So good morning, everyone. My name is Linda Nyung and I am a program officer with the Board of Chemical Sciences and Technology here at the National Academies of Sciences, Engineering, and Medicine. I want to extend a warm welcome to you all in person and to those online. Today we gather to discuss a subject of increasing importance, especially in our daily lives, indoor chemistry. It is a topic that impacts our health, comfort, and well-being. This workshop will have a special focus on recommendations from the National Academies consensus report, Why Indoor Chemistry Matters. The four sessions we have planned today will drive conversations around research progress made in this area and feature opportunities presented in this growing field. For those participating online, I encourage you to take part in the Q&A sessions. At various points throughout the workshop, the moderator will open the floor for questions. At that time, please type your questions in the chat box or you can raise your hand and we will spotlight you. Our moderates will do their best to ensure they are answered. For those participating in person, if you have a question, please walk to the microphone on either side of the room. If you can't access the aisles, please raise your hand and we will bring the mic to you. Next, I would like to express our gratitude to the Alfred Sloan Foundation. Their generous support has made this workshop possible. I also want to take a moment to give a special thanks to our workshop planners. Drs. Glenn Morrison, Dustin Popendick, and Charlie Weschler. The tireless efforts met by our planning team these last few months have been instrumental in shaping today's event and ensuring its success. All right, so I'm going to go and introduce our planners. So Dr. Morrison is a professor of environmental sciences and engineering at UNC Chapel Hill. His research is related to the chemistry and physics of indoor air pollution and its influence on human exposure and contaminants, exposure to contaminants. Recently, his group has focused on how clothing influences indoor chemistry and occupant exposure to these chemicals. Dr. Morrison is a fellow of the International Society of Indoor Air Quality and Climate, where he has also served as his president from 2014 to 2016. He received his PhD from UC Berkeley. Dr. Dustin Popendick is an environmental engineer at NIST. He is interested in studying building materials and designs and how they affect indoor chemistry. He has investigated emissions from kerosene, canned lamps, spray polyurethane foam, and non-smoldering cigarette butts. He received his PhD in civil and environmental engineering from UT Austin. Dr. Charlie Westler, a longtime researcher in indoor air quality, he spent decades at Bell Labs before transitioning to academic roles at U.S. and international institutions. Currently, he serves as a visiting professor at Tsinghua University and holds adjunct positions at Rutgers School of Public Health. Notably, he has served on several National Academy of Sciences committee, and for nearly a decade, he was on the U.S. EPA Science Advisory Board. Dr. Westler has received prestigious awards for his contribution, including the 2017 Hagan-Smith Prize from Atmospheric Environment, and in 2020, he was elected as fellow of AAAS. With over 26,000 citations, his research along with his devotion indoor chemistry policy is undeniable. Finally, I want to thank the National Academy staff, Ms. Brenna Albine, Darlene Bro, Kay Wems, and Eric Edkins. Your invaluable support in handling the administrative and logistical operations for this workshop made all the difference. Thank you for your immense contribution. At this moment, I invite Dr. Morrison, who will introduce our keynote speaker. Thank you. Hello, everybody, and welcome. I am pleased to introduce Dr. Vicky Grasian, my friend, who is a distinguished professor, distinguished chair and physical chemistry co-director for the Center for Aerosol Impacts on Chemistry of the Environment, and Associate Dean for Research in the School of Physical Sciences at the University of California, San Diego. Dr. Grasian's research encompasses the chemistry of environmental interfaces, atmospheric aerosols, and aqueous micro droplets, engineered geochemical nanomaterials, and importantly for this meeting indoor surfaces. In the early 2000s, several of us reached out to Vicky imploring her to join us in this journey of indoor science and indoor chemistry, and she joined us at several meetings and workshops, and I'm glad that she has stayed the course with us on this journey. Vicky has received too many awards to list here, but they do include the ACS Geochemistry Division Medal and Symposium, American Institute of Chemist Chemical Pioneer Award, American Chemical Society National Award in Service Chemistry, and most recently the 2024 Pittsburgh Spectroscopy Award. She's a fellow of the American Chemical Society, AAAS, and the Royal Society of Chemistry. I've enjoyed working with Vicky over the years on publications, presentations, workshops, and the recent National Academy of Sciences report. Vicky. Annie, thank you, Glenn, for that very nice introduction. I appreciate it, and yes, it is your fault that I'm here today and pulling me in in the early 2000s into a fascinating field. So how is this showing? Yeah, that's better. Okay. Yeah, thank you. Okay. So my name is Vicky Grassian, as Glenn mentioned, and I currently am in the Department of Chemistry and Biochemistry at the University of California, San Diego, and today I want to talk to you about a recent National Academy's report on why indoor chemistry matters, and this is the second workshop that they've had on this topic, and really we want to talk about prioritizing indoor chemistry research and why that is important. Oops. Okay, hold on. Oops. Okay. Thank you. I'll figure this out by the time we're done. So from this report, I want to talk about some main messages. Okay, so we'll start off with some main messages that came from this report. Some select recommendations. The reason why I say select recommendations, there are so many recommendations in this report. I have a copy, a hard copy of the report if people are interested in seeing it, but I'll also show you the URL and the QR code you can get that report from. So these are recommendations from why indoor chemistry matters. This is a consensus report. So we all read the report, we signed off on the report, and we really wanted to put this report forward so that people had this information and recommendations on next steps forward. So here's a link to the report, as well as the National Academy website. And so I'll just give everyone a moment if they wanted to use their phones and take a picture and get on the website. Like I said, at any time for people who are here in the room, if they want to look at a copy, a hard copy of the report, I have one that I can share with you. So just look on the National Academy's report catalog and why indoor chemistry matters. And so this report was sponsored by a number of different sponsoring agencies that I just wanted to mention. The Environmental Protection Agency, the National Institutes of Health, mainly the Environmental Health Science Institute, the CDC and the Alfred P. Sloan Foundation, the same foundation that is sponsoring us here today. The Alfred P. Sloan Foundation has played an important role in indoor chemistry because they had a 10 year plus program and that really filled the gap in terms of having funds to do research in this area. I will say we have learned a ton in the last 10 years from that support from the Sloan Foundation, building on things that were done earlier and then advancing the field forward because of that opportunity to do research, to do collaborative research and to interact with one another. So here's a statement of task. I don't want to read it directly to you, but basically the Academy has put together an ad hoc committee, so a committee of people from all over the country, scientific experts to really think about the state of the science regarding chemicals in indoor air. We wanted to think about under-reported chemicals, chemical reactions that occur in the indoor environment, how that transforms chemicals from source to what gets into the air. We wanted to talk about the distribution of chemicals. That's something we talked a lot about. Are these chemicals in the air? Are they on surfaces? Are they in water reservoirs? Are they in dust? Where are these chemicals and why is that important? We wanted to put indoor chemistry into the whole context of chemical exposure, air quality, and human health. That was some of the driving points of what we wanted to do and that's what we were asked to do. While we talked a lot about it with each other, everything was on Zoom. We never met in person, so a lot of two-dimensional people that I know now in small boxes. What they wanted us to do was come up with a report with findings and recommendations, so that was what we wanted to put forward to the community, to everybody, all stakeholders, thinking about what are the opportunities for incorporating what we know now into practice where additional chemistry research would be needed, what's most critical for understanding the chemistry in indoor environments, what opportunities are there for advancing and addressing the technology methods, barriers that are out there, how do we coordinate, how do we collaborate across disciplines, and why is that important? Again, we wanted to make these recommendations to everybody, to all stakeholders. I just want to note we did not focus on industrial settings. That falls under the umbrella more of NIOSH, National Institute of Occupational Safety and Health. We focused on non-industrial exposure within buildings. Here's the committee roster and the staff that we worked with. Megan Harris was working at the National Academies at the time. She gave us excellent support, and I just wanted to give her a little bit of a shout out. Some of the slides I present today, she had developed her talk at the American Chemical Society meeting, and I built on some of that work that she did. David Dorman, who is a toxicologist from North Carolina State University, was the chair of our committee. He had done several other reports, so he really knew how to lead that effort, if you will, and then we had a number of people. And I will tell you, everybody contributed quite a bit to this report. We all read every word of the report. We all participated and wrote different aspects of the report. So it was a really good committee composed of chemists, engineers, people interested in exposure science, so a variety of different people. We needed to listen to each other to understand the different fields in order to put this report together. So why does indoor chemistry matter? This is the easiest question to answer, in my opinion. Indoor chemistry matters because people spend the majority of their time at homes or in other indoor locations. In fact, often the amount of time that is reported that we spend indoors is 90% of our time, okay? Not 40, not 25, not 60, 90% of our time. And we also know there are some people who spend 100% of their time in indoor environments. Given this statement right here, I think just addresses the issue of why does indoor chemistry matter. We need to know what we might be exposed to, what's in the air, where we're breathing. All these things are important to us because that's where we are. We're mostly indoors. We have been well aware of indoor chemistry for some time. Things like radon mitigation. Before I moved to California, I was living in the state of Iowa. If you ever look at a map of where radon is, Iowa is kind of right in the middle and very much highlighted in terms of radon concentrations. I had to have radon mitigation done at one of my houses. The levels were quite high. They were quite high in our basement. It was a semi-finished basement where our playroom was, where our kids were playing during the winter when you didn't go out much and you were down in the playroom. We had high levels of radon. We had to do that mitigation that still bothers me today, that had happened in our home because radon is associated with lung cancer. There's a lot of things that worry me in the back of my mind, but something that has done a lot in places like Iowa.  