nice feature with the mechanical ventilation is it allows you to filter the air.
• 15:59
  SPEAKER_02: So most commercial buildings, when I say commercial buildings, it's not just stores, it's also schools.
• 16:04
  SPEAKER_02: It's basically non-residential buildings, have systems that will pull air out of the space, mix it with some outdoor air, and then run that whole thing through a filter and then redistribute it, right?
• 16:15
  SPEAKER_02: So that situation of being able to provide the outdoor air and mix in some outdoor air and then filter it before you heat it and cool it back to a comfortable temperature.
• 16:24
  SPEAKER_02: Those are great controls that enable you to, you know, not only controlling your exposure to what's being emitted inside, but also what's coming from outside, right?
• 16:33
  SPEAKER_02: So if you do have a live in an area with a lot of air pollution, you can filter that air as you're bringing it in.
• 16:37
  SPEAKER_02: Whereas if it's just an open window, you can't do that.
• 16:40
  SPEAKER_02: I just should also just mention briefly, you mentioned schools.
• 16:43
  SPEAKER_02: One of the great things about some of the federal government programs that happened last year was that there was money in some of those programs to help schools deal with all the extra expenses related to the pandemic.
• 16:54
  SPEAKER_02: And that money was distributed out to the states.
• 16:56
  SPEAKER_02: And it was an allowable expense from the federal legislation, and many states have adopted this to help schools and districts purchase upgrade ventilation or filtration equipment.
• 17:07
  SPEAKER_02: It's not all states, but the Department of Energy has some great resources through their efficient healthy schools campaign.
• 17:14
  SPEAKER_02: And I'll give you the website.
• 17:15
  SPEAKER_02: You can maybe, if you have a way of distributing, or just go to efficient healthy schools, one one word, efficient healthy schools.lbl.gov, and you can get information through that link and also on the Department of Energy's website.
• 17:28
  SPEAKER_00: Thank you.
• 17:29
  SPEAKER_00: I think one of the things that not only schools but businesses did also was look at standalone units of different sorts to try to help their ventilation situation.
• 17:37
  SPEAKER_00: And I'm thinking about, you know, ones that aren't not necessarily HEPA filter ones, but there are other different types of units that I know work in a variety of ways.
• 17:45
  SPEAKER_00: I was wondering what your thoughts are on whether or not those are helpful.
• 17:48
  SPEAKER_00: Even simple things like fans, I know, were other things people have started to employ.
• 17:51
  SPEAKER_02: Yeah.
• 17:52
  SPEAKER_02: So the portable air cleaners are extraordinarily helpful.
• 17:56
  SPEAKER_02: They're particularly helpful in situations where you have like older classrooms that may not have this mechanical ventilation.
• 18:02
  SPEAKER_02: Maybe they were heated with just radiator on the wall and you know, ventilation was just air leaking through all the cracks in the building shell.
• 18:08
  SPEAKER_02: So if you're in that situation, and if you're in a northern climate, let's say, or you know, southern climate, it might not always be comfortable to be able to open the window and do a lot of extra ventilation.
• 18:17
  SPEAKER_02: So the filters provide a great, great resource.
• 18:20
  SPEAKER_02: And, you know, given all the cost of everything, they're not that expensive.
• 18:24
  SPEAKER_02: You can buy, let's say, two small to medium air filters that would be good enough for a classroom, you can get for under$500, right?
• 18:31
  SPEAKER_02: So that's it's not nothing, but for health and safety, it's a pretty good buy.
• 18:37
  SPEAKER_02: And those are very effective.
• 18:38
  SPEAKER_02: Two points I'll bring up about the portable air cleaners.
• 18:41
  SPEAKER_02: First is there's a there's a company called the Association for Home Appliance Manufacturers, AHAM, AHAM.org.
• 18:50
  SPEAKER_02: They have a program where they do testing and verify what they call clean air delivery rates of these portable air cleaners.
• 18:57
  SPEAKER_02: So I would, I would definitely look at their site and only buy something that has been verified through their program.
• 19:04
  SPEAKER_02: It's actually a different spelling of the word verified, but they actually call the program verified.
• 19:08
  SPEAKER_02: So it's it's nice because it's third party, it's it's reliable, it's a known test method.
• 19:13
  SPEAKER_02: So look for their what they call clean air delivery rate.
• 19:16
  SPEAKER_02: The other thing is to pay more attention to the amount of clean air that's delivered, then a lot of air cleaners will advertise 99.9% effective, you know, efficient, right?
