Hi, my name is Lindsay Maher, I'm a professor of civil and environmental engineering at Virginia Tech, and I'm pleased to be co-chairing this workshop with John Samet, dean of the Colorado School of Public Health. We welcome you to the first in a three part series of workshops on indoor air management of airborne pathogens. I'd like to acknowledge that while today we are gathered virtually the National Academies is physically housed on the traditional land of the Nakhutchenk and Piskatawe peoples past and present. We honor with gratitude the land itself and the people who have stewarded it throughout the generations, we honor and respect the enduring relationship that exists between these peoples and nations and this land. We thank them for the resilience and protecting this land and aspire to uphold our responsibilities to their example. I want to thank the planning committee, the National Academy staff and today's moderators and participants, all of whom have worked hard to bring together this exciting event. This workshop is the first in a series of three. The next two in September will focus on schools and public transportation will cover what we've learned what's working and what innovations are most promising in our efforts to reduce transmission of airborne pathogens. We'll also identify critical gaps in research implementation and regulation in these places. Stay tuned for the announcement next week. I'm going to go ahead and share my slides now. And now I'd like to pass it over to Dr. Salmon. Okay, thank you Lindsay and welcome to everyone. I'm going to just give a brief overview of the Environmental Health Matters Initiative, which has organized this workshop, as it did with the workshop that was held two years ago. The Environmental Health Matters Initiative cuts across the National Academies that has the goal of seeking to improve the health of all people equitably by promoting evidence-based assessment, prevention, adaptation, and strategic mitigation of complex and interconnected environmental stressors. And I will give emphasis to complex and interconnected, and that underlies the approach that the EHMI has taken in the workshops that it has held. And have the next. So the objectives are shown here. EHMI seeks to engage the diverse stakeholders who figure into these complex problems. As with this workshop, it brings together scientists and others from across disciplines. It seeks to develop trusted networks of scientists and stakeholders through its interactions with local, state, territorial, tribal, and federal collaborators. It seeks to understand what policies work and what makes a difference, and it focuses broadly on human health and ecosystem health. And then it has the role with its flexibility to provide scientific input on a rapid basis during crisis as occurred with the workshop two years ago, and now with this series of workshops and others that it has organized. Next, the underlying principles through which EHMI acts are shown here, bringing together diverse groups, having its own credibility and the credibility of the National Academies. And leadership from a variety of experienced individuals who are on the committees and who are on the staff, and EHMI, as with other academies activities acts in a neutral, nonpartisan space. Next. Before turning things over to Lindsay, I just want to acknowledge that we have sponsors who come from a wide range of sectors. They include the CDC, the National Institute for Environmental Health Sciences, EPA, NIH, and ExxonMobil. I will say that all of these sponsors have an interest in environmental health issues, but they all recognize that the National Academies operates independently from any sponsorship. The EHMI parent committee has been involved in selecting workshops, the workshop topics, and a separate workshop planning committee has worked on this and the two subsequent workshops. So with that, let me turn things back to you, Lindsay. Thanks. In the background for this workshop, two years ago we had a workshop on airborne transmission of SARS-CoV-2 that was attended by, I think, 15,000 people at the time, and one of the main outputs of that was a proceedings that led to really some key publications that have helped shift the discussion about transmission and really updating our knowledge and understanding that COVID-19 is transmitted mainly through aerosols, tiny particles that we exhale, whether coughing or talking or just breathing. And so in the current workshop now, what do we do about that? Well, the goals of this current workshop series is through panel discussions and participatory exercises to review the state of knowledge about building management, ventilation, and air cleaning for airborne pathogens, to talk about experiences with management of indoor spaces during the pandemic, and to identify promising practices that can be adopted more widely to make these places safer. This is interdisciplinary and multi-sectoral. We have people from the natural physical and biological sciences and social sciences. We also have people who are experienced with building operations, including managers, ventilation engineers, and users of public and private facilities. This list shows our planning committee, which includes experts from a wide range, diverse range of different types of academic and non-academic backgrounds, and you can read their bios on the website. And I want to kind of give an overview of our thinking behind this workshop. We are interested in taking research, practice, and theory or mechanistic understanding to figure out what works through adding in systemic systematic review and expert judgment. And so that tells us something about the efficacy, kind of like what we think should happen. And then there's the next step of actually using what works, implementing that through organizational and individual actions and really looking at what the barriers have been to some of those taking some of these actions. And finally, figuring out, well, does it, did it actually work? And we need in order for that to determine that we need surveillance and evaluation. And that would then tell us the actual effectiveness of these different strategies. So here's an agenda for today's workshop. At a glance, we have four different sessions. In the first session, we will review the current state of knowledge about buildings and airborne transmission. In the second session, we'll look at scientific advances and innovations and management of indoor air. In the third session, we'll then look at organizational response and barriers to this. And then in the last session, we will have a fireside chat where we have agency and expert perspectives. Also, they're sharing their experiences and opportunities. In the next workshop series will produce a report in the format of a proceedings in brief. The next two workshops after this will be highly interactive and we'll be looking at case studies in schools and on public transportation. Participants will discuss their lived experiences during the pandemic. We'll also have breakout sessions to identify promising practices to make access to education and public transportation safer. The next two workshops will help pave the way for more effective management of indoor air when it comes to airborne pathogens. So let's get started with session one. The goals of our first session are to review the state of knowledge on building dynamics and indoor environments, and what we have learned since 2020 about reducing transmission of airborne pathogens. Our first speaker is Dr. Don Milton, Professor of Environmental Health at the University of Maryland School of Public Health. I'll take a minute moment to say that all the speakers and panelists bios are available on the workshop's website in the interest of time we're not going to go through those in detail here. And also those watching can submit questions at any time using the Slido platform, and everyone can vote on the questions that we'll try to will address as many of these as possible, during our panel discussion after the two talks in this session. Dr. Milton will be talking about what we have learned about SARS-CoV-2 transmission and indoor air focusing on the source term. Dr. Milton, if you want to go ahead and turn on your camera unmute and share your slides looks like we are ready to go. Everything looks great. Thanks. All right, thank you. So thank you so much for inviting me today to talk about this topic and follow up on the seminar that webinar that we had two years ago now. We learned about the source term in that time. We've had lots of discussion about what our aerosols, how do viruses transmit, how does COVID get from one person to an infected one person or another. And one of the things that has been a big problem throughout the pandemic is a tower of Babel about terminology. And I think that Dr. Lee, who will be speaking later, has helped us a lot thinking about how to speak about these things in ways that communicates what we mean by talking about the modes of transmission in a way that identifies the how things happen. Let's focus on the what thing is not a droplet or what's a droplet and aerosol. Let's talk about the cutoffs because we know from lots of work over many years that aerosols come in different sizes and how they behave and we'll hear probably more about that later depends on the size in the environment, but also when it enters your airways. Very tiny particles get caught in nose and throat smaller particles penetrate into the airways into your chest and very tiny particles get all the way out to the alveolar sacks in the lung and there's something like COVID that transmission, all it has to do is get into the airways somewhere it doesn't matter that it gets all the way to the alveolus because it doesn't just infect alveolar cells it infect cells throughout the airways. You can also spray with large droplets that can be seen and felt when you get hit and can land in the eye and on the mouth and nose but those are relatively small targets compared to inhaling air and the vast area of the airways. And then you can touch things or people and transfer virus to your susceptible tissues. So we've learned a lot about that and about how to talk about that over the last couple of years. We know that people emit infectious virus one of the first studies showing that there's infectious virus in the air was this one by John Lenecky published in 2020, showing that they were able to collect using a special kind of air sampler air from hospital room with infected patients and culture virus from the air. In my lab we have been collecting virus in we've been collecting exhale breath directly from people as they breathe talk, sing, and spontaneously cough. They don't tend to sneeze we've seen very few sneezes but we do see a fair amount of coughing, especially lately, and we've been able to culture the virus from that. Other groups have looked at the effect of just breathing versus talking and singing and show that as you vocalize, you generate more virus in the air. Now, and also that in the group and learned in a beautifully designed study were able to show that people who shed virus in the air had detectable amounts of viral RNA in their exhale breath were the ones who had other people in their homes infected, whereas they did not didn't seem to be able to infect other people in their homes. In our group we've been following since June of 2020. We're also coming in with COVID and measuring how much viral RNA is in their breath. And what we have seen is that alpha, Delta and Omicron the three variants of concern that are of concern, in part because they have been shown to be more transmissible than other variants are also associated with more virus shedding into the air. These three variants evolved independently. And so this suggests that converging evolution is occurring where the selection is for things that are more transmissible seems to be a selection for getting better at creating aerosols. We've been able to culture the aerosols from breath from fine particle aerosols especially also once from course aerosols bigger than five microns, and we've cultured it from saliva and from mid turbine swabs. But, although we swab everybody's cell phone we asked him to hand us your phone we swab it we have never been able to culture it from phone lines. One of the things that's been key is that we are seeing that the saliva the load in saliva more so than the load in the nose is a predictor of how much virus is in the breath. And this is important because, and also coughing how often somebody costs while they're giving the sample is important but this thing about saliva the point I want to make is that we also found by following contacts of cases that people had virus in before they had virus in their nasal swab that measuring virus viral RNA in saliva was three times more likely to pick up infection early in the course of disease than was swabbing the nose and doing PCR on the nose. Now think about rapid antigen tests they're much less sensitive than PCR and it's using the nose. This is a problem because we know that transmission since early in the pandemic has been happening before people have on set of symptoms, or right around the time waiting until their rapid antigen test goes positive is not going to work to stop transmission because it's going to detect it too late. We've also shown going back years ago with flu that putting surgical masks on limits the amount of aerosol that gets out from a person into the air. It course particles it limits very well, but it also reduces in about by about half the amount in fine particle aerosol. This was shown to be true with seasonal coronaviruses and a paper that was published in April 2020. And we have now shown the same thing is true with face masks that when you put on the face mask it cuts down the course aerosol by about 75% it cuts down the fine aerosol by about half. So that's not 100% but it's something and that's why layers are important. On the other hand, if you wear a surgical mask as personal protective equipment. It's not adequate, especially for health care workers in high risk. A study in Boston hospitals following people with exposure to patients and identifying cases among health care workers tracking the exposure back and doing sequences confirmed that health care workers were being infected, even though they were wearing surgical masks. Surgical masks are not personal protective equipment against aerosols. This has been known from the occupational health field for decades. And we need to understand that this is an air is born transmission and therefore it's important to have real PPE layers are important source control, maybe with loose fitting mask and cut out half maybe tight fitting a little better but it's the combination of ventilation and masking and filtration that can dramatically reduce the transmission and this has been now shown in a number of studies, especially in schools. But super spreading is what has really driven this pandemic and that has been true was true in the in early 2020. It's been true with Omicron. What happens is that there are some people, and you may recall in those plots that I showed about the evolution of the virus there were a lot of people had middling or no shedding. There are a few people that shed a lot. And if they are around a lot of other people and the ventilation is inadequate. There's not masking there's not filtration, you get this sort of explosive transmission. And it just takes one person. Most people are not transmitting to anybody else or just a few people, but some people manage to transmit to a lot of people. How do we protect against those things. Well, you know getting people to wear masks is hard. And we've known forever in environmental health that there's a hierarchy of controls that trying to get people to do stuff to