#15.1 - Cath Noakes: On the Frontiers of Air Quality and Disease Prevention in Buildings

Part - 1

Professor Catherine Noakes is a chartered mechanical engineer with a background in fluid dynamics.

She is the Pro-Dean for Research and Innovation for the Faculty of Engineering and Physical Sciences at the University of Leeds where she leads research into ventilation, indoor air quality and infection control in the built environment using experimental and modelling-based studies. 

From April 2020- 22 she participated in the UK Scientific Advisory Group for Emergencies (SAGE), where she co-chaired the Environment and Modelling Group sub-focusing on the science underpinning environmental transmission of COVID-19. 

She has also contributed to numerous advisory and working groups including with WHO and as part of the working group for the Royal Academy of Engineering work on Infection Resilient Environments. 

In 2021, she was awarded an OBE for her contribution to the COVID-19 pandemic response, and in 2023, she was awarded the Royal Society Gabor medal for her contribution to interdisciplinary science in understanding the transmission of infection.

We discussed as you would imagine, her work over the last few years and what the built environment can take away from this global pandemic. We talked about risk, air cleaners and her experience as a domain expert suddenly thrust into the pandemic's whirlwind.

Cath Noakes - LinkedIn
Cath Noakes - University of Leeds

Christmas Lectures - Going Viral

SAGE


 

Transcript

Simon: 0:14

Welcome to Air Quality Matters, and this is a conversation with Cath Noakes. Professor Catherine Noakes is a chartered mechanical engineer with a background in fluid dynamics. She is the protein for research and innovation for the Faculty of Engineering and Physical Sciences at the University of Leeds, where she leads research into ventilation, indoor air quality and infection control in the built environment using modelling-based and studies. From April 2020 to 22, she was a participant in the UK Scientific Advisory Group for Emergencies, sage, where she co-chaired the Environment and Modelling Group, sub-focusing on the science underpinning environmental transmission of COVID-19. She has also contributed to numerous advisory and working groups, including the WHO and as part of the working group for the Royal Academy of Engineering work on infection resilient environments. In 2021, she was awarded an OBE for her contribution to the COVID-19 pandemic response and in 2023, she was awarded the Royal Society Gaboor Medal for her contribution to interdisciplinary science in understanding transmission of infection.

Simon: 1:39

We discussed, as you'd imagine, her work in the last few years and what the built environment can take away from this global pandemic. We talked about risk air cleaners and her experience as a domain expert suddenly thrust into the whirlwind that was this global pandemic. Kath is such a down to earth, easygoing person to talk to. I always enjoy our conversations and this was no exception, as always. Thanks for listening. This is a conversation with Kath Nokes, so what do you think has been the biggest takeaway, then, for the built environment from this pandemic, kath?

Cath: 2:24

I think it's had a really massive impact in both positive and some less positive ways. On the more positive side, it has massively catapulted end or air quality and ventilation of the agenda. I don't think I've ever seen so many people talk about ventilation. We saw it in the National Press. We saw it in conversations worldwide. It made its way into scientific communities all across the world People who've never thought about ventilation before and that made it to some of the highest levels. There was a point where the Prime Minister said ventilation. I wasn't very proud of much during the pandemic, but it's taken little wins. I think that has taken something that was already a growing topic, particularly in direct quality, but it's just accelerated the conversations and it's got many more people in that. Before this I was one of these weird people who worked on some niche thing around airborne infection and now it's now mainstream. So I think that's massive positive.

Cath: 3:33

I think the bit which is perhaps more of a challenge than a negative is I think it's exposed just how much we don't know. It's suddenly got us thinking about buildings and their ventilation. There are people in quite senior levels who say how many buildings in the UK have good ventilation? My answer was? I really do not know. It's just it really got us recognising that we know very little about the vast majority of buildings. There are studies on certain sectors there's probably a little bit more on housing, possibly a little bit more on schools. There are whole sectors where there's almost no knowledge whatsoever, nothing published, and even what is there is really patchy. And then you also realise there's these vast numbers of buildings that don't have a properly designed ventilation strategy in any way, shape or form. And so, yes, we have building regulations, we have standards, we have guidance and things, but that's just. You know, there's huge numbers that just don't even touch on it. We don't have any form of ways of doing compliance or enforcement. So I think it really brought all of that out in the open as well and made us start to think about buildings as part of.

Cath: 4:55

You know, we talk about sustainability In some respects, we talk about safety, but we've not really talked about healthy buildings properly in an open conversation outside of a sort of subset of scientific communities. And I guess the third thing I think it has done is brought different scientific communities together to talk about this. So there were, there always have been people who've worked in these areas. I think some of them have kind of, in some respects those people have always collaborated reasonably well but I think it's taken those people into bigger conversations and I think it's taken, you know, it's enabled conversations beyond the sort of the core physics, building science, aerosol science, piece around ventilation and pollutants, to really start to think about, you know, the social side of that, behavioural aspects, the economic piece and the complexities of it all. You know we can try and pretend ventilation is simple, so some respects, yes, can be, but it's actually not very simple. The physics of it is very complicated and it's massively influenced by what people do in their buildings.

