Rebecca Sheesley and Sascha Usenko
Season 4 - Episode 430
How does urban pollution impact thunderstorm activity? It’s a question of interest to the Department of Energy, which turned to two Baylor professors to investigate. In this Baylor Connections, Rebecca Sheesley and Sascha Usenko, professors of environmental science at Baylor, discuss research that can uncover clues about thunderstorms in urban areas and lead to improvements in public health in Texas and beyond.
Derek Smith:Hello, and welcome to Baylor Connections, a conversation series with the people shaping our future. Each week, we go in depth with Baylor leaders, professors and more, discussing important topics in higher education, research and student life. I'm Derek Smith and our guests today are Dr. Rebecca Sheesley and Dr. Sascha Usenko, Associate Professors of Environmental Science at Baylor. Dr. Sheesley's work on air quality spans multiple continents with studies in Texas, the upper Midwest, Southern California, Scandinavia, South Asia, and the North American Arctic. Dr. Usenko focuses on the environmental fate, transport and distribution of organic contaminants in the environment. His studies have analyzed samples from all over the world. He engaged in a highly regarded research partnership with Stephen Trumble studying whale earwax last fall. Sheesley and Usenko, along with collaborators from other universities were awarded an $890,000 grant by the Department of Energy Atmospheric System Research to examine the impact of urban pollution on thunderstorm activity. And they're in the midst of that research now, and they're with us today here on Baylor Connections. Dr. Sheesley, Dr. Usenko, thanks so much for joining us. It's great to have you today on the program.
Rebecca Sheesley:It's good to be here.
Sascha Usenko:Thanks for having us.
Derek Smith:Well, great to visit with you both and learn more in particular about this project you're doing with the Department of Energy. But I want to ask you both specifically, so we can get a sense of the strengths that you each bring to this project and how you compliment one another, to talk about your areas of research, focus a little more specifically for those of us who are not in your discipline. Dr. Sheesley, I'll start with you. What's your research focus that you bring?
Rebecca Sheesley:Thanks for asking. One of my focus is just to understanding sources of air pollutants, so understanding how those sources change over time, and that can be different for anthropogenic versus natural sources, understanding how those sources can impact urban air quality, which is a lot of what we do in Texas, then understanding what is unique about those different sources. So if we're looking at wildfires, trying to understand what it is that's unique about them that we can then track those emission plumes in the environment. And then another focus of mine is on understanding how we can characterize the transport of these different types of pollutants. So as you mentioned, sometimes I work in remote environments, so I'm trying to understand where these pollutants come from and how they're transported over such long distances. But we're even interested in understanding that transport in Texas when we're considering things like dust storms and wildfires. So we're interested in understanding that transport and then also in the chemical changes in those pollutants at that time. So those are a few things that I'm interested in.
Sascha Usenko:Yeah, my group is interested in really utilizing analytical chemistry to understand complex environmental chemistry questions. And for the atmospheric group, obviously we want to look at some of the chemistry that's going on in the atmosphere, including how chemicals move or change in the environment. And those chemicals, like Rebecca said, can be naturally occurring or caused by human activities. So in that regard, I often describe myself as think about the fate transport of contaminants, specifically organic contaminants in the atmosphere. But with that, I also like to utilize analytical chemistry and advanced instrumentation. So part of my specialty that I help bring to the group is an understanding of mass spectrometry, as well as just an understanding of analytical chemistry and instrumentation. And so part of our group, employing a wide range of instrumentation to Houston in the upcoming years is really getting these mobile laboratory systems up and going with a specialty in making them so that we can take a multi hundred thousand dollar instrument and be able to travel down the road at 60, 70 miles an hour making measurements. And so it's a great combination of both the physical sciences as well as engineering aspects as well.
Derek Smith:What kind of impact can this work have and what kind of impact are you excited to see this work have?
Sascha Usenko:So I think this work is... We just even think about the work that we're doing in Texas, or even for this work particular for Houston, we're looking at the interactions between storms and pollutions, but really talking about the public health of millions of Texans and millions of people in the country. So the goal of this work is quite large in just the scale and scope, but the magnitude and the outcomes for public health is pretty powerful. There's a huge number of folks that live very close to some of these source regions or in these big urban areas, and we may be impacting their public health, not only just with the air pollution, but also its interaction with the storm cells and storm cell formation. So it's a pretty exciting thing, but it does really impact millions of people and including millions of Texans. So just from that scale alone, I think it's pretty important work.