wear PPE is the last thing you try to do. Before that you do administrative controls change the way people behave and that's also hard. So much better is to have things that are operating automatically in the background and protecting people without requiring them to do very much. And that's where engineering controls come in like ventilation filtration and air disinfection with UV. The site or UV can be very effective there have been now some animal experiment looking at hamsters infected hamsters transmit Delta very well as shown here to naive hamsters but when the UV light is shined on the quartz tube connecting the chambers. There's no transmission. And that has been using conventional UV that emits at 254 nanometers, but there are now new technologies, the emitting at shorter wavelengths that are easier and safer to use and instead of just in the upper room. And you'll hear more about that in subsequent talks. So in conclusion, there's extensive evidence now that airborne transmission is driving this pandemic. It's been cultured from room air and breath. There's more virus in the fine particles than the course particles and those fine particles can remain suspended in air for significant period of time. Aerosol shedding is associated with transmission. Highly contagious fire and variants of concern are also those viruses that shed into the air better. And that demonstrates conversion evolution of high air ship assault shedding phenotype again more evidence that airborne transmission is what's driving this. Vaccination are insufficient to prevent transmission nasal swabs and rapid antigen testing cannot detect early contagious cases and vaccinated and boosted cases shed infectious fires into the air and as I showed in cultured fires from the breath of people who've been vaccinated and boosted. So layers, including environmental interventions are key super spreading remains a major factor. So masks ventilation filtration can limit transmission and drum saddle UV holds tremendous promise to reduce transmission in high risk environments such as meeting houses, where a conference rooms convention center schools and healthcare, such as waiting rooms and needs to be explored and employed in a much greater way. So thank you for your attention. Thank you so much Don for that excellent presentation it's really inspiring to see how far we've come since in the past two and a half years, things that we, we hypothesized and made sense like we really have solid incontrovertible evidence for now about the transmission present in aerosols and needing the importance of trying to manage this better using engineering controls in our buildings. Our next speaker is Dr Shelly Miller professor of mechanical engineering at the University of Colorado. She will provide the Miller view of the state of knowledge regarding building performance to reduce transmission of airborne pathogens. Shelly your slides look great and she'll give us invitation again to speak to the National Academy and the audience, two years post our previous meeting. I will briefly just show you my outline for today. I have so much to say and so little time so I'm highlighting a few of my favorite results that's the Miller review that are important for indoor quality management funding from an infection and transmission perspective. So this question of aerosol transmission through ventilation ducks is quite interesting. What else have we learned about ventilation and filtration, I will focus mainly on those because UV is a passion of mine but that's going to be covered later. And then how do we best mitigate public buildings to reduce transmission. This question of is there aerosol transmission through ventilation ducks is is critical for knowing where the cases come from on where they might, where they might transmit to. We have seen multiple COVID-19 outbreaks along vertical lines and apartment buildings that use natural ventilation ducts event bathrooms. We have not seen transmission through mechanically ventilated buildings being studied or reported so far so let me just cover this particular case. For example, 10 cases were were discovered in this apartment building in Seoul, South Korea along this one vertical line and the apartment building shown here. And in the middle you can see this shaft that connects the all the apartments with the same vertical line. Connects them through a bowl blow hole in the bathroom now many apartment buildings are built like this, including in the Mediterranean where I spent my sabbatical in Spain and I said I'm studying a case of this kind of transmission in an apartment building in Spain as well. This can happen when there's a reverse stack effect when hot outside and cool inside or when the stack is affect reverses and it's cold outside and warm inside. We have seen it in the building I'm studying when you turn on the kitchen exhaust or when you open the window to patio, the flow reverses into the bathroom, as opposed to going out of the bathroom into the stack. And then it comes into the bathroom where transmission can occur so I think this is a critical thing we need to be looking at, and to be advancing engineering controls a simple fan and a simple duct cover is the way to go for these kinds of problems. Since 2020. What else have we learned. I think one of my favorite studies is this one that shows ventilation and filtration can reduce environmental aerosol stars Kobe to viral load. There's great study in Kevin Bend and why Mylindberg's group, which he will be here on a panel. They brought 11 diagnosed participants into a chamber and had them do work activities and and high expiratory trials, and measured both nasal swabs and aerosol. They did find a direct association between nasal swabs and the aerosol viral load. What's interesting here is they varied the ventilation in the space and saw that trials with low ventilation, less than 4.5 hour changes per hour were associated with significantly higher aerosol viral loads in the near field. Now they didn't detect significance statistically in the far field although it would look very different. We needed more measurements in the far field because it's a little bit harder to measure in the far field the concentrations were lower. Also, when you put the whole total room together you see that it's statistically significantly higher when you have this low ventilation rate of the virus aerosol. The variation was also highly effective when we add HEPA in room air cleaners. We showed that the significantly or the research group show that this was significantly lowering the viral aerosol load of stars Kobe to We've also seen portable air cleaners reduce airborne stars Kobe to virus in a study in Spain. During the third COVID wave in the winter. They studied nine households, seven of which were positive for COVID and two were not. They conducted 13 surface swabs and 16 air samples. I'll talk about the air samples briefly. The real time PCR results for the air samples showed that they were positive for virus and the homes occupied by COVID-19 patients and negative in the control homes. And the air samples were negative for virus in all homes that use the portable air cleaner, except one. And at one, the portable air cleaner was wrongly sized. It was too small for the room size. This is why we all provide tools and we emphasize size your air cleaner correctly because it needs to be big enough to clean the whole room. Now the graph on the right shows the, the home so I star means the home with I had the air cleaner and then I without a star is not air cleaner. And so these data here the PCR data shows the differentials between when you see the virus and when you don't see the virus with the air cleaner. These are the control homes and they're always negative for virus. I like this study as well that comes out of University of Colorado Boulder out of John's eyes group where they looked at. We usually use portable air cleaners to clean the whole space so that's why we want you to size the air cleaner to clean the whole room. However, the question came up is there a localized effect. This study looked at putting an air cleaner on a table with four people talking, such as in a restaurant, doing both measurements and modeling. And they show that these localized effects could reduce the particle levels between 40 and 90% depending on the location. So this space this small space with the air cleaner cleaning right there between this, this table of four people. And so I think this is a very interesting result for air cleaners there is seems to be a localized result, as well as making sure that it cleans the whole room. So this is all together now because when we really are at the point now where we have to figure out how to mitigate so many different kinds of public buildings. We can't go out to every single building and make measurements, make studies of their ventilation and figure out which filtration works best for this particular school and that particular school in this particular office building. So we conducted a study, looking at how do we do this with a modeling tool. This is the NIST model content. And it's a very powerful tool that's been used for decades to study air indoor air management strategies. The air is only mixed within each zone so if you have one floor and multiple offices in that floor or multiple classrooms, the air is only mixed in those small zones. And then we need to establish the flows between each zone. We also account for the meteorology so that is an important driver in how a building functions so in this study we did Chicago in winter. We then estimated how infection risk was reduced when using ventilation, more filters, maybe some in room air cleaners maybe some UV upper room or induct and then also masking. The educational facilities retail, hotel and commercial office spaces. I'll just summarize briefly the results here for the large commercial office building that's 12 floors. We modeled this long range aerosol transmission. Now we did a pretty conservative problem here with one infected person in the core zone on floor one, and everyone is susceptible in the building just sort of stayed in the building because they are at the whole time. And this could be something like, you know, high tech building, you know, Google where we have like cafeterias and gyms and you just stay in the building. There's 134 occupants per floor zone. We did do masks and we didn't do very efficient masks we said 50% efficiency exhalation inhalation 30%. When we added HEPA air cleaners, they were sized by different flow rates so sometimes they were effective and sometimes they were undersized but we always added UV in room at at least for air changes, and then they UV induct single pass efficiency. We did see that the figure on the left shows the relative exposure risk of the whole building compared to the core zone. As expected the core where the infected person was has the highest exposure risk, because this is where the infectors located, then the restroom on that same floor on the higher floors the stairs really ends up having the most risk but it's low. Now the figure on the right shows the neutral pressure plane and the building starts up floor seven here. Floor to floor transmission is possible as the result of the dynamics of pressure distributions in the whole building and higher floors could become vulnerable due to the combined effects of the stack effect and pressurization of the HVAC system. To mitigate exposure risk in the infectious zone we first estimate the risk level for the building population. And we want to keep the outbreak from happening so the parameter we used was the reproductive rates staying at one. The acceptable risk then was calculated for this building to be 0.75% because there are 134 occupants in the core zone. So this figure here shows the exposure risk for every mitigation strategy with and without masks. The dark blue is with masks and we see every strategy works if there's universal masking, even baseline, low air change with the Mervé filter. But if you don't have any mask, which is that, you know, that smallest part of the hierarchy that we're that we're using. What we need to do is look to see which strategy works and hear what we see is the in room UV works with 100% outside air, or a very, very large office industrial sized air cleaner that provides 10 air changes per hour so very powerful. And this will mitigate risk in this space. Here I'm talking about the relative risk reduction compared to baseline ventilation in the infectious zone and this is a way that we look at to see well which strategy is relatively more effective than baseline. So in the next three figures, we will look at this parameter, the relative risk reduction. Here we see that upgrading the Mervé filters from 8 to 11 and 13 tend to be more effective for this building than adding small portable air cleaners for that compared to baseline ventilation so these PAC one cubic meters per second 1.45 these are small portable air cleaners, more effective to add filtration in the ducks and increase the filtration effectiveness. Now the use of Mervé 13 and induct UV with baseline ventilation provides similar performance to that of 100% outside air. So if you can't get to 100% outside air well this Mervé 13 or the induct UV is an option for you. Using, let's go to the next one. And here we see the best strategies are using UV in room with 100% outside air as I stated previously. We can only reduce the highest we can reduce risk here is about 40% relative to baseline. Finally mitigation and the age back ducks of the building reduce risks in the source zone but they also reduce transmission between floors. We are looking at the first floor elevator shaft and the first floor stairs and looking to see how these are risks are really quite low, especially with the mitigations and age back ducks. Finally, we also investigated more building types. Here we have results for the school. These are the parameters for this secondary school that we simulated note that it has a very high outdoor air ratio of upwards of 70%. This can be this is a common design in some schools. This is different than the office building which was a low about 14% outside air. These graphics show that for these this building which already has a high design outdoor air supply is limited the air cleaning potential of duck strategies. So all the portable air cleaners work well for these spaces. So here, for example, we have the UV room. We have the portable air cleaner, and the, the large industrial size air cleaner all work very well to mitigate this, this classroom, as well as the auditorium and the school cafe. In conclusion, my summary is that ventilation and air cleaning reduced viral aerosol loads indoors from COVID-19 infected individuals love that study and would love to see. I see the animal study that Don talked about for UV. So that's also exciting for public buildings with reduced outdoor air supply, improving more filtration increasing outdoor air reduces infection risk throughout the building. For buildings with high outdoor air supply already additional air cleaning need is needed, particularly in small spaces to reduce the risk. And in room germicidal UV is the only air cleaning strategy to universally reduce risk to acceptable levels in all buildings we studied in all scenarios, but so is masking. So I will stop there. Thank you very much. Great. Thank you, Dr Miller for that excellent presentation seems like obviously there are a lot of different strategies that can work. Some are more effective than others. I'd now like to introduce our panelists who will share their expertise during our discussion. So panelists, will you please turn on your video now so that we can see you. Thank you very much. Dr. Malin Alsved is a postdoctoral researcher at Lund University. Dr. Seema Loctawalla