Basically, this is intrusion from the ground, often through lower levels, the basement, and then its ventilation is basically how that's mitigated. We all have CO detectors. We're supposed to check the battery on our detectors twice a year when we change clocks. I don't know what's going to happen when we don't do that anymore, when we go from standard time to daylight saving time. The CO is a silent killer, so we know about that and we think about that. More recently, since the coronavirus, people have now been using CO2 detectors to think about ventilation in various enclosed spaces in indoor environments and whether there's a good ventilation, worrying more now about the coronavirus and getting ill because of that. Also, people are using particle counters, again, to better understand aerosols and particulate matter in air. The report structure, main messages, and select recommendations, I want to go through that. Here's our report structure, basically seven chapters. Each chapter provides an overview of the current state of the science, and each chapter provides recommendations of research needs. I'll be going through some of these chapters as we talk. To set up this talk, I went to a figure. I label all the figures that I show here today and where they are in the report. If it's not labeled, it's not in the report, and I give you a reference for a figure. I went to Chapter 6, so I went sort of towards the end to get this figure, Figure 6.2. I think this is a brilliant figure, and it really represents what I want to talk about today. Basically, what this figure does is charts the fate and transport of an agent, a chemical, from source to ultimate impacts on health. Let's just go through this for a moment. You have a source. Here it is just a spray can, a puff, if you will, of something into the air. This is just one example. There are many. Then you have indoor chemistry and some engineering going on. These molecules, it just doesn't stay a puff. We all know this. It dissipates. That is, it gets transported. Then it starts to partition. Maybe it sticks to surfaces. Maybe it stays in the air. Maybe it's associated with dust. Maybe it's in a water reservoir. This back and forth, this transformations showed by this arrow, I'm a chemist. I kind of want to turn it 90 degrees, if you will, if you know anything about chemistry. Glenn says, no, this is the way it should be. Then we want to know what the concentrations are in the indoor environment. Sometimes concentrations are very low, parts per trillion, parts per billion, especially as the agent gets diluted in the air indoors. Measurement science, analytical tools are key. What some of these things that were developed during that Sloan program, some of that, the funds were put towards developing instrumentation that can detect chemicals in air at low concentrations. Then it's what's people being exposed to through dermal, excuse me, skin ingestion, inhalation. We talk a lot about inhalation, but there are also other routes of exposure. Then the dose. What's the concentration times time? That's ultimately what we want to know in order to understand health effects. What I will tell you is we were, we had one toxicologist. We had no epidemiologists. We had no MDs on our report. We are focused mainly on what we need to know in order to determine health effects. That's what this report is mainly about. Now this report, that diagram allows me to kind of color code, if you will, some various points that we'll be talking about. Chapter two mostly focuses on sources and then three and four about transformations and transport and partitioning. Then five about measurement science is in there. Then we have indoor chemistry and exposure. Starting to think about that exposure in that dose. Then a path forward is the last chapter. How do we take all of this together to understand health effects? Some of the main messages, and then I'll go into the recommendations. One main message is that environmental conditions and indoor chemistry vary between buildings based on their purpose and use. A school is different than a home, is different than an office, is different than so for a museum, so forth and so on. Really, things are very varied between buildings. Again, their purpose and their use. In this picture, and I wrote out some of these things, there are a number of different primary sources and reservoirs of chemicals indoors and just a single family home. Now not everybody lives in a single family home. There's apartments, there's dwellings, there's high rises, so forth and so on. This is just an example. We're not even talking about communication between homes and where you can have things happening in one home affecting another or in one living area affecting another. Chemical emissions from water. I go back to my Iowa example and taking a shower and smelling chlorine because something happened at the water treatment plant that they needed to take care of and there you can smell chlorine and typically you didn't smell chlorine but you could on certain days. That would be a chemical emission coming from that water system. Chemicals from building materials is also important. Fumes from attached garage. Intrusion through the foundation. I've already noted radon as being one type but there are others. Particulate matter, CO NO2 from gas appliances and cooking, fireplaces and wood burning stoves. I mean they're designed so that you try to minimize that but these things are still happening. Personal care products. All of us here use personal care products. Everybody uses personal care products. That's a source. Metabolic emissions. I won't talk too much about that. Mold and microbes associated with water, flame retardants and plasticizers, cigarette smoke, et cetera, et cetera, et cetera. So lots of different sources and this is just one example I'm showing of a single family home. Occupants and their activities impact indoor chemistry. Cooking, cleaning, I say, primping and preening. That's a personal care product I was talking about. Smoking leading to secondhand smoke. We all know about secondhand smoke. More recently we've been talking about thirdhand smoke. I think Charlie you wrote a great paper in PNAS about that several years ago. And that is smoke that ends up on surfaces. And so you can touch surfaces and get exposed to this thirdhand smoke that undergoes chemistry and changes from the initial secondary smoke which then goes and partitions to a surface. So you may say to your spouse I'm only going to smoke in this room and this won't bother you and I'll open the window but you can still get that secondary smoke and you can still get some exposure through maybe dermal exposure due to thirdhand smoke. These are the things that we're learning. These are the things that we're thinking about and so when I go et cetera there's a lot of other activities. Another main message is that researchers know very little about how humans are exposed to multiple indoor chemicals across phases and pathways and how these joint exposures interact across time scales. What's their cumulative long-term impacts on indoor chemistry, indoor chemical environment and human health? We're not exposed to one thing at a time. That's the whole point here. We're exposed to multiple things. Sometimes they react with each other. We have to understand that and we don't know very much. Another important message from this and I've mentioned this already is that indoor surfaces matter. The number of times mentioned in the report for surfaces is quite high. Chemicals, okay maybe if you do the word search you might get different numbers than I did but when I did it chemical or chemicals I got 1,054. I got 672 when I did aerosols, particles, PM, surfaces, 515, gases 239. Aerosols and particles that's another national academy's report that came out recently indoor exposure to find particulate matter and practical mitigation approaches and Richard Corsi a dean of college of engineering at UC Davis led that. That report talks all about particulate matter aerosols and I'm going to let that report stand as is. Today I want to talk a little bit more about surfaces because that's what's unique in this report relative to other reports on atmospheric chemistry or air quality outdoors. Surfaces play a role there too but surfaces play much more of a role in the indoor environment and just you know I always tell people just look around the room you're in whether you're online look around the room you're in there or in the room here you can see fabrics and wood and glass and shade you know all these different types of materials all these different types of surfaces and they play an important role in indoor chemistry they and indoor air quality they can act as a sink so you okay good that gets it out of the air I don't have to breathe it but it's on the surface you if you touch the surface but then what happens is over time because it was such a good sink initially it becomes a source a long-term source the other thing that a surface can do is you can have transformations so a chemical compound when absorbed to a surface when sticking to a surface can change its identity and so that and become a different chemical potentially a less more benign chemical potentially not potentially something that you may want to consider when thinking about health effects. Another main message had to do with the outdoor environment so how and this comes up it'll come up in a few slides how the outdoor environment affects the indoor environment and vice versa we talked about that quite a bit and how the outdoor environment is changing due to climate change in the western united states where I live now we have more wildfires the wildfire season is longer now and that is due to climate change so things are changing outdoors and that's going to impact our indoor environment. New analytical tools have been as I noted already instrumental in having us understand indoor chemistry and there still remains key challenges that really to develop this instrumentation requires some strategic investments you need robust robust measurements of air which include gases and aerosols surfaces and the dust particles on those surfaces and that is an important message that came out in our deliberations over the many meetings that we had for over a year bringing this report together you know and I would talk to some of you already about this really an ongoing need to effectively translate the scientific knowledge about indoor chemistry into practice and policy that's something that is really needed the other point in this report many chemicals found indoors have little or no information regarding their toxicity either alone or in combination and mitigating chemical hazards will require efforts in and this is a big this bullet is a big one okay in my opinion changing building design and operation that's a big ask right altering the use and contents of products and materials huge ask addressing the impact of human activity on indoor chemistry like having people change how they behave in the indoor environment one two three those are all really big asks how can we move forward how can we start to implement thinking about these thinking about things differently changing altering addressing that's really important it needs to be done so what are some of our recommendations from this report the main message is kind of laid out what these recommendations are understanding the chemical composition of complex mixtures that make up our indoor air and a wide range of residential and non-residential settings that means making measurements in these settings okay so that's that's something that we need to consider so we can really understand what's going on and or to make these measurements we need to develop these novel methods I mentioned them already mass spectrometry whatever it is that needs to be done and chemoinformatic resources to identify quantify wide classes of indoor chemicals primary emissions as well as those secondary chemical reactions those transformations creating emissions inventory specific to building types and identifying indoor transformations that impact outdoor air quality how do we do that many many different types of houses many different types of indoor environments how do we in fact start thinking about this in terms of emissions inventory creating one and I think that's a very important recommendation in terms of partitioning and transformations so that double arrow understanding the phase distribution of indoor chemicals between all indoor reservoirs and incorporating this knowledge of partitioning into exposure models understanding the chemical transformations using advanced techniques deciphering those mechanisms so that you know maybe how not to make that transformation if it's a problem both in the lab and in indoor environments we do a lot of research in the laboratory but you always have to check in indoor environments is some similar chemistry going on it's like atmospheric chemistry people measure things outside they do things in the laboratory do those agree are my doing those experiments in the right way with the right chemicals to simulate what's going on outdoors um this is an important one and I think it's going to be talked about a lot today this last bullet how standardized consensus test methods couldn't could enable potential certification programs for air cleaning products and services that's actually something that's going to be discussed more and I think it's important so when we think about emissions and how they evolve over time and spatial scales what I want to show here is the fact that we have this diagram figure 3.2 taken from one of the papers