Simon: 6:16

I landed a rather unfair question on Francesca Brady, who kind of manages air rated. It's an air quality standard, if you like, for the workplace predominantly and I asked her the question, like if you were, if you were writing the script for the development of air quality awareness, notwithstanding that nobody wants a global pandemic, would the pandemic have been in there for the recognition of air quality or not on the whole? And her response was probably not, because she felt that it was ultimately more of a distraction in the end, that it sent people off down rabbit holes and down dead ends that were often unhelpful, and we were starting to build up a narrative of healthy workplaces and the business case for air quality. So it was a question I was keen to ask you the same writing the script of the last back, if you're, in 2019, writing the script for the next three or four years, just from an air quality perspective Again, I say nobody wants a global pandemic Would it have included COVID for awareness or do you think, on balance, it's been more harmful than of benefit?

Cath: 7:36

So actually, I think it would have been in my script and I say that, I suppose, because I'm somebody who's always worked on airborne infection. That's been my focus area, so I guess it would have been, and even to the point that I remember putting in a grant application in 2008 and going to the interview for this, and my pitch was, you know, imagine a global pandemic sort of thing why we need better ventilation in buildings, and that was for hospitals more than public buildings. But you know, yes, I think it was in that, in terms of the harm versus good, I think you write the worst and rabbit holes, and I think one of the biggest ones that we could have spotted a bit sooner is explaining ventilation better to people, because we, you know, we encouraged people to ventilate and for the vast majority, particularly at home, the only thing they could do was opening a window. And whereas we know, you know, ventilation through opening a window in some circumstances can be incredibly effective it can be the most effective thing you possibly do In other circumstances it can be completely useless and it barely does anything. And I think, you know, on balance, opening a window is going to usually be a good thing to do, but it you know, we know that it doesn't work in the winter, we know it doesn't work in poor weather conditions, we know that certain flow flow, thermal conditions it just doesn't work. And I think what we've inadvertently done with in part of that is create a bit of a narrative that says ventilation equals a window and actually it doesn't at all. And, to be honest, the best ventilated buildings usually have a mechanical ventilation system of some description, because we know that that's reliable and it's not very resistant, etc. And a well designed mechanical ventilation system for the most part is probably going to do a better job.

Cath: 9:49

I think the other challenge where around air quality is, of course, the pandemic focused very much on an indoor source of microorganisms from people, but it didn't really think about the bigger picture of air quality. And when we're talking about indoor air and buildings, we have to think about all of those sources. We have to think about the indoor sources, we also have to think about the outdoor sources and there will be trade-offs. You know it's. Unless you've got endless money.

Cath: 10:21

It is very challenging to create a perfect environment and especially if we're talking about retrofitting existing properties. And with the best will in the world, however much. We know that schools need better ventilation, hospitals need better ventilation, lots of workplaces do. People do not have the money to invest in those things, so we will have to figure out ways in which to get balances in there and that balance won't be perfect.

Cath: 10:47

But we do have to think about when it's appropriate to shut the windows because of your outdoor sources, when it's appropriate to deal with the indoor sources when actually ventilation is not your solution. You should be thinking much more about source control and things and thinking about that bigger, wider range of pollutants and again, I think it's helped that conversation. You know, I'm delighted that, for example, our chief medical officer in 2022 wrote his annual report on air quality and included a massive section on indoor air, and we were very privileged to be asked to write some of that and we were asked to focus on solutions, so we got some of the engineering pieces in there which often are missing from the more health facing type of documents.

Simon: 11:36

The second note I made when you started there was about what we don't know, and it made me think that one of the things that are an acute event causes, an emergency causes, is that we're forced to take a position on something. One of the downfalls of air quality, if you like, is this long-term esoteric problem that we can ignore. It's invisible. It possibly has some impact on us at night, but whatever. Whereas the pandemic forced us to take a position, not only on risk how risky is this? How much do we need to worry about this in this particular circumstance but it forces us to take a position on everything else as well. How good is the ventilation in our assets? How do we fix that? What would a roadmap look like? What is the cost-benefit analysis of going that? So it forced everybody to take a magnifying glass to the whole process, including how do we communicate this better? The first time ever governments have had to communicate at a big scale on air quality well, I guess since the smogs in London or something. So I think that's been the really interesting transition.

Simon: 13:00

It's not that we don't know a lot of stuff. We've never been forced to take a position on any of it. It's always been academic for the research required type positions. It's never been right. Okay, kath, I'm holding a gun to your head, yes or no? What's the solution here? That's an uncomfortable place to be, isn't it? In that world?