is an associate professor formerly at the University of Pittsburgh and now at Emory University. Dr. Hugo Lee is a chair professor at the University of Hong Kong. Dr. Bill Winsley is a research biomedical engineer at the National Institute of Occupational Safety and Health, which is part of the CDC. Their bios are available on the workshop website. So we're going to, we have some, some questions that we would from a mix of questions that we've thought about ahead of time to flesh out some of these, these talks in more detail. So we will be reviewing audience questions too, and I encourage you to go to Slido to enter your questions and vote on other questions rather than using the Q&A in Zoom. Thanks. Okay, so our first question is, can we accurately describe the relationship between the numbers of infected people and the loading of indoor air with infectious particles. Dr. Milton, would you like to start with that one? Yes, okay. So, yeah, we, there's a tremendous variation between individuals as I demonstrated. And so the loading is going to depend both on the number of people and the shedding rate of the people who are infected. So as you increase the number of people, the probability of an infected person will go up depending on the prevalence in the area. And then some fraction of those people have the probability of shedding a lot of virus, but it's basically an additive thing. The more people, the more crowding, the greater the likelihood that you've got somebody shedding virus and the rate at which they shed and how much dilution and filtration you have is going to determine what the concentration is in the air. Thanks. Dr. Lee, do you have anything to add there? Yeah, I think Don made a very good point in terms of diversity and the non-uniformity among people. And the loading of infectious aerosols or particles in the indoor air also depends on the survivability of the virus, which depends on environment as Lindsay knows well. And as well as the dilution capacity of the space where people are. And I think someone also, I think Shelley also mentioned about non-uniformity of the indoor air. So a lot of parameters. And I think we made a good progress in describing it, but probably not as accurately as we wished and also as needed. That's all. Yeah, I think the non-uniformity is an important point. It plumes matter. Thank you. The next question is how does that loading depend on activities and use of respiratory protection? Dr. Alsved? So breathing, as we've found in our studies, is generally generating less, both aerosol particles and viruses that are aerosol particles that carry viruses. While when you speak and when you sing, use your vocal cords and vocalize, and that will generate both more particles if you're not infected and virus carrying particles if you are infected with COVID. So the activity plays an important role in how much you'll shed to your surroundings. Thanks. Dr. Lindsay, I know you've done a lot of work on masks. Could you speak towards that? Yeah, masks are actually a very effective way of reducing the amount of aerosol that's been expelled by people in the environment. And also, if you've got a really well-fitting mask where you've got a respirator, especially like an N95 respirator, not only is that extremely good at source control, but also provides protection for the wearer. So those are both effective for the person who's infected and also for the person who is being exposed. Great. Thanks. I'd like to turn to one of our questions from the audience, which is, how do we move from this kind of nebulous, well, we want to reduce the transmission to as low as reasonably practical to maybe a better balance between mitigation and then energy and cost. Because we haven't talked about this yet, but many of the things we've talked about, increased ventilation filtration or UV, have costs associated with them. Dr. Miller, could you take stab at that? Sure. I think that's a really important consideration as we move forward. I want to say that implementing germicidal UV and the upper room or indoor scenario is low energy and also a lower cost, for example, then redoing your ventilation system. This is why the CDC has recommended as a supplemental control to increasing your ventilation if you can't increase it. I think that we need to move towards ventilation systems that are much more energy efficient, but when you do that, you also improve the filtration of the air that you're processing because you're doing a heat exchange or energy exchange type of ventilation system. So that would help with the filtration part. And then we have the DIY air cleaners. If you cannot afford a $500 air cleaner that's commercially manufactured, the DIY air cleaners are very $40, $60 a year to maintain and very effective. Great. Thank you. We're wondering, is there a correlation between the amount of virus in the air and other things that we might be able to measure more easily, such as particles or CO2? Dr. Lindsay? Yeah. Unfortunately, there's one of the problems you run into when you're looking at things like respiratory particles coming from people is there's a lot of other stuff in the air. Sometimes the other stuff can dominate more than particles. If you feel like a room full of people, you'll get a lot of particles in the air, but only a small fraction that comes in the respiratory system. CO2 is really useful. The one problem is if you want to look at something like filtration, a filter removes particles that doesn't move CO2. That can be an important complication. Great. Thank you. I have a number of questions about UV and the use of UV and occupied rooms. Maybe Dr. Miller and Dr. Milton, we'd like to hear from you on that. So how about I talk about germicidal 254 upper room UV and Don, you can take the far UV. Just briefly, 254 UV has been used for decades to clean the upper part of the room and the radiation is directed only in the upper part of the room. There has to be mixed in the whole room, which most indoor spaces are reasonably well mixed. And so then the occupied space does not receive any radiation, but the radiation is up in the upper zone and you dose the room to make sure that this is correct. And it's been implemented and used safely for many years in facilities like homeless shelters in Boston, hospitals around the world, for example. Yeah, far UV is a newer technology. We've been employing it here to some extent at the University of Maryland. If I can share this picture of Dean Lucianiak at our commencement with UV fixtures right behind him there. You can see that this is something that can be put up even in portable installations. Actually, there's now a capability, some capability to do upper room UV and portable installations and we've been using that at recent meetings that I've been attending. It has the far UV has the advantage that it's relatively I safe, and so you don't have to isolate it in the upper room. And I think that eventually it will hopefully be much more commercially it's commercially available now. And in the future I hope the costs will come down as it becomes as production goes up and technology improves. Thank you. I have a kind of a bundle of questions here next. Does the risk of infection very inversely with ventilation so more ventilation lower risk, which I'd like to direct to. There's a more specific question actually from the audience which is about the number of air changes per hour how do they, how many do you need to result in practically reduce transmission risk. And then I'd like to come like to talk with let's see I think. I'll talk about that. And you go and then we'll go to Dr. Lacto walla seem a lot to walla on kind of how these levels of virus relate to the risk of actual infection. So let's start with Shelley here. The CH question is an interesting one that the study that I talked about showed, you know, definitely lower than 4.5 has higher virus and greater than nine has lower virus okay. So we're remaining six as a really pretty high target to to implement and this is based on some a modeling understanding of the of the indoor environment and also some work that has come out of the TV world. And so the the literature on TV has helped us to say well I think this is a good target now I maybe I'd love to hear what you go says for for adding some context to this question. Continuing from Shelley's nice comments, I guess, I mean the there is a difference between ventilation rate, which measure in later per second or change power and infection risk as shown by wealth right obviously it's related to ventilation rate, not air change power. But the air change power is very easy to use, in particular in the medical field and TV we know six are changed by two of our change power I think that's number one. And then one complexity with the air change power is about occupant density. So in in some places like classrooms as Shelley just modeled and cloudy environment or change power may be high but ventilation rate per person per capita may be low. So, for restaurant in Hong Kong we use six hour change power, it seems to working rather well is about seven or 7.5 liter per second per person, but with the air change power there's another complexity. How do you estimate the air volume in practice. So, anyway, that's my question comments. Dr love locked a wall of could you comment on kind of the amount of virus in the air how much people are exposed to and the risk of transmission and infection. Yeah, I think this is a really good point right when we talk about infection risk in each environment so obviously Don's work has shown that people expel aerosols that contain virus, particularly infectious virus right because it could be a lot of RNA in the air. Some of them may be degraded and you wouldn't ever initiate an infection. There's really nice work that was done in the UK with an actual human challenge study, where we're in volunteers were infected with stars Colby to, and they found that, you know, really less than 10 particles could initiate an infection in individuals. And so that's really fascinating to think about so you don't need a lot to become infected. And we know that it's present in the air. And so, how that changes now though with vaccination and prior immunity is going to be really interesting to find out right what the human infectious doses. And we know that immunity to viruses or like flu, as a perfect example, can change the infectious dose needed to become infected to overcome the immune barrier within us. And that can change how long the exposure time you need in order to become infected. I have a comment though Lindsay on the UV that I would actually like to pose a sort of a point on this. It's really important when we talk about the impact of UV, having in both the upper room air and in other spaces is that it's really targeting one mode of transmission and as Don showed in his, you know, slide deck transmission happens in lots of different modes. In this range, we're exposed to aerosols and plumes that are a wide range of sizes. And so close range transmission may not be impacted by UV treatment and I think a really important take home here is, we think about ways to engineer spaces. And how do we do so to target multiple modes of transmission, right, both thinking about small aerosols like maybe targeted by UV in the sort of upper room air type scenarios, but also ones that might be happening at close range. So I just wanted to post that. Yeah, that's an important point and that is one of the reasons why there's tremendous interest in far UV because ceiling mounted far UV shining straight down can potentially disinfect air at short range. So you need to work to demonstrate whether that can be achieved and what rates of UV input into the space you need to achieve that. But it's certainly within the realm of possibility. And with, we will hear a later talk from you and about this, but they've achieved, you know, well over 100 air changes an hour with direct UV. And that's not to say you can't get to those kinds of levels with upper room UV as well. But then you need to pay a lot of attention to air mixing, and, and the plumes are very important and that's where I think that it's the combination of upper room UV and ceiling fans, which are the most effective way of mixing air that need to be, we need to be paying attention to. Thank you. This is, this is not the last we'll be hearing about UV. It'll be in session to shut Dr Miller. Yeah, I just wanted to add a thank you Seema for bringing up this important point but I also want to emphasize that this is an issue with all engineering controls right them the the main HVAC system is designed to clean you know the general airspace so is in room air cleaners unless you're trying to use them in a localized way which we have seen they clean localized which could be the near field transmission effect so I think. You know when you're designing your mitigation strategies you first look at how do we make sure the entire building space is clean the whole building and then we go to the next level which is we're going to have near field transmission what do we do about those situations. Do we have enough mitigations or plans in place to to decrease that which just could be a different kind of administrative control strategy because engineering engineering controls are not great at near field transmission reduction. Great excellent points from everyone. The last question is really for all of our panelists which is what type of practical steps. Do you feel what are most promising that you would take at the kind of building level to to reduce transmission of this of SARS-CoV-2 and really other respiratory viruses also. Let's start with Dr also Yeah I think ventilation is really important and one thing that could be but we haven't discussed this the ability of not talking like having indoor spaces that allows that you don't sit close and screen to each other. Since we've seen in several studies that being loud actually emits more aerosols. So that yeah noisy spaces is not good like sitting close and screaming to each other is not good. So and that with ventilation and some yeah masks in case you have to be close as well. Great thanks Dr Lindsay. Portable air cleaners I think have a lot of potential they could be more widely distributed like in schools and places like that I think there's a lot of a lot more to be done there. Okay. So Dr Milton. Yeah I think that we're not going to close down all the bars and people are going to get close together and show to each other. So we need to be paying attention to both the long and short range transmission and I think all of the things we've been talking about filtration filtration, upper room UV with ceiling fans to get good mixing direct UV. It's going to take all of these things in combinations. Dr Miller. I just have to agree with, with of course everything that has been said but I would, I would really love to emphasize, you know, the US embracing more, more use of UV in public spaces I think there's been a shying away of this technology because it's not understood but there are there are, there's lots of expertise and there's lots of evidence that it works and we need to use it in places where it's needed like as dawn says bars and restaurants and school you know there's applications and so I'd love to see more emphasis on that and also implementing it with energy efficient ventilation. Thank you, Dr Lee. Yeah, I agree with all being said and then but I'd like to go back to what Don mentioned emphasize about super spreading events, although we do not know the minimum ventilation rate for dilution rate, but we can avoid the worst and avoid the purely ventilated spaces by doing a minimum of our buildings, whether it's a four air change power six air change proper do one avoid the one air change power open fire change power. I think that's