• 19:28
  SPEAKER_02: And and and that's fine, but it's but it's much better to move a thousand cubic feet per minute and remove 95% of the particles going through it, right?
• 19:38
  SPEAKER_02: Because you get 950 cubic feet per minute of clean air than let's say to have 100 cubic feet per minute and remove 99.9%, because you you just don't get as much benefit.
• 19:48
  SPEAKER_02: So you're looking for that overall clean air delivery rate.
• 19:52
  SPEAKER_02: And and this AHAM program will tell you that for lots and lots and lots of air cleaners.
• 19:57
  SPEAKER_00: So I guess to sort of link into another question, and it kind of goes along the same vein of, you know, good to know that there's another outside sort of party that can let us know how maybe successful some of these interventions are.
• 20:08
  SPEAKER_00: I think people have started looking at maybe other quantifiable ways of figuring out how good or bad ventilation in a room is.
• 20:14
  SPEAKER_00: And a lot of people have started turning to these carbon dioxide monitors.
• 20:18
  SPEAKER_00: I was wondering if you had any thoughts about how good they are as surrogate markers for how good or how bad the ventilation may be in a room.
• 20:25
  SPEAKER_02: Yeah, they can be very helpful.
• 20:28
  SPEAKER_02: The the caveat is that the quality of these monitors does vary.
• 20:33
  SPEAKER_02: So some of them work really well.
• 20:35
  SPEAKER_02: You can spend$200 and get a you know very good CO2 monitor that is pretty reliable.
• 20:40
  SPEAKER_02: And you can also get some that don't work as well.
• 20:43
  SPEAKER_02: So and and there's a there's a program that's being developed to kind of do standard testing of these devices.
• 20:49
  SPEAKER_02: It's not quite in place yet.
• 20:51
  SPEAKER_02: It's the American Society of Testing Materials going to have a standard test for this.
• 20:55
  SPEAKER_02: And eventually, or agencies like AHAM could use that for a certification program.
• 21:00
  SPEAKER_02: So there is that caveat, but it assuming your carbon dioxide sensor is reliable and you've you've you've you know done research and found one that has been independently verified, it is a pretty good check on your ventilation.
• 21:11
  SPEAKER_02: It gives you that baseline, right?
• 21:13
  SPEAKER_02: So, you know, if you especially when you have community spaces where you have lots of people, right, to make sure you're providing ventilation that's commensurate with the number of people you have.
• 21:23
  SPEAKER_02: So you can use there's some guidelines about how many PPM of carbon dioxide you'll want to have and stay below to provide good ventilation.
• 21:32
  SPEAKER_02: So I do think there's a role for them with just a couple of cautions that you know, the reliability, don't assume that everything you buy on the internet is going to work.
• 21:41
  SPEAKER_02: And so these third party certifications actually are very helpful.
• 21:46
  SPEAKER_00: Yeah, I think that's probably a good rule of thumb for just about anything we get on on the internet these days.
• 21:50
  SPEAKER_00: I mean, Amazon can be can be a great provider of many things, but who knows how reliable some of the things we get there are, or anywhere else for that matter.
• 21:58
  SPEAKER_00: So I guess venturing a little deeper into Into the topic and possibly exposing all the things that I clearly don't know that you can help fill in some gaps on.
• 22:06
  SPEAKER_00: I wanted to talk a little bit about air exchanges and the volume of the space and density of occupants because I think these are all things that probably fit into the equation.
• 22:14
  SPEAKER_00: I assume that the number of air exchanges in a space needed to mitigate the spread of illness, such as COVID, needs to take into account not just the space itself, but you know, the volume and also the density of the occupants.
• 22:26
  SPEAKER_00: And is that a fair assumption?
• 22:28
  SPEAKER_00: And if so, how can we say what our minimal number of air exchanges alone should be?
• 22:33
  SPEAKER_00: Is that really what we should look at?
• 22:34
  SPEAKER_00: Do we need to be more savvy about how we think about this equation?
• 22:38
  SPEAKER_02: I think you know more about this than you think.
• 22:40
  SPEAKER_02: So you're asking all the right questions, which is great.
• 22:44
  SPEAKER_02: And I'd go back to those Ashray standards for ventilation in different spaces.
• 22:48
  SPEAKER_02: They're developed by groups of experts that have to reach a consensus on what's required for the space, considering, you know, both practicality and safety of the occupants.
• 22:58
  SPEAKER_02: And as you might imagine, that the requirements, you know, will uh, as you you note, vary with or increase with the number of people in the space and with the type of activity, certainly different activities.