Cath: 13:22

It is. It is, and I think we have to be really careful that we don't end up in the political world of living by sound bites and trying to simplify everything, because there are some fairly straightforward messages that we should be giving around ventilation and indoor air quality and, absolutely, education is a massive part. This education for the public, education for professionals, education for policymakers, understanding the mechanisms that we can use to reduce sources, the mechanisms we can use to improve ventilation and things. But we also have to, you know, and we have to find a way of balancing that sort of simple messaging with recognising the complexities and certainties in it. You know, there is no one size fits all solution. Every building is different. The solution for every building is going to be different. And just because a technology works well in one place doesn't mean it will necessarily translate and work well in another place. And I think I mean you sort of touched on better, go and do some more research. I think we still do need to now, maybe. Maybe I discuss on bias as an academic that we always want to do some more research, but I think that research we don't. We do have a lot of knowledge, so we need to build on it and I think there is.

Cath: 14:47

I think there's some very practical real world understanding that we need to really understand how you know when solutions are implemented. Does that, do they work in practice? If they don't work in practice, what limits have those them working in practice? And I think you know, traditionally, you know, research funding in an academic context focuses quite a lot on novel science. Yet actually here it's much more about implementation and demonstration. And I think interesting what we have seen and I don't know if this is worldwide, but certainly in the UK there is a move for some of the funders to be looking more holistically at this and I think that's a really good move.

Cath: 15:40

So there are grant calls.

Cath: 15:42

I mean, there's a grant call out at the moment that we're responding to around health impacts of net zero in buildings and that's a really good opportunity to explore the practical aspects of it.

Cath: 15:56

Rather than thinking about, you know, can we develop fundamental new novel technologies? It's about how you look at sort of perhaps a whole systems type approach and think through well, if we put, you know, net zero retrofits into buildings, how does that have knock on effects around health? How does that have a knock on effects around societal behaviours, etc. So I think there is some really good shifts here and I mean one of the really nice things to see is that the community of people who are working in this space, which has grown, are very open to working together across a huge range of different, different discipline areas to try and tackle some of these things and working, I think, increasingly more collaboratively with you know, policy partners and practitioners as well, to enable this to have you know, to have to research there are research gaps and we need to answer some of them but to enable those to have a real practical impact on things.

Simon: 16:59

And that, suppose, again, was another thing about an emergency is. It's not just about knowledge, it's about implementation and outcomes. You know that this is being done to create a benefit and that's that's one of the advantages of this, this kind of new multi disciplinary era, really is that. I think COVID probably smashed a lot of those silos up it out of necessity that you couldn't just have knowledge without understanding how supply chains or practitioners were going to implement it in a way that was going to be effective. All of that stuff had to come together, didn't it? Very, very quickly, do you think? Do we think, those doors are going to stay open? Is your sense now that this collaboration that we saw during the pandemic has held to some degree, or have you started?

Cath: 17:48

to see people creeping off. I think just some degree. I think the the stings that happen during the height of the pandemic have obviously dropped slightly, because I mean it's inevitable that the emergency challenges have dropped off. You know, it doesn't that doesn't mean the disease has gone away. It's still there and there's still posing huge issues in hospitals and in work absences, long term sick, etc. But it the sort of emergency side has dropped off.

Cath: 18:21

I think where this is perhaps going to become more on a more on a sustainable footing is that bigger picture piece, because I think it's not just the pandemic that's made people realise about indoor air. There's obviously the very side case of our Bishack in Brochdale who died of mould and flat. We've we see increasing awareness about indoor air quality and its impacts on health and, I think, better evidence. You know, one of the real challenges with evidence is we can say, oh, yes, we've measured stuff and it's it's at a high level and it's not very good, or your ventilation is poor. But actually evidencing that that has leads to health impacts is a really hard challenge and we need that evidence because without that it's very hard to change policy. But that evidence is starting to appear now, I think, and I think those that it has sort of catalyzed groups of people to work on some of those issues.

Cath: 19:25

And I think you know it's quite interesting to see that you know huge numbers of papers and things published during the pandemic. You know some of which I probably will never read others which are fantastic, and I think it allowed us to really advance some of our knowledge, you know, particularly thinking about how respiratory particles move in an environment, how you can then use that to calculate risks, how you can use it to explore the uncertainties in that and the variabilities in that, and and also recognizing in there that you know ventilation the indoor air was only one part of the mitigations. You know you can have fantastic ventilation but if you're a meter away from somebody and you're having a long, protracted conversation with each other, frankly the ventilation is not going to be your answer there in terms of transmission. So it was about us understanding all those real complexities and yeah, I mean it's hard to communicate all that, it's hard to understand all that, but I think yeah, I really do hope that some of that is some of that learning is still there.

Cath: 20:35

I think the other thing it's opened up is some big international conversations around things like standards for buildings, you know, in terms of ventilation standards, including indoor air quality standards, that recognition that. Well, basically, we have very little in the way of indoor air quality standards and what we do have is usually very specific to certain industries or, you know, very hard to implement. But even things like ventilation standards, you know we can see that there's been conversations around the world about what should that standard look like? What's the right, you know? Personally, I think that we should be figuring out how we comply with the current standard before we worry too much about should this be a higher number? But I do think it's an important conversation because that conversation allows us to set where best practice goes, and if you can improve on best practice, then it moves everything with it.