probably a little message there. Thank you. Thanks, Dr Lockdawalla. Yeah, I think everyone sort of hit on the main topics I actually wanted to also say that for a lot of other viruses right respiratory viruses like RSV and rhino virus, they didn't go away like flew did during the 2009, during the 2019 COVID pandemic. I can see that the modes of transmission of other respiratory viruses, the efficiency of each modes are slightly different and we really need to start to understand that so having multiple strategies not only that impact aerosol transmission perhaps larger range transmission, large droplet transmission other strategies and thinking about why those viruses transmitted and again coming back to the multiple layers I think is critical. Great. So if you could talk about this for days. I'd like to thank all of our panelists for sharing their expertise and our speakers, Dr Miller and Dr Milton. Also, we are now going to transition to session to which is moderated by Dr William Benflet, a professor of architectural engineering at Pennsylvania State University. Thank you, Lindsay and glad to be here with you today to moderate this session on scientific advances and innovation. The goals of the session are to review promising innovations and optimization of existing technologies to reduce the risk of infections in enclosed environments, learn about where we stand in terms of efficacy and standardization of selected technologies and how these technologies have been used or are going to be used. So we have similar format to the first session we have three speakers who will give a short seven to 10 minute talks and then we'll add some panelists and have a discussion. Our first speaker is Andrew personally from the National Institute of Standards and Technology, speaking on ventilation management to reduce airborne transmission risks and improve indoor air quality. Looks like you've almost got your slides up there Andy. Yes, I'm waiting for them to look and you hear me. Yeah, we're seeing your presenter of you right now. Oh, let's switch screens. Oops. Sometimes it's more cooperative than others isn't it. You swap displays with that. Yeah, but my cursor doesn't want to go up there. There we go, there we go. Okay. All right, good. Take it away. Yeah, I'm talking about ventilation management, which is a whole lot better than mismanaging or neglecting ventilation, which is what's been happening in our building for far too long. You know way way before the pandemic. You know Shelly provided some good evidence on the effectiveness of ventilation and reducing infection risk and totally agree with her but that's only if the ventilation happens, only if it's well managed. I will point out that managing ventilation will also improve indoor air quality in some cases, it will improve building energy efficiency that's what we call a three for. So I want to start out by just highlighting some of the recommendations that we've seen on how to manage ventilation and buildings. The first one is perhaps my favorite which is to make sure. Look at the system make sure it's operating as this intended operate. That is not always the case. In fact, it doesn't happen a lot.  And part of that I would say their recommendations to change the existing standards to require more ventilation more filtration and other things. And speaking of more there's recommendations for more outdoor air more filtration, more open windows and so on. We'll see statements that if concentration is below some particular value. That's an indicator that the ventilation is good and the infection risk is low I didn't put a value in because I don't know what it is. I'll talk about that later on. And then there's recommendations for improved air distribution to get the air to the occupants and remove the aerosols and then the last line or some miscellaneous recommendations that I don't have time to talk about. One point I want to make is that buildings and buildings ventilation systems are extremely variable there's a lot of buildings in the country and even more in the world everyone's a special story. And the systems in these buildings are also quite variable and they impact what you can do. And, you know if you're thinking about doing something different with ventilation you got to take a look at your system type and how it's operated. Does it do you have mechanical ventilation how is the outdoor air intake control. Can you bring more air into the building a lot of folks are saying you know bring more outdoor air into the building well that's, you know if the outdoor air is clean and dry that that's great, but in August and certain parts of the world that air is hot and humid and your system may not be able to handle and cause other problems. Some mechanical ventilation systems are extremely limited in what you can do with them. I'm thinking window air conditioners and fan coil units natural ventilation we heard about that earlier. That, you know, less options for improving ventilation there you might have to go to, you know portable air cleaners and other other strategies, and it depends a lot on whether your natural ventilation system is just operable windows, or it's a truly engineered system where the air flows are based on not wishful thinking. And then finally, a lot of buildings are only ventilated by infiltration most US homes do not have outdoor air ventilation systems. And again that limits your options. So the first thing to do is understand your system and then consider your options. The reference cited there is a chapter I wrote for on evaluating ventilation performance for recently published handbook on their air quality I'm not going to go all through all this stuff, but it's a matter of looking at the system design evaluating performance and then there's some other really important things to look at. In terms of the design, I will note that not all buildings, you can always find the design documentation for for too many reasons, which is unfortunate. And if you're going to measure it, you know, I want to stay clearly that, you know, ventilation rates and air flows and buildings are extremely value variable and one measurement won't tell you very much and here's just some plots showing the variability. I'm going to go into this look at this 206 2016 paper in indoor air if you want to learn more about how air change rates vary in buildings. We've heard about CO2 monitoring. It's sure it sure it could be useful. You got to understand what you're doing. You've got to do it carefully. And there's a long history of confusion and misinterpretation with regards to indoor CO2. We're seeing a lot more measurement now we're seeing less expensive sensors we're seeing guidance, but I will state that not all the guidance is terribly clear or very well explained technically. There are really two reasons to monitor CO2 in this context. One is to use it as a tracer gas to verify that you are achieving the ventilation rate that you or someone feels is protective against infection risk. I don't know what that rate is but I know how to measure or we know how to measure ventilation rates using CO2 as a tracer gas. The other reason to do it is to use CO2 as a direct or indirect indicator of transmission risk. And that last bullet there if you're going to measure CO2 and you're going to report the value don't just give the concentration, you need the context you need some of this information listed here. We're going to learn more about these aspects of seal indoor CO2 and others. Ashray published a position document on indoor CO2 last February, free download. Hopefully you'll find it interesting and useful. I said I don't know what the value is for CO2 to demonstrate adequate ventilation. And I've got to say I'm a little skeptical of using the same value for all spaces doesn't make sense to me, because the CO2 concentration for a given space will depend on when you measure it relative to the occupancy schedule. How many occupants are in there and basically how much CO2 they're releasing, and then the target ventilation rate, you want to say ventilation is adequate well you need a target. You can get that from the design you can get that from standards you can get that from some of the individuals on call today, but you need to consider those things and come up with a what I'm calling a space specific CO2 metric, just published a paper in in the rare journal on this concept and we have an online tool, quick CO2 where you can make these calculations. And I'll be interested in folks experience with this approach. And we're about innovation today well I think the first innovation is do things right. Make sure the systems operating is intended and understand it before you make changes. This would be incredibly innovative. You want new stuff. Well there's you know some air distribution technologies personal ventilation and so on. The last new stuff I list here is to revise the existing ventilation and IQ standards to address airborne infection risk more directly. And to wrap up managing ventilation is not trivial but it's not rocket science either. It's not trivial because every system and building is unique and dynamic. It's not rocket science because we know we have the knowledge. In terms of CO2 it's a tool. But not every, you know, not every problem is a nail to hammer in with CO2, and you got to you got to understand what you do want to do it carefully. You want innovation, operate systems and as intended that would be a huge step. And then the last point I want to make is about, you know, a lot of the stuff is relatively straightforward to do in buildings where you have a budget, and you have a conscientious building owner and you have the resources but there are a lot of buildings. I'm calling them neglected buildings that don't fall into that category, lots of buildings, lots of occupants, lots of work that needs to be done. And I'll just show this list of publications. The first one hasn't been published yet the National Academy of Engineering Bridge Journal they're going to post that next week they tell me. And with that, thank you very much Bill and everyone else. Hey, thank you very much Andy for that great presentation. We'll move right along now to our next speaker Brent Stevens from the Illinois Institute of Technology and he'll be speaking on filtration and air cleaning for airborne pathogens. All right, are we up. Good to go. Okay, great. Well thanks for the introduction and for the opportunity to speak briefly today. So I'm going to tell you a little bit about you know what we know about filtration and air cleaning for airborne pathogens some of which has already been covered, but also importantly kind of what to look for when you're making decisions, you know, in this space. So as it's kind of been covered, you know I really grew air cleaning into two types of technologies right one is sort of portable standalone or in room, you know air cleaning devices that that treat air in the space that that they're serving. And the other as has been mentioned by Dr Miller and others is induct air cleaners, you know they're integrated within HVAC systems that serve the spaces in which we occupy. Now within any kind of air cleaning device or system, you could have many types of air cleaning technologies. We've sort of, I kind of group these into two main categories although there can be some overlap between the two. On the one hand you have subtractive technologies on the other hand you have whatever call additive technologies. So subtractive technologies their mechanism of action is that they, you know remove or inactivate, you know targeted contaminates for example pathogens from indoor air but when they come in contact with that technology so examples are filters that remove particles, electrostatic precipitators is another type of technology that moves particles, or as was mentioned UV GI, I kind of put them in subtractive because while they add UV there, you know, stuff that kind of, you have pathogens come in contact with their path. So some key parameters that you've got to know that from an engineering perspective are just the efficiency of the single pass removal efficiency of that technology. Whether what goes out versus what comes in. You also need to know the airflow rate through that system or that device, the relative, the airflow rate relative to the size of the space or the volume of the space that it's serving. Simple things like runtime is the system running. And then also for some of these technologies you do have a potential for byproduct formation for example ozone can be formed by electrostatic precipitators. So going into the spectrum additive technologies are those whose mechanism of action is really adding constituents that might be ions or reactive compounds to the air to remove particles or inactivate microorganisms. There's a broad class of categories here with sort of ever evolving names from ionizers ozone to plasma generators, and a variety of reactive oxygen species generators like hydrogen peroxide generators or hydroxyl radical generators. So a number of key parameters to understand here, as well as for if you want to understand the impact the additive technologies may or may not have on indirect quality in space. That's the type and amount of additives that are delivered. Any potential toxicity or adverse effects of those additives, both to pathogens and to people. And is there any potential for byproduct formation for example forming particles or gases, and any potential toxicity associated with those. There's been a number of papers in the last, you know, couple of years that have shown a variety of particle and gas phase formation from a wide variety of additive electronic air cleaning devices. What's really important to know is that some air cleaners use a combination of technologies, they might combine filters with UV or ions with filters and UV or one or the other one or two or three and so on and so forth. Some of those can be turned on and off and so forth but you really want to understand what those technologies are within a given device and it can be hard to understand sometimes. And so, where are we currently this has already been mentioned filtration and air cleaning is essentially recommended to reduce risk. You know the CDC and their guidance on COVID and ventilation for COVID and buildings has been pretty consistent with improving central air filtration more is better. Stacking, you know, and using HEPA fan and filtration systems, portable systems, and then supplementing with UV GI. The big thing to know is that these things can all be additive so you're kind of in a land of more is better to an extent. Now one thing I want to point out is in the ASHRAE Epidemic Task Force core recommendations. In addition to maintaining minimum ventilation improving central filtration. There's a recommendation to use air cleaners for which evidence of effectiveness and safety is clear. So the question is how do you know if air cleaning technologies effective and safe. The next thing you really have to do is seek performance data right so the ideal set of performance data would be test results from standard test methods and metrics, resulting from independent tests or peer reviewed literature, or at least, you know, tests that have run through the industry consensus standard. And now there are a number of tests, standard test methods and metrics for determining the efficacy of both induct and portable or standalone air cleaners and so those are listed below we won't go into too much detail. But it doesn't cover kind of everything and every type of technology. So the safety aspect, if you're concerned about something like byproduct formation or primary missions of something like ozone we do have ozone emission standards or two of those from UL ones kind of a low emission standard the others near zero. But we don't really