 Wait, does this one work? Hello, can you hear me through this mic? Oh, okay, I don't have to use this one, sweet. Welcome everybody, thank you so much for coming today. How are you all doing? Good. Nice. We're really excited for you to be here at the National Center for Atmospheric Research for our second Explorer Series lecture. For those of you who are returning, familiar faces, thank you so much for coming again. And we have this presentation live, so thank you for those of you joining us doing live webcast. Today we're gonna have a discussion about ground level ozone and the damage that it causes on different plants, including the effects on agriculture. And our scientists and engineers here at NCAR are very excited about the research that they do. And through this series, they're able to share this with you all. And we have a group of students today from the undergraduate leadership workshop. If you can raise your hand. They're all undergraduates here for a week. So thank you also for coming to this event. I hope you can enjoy this talk and it'll help you decide on your career choices in the future. We'll also be posting this talk live on our website, the NCAR Explorer Series. You can just Google that. We also have postcards right outside where you could get more information about this and previous talks. At the end of the talk, we'll have two microphones at either end of the auditorium. So we appreciate if you can use the microphones today. And today's speaker is Dr. Danica Lombardozzi. She is a project scientist in the Climate and Global Dynamics Laboratory at NCAR. She's a global change ecologist and a co-founder of the Boulder's Ozone Gardens, which includes the garden at the NCAR Mesa Lab main entrance. Lombardozzi's work uses a combination of ecological observations and global scale models to investigate how terrestrial ecosystems are changing in response to human activities. Dr. Lombardozzi received her Bachelor of Science in Environmental Science with a minor in Music at Colorado College and her PhD from Cornell University in Ecology and Evolutionary Biology. She's a founder of the Ozone Pollution Education Network and the Citizen Science Data Collection at Ozone Bioindicator Gardens within this network. Please join me in welcoming Dr. Danica Lombardozzi for her talk, What Can Plants Tell Us About Air Pollution? Great, thank you. Hi everyone. I have to stand right here so that the webcast can get me and I have to point with my mouse. And so hopefully you can all see this if there's anything I'm highlighting on the slides. As Lorena said, my name is Danica Lombardozzi and I am a project scientist here at the National Center for Atmospheric Research. So my research is broadly focused on how plants interact with climate and how human decisions are changing those interactions. And so just one example that I want to give is this is, maybe you have seen this plot before, but this is carbon dioxide, so that's here. These values are carbon dioxide in parts per million. And this axis is time. So starting just before 1960 up through 2017. And what you'll notice from this graph is that carbon dioxide concentrations are increasing through time. And that's in part due to the fact that humans are emitting carbon dioxide into our atmosphere. And this is one of the major things that contributes to global climate change because carbon dioxide is a greenhouse gas. And so higher concentrations in our atmosphere correspond with increased warming. What I want to highlight though is that plants can have a really large impact on this carbon dioxide cycle. And so all of these wiggles that you see here on the plot have pulled out into this one representative annual cycle. And what you'll notice is that carbon dioxide concentrations peak in the spring and then they start to go down over the summer growing season in the Northern Hemisphere and then they start to go back up again in the fall or winter. And this is caused by the fact that the Northern Hemisphere has a much larger land mass than the Southern Hemisphere. And so then when plants green up, they're actually taking this carbon dioxide out of the air and they're drawing it down. And so that's why we're starting to see this decrease in the spring and summer months. And then when the plants lose their leaves and start to, we call it senesc for the winter, the carbon, they're not taking up carbon dioxide anymore. And so the carbon dioxide concentrations start increasing again. And so plants have a large measurable effect on global climate. And this is one example. And so my research is really focused on answering this one overarching question. How do terrestrial ecosystems respond to and contribute to environmental change? And when I say terrestrial, I mean Earth's land ecosystems. And when I say ecosystems, that is all of the living and non-living things that are working together in a system. And so that's what an ecosystem is. And so I study everything from understanding how plants respond to changing temperatures, climate change in general, but also air pollution. And so I'll go into that a little bit more, but I also want to understand how much plants matter on a global scale. And so trying to understand large scale processes. And I do this using large scale climate models, which I'll get into in a little bit. And more recently I've really started to think a lot about agriculture and agro ecosystems and trying to understand how those are responding to and also contributing to climate change and other environmental changes. And that's because agriculture is going to be really, really important for the survival of humans in the future, it provides our