Simon: 21:31

Yeah, and I think standards are both separate to the conversation of quality and outcomes, but also inherently linked, and I think they both have to. They both have to work away in parallel and in joint venture. You know, you're absolutely right. We know a lot of our problems would be solved if we just met the standards we already have. However, that shouldn't slow the progress of standards like 241, for example. That pushes the boundary conditions of some of those standards. It says, right, okay, we need to start thinking about a different way and build modalities of buildings in certain conditions need to change. So I think both are really important. It's the, it's that smashing together of communities I think has been the real positive outcome for me that we're having conversations with people that we've never had conversations with before and you start suddenly see things through a different lens. I mean, everybody now has a bio aerosol lens they never had before.

Cath: 22:36

Absolutely.

Simon: 22:37

That strange lady that turned up at the conferences and talked about germs all of a sudden has a new level of authority in these conversations. It's amazing how that has shifted. The big thing for me. One of the things I wanted to chat to you about was the perspective of risk. For the first time ever in this uncertainty, we had to take a position on things. One of the areas that seemed to be, or one of the disciplines that seemed to be able to cope with that best, was the occupational health, the occupational hygienists, the people that have understood how to handle risk for years and frame it and talk about it in a way and make decisions. With everything that comes with the uncertainty of risk, people's tolerance of risk, people's perception of risk, how it changes over time. They were enormously well equipped during the pandemic I found, to navigate this. Did you find the same? That all of a sudden hierarchies of control became a thing?

Cath: 23:46

I never thought I'd be quite so excited about risk assessment but, yes, you're right, I think that did come in.

Cath: 23:52

And hierarchies of control is imperfect For respiratory disease because it is designed more for chemical hazard or something, but as a starting point on a framework to get us thinking about the fact there are different levels. So, yes, if you stay at home you've pretty much eliminated the risk. But that's largely not practical most of the time, except we're in the most dire bits of an emergency. So how do you do those different levels of risk analysis? And I agree, I think that was a really good framing and I think people like British occupational hygiene society they played a huge part in helping those conversations, particularly helping businesses explore how to manage risk, how to put in mitigations, recognizing that you need layers of mitigations. You can't just do one thing, you have to think about different, the Swiss cheese model piece. And actually I think when we go back to talking about communities and disciplines, I do think the sort of ventilation and indoor air communities have not quite fully connected with the occupational hygiene communities yet I think those communities are closer together now. They've always been an overlap but I think that overlap is bigger. But I think there's probably still more we can learn from each other's perspectives on that. And yeah, risk, I think, is a really important thing to think about. It's, you know, at some point you have to have what's the tolerable risk and that tolerable risk is going to be different for different people. And recognizing that, having that conversation about how you manage that and what does that look like in different settings, when are we willing to take more risk, when are we willing to take less risk that, though, all those conversations happen.

Cath: 25:50

I think from my also research perspective, there is something about the quantitative aspects around risk. You know, because we did quite a lot of research, we were quite lucky, we had a number of projects during the pandemic and actually before, which we're looking at some of these things and so trying to use something called quantitative micro risk assessment, which is a bit of a mouthful of a tool, but it's a way of actually taking sort of the physics and the biological aspects, wrapping them together and thinking, well, what might that look like in terms of somebody's exposure and somebody's chances of infection? And it really starts you thinking about. You know, it's very easy to say, oh well, ventilation is always the answer, but it might not be so, for example, if you're on a bus. You know we tend to go oh, the windows aren't open. It must be really bad. But if you're only on that bus for a few minutes 10 minutes or so your biggest risk is actually sitting next to somebody who's infected, whereas if you're sharing a classroom or an office or or even a train or something for several hours, then your risks start to go up from a, you know, an airborne perspective. So thinking about what might be the relative, the most important mitigations in different settings in terms of people's exposures and how that works out, is really important, and I think there's also interesting things there about how this plays out with different diseases.

Cath: 27:22

So if we look, for example, at COVID, covid was incredibly hard. The virus that causes it so does. Covid too was really hard to sample from the environment. It was very rarely found. When it was, it was tended to be in hospitals where there are high numbers of patients. We got better at sampling through the pandemic because those techniques improved, the culture techniques, the methodologies etc. All improved. But we found really quite small amounts of it compared to, say, other things like flu or whatever, but clearly it was incredibly transmissible. So that really starts to tell you that you need very small amounts of it to become infected. As a sort of contrast, you know there are some other other diseases where maybe you can sample in the environment. You can find huge amounts of it, yet you see very little transmission, which perhaps tells you that you need a lot less sorry, a lot more to become infected.

Cath: 28:21

So, even though you might find it in the air, it might not pose anywhere near the same risks because you just don't inhale enough to become infected. And I think we don't fully understand all of that yet. There's a lot of work still to do there around understanding the exposures and the actual infectious doses and dose response, as I say, for how these different pathogens work and how our environment changes that. And, of course, remember for biological stuff it is biological. It doesn't survive forever, so that infectivity drops off and that infectivity is affected by the environmental conditions as well. So there's this whole massive interconnected set of things that determine risk, which we have some of the tools now to calculate, but we have still got a lot of gaps in data to actually put some real numbers to it that we would be really confident over.