have byproduct formation test standards and metrics yet that's kind of in the works, but but you don't have much yet so you have to rely on other sources. And I would call them they're the least useful kind of performance data would be none at all. But somewhere in the middle you get what I would call potentially or sometimes useful performance data that's provided for a technology or a device. This is usually like a non standardized test method and metrics that's been used. It may be published in the peer review literature but more often than not provided by a manufacturer. And their literature and so on so I'll speak a little bit about kind of some of the things you have to look out for in interpreting performance data because that's the next step right once you have data you've got to interpret the data. So first off for standardized tests and metrics it's really pretty straightforward, which is useful for single pass efficiency tests right there's how much of a pollutant comes out versus how much goes in. For filters there's a wide variety of acronyms, MIRV, HEPA, there's other other other versions, essentially for each one of those if you've got that labeled on the product the more the better right. It also has a standard 185.1 for UV induct efficacy. So you can look for these things to help inform your decisions and generally the higher the rating the higher the removal. And then for, if you only have sort of efficiency data you also still need to know other things about the system you need to know the flow rate through the, through the filter the air cleaner determinants impact and you can calculate an effective clean air delivery rate or CDR if you know both of those things. So both cleaner delivery rate or CDR. This is a very useful term for comparing technologies and the impacts that they can have on pollutant removal, including passage and removal. And so the most widely used is the Association of Home Appliance Manufacturers, AHAMs AC1 test method is a test chamber re-inject particles and measure the decay with and without the air cleaner operating and outcomes of CDR. So it's very useful for testing portable or in room air cleaners. AHAM on their website has something like 800 products that have been tested for a CDR and you'll see products range commonly from maybe 25 or 50 CFM at the very bottom cubic feet per minute of clean air delivered of a certain size range, which translates to the size range of particles that are of concern for airborne infectious disease transmission. You see that at maybe 25, 50 CFM at the low end up to like 500 CFM at CDR at the high end. And again, the higher the CDR, the greater the removal that you'll have. One really important note of caution is you may see a CDR on a product for a device, but make sure you know what units it's in. You'll see different units used. I've seen like cubic meters per hour, which actually gives you a larger number than CFM. So you have to convert. You have to nearly be an engineer, right, to evaluate these. I've also seen things like leaders of air per day, which can be kind of confusing to interpret 28,000 liters per air per day or something like that. And interestingly, the do it yourself solution, like the Corsi-Rosenpoel box solution where you kind of strap more of 13 filters or higher to a box fan, you know, these are recently tested and shown to deliver up to like 800 CDR in cubic feet per minute for particle sizes of interest at much lower costs and a lot of commercial solutions at least upfront costs. So those are really promising. As many of you know. And interpreting, when it comes to interpreting performance data from non-standardized tests and metrics, you really kind of have to have a little bit more level of interpretation. A classic example throughout the years is microbial inactivation tests that come from chamber tests. For example, you'll see an air cleaning technology, you know, reduces viable pathogens by 99% and in an hour in a test chamber and you may be provided with data from a test report that looks like this at one hour, you know, E. Colise reduced with the air cleaning technology operating in the chamber by 99% compared to the control condition, which just is the background loss rate. So many of you and some colleagues have recently published an article in the ASH rate journal that helped you try to interpret this performance data. So interestingly, when you take that, although 99% sounds, you know, quite, quite good. If you fit that data to like a first order linear biological decay model, what we can calculate the relative loss rates and that's what really matters in this space. And if you compare those loss rates against each other, you can get an equivalent CDR of a technology like this that is maybe only like 22 cubic feet per minute. So on the very low end of the products that are kind of available on the market. And it's worth noting that a 250 CFM cleaner delivery rate air cleaner in that same chamber would give you far more reduction, 99.999 plus percent in an hour. So just be careful. We've also, my colleague Elliot Gall at Portland State has led a collaborative construction of this spreadsheet tool, ACET, the air cleaner efficacy investigation tool where you can kind of plug in air cleaner performance data and yield metrics that you can translate or try to translate to real world spaces and compare to other technologies. And so my last two slides here I'll finish with for non standardized test methods metrics. You really have a number of questions to ask because without that level of standardization, you're kind of in the woods or in the dark. So I know if you have test data for a product or a technology from chamber test results from chamber test, you know, you want to know how does that translate to standard metrics or other metrics and real life conditions, you know what was the chamber size how does the chamber size effect interpretation of the results, if at all, you know for additive technologies that add constituents reactive constituents to the air and so forth. You want to know that for that efficacy performance data. You're tested at real world constituent levels that you would see in real spaces, and we're any chemical or particle byproducts measured is that a concern for air cleaners with multiple technologies again something that might combine it using system plus an ionization system, which technologies were active during testing and were they ever tested with one on one off and so forth so what is really contributing to the efficacy. So I have a couple of questions to ask. So I want to thank my close collaborators LA gold Elfin farmer and Muhammad had a job, especially, because a lot of this content and thought process comes from an article that we published earlier this year in the ashrate journal where we try to help people interpret air cleaner performance data. And then I just provide another a number of helpful resources here. Thanks, including the ashrite position document filtration and air cleaning, which is a really really useful tool, and these others as well. So thank you. Thanks very much Brent that was really packed with with information I'm sure people want to digest those slides that their leisure when they're available. Our third presenter is you and Edie from minewells hospital and medical school University of Dundee, who will speak on far UBC for the inactivation of airborne pathogens. It's like your slides are up and you can take it away. Thank you very much. So thank you for this opportunity to present here today. Most important thing that I'm going to say today is first of all thank you to all of my collaborators on this research, they know where they are, and there is a list at the end of these slides as well. I've only got seven minutes so I'm going to be talking fast. You can play me back in half speed if you can understand me when the presentation and the recording comes out and I'm going to be selective and very brief. I would encourage you to take a look at our website and our YouTube channel for more detailed information if you want. I don't have any conflicts of interest, so that's first disclosure, and really I'm going to start the presentation with the end message for the take home messages. So I'm going to be talking about far UBC, and it is a fact that it will quickly inactivate pathogens in both the air and the surface in the laboratory setting, even in a big laboratory. And we already know, as we've heard that the upper room form of UBC at 254 nanometers has been proven to reduce transmission of airborne diseases in the real world. And so that leads us to the hypothesis that far UBC will also work in the real world. And if we switch to safety, we know for a fact that the wavelengths used in far UBC do not penetrate far into tissue. In humans they don't cause acute reactions. And when we combine those two facts with data from some mouse studies we come to the hypothesis that it also won't induce any long term adverse effects in the skin. So if we go just right back into the basics of what ultraviolet C is. So ultraviolet C is part of the electromagnetic spectrum, and it covers the range from 100 nanometers to 280 nanometers.  And in fact, we're not really interested in wavelengths below 200 nanometers, and because they don't transmit through the air. So it's the 200 to 280 nanometer region we're interested in. It's the germicidal region where these photons can inactivate bacteria and viruses and stop the pathogens from replicating the particular area that we are going to focus on that's called far UBC. It's not actually an official term, but it's become to be known the wavelength region between 200 nanometers and 230 nanometers. And by far the most common technology which has been explored in this area is the Krypton chloride eczema lamp, which has a peak emission at 222 nanometers, but also has some longer wavelength lower intensity missions as well. And safety, so there are two organizations who produced guidelines on limits of exposure to all types of ultraviolet. That's ECHNERT and ACGIH. They have slightly different guidelines. But the important thing is that you always have to consider all of the emissions from a lamp. I'm going to be talking about Krypton chloride lamps. And on the slide here you can see the difference between unfiltered and highly filtered Krypton chloride. By filtering what I mean is reducing those emissions above the 230 nanometers. So let's delve into a bit more depth into this first fact then. There is a wealth of evidence now showing that far UBC will work on both airborne and surface pathogens in the laboratory. There are very high log reductions for just a few millijoules per centimeter squared, much lower UV dose than is allowed in the exposure limits. And as I say, this is in laboratory quite often, I'm small laboratory studies, but we have also looked at it in a larger sort of room sized laboratory where the lamps when they were deployed. And we had continuous production of ASLIS staff audience. Depending on the intensity of lamps we could get somewhere between 128 and 322 equivalent air changes per hour, or in the medium scenario from 27 to 46 equivalent air changes per hour. And the link to that papers at the bottom of that slide. We know that far UVC works in the laboratory. And we know it's roughly equivalent to the conventional 254 nanometer upper room UVC again in the laboratory, but we know that the upper room UVC works in the real world. It's been almost 100 years since the first studies were done, showing that it does reduce the transmission of airborne diseases in a real world scenario. So if the UVC works in the 254 works in the real world, and the 222 and 254 are the same laboratory that brings us to the hypothesis that the far UVC will also work in the real world and there are ongoing studies now to investigate that. Switching through to safety then and we're concerned with wavelengths that are less than 230 nanometers. We know from computer modeling, we know from mouse studies, and we know from human studies as well that these wavelengths won't penetrate very far into tissue, and you can see some references on the slides, which will be available in the handouts. We also know that if you appropriately filter the crypton chloride lamp to remove those longer wavelength UV emissions, you don't get acute reactions in human skin until you get up to very, very high doses doses which are higher than the exposure limits. So as I say if you combine these facts with the mouse studies which have been done, which have looked to see if mice would develop any long term effects, and the mouse didn't when they were exposed to the far UVC. And then we come to the hypothesis that it's not going to, or it's not likely to do some adverse effects in the skin. More research is ongoing in this area. These are just some of the sort of research priorities for me. I'd like to see some more real world efficacy studies there's only been one published a date but they are I know they are coming. We'd like to see more on the interaction with the human eye there's only one clinical study and we've done and it is actually yet to report. It would also be useful to know how do you best deploy far UVC and make people aware of its limitations because start the pandemic there were a lot of products which came out, some of which would be completely useless. So I'd encourage anybody who's involved in research to get involved in research in this area there's lots of questions to be answered. Again, those are my take home messages and sorry for the briefness of it but if you would like more information please do visit our website, visit our YouTube channel and thanks for listening. Hey, thank you very much, you and into all of the presenters for those great presentations to start off our discussion. So, now we'll introduce three additional panelists who will help with the q amp a we have more was Atari Dr, more was Atari from design partners and other Kevin venom while number from the University of Oregon, and Dr Catherine Ratliff from the US Environmental Protection Agency and in the interest of time we will not go into their extensive qualifications, the speakers and the panelists you can find their bios at the website with that we will go to the questions and perhaps we should start with some of the questions from the audience since there are quite a few and many of them have to do with some of the technologies when talking about here's one to start with how concerned should we be about avoiding crowded places like airplanes movie theaters, concerts and classrooms. Maybe I'll send that one to doctors Atari to begin with and then others can add on. Thank you and hi everyone. I think the question is more. What type of ventilation and filtration is there in these in these spaces. This is essential question, and we have been providing guidance throughout the pandemic on how to clean the air for crowded spaces. So I would be concerned if there is no enough a clean air coming from either ventilation or filtration, but it's hard just to say in a blanket statement without knowing the status of the air in the in these spaces. Okay, thank you. Another question I think it may be Andy could shed some light on is what proportion of densely occupied buildings and in the US and other wealthy countries versus lower income countries have good ventilation. Can you speak to that at all Andy. Sure, sure, I mean I trim my slides back from earlier presentation and one thing that one bullet I took off is that, you know, actual air flow has been studied in a tiny tiny fraction of the buildings that are out there, certainly not representative but we really don't know, you know, and as Mara was referring to, you know, if you go into those crowded spaces sure you want a healthy ventilation rates and good filtration but but how do you know, you