• 23:10
  SPEAKER_02: The more active you are, the more you're breathing heavily, the more respiratory aerosol you will be expelling or or emitting.
• 23:18
  SPEAKER_02: And then for the other people, the more they're gonna be breathing in.
• 23:22
  SPEAKER_02: So the more activity there is a gymnasium again or a workout room or a dance hall or something like that is gonna need different ventilation, or even something like a train station where people are moving around a lot, it's gonna need different ventilation than an office that you know has one person every hundred square feet.
• 23:37
  SPEAKER_02: So, yes, the the the the number of people, these are all considerations.
• 23:41
  SPEAKER_02: And you know, if you can't afford your engineer, you don't understand the ashtray standards, you know, just generally knowing that you're gonna have to provide more ventilation for more people, pay more attention to smaller spaces too, right?
• 23:54
  SPEAKER_02: Because again, when you're in a smaller space with someone, it's more likely you're gonna breathe in what somebody else is breathing out.
• 24:00
  SPEAKER_02: So, you know, larger spaces are generally less risky and still do need ventilation.
• 24:06
  SPEAKER_02: And the amount of ventilation is gonna depend on the number of people in the activities.
• 24:10
  SPEAKER_00: So it's fair to say then that if we have a conference room that's I don't know, 300 square feet and a conference room that's 600 square feet, the smaller one, you might want to have more air exchanges, or is that not exactly accurate?
• 24:23
  SPEAKER_02: Well, so again, it's gonna be mostly it's gonna be per person, right?
• 24:28
  SPEAKER_02: So the same number of people you you might have the same air exchange in those two spaces.
• 24:33
  SPEAKER_02: But if you're just having a let's say a one-hour meeting or something, right, it's gonna take a little bit longer for things to build up in that larger room.
• 24:41
  SPEAKER_02: You know, it's kind of an your intuition to this.
• 24:43
  SPEAKER_02: If you if I think most people don't normally think about this stuff because they're dealing with you know living their lives.
• 24:50
  SPEAKER_02: But if you stop and think about these things, I think a lot of people I've I've noticed in in discussing this, but just people who are not professionals, not endure quality scientists, you know, once once people stop and think about it, a lot of this is intuitive and they're able to sort of you know use that as guides as they you know move through their lives and and and are in these different spaces.
• 25:08
  SPEAKER_02: So again, you walk into a room, look at how crowded it is, how big the room is, right?
• 25:13
  SPEAKER_02: If there's you know 20 other people in a small office is going to be very different than being with 20 other people in a gymnasium.
• 25:20
  SPEAKER_00: Absolutely.
• 25:20
  SPEAKER_02: And the practical thing is as you're having meetings and things like this, you know, using larger spaces when you can, right, to get that benefit is is a when it's available, is a relatively simple thing you can do.
• 25:31
  SPEAKER_02: If you if you could meet in a larger space versus a smaller space.
• 25:34
  SPEAKER_02: And that's it links up with this idea of doing all these activities outdoors, right?
• 25:37
  SPEAKER_02: What is outdoors other than a really, really, really, really big space, right?
• 25:41
  SPEAKER_02: We we actually the atmosphere does mix, but when you're outdoors is essentially an infinitely big space, right?
• 25:47
  SPEAKER_02: Whereas if you are sitting in a room, it's a it's a it's a more contained space.
• 25:51
  SPEAKER_02: So getting into larger spaces is a good option when it's available.
• 25:56
  SPEAKER_00: Right.
• 25:56
  SPEAKER_00: So I guess as a follow-on to that, if we discuss dilution versus increasing fresh air or new air coming into a space, in a given space, is there any data that can help us to understand whether one is preferable or more important than the other?
• 26:11
  SPEAKER_00: Is it more important to disperse the air in a room by using fans to circulate and dilute and mix the existing air?
• 26:17
  SPEAKER_00: Is it better to bring in something fresh?
• 26:19
  SPEAKER_00: Thinking about a situation where again, if you're sitting in a conference room, is it better to get some fans into that room to move the air?
• 26:26
  SPEAKER_00: Or better to forget about the fans and open a window or somehow adjust the air handling so that the intake of fresh air might be different?
• 26:33
  SPEAKER_00: Or, you know, again, and they said it would be in this scenario, some set conference room of a set space.
• 26:39
  SPEAKER_02: One caution you mentioned fans, the one caution about fans is when, and let me go way back beginning.