Simon: 29:22

I'll probably butcher Ben Jones's comment, but it was something like we can with 100% certainty say now that your chances of catching COVID, according to our models, are somewhere between zero and 100%. And it was. It was ingest. But I think I think the interesting thing about COVID was that it tangibly demonstrated the complexity of risk to people, because they could, in plain English, understand all of these confounding factors, that some people are more susceptible than others, some people were in a space longer than others, some people would receive more of a dose than others. You might have one kid in a classroom that's infected, you might have eight. Your classroom might be big or small, might have good ventilation, bad ventilation. You know like, and it goes on and on, and on and on. Like. The complexity of understanding an outcome is really hard in air quality.

Cath: 30:25

I think one of the things that made it even harder for COVID was that we know that super spreading played a part in that. So you have a small number of people who could infect huge numbers of others in a very short period of time, but you've no idea who those people are and actually when we did, did risk models on this. So one of the parameters you put in is the viral load of the infected person, and yet the data we've got around, which came from the national data around swab tests it varies by about 10 orders of magnitude. So you can just see that this number doesn't matter. Your ventilation moves over like one order of magnitude and this number goes over like 10 orders. So you just see this totally dominates any calculations you do and it becomes really challenging. And we probably know that that boundary is not that big, but we don't quite know how to narrow those down yet. So it's yeah, there's still a lot of work in there, but I think we've started to think about how you explore that in a lot more detail.

Simon: 31:30

I guess you see a lot of the translation of what we've learned and how we started to talk about this, then filtering into the more broader air quality conversation, because we have the same challenges framing risk when it comes to exposure to cooking pollutants or traffic pollutants or, as we were just talking about our Bishak and exposure to mold spores and concentration damper mold.

Simon: 31:56

It's going to be interesting to see how that journey translates now.

Simon: 32:01

I think we've found some ways of better articulating some of the complexities, and one of my favorite at the moment is that, regardless of the nuance and complexities of the inputs, ultimately in most built environments the levers that we have available to us to pull to affect an outcome often are only a handful, and that's background ventilation, local exhaust ventilation, source control and administrative controls, knowledge and education and training, perhaps with the addition of air cleaners as well, tacked on. But really actually as complex as all that stuff is sometimes, we're better off framing it in the from the perspective of the levers you can actually pull the stuff that's within your control to affect an outcome, and that's where it goes back to your point about it's not being very good at doing what we should be doing anyway, and that is, providing adequate ventilation and decent local exhaust ventilation. We just got that right. We'd at least be able to park the ventilation bit. But I think the challenge of the pandemic was everybody very quickly realized we weren't really doing the basics very well, which meant it was just another layer of uncertainty into every built environment.

Cath: 33:23

I mean, I think one of the challenges is, in a way, it's a little bit unfortunate but that we had cost of living immediately after the worst of the pandemic, so we're now trying to learn to live with a virus. Well, people are going back to society at a point where everybody's now really concerned about their energy bills. So I think we unfortunately in a lot of places people unlearn things far too fast because they prioritized shutting the windows and keeping the heat in and that then really again goes back to exposing the fact that we don't have adequate environments and the levers that we've got are really quite limited. I think there is a lot more we can do around helping people understand those levers in different spaces and there is a big education piece in there. Some of the projects we've worked on have looked at doing that.

Cath: 34:19

So a really nice example is from a university of Sheffield which Abigail Hasway has done as part of a combination of our Protect Study that we had and our Future Urban Ventilation Network and some other work that she did.

Cath: 34:33

It was with the City Council there and they worked to look at ventilation in hospitality venues. So they were going in bars and restaurants and nightclubs and things and put into both a combination of doing some measurement but also to find out some of the barriers and the motivations around that, and there's all sorts of complexities. Now, if you're a nightclub, well there are some weird things about atmosphere being part of it, you know, being hot and sticky. But there's also some really practical things you know, like if they throw open all their doors, you know they tend not to have windows but then they have issues with noise and then they get shut down there. But that work ended up with some really practical guidance for environmental health officers. That then you know we've had a huge engagement with that around providing that information to businesses. So there's, you know there's some really nice ways in which we can show we can do it, but it takes time and effort and we need to expand that all further into many more settings.

Cath: 35:38

Yeah, you can't, I also want to wave a flag for maintenance here as well because I think you know we, we're we're.

Cath: 35:46

You know lots of people talk well, we can't afford new ventilation, we can't afford to do this, but we're rubbish at maintaining our buildings. You know, we paint windows shut, we don't we. We block things off, we tape over grills, we don't maintain HVAC systems, dampers don't work, etc. And it's basic and we really should be waving the flag and saying you know, and perhaps this should be part of risk assessments in buildings, perhaps this is something where people like building safety regulated come in eventually, which is actually showing that you have done the, not just the basic minimum ventilator, but you are. You have a proper plan for how you maintain your building which includes ventilation, because you can't get away with it with gas, can you? You have to maintain, you have to maintain combustion sources and heating and things like that.