Derek Smith:You used the word atmospheric particulates, what are some sources of these? In particularly, as people maybe picture driving around Houston, if they've spent some time there, what are some sources and what are some of these particulates? What do they consist of?
Rebecca Sheesley:These particles can have a lot of different sources. So you can have direct sources of these particles or primary sources of these particles. Things like motor vehicles can emit a lot of particles directly. If you've driven behind a diesel truck and seen the black smoke, those are black carbon particles. You can have smoke particles associated with dust storms, so things like the big Saharan dust storms that come across the Atlantic, those are sources of particles. Things like wildfires are sources of particles, but then you can also have particles being formed in the atmosphere from chemical reactions of various precursors. So the particles can be a very complex mixture of organic compounds and salts and metals and a wide variety of things.
Sascha Usenko:One of the things that's exciting about the atmospheric chemistry is the fact that a lot of the aerosols can be directly admitted, like she said, or even produced in the atmosphere. But a lot of times those particles also change over time. So it's a very fast and dynamic system and that really lends towards what type of equipment and instrumentation that we have to have in order to study those very fast and rapidly changing dynamic systems. So we need a lot of real time instruments to go after those scientific questions.
Derek Smith:As you study these, Dr. Usenko, what are convective cell events and why is the Department of Energy in particular interested in them?
Sascha Usenko:So I think when most people think about convective cells, they might think about from their point of view where they're at the ground and they can see these big storm cells coming through and these big uplifting events of convective air moving higher and everyone sees big stacks of clouds forming. And they often think about those with severe weather following in the path. And so when we think about those systems coming into an urban atmosphere, there's an opportunity for that system to be changed or altered by the air quality or air pollutants within that system, changing potentially the strength of that system. And in part, that's what Trace is looking at is looking at how those cells form, how strong they are and how they might change across an urban landscape. And so we see these cells, but sometimes we look at just from like a meteorological, we'll watch the storm front approach a city, and all of a sudden explodes in intensity and really heightens our senses think, what's going on? Why did all of a sudden did it change so rapidly as it approached or came across that urban landscape? So DOE is interested in that particular question of how we're interacting with these, basically due to our human activity, releasing air pollutants into the atmosphere, and then those being drawn into those systems.
Derek Smith:This is Baylor Connections. We are talking to Rebecca Sheesley and Sascha Usenko, Associate Professors of Environmental Science at Baylor. And Dr. Usenko, you talked about instrumentation and as you describe what it is that we're looking at and that question they're trying to answer, an obvious question is, how do you go begin gathering that data and from all of these different sources out in the field?
Sascha Usenko:The nice thing about atmospheric chemistry, it's a very collaborative network and people have expensive toys and they bring them together to try to answer these complex questions. And what you're talking about Houston, yeah, there's a lot of spacial differences as you go across Houston, and this is going to contribute to big spatial differences in potential air quality. And so some areas may have increased air quality due to those real local type of emissions. So when we approach it, we have to think of it from an experimental design. We have to be able to tease an event or an episode or a region against another. That's an often way that we'll approach this. And so with our real-time instrumentation, we can in fact, either set up in a stationary location and then have the air quality or the airflow move across that stationary site, and then we can look at the differences over a function of time. We might think about this with like urban traffic, having a known time period associated with it. Early morning rush hour traffic increases certain pollutants in the atmosphere associated with those activities. For the last couple of years, Dr. Sheesley and I have been accumulating, through different external grants, a wide range of analytical instrumentation capable of making real-time measurements for both gas and particle phase pollutants. We then have put those into what we call an air quality mobile laboratory that allows us to drive around Houston and both sample at different locations for extended periods of time, or to just make measurements while we're driving. And this experimental design, this set up allows us to really tackle the complexity of Houston, both in changes seasonally, daily, and of course spatially over the greater Houston metropolitan area.