and literature Westler Westler and Nazaroff 2008 to modified a little bit but you know we think about it in a big picture way chemicals in the air what's going on in order to understand this we need research like that on the right-hand side and so that is really diving down into that molecular level detail of what is going on so to understand this we need research like this and so I'm trying to make that connection and make those arrows in my own laboratory that that round circle on the left is just one of a diagram that I used for the the grant I got funded from the Sloan Foundation we wanted to look at a lot of different types of chemistry and we showed it in that diagram but one of the things we wanted to look at was this molecule called hono nitrous acid it forms in indoor and outdoor environments there is some concerns about it from health effects also it dissociates into the hydroxyl radical which is an oxidant in indoor and outdoor air and so we wanted to understand that that and and it forms on surfaces so we wanted to understand that chemistry a little bit and so we did some surface chemistry of NOx to produce gas phase hono and we used different building materials a cement painted wall we used a clay material kaolinite that's used in building materials we used a zeolite and what we found is that chemistry is different on different surface materials and in particular we formed a lot of hono nitrous acid on kaolinite in the painted wall but very little when we had zeolite and cement so you know you can think about a strategy now if I don't want to produce must hono in the gas phase I can use zeolite and cement maybe okay let me just say maybe for now I'll get back to that in a minute and the reason why we didn't get any hono from zeolite and cement is that the deprotonated form nitrite was staying inside of the zeolite staying inside of the cement and how it was interacting with those surfaces was very strong and so you weren't getting that hono into the gas phase see the level of detail that I learned things on okay and so but it starts to tell us that different building materials will do things differently now okay why don't I just say recommend zeolite and cement and never use kaolinite or painted while we have to but what would you why do I say I don't want to say that immediately because now it stores nitrite so wonder what conditions will that get into the gas phase as hono is it high relative humidity if you're using some some acids get into the air and so this is just the start of trying to understand how materials interact with nitrogen oxides especially as they relate to hono formation here's another example limonene this is work all done by funding with the Sloan from the Sloan foundation we did a study looking at limonene this is a cleaning product shown on the left we looked at it alone that is there's only one one chemical there interacting with a surface and these are some of the we worked with the dug to bias who does molecular dynamics simulations we work with minabu shawarra who does chemical kinetics we make the measurements so that's the graph in the middle on the left hand side and what we see is we introduce some limonene towards like a glass surface initially we see a large increase in the coverage on the surface of limonene sticking on the surface we remove the limonene and then the concentration just goes down so what happens we can say this surface is a sink for limonene but then it's a source but this is on short time scale so this is not something that we would worry about too much the other thing that I mentioned is that we looked at other surfaces and some surfaces can transform limonene mainly oxidize it to another form but what I really want to show you is another experiment we did on the right hand side we looked at limonene plus other chemicals and air and this project was motivated by some of the things that had come out of a home chem that we Delphine farmer and Nina Vance led that effort where we started to look at limonene and maybe bleach so different cleaning products and then what could happen is those two so bleach H O C L C L 2 and limonene it can form gas phase products mainly oxidation and chlorination products and what happens now is these gas phase products stick more strongly on the surface than limonene and that what that means is that then they become long term sources of these chlorinated compounds these chlorinated hydrocarbons and so these are the kinds of chemistry that we see so the surface interacts more strongly with these chlorination and oxidation products but what happens is they come off more slowly so that's it's a sink but then the surface as a source of these products over time some surfaces can further transform these products so details details details now this came out terrible and I don't know why because it was fine on my computer but pretty much what we need to do is we need to understand you know the the complexities of these surfaces and I I was using fairly simple ones if you look around the room there are much more complex surfaces fabrics for example try to understand and probe that chemistry understand them we need new approaches new mechanisms are coming out from those studies modeling the chemistry of indoor surface and connecting surface chemistry to real world indoor measurements and ultimately you know going into that figure 6.2 if you will where I should draw that line over to health effects and try and understand how that impacts health okay building a measurement some recommendations really integrating indoor chemistry considerations into building system design and mitigation approaches separate fields people don't talk as much as they could wouldn't be great engineers in consultation with indoor air scientists thinking about buildings applying and developing new analytical tools I already mentioned that probing the chemical complexity gases aerosol surfaces you know lessons learned during the COVID-19 pandemic and this will be discussed a little bit more importance of ventilation and filtration and that cleaning methods can add chemicals into the air and so a recommendation is that testing methods standards are needed for commercial air cleaners both products and processes and this is a diagram from Doug Collins and Delphine farmers really nice paper just looking at different methods of cleaning air and what that means in terms of indoor chemistry really important work opens our eyes about what do we mean by cleaning and in fact oftentimes there's really not a lot known and so this is really important so these transformations are coming they're coming about when we use these indoor air cleaners and and it will be expanded upon those thoughts lessons learned during the COVID-19 pandemic cleaning surfaces not as important as cleaning air through ventilation and filtration for the coronavirus I think that we can all agree about that lessons learned during the CASA experiment that Delphine led a chemical assessment of surfaces and air cleaning surfaces with soapy water mopping and wiping most important and cleaning air of persistent volatile organic compounds from wildfire smoke and indoor air by removing VOC reservoirs okay that's a lot okay so in one case we're trying to get you know aerosol transmission of COVID coronavirus you have to clean the air that you want to filter the air you want to ventilate the air here in this particular case wildfire smoke got into a house a test house the NIST test house and it was persistent they ventilated but it was persistent again came out again and that's because surfaces were reservoirs for that smoke then you clean the surfaces right through mopping wiping soapy water mopping wiping and that removed the VOCs so these lessons are not contradictory you have to think about what you're doing okay so in one case cleaning surfaces really didn't help the situation in one case it really really did and this is just because of what we're doing what we're looking at the processes that are involved exposure in health here we have exposure pathways I like this this diagram as well from chapter six inhalation ingestion dermal contact we talked about some of that already some of the recommendations are centered on really updating national human activity pattern surveys to capture people's activities in indoor environments understanding indoor exposures to come contaminants that are outdoor in origin but maybe undergo transformations understanding exposure and health impacts on a wide range of indoor settings future standards guidelines or regulatory efforts and I like this one too new approaches for measuring exposure in children they're doing different things we were just talking about that earlier and I learned a long time ago talking to exposure scientists as well as people in the health field children are not just small people okay they breathe more rapidly they have different activities there's so much that are different than than the larger adult there really needs to be new approaches for measuring exposure in children that's a recommendation in chapter seven we talked about a path forward recommendations cutting across different topics I just want to go to them because I want to keep us on time accelerating the field forward the Sloan Foundation played an important role over the last decade by providing resources funding on a scale that made people able to do research in their labs and collaborate across labs and collaborate on really important field studies I'll call them home chem and CASA and that funding is over so there's going to be a gap going on right now as people try to figure out ways to continue the work that they're doing and so I think that we really need a national research priority focused on indoor air and indoor chemistry for the reasons I showed you in one of my first slides that's where we are it's important to engage and collaborate and connect across the indoor chemistry paradigm and across of course disciplines we all need to hear from each other to learn and to move forward so in collaboration a need to engage across disciplines this is a complicated slide but it's it's really not basically what I'm showing you here is an indoor chemistry model on the left and an exposure model sort of on the right and what I'm saying is okay so one's in chapter four and one's in chapter six so we need the indoor chemistry model plus the exposure model in order to understand health effects we need to bring these models together and that's a new paradigm for understanding health effects it sounds easy you know actually adding them together is going to require some effort some collaborative effort how do you put things in your model in the exposure models right now it doesn't have those transformations or anything along those lines and so really bringing these together does represent a new paradigm for understanding health effects recognition of this important problem as a national research priority just labeling it again collaboration and great engagement across disciplines invest in coordinated interdisciplinary research application of knowledge a key takeaway from this report science and technology is needed from the fundamental to the practical and so I think that I hope I represented that report well others will expand upon different aspects of the report we tried to really survey the state of the science and provide in many ways through the recommendations a roadmap for moving forward in this very interdisciplinary multi-disciplinary important from our health perspective the field of indoor chemistry thank you I guess you guys can hear me right okay great so I'll be moderating some questions and then a panel session after this and we've got a few questions coming in on the chat as well so I'm going to actually start with my own question and then we can move on to some from the audience and some from the chat as well okay so I'll start off with a broad question based on your research experience and experience writing this report what direction do you see your research heading so thank you Glenn for that question I think there's a couple of ways I want to answer that question so as Glenn noted my background is in this area of surface chemistry and surfaces and what I would tell you is that a lot of the molecules we detect indoors we know very little about how they interact with surfaces and so and really most importantly was some of the studies I showed you with limonene when you had multiple chemicals involved I really want to look at this surface chemistry in a realistic environment of the different chemicals that are in the air to better understand what is being formed so I I think that partitioning and the transformations are something that we can as a group in my research group can help add into this whole field I'm really interested in the indoor outdoor exchange how you know things like wildfire smoke can impact the surfaces and the chemistry that occurs in indoor environments and those are some of the things that I'm thinking about in in