Simon: 36:40

Island's a good example of that. The, the Health and Safety Authority in Ireland, have released released the code of practice for indoor air quality in the workplace, and it's a fairly benign document on the face of it. It provides some very basic knowledge of what air quality is in the workplace. It talks about what adequate ventilation should be. It's nothing outside the bounds of simsie guidance or ASHRAE guidance for litres per second per person. But buried within that document is the very reasonable request that at least once every couple of years you should provide evidence of the performance of the ventilation system in the workplace, the. The bombshell within that is nobody's ever looked at the ongoing performance of any ventilation in any workplace ever that every single one of them has just been run to failure. You get air conditioning surveys that check the, the F gas and do that.

Simon: 37:38

But nobody's gone in and measured. If the the the meeting room, is still delivering 10 litres a second per person and and the hidden trip wire within that standard is now slowly those organisations, at some point the Health and Safety Inspector is going to be on that premises and we'll go. You know, can I see your fire drill? Great Thanks. Can I see your ventilation assessment please? And they'll go. Your ventilation, what now? And? And so that will bring that to the fore.

Simon: 38:07

And, speaking to some colleagues in France about it, they've been looking at how you implement these ongoing monitoring of ventilation system in non-residential settings and they've largely concluded that unless you catch it at new build, it's basically a waste of time. No ventilation system has ever been set up to be checked that and probably we're going to end up having to do it through low cost monitoring, you know, environmental monitoring, checking things like CO2 levels and things to try and get an idea of performance, because practically most ventilation systems have never been set up to be checked on an ongoing basis and it just shows the value that we place or did place in ventilation and hopefully that will change. You know, would be my hope.

Cath: 38:54

So yeah, I mean you touched on monitoring there. I think really that's that has to be one of the parts that play in this, and it's not straightforward, even that, you know it's. It's very easy to put a CO2 monitor in somewhere and go hey, look at these numbers. It's much harder if you say don't use that for some form of regulatory purposes, because you have to then think about specification of the monitor, specification of its location, how many times you're able to go over whatever limit it is, for whatever reason, etc. Although I mean I say in Belgium they've, they've implemented it or are implementing it. So there is a move there and I think you know again we talk about positives that have come out.

Cath: 39:38

One of the changes that happened as a result of the pandemic was the UK building regulations were updated. They do explicitly in their highlight airborne transmission and infection. They explicitly state higher ventilation rates in certain spaces, including places, for example, like performance spaces, where people might be singing or people might be more active. And they also do state the need for and or monitoring in certain places, I think offices particularly. And now you know it's. It's baby steps in some respects because of course that applies to new builds, but hopefully that does filter through into best practices we go forward.

Cath: 40:25

I do think that retrofit is something that really needs to be looked at and this was like we did a lot of work with Royal Academy of Engineering on. We have this big piece of work called infection resilient environments which looked at, looked in the first phase, just looked sort of in the middle of the pandemic about what was needed, but then had a sort of second phase which looked more strategically and you know, the one of the big things that that picked up was was around, as well as sort of enforcement and compliance, was around retrofit and how we we make sure that that. You know, we we make sure that standards are there for retrofit and that that we have the right things happening and that that ties into net zero policies, because I think there's a massive risk that people in their rush to make buildings more sustainable basically screw up the internal environment at the same time.

Cath: 41:25

Yeah, for sure that's a technical way of saying it.

Simon: 41:28

Yeah, I posted something on LinkedIn the other day with a house in a sealed, airtight bag, saying, in a rush to seal our homes from the cold, let's not forget we have to live in them also. And it blew up a bit People going that that's a dangerous kind of picture to paint, but I went. Well, it's kind of true. You know we do. We do seal up these buildings from an environmental perspective, from an energy perspective, and haven't in the past thought about ventilation very well. And the reality is and we've seen it with the cost of living crisis that nothing beats no ventilation for energy efficiency. You know people's instinct is to hunker down and close things off and shut stuff down and you know, keep the heat in, but there are unintended consequences of that, you know.

Cath: 42:16

Which I always say my greenhouse is, is a really sustainable building. You know it uses no energy whatsoever. I pretty much hate to live in it for many reasons.

Simon: 42:26

Yeah, and you know a lot of work I do is with kind of strategy work with housings and housing organisations, and one of the things they're having to get their heads around now is strategies around ongoing maintenance and budgeting For, rather than it just being a run to failure strategy for bathroom fans, that they actually now have a plan for the replacement and assessment of performance of systems, because for the first time ever, it's another result of an emergency. The conversation dampen mold emergency, as we see it at the moment following the death of our Bishak, is they're now going to have to stand over the performance of ventilation systems for the first time ever Rather than just does it make a noise? Yes, we've got a bathroom fan Now for the first time.

Simon: 43:17

Somebody's probably going to ask the question is it delivering a whole house rate? Are we delivering flow rates in accordance with standards? Because the governance board of the housing associations being drawn across the coals now if it doesn't. So it's a very interesting dynamic to see shift from a shift from product specification replacement like for likes to actually specifying a performance and saying, right, what should this building actually have and how do we make sure it delivers? That is a really big shift in focus and I think that's another thing the pandemic has done is shifting people to going well. It's no good saying we've got a window. Is it doing enough? People want to know yes or no.