Rebecca Sheesley:Because we have done a series of studies in Texas starting locally here near Riesel, we've done studies in north of Fort Worth, and then studies in Houston in 2013, we've been able to see questions that we weren't able to answer previously because we didn't have maybe as much instrumentation. So previously we would do filter sampling and we collected every 8 to 12 hours. That wasn't high enough time resolution for the types of questions we wanted to answer about the speed of changing sources and changing particle concentrations. And then we had questions about the atmospheric chemistry, like what kind of gas phase compounds would contribute to ozone or gas phase compounds would contribute to chemical reactions in the particle phase? So then we purchased VOC instruments and developed offline techniques for gas phase measurement. So we keep paying attention to the questions we weren't able to answer in previous field campaigns, so that each time we can bring a more precise set of instrumentation and be able to answer the questions that we really would like to answer in terms of the chemistry in Houston and the sources in both the gas and particle phase. So a lot of this is just hard earned experience with air quality questions in Texas. We're very lucky to have such fertile ground here close by to us that we can continue to ask new questions as things change in terms of climate and sources and wildfire activity and population increases and industrial changes. It just gives us a continuing source of new things to... New questions to ask and new techniques to apply to existing and long-term questions.
Sascha Usenko:And with these complex questions, there's another opportunity too for us, and that's really to build collaborations with different groups. And so the Tracer map campaign has collaborators from both U of H, Rice and UC Riverside. And so we've built this mobile lab and then it allows us to basically invite or to have these collaborators bring their instrumentation as well. And it's the combination of that entire group's effort and work that allows us to tackle multiple compartments of the environment, not just what's in the particle phase, not what's just in the gas phase or just in the [inaudible 00:13:03] system, but all of those in combination. And then even within that mobile laboratory, that mobile laboratory group's effort is then working within the larger DOE deployment, the AMF one deployment as well to help answer these questions. So we are lucky that we're so close to Houston and within Texas and the fertile grounds that are here for atmospheric chemistry, and it really does gain the attention of the national audience, as well as both the federal agencies, as well as academic groups as well. But really it is a concerted effort and a big collaboration amongst a number of tier one institutions.
Derek Smith:I'd like to ask you both this, and I'll start with you, Dr. Usenko. It's a little bit of a two-part question we can break up. But as you think about all the data that you are collecting, what are some of the clues embedded within that, that are of particular interest to each of you? How do you aggregate all this data together into something that's really useful long-term?
Sascha Usenko:Yeah. Of course, everyone's excited about what their main interests are. And then with collaboration, you have to be excited about other people doing good work as well, and then the intersection of those. So for me, I'm thinking about organics and so I get really excited about this next couple years of thinking about some of the volatile organic compounds, some of the sources are, what's changing about them, and their interactions with the particular matter chemistry as well, the aerosol chemistry as well. So there'll be things that I get excited. I might see, depending on what's going on that day, it might be a stormy day, it might be a clear day. So it might be a photochemistry question. And those are going to be the things that are going to be exciting. I'll see something of interest and pop up. Maybe a VOC as it relate to a natural occurring, or maybe from an industrial source and all that stuff is exciting. It's real time it's happening, so it is really exciting to even begin thinking about the data right at that point. That's really, as soon as we start getting real time data, you start thinking about what's going on. You might have a particular event that triggers excitement across the whole group and so then everyone's really then focused and intent about trying to understand what's going on within their data, the quality of their data, so they can begin to move on to that next step. And that's really to finalize the, what we call QAQC, the quality control quality assurance, to make sure that our data is sound so that we can start that interpretation. And then, because it's a collaborative effort, we work with the DOE group, we're on monthly calls now. We'll continue those monthly calls to talk about what our preliminary interpretation is to see, "Hey, we saw this. Did anybody else see anything that would help support that? Or could help me distinguish between is it A or B that's driving this type of chemistry?" So there's a whole process that goes on after this, that the first it was collecting the data. And once we have that, we'll really be in that interpretation. But everyone will have their own scientific questions and to be funded for this, we have our own scientific questions enrolled there, but then we'll also help to answer the larger Tracer questions as well.
Rebecca Sheesley:We're both interested in those volatile organic compounds. We're interested in how those interact with the particulate matter, which of those compounds are emitted from vegetation and can act in the atmosphere to produce more particles, and under what conditions that can happen. We're also very interested... I'm interested in the biomass burning side of it, so understanding which of those compounds are associated with biomass burning, because we do a lot with biomass burning in Houston. But then also we have this separate line where we also look at aerosol optical properties, things like black carbon and brown carbon, which can have direct radiative effect. So some of it, we have these set questions in mind, but we're also as field chemists, we're very opportunistic. So if we see something interesting, then that's what we're going to pursue and that's going to drive some of our questions and drive some of the research that we have. But to be honest, we also, we have a very collaborative process with our students. So there'll be grad students working on this and they'll see things that we don't see and we'll work with them to help them see new and different things. So some of it I'll have questions that I want answered or Sascha will, but we'll also just sit back a little and give the students space to ask their own questions. And that's a very exciting part of it as well.