• 26:45
  SPEAKER_02: You started this conversation about COVID, but uh, you you mentioned earlier, right, that this doesn't just apply to COVID, right?
• 26:51
  SPEAKER_02: This applies to flu season every year.
• 26:53
  SPEAKER_02: A lot of these things that we're talking about now are things that I think we as a society are all learning are helpful generally, not just for COVID, but for all these airborne infectious diseases, right?
• 27:03
  SPEAKER_02: So that's that's the first thing.
• 27:04
  SPEAKER_02: The second is the spacing is helpful.
• 27:07
  SPEAKER_02: If you just put a fan, you have this small risk, but of of connecting people who would otherwise be maybe spaced out.
• 27:14
  SPEAKER_02: So you don't want a fan blowing from one person to the next person.
• 27:17
  SPEAKER_02: It's not like a high risk thing, but it's it's it's an unnecessary risk if that person who's upstream happens to be infected, then you're just connecting that person to another person.
• 27:26
  SPEAKER_02: So you'd be a little careful with fans.
• 27:28
  SPEAKER_02: Absolutely.
• 27:28
  SPEAKER_02: So the portable air cleaners are helpful because a lot of them are designed again to push air kind of from the lower part of the room to the upper part of the room.
• 27:36
  SPEAKER_02: So they're not blowing from one person to another and they're filtering at the same time.
• 27:40
  SPEAKER_02: Ventilation is a special feature.
• 27:42
  SPEAKER_02: We mentioned, you know, filtration, we mentioned ultraviolet, both of those are really great technologies and should be used.
• 27:49
  SPEAKER_02: But there's a lot of things that we call bioeffluence, so things that we emit from our bodies, which is some of the reason why when you get in a crowded room with a lot of people that's poorly ventilated, it starts feeling stuffy and unpleasant, right?
• 28:02
  SPEAKER_02: So we've known about this for a long time.
• 28:04
  SPEAKER_02: And that was actually the start of ventilation standards was to say, okay, we want we want the air to be pleasant and enjoyable and have a feeling of being fresh rather than stale.
• 28:14
  SPEAKER_02: So ventilation helps us do that.
• 28:15
  SPEAKER_02: So ventilation is kind of a special thing.
• 28:17
  SPEAKER_02: You want to provide some minimum amount of ventilation, but you don't have to ventilate like crazy.
• 28:22
  SPEAKER_02: That's if you follow those Ashray standards, that's usually enough ventilation.
• 28:26
  SPEAKER_02: And then on top of that, you can layer the filtration or UV or other other controls.
• 28:31
  SPEAKER_00: Got it.
• 28:32
  SPEAKER_00: Thank you.
• 28:32
  SPEAKER_00: Moving forward, what do you think are research areas that would help us to continue to understand and improve air circulation and ventilation as we navigate through the pandemic and beyond?
• 28:42
  SPEAKER_02: Oh, that's a great question.
• 28:43
  SPEAKER_02: We we we actually have just written a paper on this that we hope will be accepted to the journal Indoor Air any day now, looking at this very question of what research is needed.
• 28:54
  SPEAKER_02: I think one of the things is needed, this is a show that's going out to a lot of medical professionals, and you know, the evidence-based model is really important in medicine as it is in indoor air quality.
• 29:04
  SPEAKER_02: So I think that we know all this stuff works physically, but getting the epidemiological evidence to back it up.
• 29:11
  SPEAKER_02: So, for example, studies showing that schools that are well ventilated and have good filtration, we know that poor ventilation actually leads to more illness absence, lower learning, things like that in schools.
• 29:24
  SPEAKER_02: It'd be good to build on that database of showing that, again, ventilation and filtration can actually reduce the transmission of airborne infectious disease in places like schools and offices and public buildings.
• 29:37
  SPEAKER_02: So and anything where we can track people in infections, right, of getting better tracking systems so we can quantify the benefits of the doing these controls.
• 29:46
  SPEAKER_02: I think that will also help justify the expenditures, right?
• 29:49
  SPEAKER_02: So building owners, if you say, hey, we we know this works, they might say, well, you know, how much?
• 29:54
  SPEAKER_02: What's the benefit I'm going to get?
• 29:55
  SPEAKER_02: If you could say, hey, look, the schools that are doing this are reducing their illness absence every September and October by 40% on average, then that's a really compelling, you know.
• 30:07
  SPEAKER_02: I I made up that number.
• 30:08
  SPEAKER_02: It's not like I don't know what that number is, but but I would like to know what that number is, right?
• 30:12
  SPEAKER_02: To know if you do provide routine, you know, routinely provide ventilation filtration.