Cath: 44:05

Absolutely. Yeah. There's a much bigger question than that. It's a mindset shift as well. And then I think, as well as I mentioned maintenance, I think we should be thinking around installation, commissioning and training. For who does those? How do you make sure things are done right? Because an awful lot of things are set in stone wrong from the word go, not because the design was wrong or because a wrong choice was made, but because it's not been implemented correctly.

Simon: 44:42

Yeah, or it's just the perspective is slightly off, which means you don't get the outcome that you don't get the benefits yeah.

Simon: 44:52

How did? How did you find it as a domain expert or a sector expert, being thrust into the centre of an emergency in the way that you were, because I kind of joked at the strange germ lady appearing at conferences, and I mean that in nice as possible terms, you found yourself, as a domain expert, suddenly pivotal in pulling together, being the glue in the middle to a lot of these interdisciplinary perspectives. How did you find that personally? Because, like you, were right there front and centre for a good couple of years, weren't you?

Cath: 45:36

It was, yeah, it was a very weird experience. It was, yeah, it's a really hard one to say. Even now I don't know if I fully processed the whole thing and I don't know how long that takes to do. I mean, I was thrown in. I was properly thrown into it in April 2020 when I was asked to do a paper for SAGE so the Scientific Advisory Group for Emergencies in the UK and then asked to set up a subgroup of SAGE and to co-chair that subgroup, and that just it was a whirlwind.

Cath: 46:14

After that it was sort of before that I'd actually been involved in some discussions with hospitals and we'd done a little bit around how do you repurpose spaces in hospitals, how do you look at the ventilation, think about oxygen, all sorts of things there. But this just like threw it straight in and it was a real insight into the sort of scientific evidence requirements that are needed to inform an emergency and I mean it was incredibly hard work. We had an amazing group of people who we had. I mean, just to give you an idea of the timeline, I first was got an email I think it was the 7th of April. We were asked to put a paper together for the 14th of April and the Easter weekend was between those two. So we pulled this paper together, myself and colleagues at Leeds, to just and at that point the evidence around COVID transmission was certainly what was in the public domain was really patchy.

Cath: 47:14

There were some very early studies in pre-print out there, but just about everything else we had to draw on what we knew about other respiratory diseases, sars, influenza, etc. And what we knew about things like the physics of particles, ventilation. So we were thinking there not just about air and ventilation, we're thinking about the whole thing, including close range larger droplets as well as inhalation of smaller aerosols, thinking about surfaces and contamination. And really at that stage we couldn't take anything off the table because you knew that there was a massive gap in the evidence, so trying to think about anything possible. And then, of course, we then created a group within another week and published another paper within a week after that. So it was just a phenomenal amount of work with an amazing group of people in a very short period of time.

Simon: 48:20

And for context, so April going into Easter, we're in the height of the sliding to lockdown. At that point we were in lockdown, so we went to lockdown here on the 23rd of March.

Cath: 48:35

So this was, and a lot of the questions at that point from policymakers were starting to think about. Well, what understanding, transmission in the environment because of what do we need to put in place for when people do start to come out of lockdown? Were you already starting?

Simon: 48:51

to think about that at that point, because my memory of the March-April period was everybody had Italy in their foremind about how bad could this get, and it was this flattening the curve, trying to just slow everything down so that we can find a level that the systems can cope. And different jurisdictions had different stressors because of what they kept their own capabilities. So Ireland had almost no ICU beds.

Simon: 49:24

So, our panic to flatten the curve was out of pure necessity. We were running out of beds really fast, so there was that going on, but you were saying even then you were starting to say, right, okay, because this is unsustainable. Complete lockdown for more than a few weeks. How does this trajectory look like out the other side?

Cath: 49:45

Yeah, so there are people who were. I mean, I wasn't directly looking at that, but there were people who were looking at what the trajectory might look like and then looking at that practicality of well, both when you come out of a lockdown, but also not everybody could lockdown, the people who had to carry on working had to carry on interacting. How do you enable those environments to be safe? So one of the roles I guess the biggest role we played there was around the evidence base, Evidence from policymakers around what we know and what we don't know about different mitigation measures, about transmission, et cetera, and of course it's an emerging evidence base. It's a hard one to put together.

Cath: 50:34

There's a massive set of uncertainty in there and I think there was a bit of a feeling At the beginning I think you sort of almost just jump in and try not to think about it too hard but over time there was that growing awareness that we there was a big responsibility because the things that you said scientifically, where you had evidence and where you didn't have evidence, then played out into policy. So to be absolutely clear, we never made policy that's the decision of the politicians to do. That's way above my, my grade. But you're aware that the evidence that you provide has an impact on those decisions and therefore there is quite a big responsibility to think, well, have we got this right? Have we got this as right as we can?