my lab and people in my lab are interested in right now cool um are there if there's questions in the audience just go ahead and go up to the microphone is all right I'm going to go ahead and see if I can find get one from the chat so a question from the chat was do fragrances and other toxic chemicals change like second hand smoke and third hand smoke to make additional hazardous chemicals and I would say that's a good question that's a good question and um wait could so do they change well do fragrances change in yours I think so okay yeah yeah yeah and so trying to understanding those transformations and you know they do end up on surfaces um but I think very little is known about that right now unless you've done it Glenn no no I well there's the question I was sort of breaking into two one is do they change and does it matter yeah um and so if we don't know what it changes into we can't say whether it matters or not and the other thing I want to mention about fragrances we all don't use the same type of personal care products fragrances you know that's you know based on a lot of different things that each one of us uses in our home and so being able to really look at the broad range of fragrances that are used I think is something that's really important and it does add to the indoor chemistry fragrances add towards the indoor chemistry and what's going on so you collaborated quite a bit with other research groups in the Sloan program in keeping with those recommendations from the report which you highlighted where do you see sort of your where do you see fruitful collaborations occurring for you and your research group so we did get a really wonderful opportunity to collaborate I mentioned a few you know with the the field experiments in different homes modeling people working in modeling of indoor chemistry so that was and has been completely very fruitful every collaboration that we've done I've learned something from to do the experiments in my lab better and just learning new things all the time and then moving that forward to what we know from those studies into the exposure models and how do we help make bridge that so we better understand health effects is something that I think would be a really wonderful next step so really having a group of people in that indoor chemistry paradigm that we kind of talked about and showed everybody at the table I think would be very helpful and I'd like to collaborate with everybody and we would all like to collaborate with you so there were several comments that are in the same bill you I can I can ask one or two of them but I'll start with well actually I'll combine a couple we can identify many pollutants and contaminants but do we know the true risk associated with each of or the combination why is there no mention of risk or harm either from acute or chronic exposure yeah so that's the big that's the big question we don't and I think I try to point that out we don't know the risk we don't know the harm okay that's that was a big part of that report was that we don't know what the risk or the harm what what those are and so I think that was clear in the report and in the recommendations of what we need to do next so there's another question are there instruments to measure chemicals that come into the house or school from outside like dryer fumes coming in from neighbors yeah that's a good question I mean you know so with the span of instrumentation yes there there are definitely instruments that can you know test what you know detect what's in the air a lot of people use mass spectrometry to detect exactly what's in the air but the if the question is is there something that I could hand you or you can buy on amazon or I don't I don't think the answer is yes you know if it's forming particles you can get a particle counter there's not they're not too expensive if you're getting CO2 you can get a CO2 detector but the there are instruments but they are not like widely available they are very specialized instruments right now and and that can detect many many things and that was some of the beauty of the Sloan program was using these instruments to study indoor chemistry in a variety of settings so here's a actually I'm going to jump to one of my questions and we'll go back here to one of these um so I think you've touched on this several times but if you were making the case for fundamental chemistry studies to some of the folks here who are looking at the practical outcomes you know the the folks that are doing building management and operating schools you know and making decisions at that level you know how do you argue for the fundamental chemistry so um and how does it it's argued in the report as well yeah so what I would say is that a lot of the chemicals in indoor environments um and I've said it a number of times we know very little about their chemistry okay we we know very little about their chemistry if we want to have uh you know the best air quality in buildings we're going to have to know something about their chemistry I will say that there are chemicals in indoor environments that if you look in the literature there is not one study there is not one study there are zero studies on how those chemicals interact with surfaces in this report we talk about the role of surfaces sinks sources a place where things can transform and I'm telling you that there are some chemicals many chemicals detected in indoor environment we have no knowledge zero knowledge about how they interact indoors and so that to me is a situation where you need to build up that knowledge base in order to do the best job of you know that one two three we mentioned of what needs to be done how buildings are made what materials are used we need to understand what's coming off of some of these materials again how are they transforming how do they capture chemicals and what they do there so we have no knowledge in some cases and I think that is not serving anyone well and so including the building community the microphone tray thank you uh trey thomas consumer product safety commission you just mentioned the the devices the air monitoring devices you can purchase and some of them are less than a hundred dollars you can buy them online we are beginning to see consumers who are purchasing these they're making measurements and I think it's a big question what do we do with the data so I just wanted to see if you had any insight in terms of their accuracy is this good for screening perhaps is there any usefulness for the data that could potentially be generated by these these products I think you know citizen science is important and I think that we should be utilizing that more and more but people your co2 counters measuring three thousand I think it's parts per thousand uh open a window uh turn on a fan you know it's telling you something if you want to have more ventilation if you're worried about things like coronavirus it's telling you something part of particulate matter you're cooking something and you have your fan on low let's say or don't have it on and your particle counter is going off you turn on that fan you can see the response if you're if your filters are clogged you know it's not responding it tells you something what you can do you have actions that you can do that can help you and and make the air quality better um where you are so there is some use perhaps there's definitely some use and I really like I said I do believe in citizen science so how can we get more uh of that to citizens I think um we've learned over time in many cases I you know affluent michigan various cases that if people were able to make measurements of things they could have been in a lot better situations thank you all right we'll do one more chat question um PM and aerosols provide available and high surface area for gaseous chemicals how would you consider to address this aspect so um exactly right and so there's surface chemistry going on particles surfaces particulate matter and aerosol surfaces I didn't talk about that too much today but that is something that people do look at that's how particles grow you know gases stick to the surface of these aerosols of these particles that in fact is how in some ways secondary organic aerosols grow indoors is through that chemistry happening at the surface and so you make you make a great point I focus today mainly on stationary surfaces but also particulate matter and aerosols also matter well thank you uh Vicki and let's all thank Dr. Grassian for the presentation all right I get to introduce the next speaker so I am pleased to introduce my colleague and friend Dr. Barbara Turpin who is a professor at the University of North Carolina in environmental sciences and engineering her expertise is in aerosol science atmospheric chemistry and environmental engineering she's a caltech graduate and has received her PhD at the Oregon Health and Science University she combines laboratory experiments chemical modeling and field research to improve the understanding of linkages between air pollution emissions and human exposure through her research she seeks to reveal fundamental processes needed to accurately predict human exposures to airborne contaminants both outdoors and indoors she's been well known for her work on the formation of organic particulate matter through aqueous chemistry but also for many other studies and in the indoor field quite well known for her work on what was called the RIOPA study which was one of the early really intense studies of many many indoor environments and studying the chemistry taking place there um she's received numerous awards including the Hagan Schmidt Ord and his uh fellow of AAAR the American Geophysical Union and AAAS she has been editor or on the editorial board for several journals and has given numerous plenary and keynote presentations interestingly she was a member of the US fencing team and was a national champion in 1992 she's also an outstanding colleague and is one of one of the reasons I chose to move to the University of North Carolina in 2017 so let's welcome Dr. Turpin probably one of the most important things I did as department chair is figure out how to get Glenn there so very happy about that so it's my pleasure today to talk to you about um uh sources indoors and if I can figure out how to name this or is it this one all right you already know that um the indoor environment is a really important exposure location because we spend a lot of time indoors unfortunately because I really prefer the outdoors myself and not only that we are often in close proximity to source emissions that we because we're generating them through our activities there's a limited dilution of those sources so that means that the concentrations are higher than we would like and there's a complex and evolving mix of chemicals from many different sources that include human activities consumer products and materials chemical reactions biological processes and the outdoor air and one big challenge that we have is that because you know there's proprietary information about products that makes it difficult to know you know even for me as an informed citizen I don't know what I'm bringing into my home when I buy things that drives me a little bit crazy um just like when we deal with outdoor air we have both primary and secondary sources and primary means chemicals that are emitted directly from let's say cooking for example or perhaps volatilization from surfaces by secondary I mean emission of chemicals that are formed through indoor chemistry and this could be um you know some of the things we probably know the the most about is when um ozone reacts with surfaces your skin lipids for example and some you know it's going to oxidize but also fragment those compounds and some of them will be volatile and they'll be emitted from your skin then I'm going to talk both about sources to indoor air and a little bit about how the indoor environment you know how you can think of okay I am an engineer so you can think of the indoor environment as a little reactor and to some extent we're bringing air in from outside we're processing and changing it and then emitting air to the outside so I'll talk a little bit about indoors as a source to outdoor air okay um one thing so there have been some really high quality scientists working in this field for a very long time but a small number of them and we've made a lot of progress in the last 10 years because a bunch of new scientists and new instrumentation and new ideas have come into that field there's been more money invested in research in indoor air one of the things we've known for a long time it is that um gas phase hydrocarbons vocs volatile organic compounds are um at much higher concentrations indoors than outdoors and really um this is a really good indicator that uh there are significant indoor sources so chemicals with higher indoor concentrations have significant indoor sources we also now know that um oxidized vocs or water soluble organic gases are at