know, how do you know that that's being provided. And I think that that's one of many big questions. And any others like to add there. So we'll go on to a question about co2 monitors. Where should we put them that that's one of the eternal questions about co2 monitors is, is this the monitor measuring what we want to measure. Perhaps, Kevin, would you like to try that one. Yeah, sure. I think, practically, you need to be able to see it and reach it but I think ideally, it would be near return air grills where the, where the air is getting sucked back out of the room. It's probably your best chance at a representative or integrated signal for the space. Oftentimes, you won't know what is the supply air, or the return air just by looking. Yeah, it's often the dustier one. But that would be a good place to start. Right, thank you Andy's got his his hand up. Yeah, I'm Kevin answer makes total sense you know I don't know exactly where to put them but I know some places not to put them, you know you don't want to put them in front of the supply then that's not going to tell you what's in the space and you put them, you know, in front of the people's exhalations and, you know, there's some guidance out there but not much, and there's some thoughts and some studies but that's a tough tough question but really important if you got this contraption where you put I have mine on my desk, but I'm trying not to breathe on it. All right, excellent. So our next question. How closely should scientists work with industry partners in building air quality, addressing possible financial conflicts of interest and desire to keep prices high. I might ask Dr Ratliff to speak to this because you're involved in testing. Sure, thanks for the question. I think it's really important from an innovation standpoint to leverage all the expertise that we have across government industry academia. One thing I would add on to that is that in order to truly advance these technologies, we need to have some better standardization of test methods so we need to understand how one device works compared to another in a given setting and also how that testing can be extrapolated to real world settings so I think, you know, priority needs to be to understand how to come together and get behind some standardized test methods. Yeah, thank you and do you'd like to add on there. I mean if the researchers don't talk to the people who design and operate and maintain buildings. You know, we're not going to make any progress we need to understand their world. So we can deliver our results to them in a way that's going to have some impact. Thank you. And now a question about UV and something we didn't really address which is surface cleaning with robots which are usually used in unoccupied spaces. Are they effective. Perhaps you and could could speak to this. Yes, the robots, which are typically available at the moment, use the conventional 254 nanometer and are somewhat autonomous, they can go into a room and you can close the room often and they'll do their decontamination. What they found from the studies in the hospitals is that those rooms have to be manually cleaned first. So you have to clean them first and then the UV is an adjunct on top of that to provide that sort of terminal room cleaning. So we don't think that 222 nanometers will be as effective because of is highly absorbed by other proteins and anything else in the environment so we don't think it'll be as useful for surface cleaning as it is potentially going to be for air cleaning. So even if it's permanent installation. Okay, thank you. Next question, how do we convince medical professionals to accept aerosol transmission for all infectious respiratory diseases, rather than a large droplets I'm not sure that's a question for this group but someone asked it during our session so who would like to step up and, and address that. I can just share a story about working with medical professionals and it was transformative they I was working with some OB doctors at a hot at the hospital, do it in labor and delivery early in the pandemic. They were struggling to rank high enough in, in the, in the structure to get higher quality PPE in the early days when it wasn't widely available and you know by collaborating with them and bringing their expertise to the equation we did aerosol transfer aerosol measurements and OB wards labor and delivery rooms, this even the surgery rooms and working with those medical professionals helped create some evidence that aerosol particles were in fact being created in a high abundance with viral load included in them during the labor and delivery process, probably mostly from heavy breathing during delivery but also was evidenced in the surgery rooms where it was a much more sedate environment so I'd say collaboration is key. Thank you. To determine the best location of personal air cleaners and UV GI within a room. Do we need to do CFD or is there a acceptably accurate procedure for for good results and because it mentions personal air cleaners and I know Brent's thought about this I think I will ask him to respond first. Yeah I was going to ask you to respond to I thought a lot about this and as an engineer I think the it's very it's like it's it's instinctive to say yes, but I think the answer is practically no so maybe theoretically yes if you really really want to try to understand the dynamics of a space. And how a portable air cleaner for example might interact with that you need to know a lot about detailed flow information and so forth. But a model won't really give you that necessarily right so colorful fluid dynamics is sometimes what CFD is referred to and Andy told us how a lot about how much production conditions vary in building over time and so forth so you you could actually get misled quite a bit but by that sort of thing if you're outside of design conditions. So can be useful but technically but practically often not, you could do detailed measurements of so forth of each space but as Andy's mentioned you know we would we just kind of need to do the basics and a lot of buildings. And at the end of the day, other factors like, is there an outlet there, is it too noisy, does the airflow effects of people's perception of comfort in the space, end up kind of trumping a lot of these other factors. So, there is certainly a component and a space for design and commissioning, but sometimes it just sort of doesn't matter and if you can get the systems deployed, and enough of them you can make an impact. I'll ask you and as we move, perhaps in the direction of whole room irradiation with with far UV is it going to become easier to specify to UV systems, because we don't have this problem of how much air is moving through the disinfection zone. Yes. So for far UVC, and I wouldn't say that we're at a stage where we know exactly what the optimal UV concentration in the room would be. But what I would say that is that it just makes common sense that you flood the room with as much UV as possible to sustain within those exposure limits. Now that could end up being quite expensive, because you might need lots and lots of lamps. And it might be that you can get away with fewer lamps. But here on the side of caution, for the time being, just the approach of putting enough that you don't exceed exposure limits and you cover as much of the room as you possibly can. Thank you. Another UV question. What do we know about UV and indoor air chemistry wouldn't UV start a lot of reactions that we don't necessarily want. So someone here who's who's strong on UV photochemistry. Something you'd like to address Catherine or Brent. Yeah, I'm not but I can speak to just kind of I think we're the state of the perspectives are there. Some of our outdoor air chemist, you know, colleagues published a perspective last year on indoor air chemistry from various air clinic technologies and so forth. And I think what we know from outdoor air is that, yeah, maybe, maybe, but I've seen, I think I don't think I've seen any studies for indoor. Yeah, I'll say that everyone should be interested in the new national academies report on why indoor chemistry matters and in the management chapter chapter five of that report. And that's discussed and we found very scant literature on UBC reactions with with indoor surfaces or air chemistry, one paper on on toluene that didn't seem to raise a lot of concerns but maybe there are others, Kevin. Yeah, I want to be careful to not, you know, rain on the parade of UV. I think it's an important strategy and I've also worked a great deal on just normal irradiation even that visible radiation irradiation that comes through windows and it can have effects as well so I think it's absolutely an important tool in our sort of layered risk reduction strategy, but I just want to open a little bit of a conversation about it and say, we want it to continue to work. We want it to continue to inactivate the things that we want to inactivate. There's some question about long term unintended consequences. I'm not talking about viral resistance necessarily or, but I'm just saying these, this is a solution that's an attack all solution. It's an additive strategy, it is going to it, you know, try to inactivate all microbes, regardless of whether it's immensal or potentially even beneficial as we learn more about healthy indoor microbiome so I just want to say, we want to apply it wisely, we want to think about higher risk spaces, perhaps we even want to start to open up conversations about. Now is the time to use it and maybe now isn't the time to use it, which mean means we need some input mechanisms to decide how and when to use it most wisely. Yeah, I just want to add to that it's not even just you know chemistry or an emissions standpoint that we might be concerned about but there's also material compatibility things to think about you know as these indoor interior surfaces are getting irradiated potentially constantly that could have degrading effects on the materials present and, you know, to the points that have been previously made to I think, considering things like the amount of particular matter other constituents in the air potentially impact on how effective UV could be in particular spaces so all of these things need to be kept in mind when designing and deploying these. Yes, and there's also this I'll mention there's an ASHRAE research project you can look up that looked at degradation of the materials at high levels to 254 Andy. Yeah, Kevin reminded me one of my favorite points. And it's not specific to UV but it's really specific to any new technology, you know particularly the more sophisticated ones. We don't do a good job keeping the old technology, you know maintained running properly and so whenever I see somebody coming up with some whiz bang thing I'm like, you know that I love your brochures that's beautiful but you know we can't keep our, you know, our technology running properly so who's going to maintain that, you know, that's always a question. I think we're getting close to our last question here maybe this will be the last one. Another UV question there are studies on eye skin safety for far UV it's categorized as UVC and is limited only 23 milli joules exposure is that Stanley does how should far UV be used in real life that's for for you and so interestingly in the slide I showed with the medium scenario. That was equivalent to about 23 milli joules per centimeter squared. If you were to be stood directly underneath the lamp for eight hours, which of course is highly unlikely so so ultimately that the individual would get much lower dose than that. And even at 23 milli joules per centimeter squared, there is still a 92% reduction in the pathogen load within the chamber, which which is incredible. And actually the AC GIH has different exposure limits for the US, and it's up to around about I think it's 146 milli joules per centimeter squared for that particular wavelength. So that was the high scenario and then there you were up at 98.4% reduction. So I mean, fantastic reductions, I think. And even from the conservative estimates from from what shelly Miller was presenting earlier I think I think it was equivalent to four equivalent air changes per hour, and it's still performed incredibly well so. I thought but always is the train is reached the station we're going to have to draw this to a close. So I want to thank everyone for their, their participation with presentations and the, the q amp a very quick summary. Since we're up against time, I think we've seen that there are really a lot of good tools that we can use to help control indoor pathogen exposures and that we're making progress in understanding the existing ones better and developing some new ones so I think there's a lot of optimism but I think we also heard two important points one was the buyer beware. A nature of Brent's talk that there are a lot of products in the marketplace that need to really be scrutinized and I think that's a direction we're heading with standards and the other was Andy's point that if we would just fix the buildings we have. It's a pretty good start to it to addressing these problems and could could say more but we'll have to stop there and again. Thank you very much and we're now going to take a break until 130 unless the, the leaders give us a little extra time. And when we come back. The the next session session three will be moderated by Monica shock Spana from Johns Hopkins Center for Health Security. And with that will will go on break and see you in a few minutes. Good afternoon everyone. I'm Monica shock Spana a senior scholar with the Johns Hopkins Center for Health Security and it's my pleasure to welcome you to session number three. Organizational change response and management in the face of the pandemic or future crisis. The goal of our session is to explore how organizations responded to the social and the technical challenges of managing indoor air quality to reduce risk for airborne transmission of pathogens. So our format's going to follow an earlier pattern of having three distinguished speakers followed by panelists who will then react to what they've heard in the context of their own work and or the workshops larger themes. I would encourage audience members to raise questions via the Slido platform so thank you for that. Let me introduce our first speaker. Dr. CY Wu, who's professor in the Department of Environmental Engineering Sciences at the University of Florida. CY is presenting on behalf of himself, and also Dr. Faye McNeil who's professor of chemical engineering and earth and environmental sciences at Columbia University. You'll see that the title of CY's chart and phase talk is engineering innovation and messaging to support decision making for minimizing exposure risk to infectious virus aerosol. So CY, I just want to make sure you've turned your camera on and unmuted yourself and the screen is shared. And please remember that you and the other speakers each have about seven or so minutes for your presentation, leaving time for a rich discussion. Thanks CY over to you. Thank you very much for introduction and good afternoon. We are very honored to have this opportunity to share our thoughts about engineering and innovation and the messaging to support the decision making. So the first one we want to talk about is messaging and a simple, clear, accurate message is very important to public health. So let's say I wanted to talk about the importance of ventilation and so among the three scenarios shown over here, which one do you think has a higher virus aerosol concentration? Is this a patient room? Is this a fitness center or self isolation room? To be surprised to many people, actually, surprising to many people in isolation room actually has a higher concentration. Let me show the results over here. It has a very low