Cath: 51:32

And there may have been times, I think, when you've got some good instincts and things, but you can't write evidence on good instincts. You have to write down what is known and where the uncertainties are, and that then plays into it. So I mean, I think the other thing I found with all of that process was I interacted with a heck of a lot of different scientists and different disciplines, so particularly mathematical modulus, epidemiologists, behavioral scientists etc. As well as the people I am more familiar with and the sort of building science you know the environmental, microbiology type spaces and I learned an awful lot from some of those other disciplines. I think I became I think I became a better scientist because of it, because I think it made me think more about uncertainties, evidence and the knock on complexities and I think you know the people I probably gained the most from was behavioral scientists, because I think was an engineer.

Cath: 52:45

It's very tempting to go, oh yeah technology, oh yeah this, and you know we do another CFD model and hey look, we've modeled what happens. But we know that doesn't happen. It just doesn't happen in reality because there's people in the mix and you know all things have performed so much better if they didn't have people in them?

Simon: 53:04

Yeah, wouldn't our lives be easier?

Cath: 53:06

Yeah, I mean our lives would be so much easier. But we have to think about what people do. We have to think what their motivations are for different things, and they don't always do what you think they should be doing. They do all sorts of weird things. Yeah, I was saying something the other day. If I had my time again.

Simon: 53:21

I'd love to have done more social science in my life. I think that that is so fascinating and so underrated for outcomes.

Cath: 53:31

That's a bit of biology, I think.

Simon: 53:34

Yeah, yeah, for sure, I mean. My recollection of the time as well, although we were a bit later to the party with the ventilation group in Ireland was just the overwhelming amount of evidence. You had to read documents you had to read to try to be able to have an opinion. Both standards were coming out left, right and centre from SIPC and Ashray and Reaver and loads of engineering advice. You had loads of advice on epidemiological advice coming through and scientific advice coming through. Were you involved in that odd clash between disciplines of what was meant by airborne and what were the implications of calling something airborne? Because I think that was one of the, for me, the greatest examples of how language, even between disciplines, can have completely different meaning and completely different implications out the other side of it. That can become a real sticking point and a really slow action down, because you haven't developed a common language beforehand to be able to navigate a scenario like that. And that airborne one was a biggie, wasn't it?

Cath: 54:55

It was a massive one, that one. And yes, to some extent I was involved in that because I was involved with the group 36, so that Lydia Morhouse, who led and writing a letter that said we need to recognise airborne transmission and really trying to bring that evidence to the fore, and I think, yeah, you know, from day, one of the activities that I was involved in, airborne transmission was on the table, but it almost had to come from a position of well, at the moment, with washing hands and doing surfaces, I couldn't just pivot to everything being airborne. And I don't think that's right either, because I think I don't personally think we can dismiss hands and surfaces. I think a lot of the time they play no part. But there are some environments where we touch a lot of stuff and you know it's not just thinking about the aerosol and droplets from your mouth that land on something.

Cath: 56:08

If you're ill you cough in your hand and you know you end up with contaminated hands and you can see that in some of the data. You can see where you see contamination in environments. Some of it is the surfaces immediately around, which is deposition, but some of it is like handles and things, which is clearly from somebody's contaminated hands. But I think, yeah, you know, I mean, if you think right back, we had suspicions around different modes of transmission. I think we fairly quickly probably right from the beginning, you know knew that when you're close to somebody you're going to inhale it. We can debate whether that's what size of particle that is that's involved that you're going to inhale it. I think evidence around longer range airborne transmission so, you know, the other side of the room or in the room next door or whatever that evidence was a lot more patchy and what we started to see in the first few months was you saw these super spreader outbreaks that it was very hard to explain in any other way.

Simon: 57:17

There's been. There was a good study out there a few weeks back from Germany where they had good control cases of classrooms with filters and not with filters. It became a bit contentious, actually online, but there wasn't any clear evidence of any benefit from the filters in the end because they just couldn't be sure whether the kids were catching it outside of the classroom environment ultimately. So even when it was airborne, it's very difficult to create a straight line between an outcome of something being airborne and that's where you happen to catch it, because unless you can measure it in that environment which, as you said at the beginning, was being one of the big challenges with COVID it's very difficult to prove those straight lines.

Cath: 58:01

I think you know, I think this is where it became a challenge in that, you know, to start with those were being dismissed. People were saying, but what about X, what about Y? I think over time that got recognized that it was important. But even now the extent to which a ventilation measure will reduce transmission is uncertain. I think we know it does. I mean we've we run a study in schools in Brockford in the UK where we've had air cleaners in classrooms and we do see a reduction in illness absences in those classrooms. But I don't know that that would play out absolutely everywhere. And you know again, imagine, I'm not sure, was the one in Germany, was that an early year setting with a year old kid yeah.

Cath: 58:49

So early years setting will kids could interact very closely. So maybe yeah, you know, maybe that actually you know, you can have as good a ventilation you like, but if they're transmitting it very close range, you know you might just never see the effect of the ventilation because something else has just completely swamped your risks.

Simon: 59:12

It's a bit like risk misogation in a nightclub If people are sucking the faces of each other, there's not much ventilation is going to do about that. Yes, yes, yeah.