much higher concentrations indoors than outdoors meaning that there are indoor sources right so this is a study of 13 homes in North Carolina and New Jersey and the red it's the indoor concentrations and the gray is uh our measurements from immediately outside of those homes you can see they're more than 10 times higher so in this case we've measured total water soluble organic carbon in the gas phase and the reason we did this is then to try and understand how much of that material do we really know anything about so what are the chemicals that make up that that mass and so I want to point to the value of doing a mass balance um in order to just see you know what what do we know and what do we not know how much to what extent do we understand the big picture so these figures are from the CASA campaign which took place at NIST thank you Dustin and at their zero energy test house and there we found that the indoor WSOC concentrations in the gas phase were about 20 times the concentrations outdoors and on the left there you see a mass balance on the house background so this is when there are no people in the house and there are no purposeful activities going on it's just the house and the concentrations were quite high I was surprised at how they high they were but we can identify most of the mass at least more than half of the mass using mass spectrometer mass spec tools I think these measurements are probably from John Abbott's group on the right a Delphine farmers group also did an experiment where we simulated the infiltration of wood smoke to think about what would happen if there was a wildfire nearby and we also did a mass balance on that now I can kind of guess what some of the rest of the mass is because I've also worked on wildfire smoke characterization so we do know a little bit more about this but you can see that there's a lot of the mass missing when we use our standard high quality tools I want to also point to the real value of real-time measurements in locating pinpointing or identifying sources so here's one example this is a home where we ran some perturbation experiments in a way we in this day on this day we did we cooked breakfast three times okay and so when I first did a mass balance on water soluble organic carbon we found lactic acid a fair amount of lactic acid I said oh that's from people but here we can see the dotted line here and here and here when we were cooking bacon and eggs lactic acid is really high so now we know probably that lactic acid comes from the bacon cooking the bacon that makes sense to me there are a small but significant number of studies now where real-time mass spectral methods have been used in the indoor air study and these are very very informative for many reasons here's another example mass spectral methods have really high sensitivity to chemicals to individual chemicals and so we can even measure trace concentrations of really concerning chemicals when in the process of doing performing indoor activities and so we got about three or four different brands of microwave popcorn we microwaved them and with you know of course the oven door microwave oven door closed which you have to do to get it to operate right that's a good thing and we left our chemical ionization mass spec running this about six feet from the microwave and you can see the emission of 6-2 FTOH so this is a per PFAS compound it's a fluorinated alcohol and you can see the parts per trillion values of emissions from only one you'll be glad to hear it's only one of those three or four brands that we tested but repeatedly okay organic particulate matter is also about twice as high indoors than outdoors indicating that there are indoor sources of organic particulate matter so this is from the REOPA study and so it's a little bit old at this point but still useful we measured in 300 homes in the United States in Elizabeth, New Jersey, Houston, Texas and Los Angeles County California so these are New Jersey data and I'm showing the PM 2.5 mass balance for immediately outside of those homes and then inside of those homes and so as the outdoor air comes in the concentrations you know material is lost particles are lost as they go into the building and they're lost through deposition inside of the building you can see that the concentrations here in parentheses the concentration of sulfate in indoor air is lower than in outdoor air and the concentration of particulate organic matter though is more than twice what it was outdoors right concentration of elemental carbon is lower indoors than outdoors so anyway what this tells me is yes of course particles are lost as they come indoors they're lost through deposition indoors but when they're indoor sources as there are and in the case of organic particulate matter then the concentrations are higher indoors when we take apart that data so we factor the indoor PM concentrations into the material that came from outdoors and the material that comes from indoors and I'll spare you the details as I don't have time you can see that again that this blue fraction that's called other is much smaller in the indoor PM of outdoor origin we didn't measure nitrate so that other is mostly water and nitrate and I think what's happening here is that there's a lot of ammonia in indoor air the ammonia partitions to surfaces we know this now and when you bring those particles in from outdoors um nitric acid in the gas phase gets sucked up into the walls and that pulls nitrate out of the particles okay but you can see also that the oh no oh no where am I going I'm going here we go you can see also that the indoor indoor generated PM 2.5 is mostly organic okay who cares um what are the potential implications of this so you know we we do know that there are health effects associated with PM 2.5 adverse health effects and there are also some other more subtle things that could be going on that you know that we really ought to know about so organic particulate matter we know that organic compounds do tend to partition to organic particulate matter in in the outdoor environment that's in part how secondary organic aerosol forms and so this emitted organic particulate matter could be a vehicle for the transport of reactive chemicals or toxic chemicals into the lower lung in the indoor environment and it could alter the fate in general of those chemicals we know there's a paper from Yelena Nomova from the early 2000s that shows that as PAHs come in from outdoors they repartition between the gas and the particle phase so more of those PAHs ends up in the particle phase indoors and that's associated with carbonaceous aerosol concentrations and so this provides some evidence for that but we don't know a lot else right how does this additional PM 2.5 affect the partitioning of things like reactive oxygen species or toxic chemicals like PFAS and and how does that we expect then that that would alter their fate ammonia concentrations are much higher indoors than outdoors indicating an indoor source about a factor of 10 or so probably in homes so in the CASA campaign are my colleagues injected ammonia three times in one day and you can see it here on the screen if all of the inject ammonia that we injected into the home remained in the gas phase then the concentrations would be up here in green right but we measured that ammonia and what we measured was down here in yellow so what happened to all that ammonia we believe that it partitioned probably reversibly we don't know for sure to indoor surfaces and so that the indoor surfaces are a huge reservoir for ammonia so at the end of the 24-hour day where we did this injection three times about 70 or 80 percent of the injected ammonia was in those house reservoirs that's huge right I'm kind of an advocate for water I would say in the environment in both the outdoor environment in the indoor environment and so I find it really interesting you know I've been wondering like how does water on all these surfaces affect chemistry and partitioning and does it even affect chemistry and partitioning in indoor air we try not to let the humidity get too high indoors but we did this experiment both on a high relative humidity day 70 percent and a lower relative humidity day 40 percent I know in some parts of the country the humidity is much lower than that and when we did our best job to fit the data with a model the best fit model including reversible surface reservoirs says that the surface reservoirs for ammonia were 50 percent larger on that high relative humidity day so to me that tells me that there's enough surface associated water in the indoor environment to make a difference to partitioning and probably to chemistry okay who cares right what are the potential implications of all that ammonia in indoor air well when ammonia gets sucked up into surfaces it changes the pH of the surface and that will affect partitioning so acids like acetic acid there's a lot of that in indoor air get pulled into the surface also nitric acid would be another example but also bases come off that surface so nicotine for example comes off the surface that's something that we do know from previous work but there's there really is still now we know how ammonia works and that it's important indoors but there's really a limited quantitative understanding of the impact of ammonia on indoor air okay recently I've been doing research on PFAS outdoors and in indoors largely the our state government got us involved in that and I'm glad that they did it's been very interesting project and we have a lot left to do so these are the plot here shows 26 ionic PFAS species these are carboxylic acids sulfonates and haps and what we found is that let's see we did a study of 10 homes in North Carolina and that the concentrations of ionic PFAS are two or three times higher indoors in these single family homes than they are immediately outside those homes and they're a factor of 10 higher indoors than they are in the regional outdoor background okay so we know there are sources of ionic PFAS in homes and we also measured nine neutral PFAS so these are FTOHs and fozies okay and the concentrations of ionic PFAS in homes are on the order of pica grams per cubic meter but neutral PFAS are nanograms per cubic meter much higher concentrations so we think there are sources of those indoors as well this shouldn't come as no surprise so these PFAS per and polyfloral local substances are manufactured chemicals why do they make them yes they make them for firefighting phones but mostly they make them for use in consumer products so you'll find they're probably in the carpet here and on the seat cushions I'm guessing okay um we're I would say lucky that there's been a fair amount of work relatively speaking in trying to characterize the concentrations and the species of PFAS present in consumer products okay but one of the things we don't really know is how do you predict emissions from what's in those products there is a challenge in terms of understanding you know there's kind of an evolving formula in terms of what what is manufactured and what is put in the products there are more than 10,000 PFAS species that have been measured somewhere in the environment um so what are the major sources to indoor air you know where where is the the air con where are the air concentrations of PFAS coming from and what influences their partitioning to particles and to dust and to indoor surfaces what processes and pathways drive indoor concentrations and exposures and emissions to outdoors for example and are buildings a significant source of PFAS to the outdoor air okay surfaces can have a huge impact on air concentrations there are large losses of compounds from the air and also surfaces can be a source but they can also be a reservoir that then releases those compounds later so this is um you know the the impact of sources of surfaces is much larger indoors than it is outdoors so this is an example we measured with the chemical ionization mass spec in one home um uh these are the major water soluble gases present we believe acetic formic and lactic acid there and every time the about every hour this was summertime about in North Carolina remember anyone who's been there right it's more humid than it is here and you have to run your air conditioner or your house molds i i believe somebody told me that um so every time the acetic and formic acid peak drops that's because the air conditioner was turned on and when it raises comes up again that's when the air conditioner turned off so i believe that the losses of these water soluble gases occur in the ac system probably to damp surfaces they increase again rapidly probably because they're coming off of surfaces that are serving in the building that are serving as reservoirs for these gases okay so indoor surfaces in the indoor environment the surface to volume ratios are really high compared to the outdoor environment indoor surfaces the surface soiling or the surface films on those surfaces and then surface associated water