Derek Smith:When you talk about student involvement, this is work for the benefit of all of us, but is it, for you guys, particularly as environmental science professors and when you think about all the impact that that can have on all of our lives, is it fun for you to see your students see that correlation between their future, the future of the environment that they'll live in someday and a project like this one?
Rebecca Sheesley:It absolutely is and it's very exciting with undergraduates and it's very exciting with graduate students. So with undergraduates, we have various undergraduates who work with us and they may not want to pursue a career in air quality, but it doesn't matter if they're going to be medical doctors or lawyers or business people. To have additional people know about air quality and understand some of these concepts is fantastic and that's part of our mission here. For the graduate students that we work with, ideally they're going on in a career in air quality and atmospheric chemistry. So we have different objectives there and different expectations. And we really hope that they dig in and find some niche to it that they're really fascinated by. But it is, I think one of the main reasons that I got into environmental chemistry is because I wanted to have direct application for the science that I was doing. I wanted it to help and I wanted it to be of benefit to society. And so this is why I do air quality and why I do environmental chemistry, is because I wanted to have the science that I'm doing to have a very direct application and be directly beneficial. So I think the students that I have share with that, share that goal a little bit.
Derek Smith:What's the timeframe on this, as you look forward to... As you interpret the data and look forward to trying to answer some of those questions, what's the timeframe look like for you all?
Sascha Usenko:Well, we have for the Tracer map, that's going to be in 2022. It got bounced back by one year due to COVID. So we're looking at the summer of 2022 to do data collection, and it will really happen as soon as we start collecting data. So there's a forecasting group to help identify events, within events being identified, measurements will start to be made and then data interpretation will immediately jump from that. Everyone in this group will basically want to present their work at a conference, that's that first step in data dissemination. And that's usually going to occur in December for a lot of this group. And so there will be a concerted effort to get their data ready to go, and we will as well so that we can present that with the whole group. And then it's a great chance for everyone to see what everyone else was able to come up with as well. And so over the next couple years, it's going to be a process of finalizing the data sets, sharing those data sets, and then working within our group here at Baylor, our collaborative group within the Tracer map systems, and then the larger Tracer DOE funded groups as well. And there's also funding from NSF and others. So there'll be a lot of opportunities to get out publications. There'll be a number of independent publications from our group, but then larger publications as our data set then is merged with larger data sets to answer even more complicated potential questions or to support other people's findings as well. So that data set will last for years. We've had projects before that were in 2013 and we're still working at that data. As we learn more, we go back and reinvestigate what we've done. So it's not a one and done. There will be lots of opportunities to do that. And of course we have other campaigns and other air quality activities going on in Houston during that time. We actually, Rebecca and I have another whole other project called BC Squared that operates in Houston. And so it'll be interesting even to see just between our groups and those two projects having data, if there's a complimentary data set to come out of that as well. So it's just going to be busy, busy, busy. But for the students, there's a lot of opportunities to work with some really great folks and to publish some really meaningful data.
Derek Smith:Well, that's great. That's exciting. We'll look forward to seeing that and some of the fruits of your other projects, especially knowing that that benefits certainly our home state and beyond, as you said. A lot of this in our backyard and along the coast and elsewhere, and certainly here in Central Texas to benefit us. We'll look forward to seeing that. Well, Dr. Usenko, Dr. Sheesley, I really appreciate your time in sharing this today. We'll look forward to seeing more. Congrats on the grant. Thanks so much for joining us today.
Rebecca Sheesley:Thanks Derek.
Sascha Usenko:Thank you.
Derek Smith:Dr. Rebecca Sheesley, Dr. Sascha Usenko, Associate Professors of Environmental Science, our guest today here on Baylor Connections. I'm Derek Smith. A reminder, you can hear this and other programs online at baylor.edu/connections and you can subscribe on iTunes. Thanks for joining us here on Baylor Connections.