air change per hour. On the other hand, the COVID patient room and fitness center, they have a much higher air change rate and therefore low concentration. So I hope this kind of a very short message and the image will stick better. And then another thought is the importance of the information availability, which actually has been touched upon earlier. So in March 2020, and I was talking to our doctors at the student healthcare center about the possibility of aerosol transmission and their response at that time was really, okay, so I said, let's do some air sampling at your place. And we placed our sampler three meters away from evaluation room where the symptomatic students are seen by the doctors. And then the evidence of the virus in our sample available on the next day immediately changed their mind. So all the staff or switch from surgical mask to wearing N95 and also the respiratory ward operation was moved to outdoors. And remember, at this time, there was, this was way before CDC provided any guidelines how to better protect the workplace. People do make a wise decision when information is available. And next, another example is about the droplet versus the aerosol transmission, which Professor Milton also pointed out earlier. And so in the beginning, the WHO's medical experts were not convinced about the aerosol transmission when there were virus RNA data available for the airborne SARS-CoV-2. After we have been able to collect and present the viable SARS-CoV-2 collected the more than two meter away, and we also show that the genome sequences of the air sample exactly match with the corresponding sequences of the virus isolated from the patient. Then these medical experts got alerted and started to change their mind. So again, the importance of available information. And another important lesson learned in communication is that we need to understand that the same, the same term may mean very different things in different disciplines, different societies and different cultures. So I recall when I first started working on collecting flu virus aerosol, and I was instructed by my medical colleagues that, oh, aerosol particles are less than five micrometer. And this is, well, my response at that time is, huh, why? Why is that? Because in my environmental engineering training and the definition of aerosol is not by that simple size. And Professor Lindsey Ma has a great article explaining how the medical field that derived the supply in Michael, and which is just very mysterious to engineering professional like me. And it has been inquired about whether regulations policy or technology innovation is more important. And we would argue that actually both are complemented to each other. So let me show one example, which is the on-the-spot detector for the SARS-CoV-2 or influenza virus aerosol developed by Professor Huffin at our University, University of Florida. So this is to show that you can get to be positive for SARS-CoV-2 and for the flu virus. So just imagine you have such a tool in your place. That would definitely help you make a decision because you know there is such a virus at your place or not. And then another very open decision makers do not have all the information they needed to help them make a decision. And one example is the air change per hour in the naturally ventilated buildings. So in that case, engineering can come to help develop methods to get them past the roadblock and help support the decision making process. So one good example is the use of carbon dioxide sensor, which has been pointed out earlier, and for the naturally ventilated space. And this shows the examples for the classroom and a popping them event to determine the ventilation rate. And this method was not available and it was developed before, it was not available before COVID and it was developed during the pandemic by engineers because of the needs of the facility managers. So next now, with such a tool, we can then better understand how our school buildings are doing in terms of the indoor air quality and the associated exposure risk, hopefully. And the left hand side shows that in the Northeast United States, the natural ventilation is not that good and needs to be supplemented with air filtration or other technology as pointed out in our previous sections. But on the other hand, the in the West Coast, it's it's very different the natural ventilation actually was much better. The natural ventilation in the old building is much better than the new buildings that are equipped with the mechanical ventilation. So with this tool, it allows us to see the geographical difference, which is a very important piece of information, we try to set to the right policy. Next, let me illustrate another good use of new technology. So the use of this carbon dioxide monitoring actually showed in a music classroom actually showed a very high concentration during practice, which was after hours when the facilities did not expect the people to be there but there were people trying to do the practice and they turned off ventilation at that time. So once the data became available, the facility manager adjusted the ventilation schedule, and you can see on the right hand side, you have a much lower carbon dioxide concentration in the green by the green color. So this shows how it can help facility managers to really, you know, make a decision to improve the air quality. So hopefully with the above slides, we can have some take home messages. The first one is a simple clear and accurate message is very important to public health. And second one is most people will make a wise decision when relevant information is provided to them. And the third lesson is do not assume everyone uses the same language and the definition. And the last one is that regulation policy and the technology innovation are complementary to each other. Decision makers often lack some of the information that needed to make decisions, and in that case, engineering innovation can help provide solution that supports the decision making process. And another important point is that we should build trust with the community by engaging the community in collecting and sharing the data. Here is the list of the references we use and they will be available to the audience. And finally, before I stop, I would like to acknowledge the financial support from different agencies and also a lot of collaborators who made the discovery possible. And if you have any questions definitely do not hesitate to contact us. Thank you very much. Thank you so much CY and also Faye for that engaging presentation. Our second speaker is Dr Sandra Kraus Quinn, who's a professor and chair of the Department of Family Science and also senior associate director of the Maryland Center for Health Equity at the School of Public Health with University of Maryland College Park. Sandra, if you would please turn on your camera, unmute yourself and share your screen. And I think the relevant part of Sandra's title is and it follows nicely from CI CY and phase of presentation that social context matters. Okay, and I think that the staff is going to share my slides. So social context matters we have heard a lot about the technology. We, we have heard a lot about what is possible. And yet, we need to be thinking about the social and broader context. So, I'm so I'm not clear who's doing the slides here. Can you see your second slide. No, I don't see any of them. Audrey we see a list of files of PowerPoint. Thank you. So I'll keep talking while we're getting the slides. We know that there are a number of challenges to implementing the kinds of technology that would help us to protect human health. We just put a broader context on them we've been talking about some of the engineering challenges. But many of you are going to be representing or are part of large organization mayor and our audience may be part of large organizations who have resources, who can garner resources, who may have the technological enhancements, you know, available to them, may control their own building space and can implement change. When you're talking about and I'm going to use some examples from smaller spaces, small school systems, local churches, community health organizations, small businesses that do not have the resources really, they may not control or own their own space so they can't make significant changes in some of the systems like HVAC, it may be an old facilities where they can't open windows. So that's context that becomes a health equity and social justice issue. But there's more. How about all the stakeholders, be they in churches, be they in big business, be they in government. Next slide please. So, I want to share a an example two examples really of the human and social context and two different emergencies that involved airborne transmission. The anthrax attack of 2001, in which anthrax was found in three large postal facilities largely staffed by minority workers, and then today's pandemic. In anthrax there was a terrible relationship between management labor that predated the anthrax attack. There was zero trust between the two entities. Today we know that we have misinformation disinformation polarization that has led to limited trust and large segments of our population. In both cases anthrax and COVID we have a novel agent. We also have in many ways novel ways of mitigating the risk. And, and so our communities are workers, etc. may not understand either the risk or some of the mitigation. What does all this do it increases their perceived risk. So this is some of the, the human context next slide. And I'll just say that, you know, we know in this, this quote states it that it's critical to consider the human factors, the values, the behaviors, the concerns, the information needs. Next slide. So I'm going to give you an example of a small environment. So the Maryland Center for Health Equity since 20 child has worked with local black barbershops and beauty shops in the DC area and Baltimore. We work with local churches and other organizations. So, the minute the coverage of the COVID started. We were hearing from their barbers and stylists here are the questions they're getting here with their fears remember barbers and stylists can't work remotely. They're their hands on their clients. So we were hearing their questions their concerns, and we took them seriously so we started something that continues to today. And that is virtual townhouse Dr Milton was part of them several times. And researchers working on the vaccine clinical trials, healthcare providers, policymakers and lots of community members, where they could each talk to one another. That made a difference and starting to build trust and reduce misinformation. Dr Milton, you know, has been an amazing partner with us. So, early on he made sure that we had saliva test and our shops. He helped to make sure we had masks in our shops. And with everything that was introduced in these shops. What happens it becomes an opportunity for dialogue and building trust. As time went on, our undergrad students again with some support from Dr Milton's team are undergrad students built course he rose and thought boxes, and they have now been you see them in a couple of the shops but they're in churches. They're even going to uncork creativity for older adults, which is where older adults sing. And we have course he rose and thought boxes that those rehearsals and concerts. So all of this points to what I think are sort of the critical lessons next slide. Engineering as part of the solution we know that and the extent to which we can do things that are passive and don't, you know, make big demands on people. But we also know what is critical is ongoing respectful bi directional communication that joint planning needs to include everyone in a meaningful way so that their concerns are listened to, and that they can be part of the solution. Every opportunity we've had to introduce unfamiliar ways to mitigate risk has become an opportunity further for further dialogue, and for building trust. And that's essential, whether you're in a large corporation, or in a local community setting. And finally, I need to come back to what is near and dear to the to many of our hearts is the issue of improving air quality and reducing airborne transmission is also a matter of ensuring health equity. And that is a critical issue considering who has been disproportionately impacted. So I will stop there next slide and turn it back to Monica. Thank you, Sandra for that wonderful and eye opening talk about the importance of the human or social systems. And in this challenging environment. Our third speaker is Reverend Anthony Evans, who is the president of the National Black Church Initiative, which is a coalition that includes over 150,000 churches in the United States. So Reverend Evans, please. I see that your cameras on, and you're unmuted, which is great. And either you or staff are going to share slides. Let me make sure they get up. They can go to the first slide. Yeah, Reverend Anthony Evans, President of the National Black Church Initiative of coalition of 150,000 churches. When covert first happened, we started mobilizing the uniqueness of NBCI is that we are a health initiative and can be considered the largest faith based African American initiative in the country. We're starting critical education and information to our congregations over the past 30 years. By doing so, we had to trust of our congregation, which constitute 27.7 million African Americans in terms of that type of stuff. You can go to the next slide, the first slide. So the bottom line came down to how do we respond to covert. And we responded to covert. And just like responded to all crisis in the African American community. What we did not have is two factors in this plays out to today, we inefficient resources in terms of money. And the second thing we did not have was information critical information. I think even a third thing that we did not have but we corrected it. And that is critical health personnel, who was able to give some direction. And what how we approach this end air situation. But first we had to deal with the virus, and we did not know the transmission of the virus. Of course we listen very closely to CDC and the rural health organizations, and even today our churches are experiencing this largely because they unable to follow those rules and regulations to the T, six weeks upon six feet apart. Isolation, if you got the virus, stay at home. We have remarkably adapted to this crisis that we have had in our country. And now of course we are adapting to the monkey parks and other air pollutants that we are unfamiliar with. Remember, we are a faith based organization, not a scientific organization. But what we had an advantage of is that we are familiar with health, health care information critical health care information, how to get it which was most important, and then how to share it. So, we didn't sit back as a community, but the country continued to sit back. And this is not to complain, but the evidence is very clear to us, what happened during COVID. And when the numbers come out in terms of the modality as well as the death and dying in the African American Latino community, no one will be surprised. We will constitute a large block of that due to health equity, due to the fact that this country still have not learned how to share resources with minority community and a timely fast way. And we're talking about technical assistance, we're talking about money resources, and we're talking about material. I believe that the black church has been remarkable response in this red here. To the fact that we have gotten to the first phase, if we can say that scientifically of COVID and now we entering to a second phase of COVID and maybe a third phase. Our response in the second phase is a