are all really important parts of the system they provide in some cases sinks or reservoirs for chemicals and also primary and secondary sources of chemicals i just stuck this slide over here too to remind myself and you that some of those surfaces come in very close contact with us right and so part of our work for example has been looking at how PFAS in the air partitioned to initially clean non-treated clothing and provide perhaps an opportunity for dermal exposure this could happen with other chemicals as well phthalates for example and in any case an important thing about surfaces is that surface reservoirs prolong the residence time of chemicals indoors and that allows much more time for reactions to occur because out indoor air doesn't spend that much time indoors okay and so that provides an excellent opportunity for secondary for chemistry to take place and for emissions of new chemicals from surfaces we know that so surface soiling and water alter partitioning we really don't understand their role in chemistry it certainly could be that windows are a great place for chemistry because we have sunlight coming in and we could be producing radicals on those soiled surfaces that then react with the chemicals that land there and produce other things okay there is an excellent opportunity to use real-time mass spectral methods to measure emission rates with excellent sensitivity and so some of my colleagues have done this in real buildings they bring a little reactor basically and they stick it right on the surface the real indoor surface they'll run something through like ozone or something like that to simulate the oxidation and then measure the products coming off this is a great idea we weren't quite as clever and so in my lab we put together a little flow reactor we put rain jackets in it you know waterproof rain jackets and we measured the PFAS FTOHs coming off those rain jackets these are these neutral PFAS fluorotelarmer alcohols are byproducts of the production of the carboxylic acids the the PFAS like PFOA and PFOS these compounds that they're trying to produce for to make the rain jacket waterproof but it turns out there's there's a lot of these neutral PFAS present as well so understanding so I'm think about trying to understand an environment as an importantly inter iterative process we need to go to the real environment and make measurements to build hypotheses about how things work then we have to test those hypotheses in controlled experiments in the case of the indoor environment because of the complexity we really need to do that maintaining some of the complexity of the indoor environment and a really nice thing about in studying indoor environments is while indoor environments are diverse and complex it's much easier it's actually possible to control the operation of the building to make to tweak and perturb things in the building to test our understanding of the chemistry and I think that's really important okay just I know I'm about out of time here it looks like but I wanted to point out that buildings are also a source of chemicals to the outdoor environment so we've looked at this a little bit for PFAS very recently and we can see that for one single-family home the emissions of nine neutral PFAS are much greater than the emissions of 26 ionic PFAS to me actually this tells me we may be missing a bunch of PFAS coming from the manufacturing plants because they measure a lot of emissions mostly of ionic PFAS and tend not to report we wanted to compare our emissions from all of the homes single-family homes in the United States to emissions from some other source and we can't find these neutral PFAS in the emissions inventory for the manufacturing plant um in this is an excellent case for a mass balance you know there's 10,000 or more PFAS out there somewhere how much of the mass are we capturing what are we missing you know um that's you know just an example of things that we need to do okay so I think that you know we we 10 years ago I would say we we had a a foundation of a very small number of very good scientists working in this field there was an influx of energy and funding for research over the last 10 years that's brought many more people into the field and new instrumentation we've made a lot of progress actually in understanding the underlying drivers of chemical dynamics and progress and developing and demonstrating tools and methods but we really need to develop a quantitative actionable understanding of environmental the indoor environment and that will benefit from this iterative process of really testing our understanding with models and realistic settings and comparing those model results with measurements we also in order to do that we'll really need to identify sources and measure emission rates um and so I'm going to stop there I'm sure I'm out of time okay thank you thank you Barb um we have a few minutes for questions and Linda's going to pull up some of the the chat questions again if you have a question that you'd like to ask Dr. Sherpin please come to the microphone um so uh so right now how does our current understanding of chemical complexity inform your research program oh yeah um I think that um what it means for me is that I can't just come up with a hypothesis that I test in the lab in with simple systems right when um you know doing controlled experiments is really important to under developing understanding and testing your understanding but those controlled experiments really have to happen either by bringing the complexity of the indoor environment into the lab or bringing the lab into the indoor environment you know making use of those making sure that for example if you're studying chemistry on surfaces you're using authentically soiled surfaces that's anyway that coming accounting for that complexity is the only way I think that will move forward in a uh in an actionable and quick way okay um uh Trey yeah um excellent talk question in the early 2000s with the PFAS and we focused on the PFAS and PFOA the longer chain sort of precursors like the C8 and there was a I guess a push to go to the shorter chain and less toxic and hopefully less toxic what are you seeing now are you seeing these shorter chains or are you seeing fragments of the polymers particularly in these airborne exposures yeah we um our measurements for PFAS really started um recently um and uh the the long chain acids and sulfonates are still there um we know that um FTOHs for example uh these fluorotelomer alcohols um are oxidized by OH radicals to form acids and so we suspect that in the outdoor air the PFAA the PFOA for example is still present in outdoor air probably because of photochemistry okay um so yes in indoor air and in outdoor air we see these legacy compounds and we also see the new compounds as well thank you so we're bringing out of time but um there was a related question um the that was um have you looked for ultra short PFAS oh yes um yes um actually I'm really pleased at how many standards we were able to get we always want more and they're expensive but um yes we see the like the new compounds as well as the legacy longer chain compounds right I think we have to move on to the break now we um I have a break a 15 minute break and we will return at 10 50 oh hi everybody um we'll go ahead and get started with the next session we have a panel discussion related to this um this broader session on chemical complexity we're calling it assessing chemical complexity in indoor environments and we are joined in this panel um but I'll go straight down the the line here Robin Dodson the associate director of research operations and a research scientist at the Silent Spring Institute Vito Alacqua acting director of the Center for Scientific Analysis Office of Radiation and Indoor Air Office of Air and Radiation U.S. Environmental Protection Agency Zhao Yulu senior physical scientist at the U.S. Environmental Protection Agency and Barb Turpin professor at the University of North Carolina in Chapel Hill um so I will be asking I'm moderating the session I'll be asking some questions of the panel some specifics some broad um the folks online or here can also ask questions if you'd like to pose a question come to the microphones we'll keep an eye on the chat um we don't have a huge amount of time we have about 25 minutes to do the panel so we'll see what we can get to um all right so what I'm going to do is start with um uh this question um and I'm gonna start with Robin because he's right right right next to me uh give me some thoughts here um do we know enough about the chemical composition of indoor environments to assess exposure and make recommendations for safe practices yeah so that's a it's a hard question I think we don't know enough yet I think there's a lot to learn um as I think the both speakers this morning had talked about um there's still a lot to learn but I don't think that that necessarily means there's not time for action or or kind of prioritizing some recommendations um I think particularly people want to know what they can do um and I think that we have enough information to provide that to folks um and I think we should even in the kind of operate in this area of kind of not yet knowing the you know definitive answer that we need to move forward um and continue to do the work but also still providing some real practical information to people um in their homes and you know people are really concerned about their exposure so um keep on going but we need to get it out there what we do now when you say practical information that we are like what can you just give me a couple of examples no so I mean I do a lot of home-based studies with uh folks um and we always sit down and have these conversations of you know we might share with them what their levels were in their house and they want to know well what can I do about it um so even things like you know leaving your shoes at the door and increasing ventilation if that's appropriate um people want to know that now and we need to communicate that a sign test we need to communicate um what we're finding right so Vicki had mentioned like she's not going to go out and recommend certain building materials necessarily just yet but maybe we can start kind of pushing things in that direction to provide evidence-based or empirically based um uh tips recommendations for homeowners okay great does anybody else want to uh speak to this broad question about making recommendations for safe practices? I can just follow up with what Robert said for example EPA we have those voluntary programs such as the safer choice program also designed for environmental capacity sites and the program like that also we have the indoor air school kids those are good programs to help the people to be aware of the indoor air quality issue great um I wanted to point out and I meant to mention this before that we were supposed to have uh John Abbott a professor from the University of Toronto on the panel as well but he couldn't make it because he was ill but he did actually answer this question um in absentia so I thought I would provide that answer from him so the question was what do we know about chemical composition and recommendation so he said we know a lot about some commonly recognized pollutants increasingly so with the deployment of low cost sensors however the recent advances in sophisticated analytical instrumentation have demonstrated the very high degree of chemical complexity that exists indoors strongly suggesting that there is a lot we don't know there is true this is true not only with respect to primary pollutants but in particular to secondary ones formed by chemical transformations and we'll discuss more about that later today uh transformations many of these species are challenging to detect even with today's instrumentation highlighting the need to continue to deploy the latest advances in analytical chemistry indoors and we'll probably make the point too that despite the fact that they're it can be difficult to detect they still that does not mean that they're um meaningless you know that they still have meaning in terms of they may have meaning in terms of health all right so um let's uh see are there any uh okay I will continue my line of questioning um so what analytical techniques and tools could advance or understand and you can be broad about this but um about what you're thinking about the tools that you think we should be deploying and where and how we should be deploying them and think of what I'll do is jump over to Barb for this question here we go that's funny because I just thought of my answer to the last question so here we go you may you may retrospectively answer that question are you are you thinking that um I was going to be a little bit obnoxious perhaps and say as a consumer well so first with my science hat on I'll tell you that you know the most effective way to the most effective way to clean the indoor air is to find the sources and remove them right and as a consumer I