• 30:17
  SPEAKER_02: And as you mentioned earlier, masks, you know, we're doing it now, but everyone's, I think, you know, maybe we have a situation where every year the kids go back to school and for the first month that they're back to school, they do wear masks and, you know, or or some of them wear masks to try to reduce this.
• 30:30
  SPEAKER_02: But the more we can do on the building side of it, I think it's a backup to that and a layer on top of that.
• 30:36
  SPEAKER_00: I think it'd be great if, you know, if this pandemic, at least for us, gave us the opportunity to look at other things that we can do to improve the way that we live in in buildings and in certain spaces.
• 30:46
  SPEAKER_00: I think that'd be a great thing.
• 30:47
  SPEAKER_00: And to your point, research into these areas would definitely be a welcome thing.
• 30:51
  SPEAKER_00: If someone can show a reduction of, you know, of illness and absence, not only for school, but at work, I think that would be a welcome data point.
• 30:58
  SPEAKER_00: Do you have any final thoughts for the listeners of the podcast?
• 31:00
  SPEAKER_00: Anything that I didn't discuss that you think is important to share?
• 31:04
  SPEAKER_02: Yeah, a lot of this stuff can actually be brought home.
• 31:07
  SPEAKER_02: We we talked a lot about community settings and and healthcare and schools and offices, et cetera.
• 31:13
  SPEAKER_02: But a lot of these things also apply in our home.
• 31:15
  SPEAKER_02: So at home, we spend a lot of time with our family, hopefully, or other members of our household.
• 31:20
  SPEAKER_02: So if you have a member of the household who's particularly vulnerable, for example, right, you might want to be a little more cautious in how that person is interacting with people in the household who maybe have a job where they have to interact a lot with the public or with school children going to school.
• 31:35
  SPEAKER_02: And so some of these same controls of paying attention when you're together in small rooms, providing ventilation, certainly portable air cleaners, that stuff all works at home as well.
• 31:45
  SPEAKER_02: And especially when we're interacting with people outside of your household, right?
• 31:49
  SPEAKER_02: So for a lot of the pandemic, people were reluctant to have guests to their house, right?
• 31:53
  SPEAKER_02: And and the public health recommendations were against doing this, doing that.
• 31:57
  SPEAKER_02: And you know, we we in our household we followed those public health recommendations, but as soon as we could, we had people over.
• 32:02
  SPEAKER_02: We love having people over.
• 32:04
  SPEAKER_02: But when we would have people over, we would just take stock of okay, is there anybody here who's vulnerable?
• 32:08
  SPEAKER_02: What kind of professions are people having?
• 32:10
  SPEAKER_02: You know, like what's their risk profile?
• 32:12
  SPEAKER_02: And we would provide extra ventilation and filtration so we could still enjoy the company of our friends in a safe way inside our houses, but with again, you know, the portable air cleaners, maybe we're running, or we had a window open or you know, an exhaust fan on, or some combination of those things.
• 32:26
  SPEAKER_02: Again, the layered controls, maybe we sat if we're having dinner together, you know, depending on the situation, we maybe sit, you know, space the table a little bit if we could, have fewer people.
• 32:36
  SPEAKER_02: All of that stuff still applies.
• 32:37
  SPEAKER_02: And again, I think especially when you get into flu season and things like that, those protections can work across all buildings, really, not just not just schools and and and healthcare.
• 32:47
  SPEAKER_00: Thank you.
• 32:48
  SPEAKER_00: I think those are really important things to bring up.
• 32:50
  SPEAKER_00: And I think I've now realized that the safest person maybe to go have dinner with is actually someone who does what you do, because I think a lot of us haven't actually thought about recommending those types of interventions in in the home.
• 33:01
  SPEAKER_00: So, Dr.
• 33:01
  SPEAKER_00: Singer, I want to thank you very much for sharing your perspectives and experiences and for really such an educational and great discussion.
• 33:09
  SPEAKER_02: It was really a great pleasure.
• 33:10
  SPEAKER_02: I really appreciate you taking the time and calling attention to the benefits that can be had from using ventilation, filtration, UV, and other building controls.
• 33:19
  SPEAKER_00: This podcast can be accessed on Shea's online education center, learning CE, under the Rapid Response Program, where you will also find resources such as the Shea COVID-19 town halls.
• 33:30
  SPEAKER_00: This concludes today's episode of the Rapid Response Podcast.
• 33:34
  SPEAKER_00: Thank you for tuning in.