little bit more robust. What we have done is that we have taken the steps to consult with experts around the country in terms of airborne diseases like COVID. So, and what we are doing in New York and New York State, particularly the Bronx at Mount Bethel Baptist Church. And next slide please. Under the leadership of Dr. Kendritch is the fact that we have inaugurated and set a sample of the first virus suppression church. So what does that mean. That means that this congregation have decided that they will participate in a year long study on how to suppress the virus in their church that would mean improving the air quality of the church. That mean improving the protocols, covert protocols of the church. That means changing the aid access them of the church, and that also mean in training modifying behavior. So this congregation of 300 people that will be monitoring throughout this year, starting in September and going to next September, we're going to completely physically reorganize their church. We're going to put in new air conditions that that is close to whatever industry standard to reduce virus suppression. There is, we are going to put in air, air, air, fresh air monitors in the church, we're going to work very closely with the New York State, the PPA, and the New York Health Department to measure effectively how well we do this. We're going to provide training, education protocol. We're going to try PPEs to every member of the congregation. Every member of the congregation will be subject to test once every three months. So every member of the congregation will have about 69 tests by the time a 68 tests, four to six tests, depending upon their likelihood. They have agreed to be vaccinated. This congregation I can proudly say is vaccinated at 98%. And that's in connection with our 100% congregation vaccine program that we launch. And we want to thank J&J for a small grant to make that happen. We also launched the VAX News, which is our newspaper that gives a point by point protocol to our members on how to suppress the virus. So in this particular situation, as we have moved from first phase in terms of controlling the virus and getting the vaccine to the second phase in terms of improving the air quality in our churches, also improving the protocol to suppress the virus. Our point is that if we can take Mount Bethel of Bronx, New York, and install these particular virus suppressant measures that we can share it with other faith communities around the country. And this is one area that the government do not have to be concerned. Of course, we are not doing this on our own. We are consulting with the experts. No one told us to do this. And let me preach this. No one told us to do this. This is a reaction that we have to do as clergy for the betterment of our congregation. And for this situation, it will be the betterment for the entire society. Because if we are successful in suppressing the virus by making, by instituting these measures, I guarantee you large venues will follow our protocol to make sure that they are safe within their venue as well. So we're looking at air quality. We'll be looking at behavior modification. We'll be providing a physical remake of the church AVAC system. We're going to be testing the outside air as well as the inside air. We're going to do a comparative analysis. We're going to follow 300 people for a year in terms of their behavior in terms of virus suppression. We're going to test them. We're going to ask them to wear masks at the church. We're going to reduce singing at the church. We're going to do a number of actions to suppress the virus, and we're going to share that data with the general public. So thank you. And I'll look forward to answering questions along with my distinguished colleagues that I've been able to provide this way. Thank you so much, Reverend Evans. You and your two previous speakers have really talked about the integration of human systems, biological systems and engineering systems, and we have to pay attention to that complexity. I'd like to invite our panelists to join me virtually. So we have Mr. Nick Starchy, who's director of policy at the Royal Academy of Engineering in the United Kingdom. He leads the National Engineering Policy Center. We have Ms. Peg Seminario, the former now retired safety and health director for the AFL-CIO, that is the American Federation of Labor and Congress of Industrial Organizations. And Mr. Dave Rouson, who's the director of the U.S. Environmental Protection Agency's Indoor Environments Division. So if our panelists could turn on your cameras and unmute yourselves. What we're going to do in this part of the session is have each of you take about two minutes to react to what you've heard in the context of your own work or your perspectives in relation to the workshop themes. And again, I'd encourage the audience to register questions on the Slido platform so we can incorporate them into the conversation. So Nick, Mr. Nick Starchy, if you could kick us off with your comments please. Very happy to thank you very much. It's great to join you. So as somebody's director of policy to an engineering organization, actually the first thing I reacted to most positively was what Sandra said. This engineering is a part of the solution, but only a part of the solution and communication with people is really essential. We did a study for our UK National Security Chief Scientific Advisor on how to make buildings infection resilience and what we found. This is actually levels of knowledge about how to manage your building for infection resilience are quite low. And that people simply react to what you complain about very often, and people don't know that they need to understand ventilation. People won't complain about how many air changes are now happening in the building so people do the things which are visible to them. There's no alcohol gel out there make sure the place is clean that reassures people, but they don't know that the ventilation is doing them harm. So I completely agree that both information to the public and also people information for people who are managing the building, who may or may not be very expert. We spoke to people with extremely sophisticated systems, the chief engineering place, but many buildings are operated relatively casually by somebody who's got a different job as well. Giving people just basic engineering habits of mind to assess the risk in their space to understand their space and make sensible interventions are really important. And finally to achieve a really fundamental change in the way our buildings are built and managed. I think we need to take a systems approach so that we fundamentally change the system so that we're in a better place for the next pandemic. That means clear standards. So we're thinking at the design of a building, thinking of it as a place which keeps people safe so that it's infection resiliency is on the radar of regulators. It's quite often it isn't at the moment, and people will have a squeeze but on them for carbon monoxide but they won't necessarily have a squeeze but on them for whether the building is infecting resilient. And finally, we have good education for people. Thanks so much Nick. Peg, inviting you to share your reflections at this point. First, I just want to thank the folks who put this workshop together and then this panel has been terrific and very inspiring so thanks all of you for all of your terrific work. You know, let me just say that working with the unions during this pandemic and you know previous outbreaks, etc. I think the frustration of trying to get action on things that we know has been, you know, incredibly, incredibly frustrating. And one thing that I think is really critical for all of us doing this work right now is, you know, to emphasize that this pandemic is not over the risk is not passed on CDC came out with her new guidelines last week, and said it's up to you as an individual to do this and included in that was ventilation was good that they included ventilation. But what's really troubling here is there still needs to be a public health approach organizational approach and organizational responsibility. And where we need to go is to keep pushing that, and that it's not up to just individuals to do this it's up to those responsible parties to take action. And our job is to help them do that. And as Nick said providing them the information, but the basic tools. I mean, some of this is really beyond a lot of folks, but there are a lot of people out there that want to do the right thing. And so I think we have to look in this space of those that are trying to deal with this pandemic on the ground, and give them the information and the tools. And it's most important to target that to those populations that are really at high risk. We know, as everyone on the panel has said that there are populations and there are groups who have been very impacted in this pandemic and they continue to be. The populations are still predominantly, you know, much higher rates in Latinos and blacks here in the United States and that's going to continue to be the case, because those people are still the most exposed, the most at risk and have the least control over how to manage their health. And so it's our job to basically target some of these efforts, not only outreach, but also the, you know, the practice into those communities where it can make the most difference. So again, thanks to folks and it's great to be with all of you today. Thanks so much, Peg. Dave, we'd love to hear your reactions and your commentary please. Monica just briefly by way of introduction again. I am the director of EPA's indoor environments division. And so as I participate in today, you'll hear some flavor of me speaking as a as a member of the of the federal government and sort of how how our role plays uniquely in the coven 19 response and and other efforts to try and improve the built environment to prevent airborne transmission of pathogens and other pollutants, although I'll also be speaking generically as a as a member of the greater public. My division is responsible for non regulatory guidance for homes, schools, offices and commercial buildings. And as we've been engaged along multiple fronts, I think one of the things I want to emphasize is is the unique opportunity to exist now, I think to dramatically improve general public understanding of folks in their homes as well as all the different entities that that as, as Sandra was mentioning impact the built environment, the critical role that indoor air quality plays in health and well being. There's a unique opportunity here to scale up proven engineering controls and practices to fast track innovative research and development. To mobilize public and private assets to make sustained sustained improvements to indoor quality, not just a once in the moment change to help address the COVID pandemic, but long term sustained improvements in the built environment. We've heard throughout this workshop significant public health gains can be achieved by improving building ventilation filtration and air cleaning. And those kinds of improvements are not only a critical component of addressing the SARS COVID to virus, but well managed IQ has multiple co benefits. Not just airborne viruses and other passive pathogens but also reductions in PM volatile organic compounds and other pollutants and buildings, resulting in a range of important health performance productivity and economic benefits, including children's education and, and life quality of life improvements over the long term. And where we sit. It's, it's, it's apparent to professional organizations, HVAC related industries trade unions. They've been on the front lines building owner managers facility managers. They're doing things to mobilize resources to help those responsible for operating upgrading maintaining buildings. When we send the federal government the early signals are the federal funds that came through the American rescue plan are being used to support ventilation and other indoor quality improvements there's encouraging action there, but there remains important and significant work to do to help the schools and other buildings improve indoor air and as we were saying earlier to educate help and support families, particularly from an equity perspective to improve ventilation indoor quality in their homes. Great thanks so much for sharing those comments and reflections. I'm going to pull some of our pressing questions from the audience. And what we start with Nick. What regulations or incentives are used in the United Kingdom to improve operations and maintenance of buildings, so that they perform up to standards. It's a great question. And it might be useful to think about the different life stages of a building and doing that in the design stage, the construction stage, and in use. We're working the performance of a building in terms of ventilation and keeping the population within it healthy flies under the radar we're working with BSI or speaking with the BSI, which is the main standards body in the UK about whether we can develop some more meaningful standards on infection resilience so they can be embedded into the design of buildings because at the moment there's a paucity of standards so you know what good looks like in the first place. So building regulations cover the design and construction of most buildings in the in the UK. There are things about health in the building regulations, but we think it can be made very much more visible. So there's an explicit responsibility to construct a building which has a functional requirements to provide an adequate indoor environment for the inhabitants, and to pull that out and make it an explicit part of the building regulations at the moment it's quite scattered. So building is in use, quite often local authority inspection is what keeps it being used properly, and there's a need for in use regulations, so that local authorities know what they're inspecting against, and so that the performance of the building in terms of ventilation in terms of the general health the occupation, the occupants is a higher priority when the building is inspected. Thanks so much and I'm going to invite peg into this conversation we just heard sort of a United Kingdom. presentation, but peg you've been a thought leader in occupational health and safety for a long time and know the importance of productive regulatory system so I was wondering if you might give us a US perspective. I think the approach should be similar here to the US is what Nick has laid out. The question is how do you do that and get there, because we have both a federal system and we have a state system, and we also have a system of codes in this country. So I think we have to look and identify, you know, in each of these areas here as to what kind of standards of be very clear as to what we're talking about here as far as, you know, the take the recommendations and turn them into requirements that are focusing on some of the new buildings going on. I think we need to look at that also in the context of all the money that's going to be coming into energy efficiency decarbonization, and link that up. And I think, importantly, how do we deal with the existing building stock, and particularly in those areas where we have buildings that have no ventilation but so ever. You know, there are regulations and regulations in this country have been what have moved environmental protections, whether it's the general environment, air pollution, the workplace and so I think we need to think about what kind of regulations. And in the workplace, I think we could develop those regulations. Because there's been a lot of pushback to having anything mandatory in place so I think we have to get over that hurdle, the recognize that we do need standard