find it kind of surprising and a little bit annoying that actually that um we let companies make all these products where we we don't make them test them for emissions right so how come I bring products into my home with no idea what they're emitting into my air um that seems you know kind of wrong to me so I think it would be wonderful if we could solve that problem maybe that's not easy to solve so the we we do do emissions testing of some things but maybe I guess the majority of things that may come in our homes have we don't do emissions testing on is that that's true no so so that's with that in mind what kind of instrumentation do you think we're we should be deploying more or to help us understand this complexity yeah I think there's a good role for a tiered approach um you know when we bring these real time highly sensitive instruments into an indoor space we're we're looking at one or two spaces at a time right where you can't just do that anywhere it's a big imposition to bring those big instruments into a building especially a home and that means that we're not really studying the diversity of spaces that we have and we're probably overstudying um sort of if we're talking about homes middle income or upper income homes right um so I think we do need a tiered approach where we have where we cover a lot of buildings with some measurements and so those are probably integrated samplers um or you know low cost sensors and things like that and then you can benchmark against that so um you know you can do a small number of highly controlled experiments in real spaces that fit within that exposure framework and you can kind of understand um and accommodate um the diversity of spaces in that way yeah push the button here and maybe it's a more general comment that a lot of the people here know about the bears repeating for more in general so one of the successes that we have had in in later years and all the progress that's been pointed out to us it's it's been really from the idea of bringing outdoor instruments indoors that was pioneered by the Sloan Foundation earlier efforts and and I think that's something that we want to continue to pursue in terms of we have already a lot of the tools to characterize what we want to to know it's uh it's there are there challenges of course but we want to move away from this situation where indoor air or indoor air chemistry is sort of the ugly step sister to ambient air because ambient air is regulated and so we have need for investments we want to have the same understanding that we have for outdoor air bring it indoors and those instruments that may be useful yeah I just want to add two is the importance of developing tools like non-paragated analysis um for discovery basically of what's indoors with that is not only working with a great chemist to do that but also you have to deal with the data side too and I think we need to continue when I think of you originally asked this is like tools I thought it's not only just like instrumentation and maybe even like the instrumentation they might have in the lab mass spec and other instruments but then also the tools the statistical tools to actually interpret and understand the huge amount of data that is produced with that those kind of methods I think that needs to have developed in collaboration and kind of in hand in hand as we kind of think about how we can really tackle understanding the complexity indoors so actually I'm going to take a look so are there okay I haven't looked at these so I want to take a look quick on the um so this is a very specific question um oh sure I'll get you after this question okay yeah um how do we fill the gap between PFOS currently being measured and the greater than 10,000 out there using current technology so uh Jiu did you want to speak to that so I think yeah well there are a lot of PFOS it's it's very actually it's not realistic to study individuals all the time but we have information about the some of those PFOS we also we can use non-target analysis to detect more or understand more of the their source faith and transport we also have the suspected screening mode mass spectra which combined enhance the traditional methods with computational assessment prediction or data analysis that will help uh to enhance the pace of the chemical uh assessment I think so so with non-targeted analysis the the species have to get to the detector right so it's a little bit more than that so are there techniques that uh help you capture the broader range that of uh the PFOS have different physical properties? I'm not aware of that right now no I don't but that's something definitely would be interesting the other thing is like for emission testing or source characterization or a mechanism study you may want to think about the AI technique and also the remote controlled robot like robots those kind of things yeah interesting Barb did you want to there are methods they're pretty pretty new but to measure so you extract the organic compounds and then measure all the flooring in those organic compounds um through IC for example that's one way to do it so uh Dr Thomas? Yeah kind of a provocative question and tier you know we have a lot of data gaps and one way that we talked about meeting them is through models and part of it you need data robust data you know for models so one is that still an approach and two can we use AI and machine learning tools we're seeing this as other informatics areas that help us to collect and share data and actually can it help with the modeling so the question is collecting the data and are these new tools that are coming online a way that we can help to meet develop robust models and meet data gaps? Well I can speak to the measurement part not the AI part necessarily um but I would say that there are data gaps and I would say unfortunately I mean I do a lot of work in the SVOC space so flame retardants, PFAS, phthalates um and part of the reason uh getting measurement data is really hard um and it's expensive it takes time um I think it's very worth it because I think as I think Barbara actually did a great job in her presentation kind of talking about how we need this you know I guess in the report it's called a three stooled kind of approach right but that we need to have this kind of iterative talking between the models and the um and the experiments and the measurements and so I would urge us as there are data gaps to actually keep providing the resources to continue to collect the measurements because I think that's going to be very important to inform any of the other aspects and what I mean by that is that we go into people's homes and we find say phthalates and the levels in indoor air are orders of magnitude right I mean like thousand time fold between the lowest level and the highest level and that's that's tricky like we have to ask why and then cramming that into a model is tricky too right like do you represent the the middle of it do you represent the high-end exposure so um I think we need to continue to try to address some of those data gaps by continuing to collect the measurements even though it's a hard thing to do add something else too I think that's um very worthwhile question to ask how we can use AI techniques and I definitely second your thoughts on measurement because that's really the basis from where we start I think we're just filling our way around this point on what is possible but what has been shown lately in terms of progress is really uh manipulating language and manipulating language certainly has its purpose here the we were talking before about how do you get the information to researchers that about things that are being measured how do you find it this this is a whole open field of possibilities really when you have so many different compounds that are being measured in so many different contexts may not be someone who's really interested in indoor chemistry but on a particular product or in particular so there there's certainly a scope there if we are talking about helping us understanding that's a whole different level of uh of process and I think there was an interesting national academy's workshop on on on use of AI to make science and the 2050 challenge to do to do use AI for a Nobel prize winning discovery I think there's scope there but we really need to build the infrastructure with including the chemoinformatics way of storing the data in a way that can be used by these other tools so talking about the machine learning I think the one of the application is the QSAR model for example for PFAS uh we don't know the chemical physical chemical property for a lot of PFAS so if we have some experiment data we can use uh we can develop QSAR models through machine I think that's a good way so the QSAR models are um there could they be combined I mean I guess with you know AI and in a way to sort of bootstrap that more rapidly okay okay good um so this sort of is leading towards this this question we've been talking about measurements and and sources and source control and things like that but um let's talk a little bit about um how we deal with this from a regulatory perspective so um you know what regulatory mechanisms do we have right now for guiding complex sources I mean do we what do we have that that's either doing it directly or indirectly um anybody can jump in on this um so I I think we need to be a little bit try to be a little clever in this space about what are the regulatory mechanisms I think there are things like TOSCA at EPA can tell us which chemicals can actually be used in the products um we could think about source control and thinking about what actually chemicals can go and building materials and things like that one thing that I do think an area that I think that we could make some headway is thinking about um kind of the green building space or the energy efficiency space and those certification programs um indirectly right so for example HUD requires a certain amount of their properties to meet certain energy efficiency standards what if those energy efficiency standards green building standards included they kind of include it now but they actually required information about material specification so that these what is actually put into these buildings um is meet certain requirements um or does not include certain chemicals um I think that's an indirect way to kind of have uh it's it's not a policy lever necessarily but it is a it is a way to kind of use that system to um affect millions of homes particularly homes that might be for low income residents um and I think we need to kind of be creative um in that space so you did you want to so uh what I want to say is uh EPA we don't have we all know we don't have regulations for the authority to regulate any indoor chemicals and the concentrations but as Robert mentioned we have PASCA we also have indoor air act um those will help to uh major I mean regulate or in the other way not directly way uh regulate some of the uh chemicals for example under TASCA we have the thermally high emission standards for composite old product that will directly impact the indoor air uh indoor thermally high um concentrations I wondered if we wouldn't have some comments some answers to that question from the audience as well because I think we have folks from NIOSH in the back and Consumer Product Safety Commission here as well and so it seems like you have some control over uh indoor spaces yeah no comment I see oh somebody's coming to the microphone that's great so um all regulations are different so different regulatory agencies will have kind of different uh statutory language and requirements but I think there are some similarities so any regulation would be based on a combination of measurement and model data and any available data using the best available science we would be looking for transparency so you know when we do math and show exposure equals x hazard equals y risk equals z and can others reproduce that math and you know I think for indoor chemistry and um taking what you're learning from these really in-depth measurements and what I would like to see would be operationalizing that and generalizing that to be able to say what what did we learn in these couple of homes with really in-depth measurements can we apply that more broadly to different kinds of buildings or different kinds of spaces um there's an exposure factors handbook chapter chapter 19 called building characteristics and what's in there right now is air exchange and room volume and house volume but you know other things could be added to that like surface to volume ratio or interzonal airflow or relative humidity and you could see how you could get these different kinds of building spaces that represent different parts of the country so if you put in one emission rate you would get a range of you know potential concentrations across the country and increase your kind of ability to generalize what you're learning between measurements and models any other thoughts from the audience on that question okay oh sure one more thing here and so first as a federal employee I'm not supposed to argue for particular regulations or legislation but I think we should but not it's not because of that that I want us to take a moment to perhaps appreciate the fact that it may or may not be the right tool at this point in time for our understanding of indoor chemistry to have regulations on on the table there are perhaps other avenues and other ways of that increase in the process also the public understanding I just because I said before the indoor chemistry doesn't get as much attention as perhaps outdoor air but the additional legislation and regulation may not all solve as many problems as as we think and some of our colleagues that have operate with um in spaces that are more highly regulated can testify to that so there are some advantages we want to move carefully but particularly we want this these tools to follow the science rather than preceded that that to me seems the most important thing Tray it's easier to ask questions than to answer them and again these these are my thoughts and not those of the commission I do want to follow up my colleague Charles's answers that we do the and as EPA said you know there's no direct to understand regulation of the indoor air we do have authority over products and you know and I'm on a panel later can talk a little bit more about that but I but individual products and we tend to look at emissions from that product and you know the potential risks you know there are other agencies like FDA that have jurisdiction over personal care products and so forth so there there are you know cross jurisdictional issues but I think to the earlier question again there are regulation for these products regulations under the for example the federal hazardous substances act but again this is it's been on a primarily product by product basis we are talking about ways to look at mixtures of chemicals and I think later we'll talk about reactions so I think that you know one of the questions and I think as we're talking about research needs is better understanding and I think that's going to be sort of a thought that I'll have throughout the day is is that you know do we have the data to be able to understand what these mixtures are what these you know reactions are what what are we seeing in the indoor environment and from our perspective what's coming how is that resulting from you know individual consumer products I'm going to move to a question from the chat so there's a question about are there any dallys known for PFOS and by dally I think they're referring to the disability adjusted life year I'm not sure that this group knows about dallys for PFOS specifically but there's a related the the question goes on if ventilation rates are reduced through use of an IAQ procedure concentrations of PFOS and I guess organic acids I'm not sure I think so could increase indoors thoughts so yes if you reduce ventilation then probably the concentrations will increase that's true and I guess I would say that much more is known most of the tox toxicological information about PFAS is for ingestion and there's not very much at all for inhalation so we just don't know okay so I'm going to ask that question I've I want I always like to ask um what are you passionate about right now and I oh by the way speak to the microphone from what I understand they can't hear when I turn away so yeah what are you passionate about right now I'll go down the line um well I guess a lot of it but I guess something that kind of rises to the top is actually providing and I talked about this at the beginning as evidence-based recommendations for mitigating exposures and that can be as simple as you know we did a study very recently that we're putting the Corsi Rosenthal boxes in classrooms that's great for COVID that's why they were there but we found actually they significantly reduced airborne concentrations of phthalates and PFAS and that is something that I think we need to keep testing those like that was kind of the hypothesis it worked and when we find these findings we need to share that and we need to get that out there so developing these kind of mitigation strategies and testing them I it's kind of where I'm a lot of my research is focused right now well personally I find the modeling aspect of indoor chemistry the most exciting at this point and for a number of reasons first because it's certainly an interesting tool and we can do a lot of what-if analysis that would be difficult to do otherwise that's true of every modeling but I think in particular for indoor environments modeling is indispensable because of the one of the greatest challenges really of operating in indoor air is the variety of indoor spaces the air that we have in this room right now it's different from that in in the next building or for that matter even in in another room of the same building and some of these differences matter some don't but the way to understand them is really yes you have to measure but you can't possibly measure everything everywhere and so certainly this is one of the tools that that help it also helps in trying to understand what are the most impactful changes that you can make because of the freedom essentially that you have to that you can play with the different parameters and the different solutions so these are there would be more but I just want to say that despite the passion we always have to modelers have to remind themselves all the time that what they're looking at is an abstraction of the real world in the same way that a map of a building is not the building and so experimental measures and verification of everything that we do is is necessary so I'm currently interested in developing methods and test protocols for starting the indoor chemicals source and faith and transport and the mechanisms also the exposure test protocols especially for chemicals from consumer product and building materials I would like to see like a very standardized generalized test method instead of just focusing on one chemicals at a time thank you oh my first thought is that I should say I'm passionate about being outdoors which is true but you know what I think it would be really helpful is if we designed a field campaign and I think that design somewhat to some degree was led by modelers but we don't do it now right we do it maybe in four years okay and by designing that field campaign led by modelers we will figure out what are really the key things that we need to measure before we go to the field before before we do a you know and and then the purpose of that big field campaign would really be to test our understanding right and I would I think that would be really helpful in directing the measurements people to the most effective and important things to do in the meantime you guys are very succinct in your passions I like that you're right to the point we have a few minutes I'll take one more from the so here's an interesting question have any studies been done in schools versus housing when children come home from school they reek of chemicals any thoughts there or anybody in the audience has done any schools related work that could speak to that question we have tried to get into schools it is really really hard to do measurement studies in schools there are some good studies out there that look like use some kind of low cost sensors in schools and things like that but a kind of a quantitative assessment in schools is pretty difficult to do so it's yes I mean that would be a great thing to look at it's just practically very difficult to do yeah I see a lot of nodding heads out there in the audience folks that have tried to do this or are participating in that and they find it very difficult any comments on that on that yep could you go to the microphone I would say also it is hard to get into schools and each school is different so you find a lot of schools with varying HVAC systems and age of buildings and how they're operated and level of support within the school itself so I think that makes it even harder to grapple with doing those types of comparisons all right thank you we have a couple of minutes I had one more question that's sort of getting into some details but so what we see and what we've seen in some of the talks here and what we'll see in later presentations is that we have these sources that we think of as primary sources and then we also have secondary we have these transformations that take place and both of our speakers alluded to some of those transformations how do we from a you know recommendation perspective regulatory perspective or otherwise value the primary versus the secondary if we have enough information to to say what's going on can we can you regulate something that isn't originally put into that environment because it was changed in that environment let me let me try it first so this is an interesting question because it really goes to the root of why we're doing indoor chemistry in the first place and and we must recognize that we have had some successes if we just focus on primary pollutants and and taking a look at those and what can we do is to reduce those first and secondary pollutants are second order effects so in a sense you have to understand first how important it is compared to the primary ones and then decide if it's at what level of attention it needs to rise we know fairly well what is the list of pollutants to bear the burden that it inflicts the greatest burden of disease on people and as it was even just a very recent paper that we did that analysis I think Marantis and others that they really looked at that and so we know it's PM it's NO2 and other nitrogen species it's how they hide sense so the first approach would be to say well let's take them individually at isolation you get the biggest bang for the buck by doing this in this in this particular order but but then you have to really look at a second look is to really say well okay some of these pollutants like you were saying are not released by anything that we have in there particles is a classic example and the one and the one that has been studied the longest so how much of the indoor particles are coming from secondary reactions indoors as opposed to particles emitted by the activities or coming from from outdoor air it depends of course that's not the kind of answer that we want but but that's where our understanding of the indoor air chemistry as a system is is helpful and the same we could do of the other species that are listed as well and let me stop and see if others want you want us to talk more just that's just one yeah we're basically done but you can say a few I would guess that you know it's complicated too because of the they're often two actors so let me just take the case of if you if one places an indoor air cleaner in their house that generates OH radicals is it the VOCs that go into the indoor air cleaner that are the problem because they then make oxidants you know aldehydes for example or is it the or is it the indoor air cleaner produced OH that makes the problem so you know there you go let go ahead let me pick it up again on that because it's an important point I think that this this aspect it's really critical and and it's why we want this understanding it in some ways we are seeing happening indoors what has happened with outdoor air in the past where people for example trying to regulate O's and to regulate to reduce O's and the dilemma was do we reduce the which precursors do we reduce the nitrogen oxides do we reduce the VOCs that's to the point that Barbara was was talking about and I think that in it's been raised more recently to our attention really that yes we have been looking at all the oxidants indoors they are certainly important but we also probably want to start thinking about levels of bringing the volatile organics down because that is really one of the fundamental ingredients here one in which we can have some control at least and we have talked definitely about that the stuff that we bring into our accounts there are questions here just I want to offer a very succinct answer to the question you asked a few minutes ago which you asked about regulating the secondary pollutants and I think that this shows us the value of studying indoor chemistry because the only way to regulate or control those secondary pollutants is to understand the most important primary factors that we can control so that would be certain types of chemical air cleaners regulating ozone or trying to reduce the amount of ozone that comes indoors because we know that that's going to produce secondary pollutants so again the succinct answer is you can't regulate the secondary but being aware of the secondary helps you identify what you can control thank you Brett so we do need to take a short break I want to thank our panelists for taking the time to speak with us and we'll try to get back in about five to seven minutes that sound good quick break