food. So we need to know what's happening to our agricultural ecosystems. So today I'm gonna focus mostly on talking about ground level ozone and how it affects our ecosystems. And so I split this talk up into three parts. The first is trying to understand what ground level ozone is. The second is how does it impact our ecosystems? And the last is what can we do? So I'll start with what is ozone? And so I wanna pose a question to you. I think probably many of you know the answer to this, but is ozone beneficial or is it harmful? What do you think? Yeah, it's both and you're exactly right. It depends on where it is. So ozone is three oxygen molecules connected and it's functioning in our atmosphere is very dependent on where it is in the atmosphere. So the exact same chemical compound has different functions in different parts of our atmosphere. So I'm gonna focus mostly on these two bottom layers just right now. The ozone layer is the ozone where, well it's the ozone, sorry, the stratosphere is where the ozone layer is. And the ozone layer, it kind of acts like Earth's sunscreen. So it blocks harmful ultraviolet rays from hitting Earth's surface. And this is actually where 90% of the ozone in our atmosphere resides is in the stratosphere in the ozone layer. And so this ozone is good, but the same because it keeps us from getting sunburn. And you probably have heard about the ozone hole. That occurs here in the stratosphere in the ozone layer. And so ozone has been depleted there. It's recovering, so that's a good thing. But the same exact chemical, that three oxygen molecule ozone at the ground level where we interact with it, it's toxic, it's toxic to both humans and to plants. And so I'll talk a little bit more about that and I'm gonna focus the rest of the talk for today on this ground level ozone. We also call that tropospheric ozone. So ozone is one component of smog. And ozone is a really tricky pollution problem because it's what we call a secondary pollutant, meaning that it doesn't come from a specific source. So it's not coming out of your car's tailpipe. It's instead, it's formed chemically in our atmosphere. And so ozone is formed through the reaction of nitrogen, oxides, volatile organic compounds and sunlight. And so that's what forms ground level ozone. And I'll go through each one of these. So nitrogen, oxides are reactive nitrogens. There are natural sources of these, but next I'm gonna show you the human-made sources because this is what's causing the increases in ozone in our atmosphere. And so for Boulder County, the human-made sources of nitrogen, oxides come from three primary sources. First is vehicles. So any sort of combustion, I should say, is going to form nitrogen, oxides. And so vehicles are one of those things. There's one good thing to keep in mind is the reason that we have catalytic converters on our cars is to reduce the nitrogen, oxides that are coming out of our cars. And that has actually dramatically decreased ground level ozone concentrations throughout the United States. So vehicles are a major source of nitrogen, oxides. Non-road mobile sources are also a major contributor to nitrogen, oxides in Boulder County. And so these include things like construction or generators, pumps and lawn mowers, any kind of engine that is not specifically a road vehicle. And then industry also makes up a large part of Boulder County's emissions. And I don't know specifically which industries in Boulder County are contributing to the NOx emissions, but industry, the largest industrial sources of NOx are things like fertilizer creation. So when we're making industrial fertilizer, that's a big source of NOx. And also making synthetic fabrics. The acids that are used to make synthetic fabrics contribute large NOx sources. All right, so the next component that we need in our atmosphere to form ozone is volatile organic compounds. And again, there's a lot of natural sources of volatile organic compounds. And what these are, just before I move on, in case you don't know, we call them VOCs. And what they are, they're carbon-containing chemicals that can evaporate easily into the air. So think of paint thinner or the smell of gasoline. Those are volatile organic compounds. And so in Boulder County, there's a lot of different human-made sources of volatile organic compounds or VOCs. Again, vehicles and non-mobile road sources are two of the larger contributions. I also want to highlight solvents and surface coatings. These are things like paints, paint thinners, the asphalt. We re-roofed NCAR about a year ago in some of the surface coatings on there. We're also volatile organic compounds. Oil and gas is another big source. And so the reason that I want to highlight this particular source is because natural gas is primarily methane. And methane is a special type of volatile organic compounds that can form ozone. And so when we have leaks from natural gas fracking, that is actually a big contribution to ground level ozone. And so that's another component of the volatile organic compounds that's going into this atmospheric chemistry that then forms ozone. Okay, so back to our equation. The last thing that I want to highlight is just sunlight. Sunlight is really important for catalyzing this reaction because it starts by breaking apart some of the chemical compounds and then those chemicals can react. And that's ultimately what forms ground level ozone. So now that you know how ozone is formed, I want to ask another question. When do you think ozone levels are the highest? What season and what time of day? Okay. I'm hearing a lot of different things. And I did hear the correct answer out there. It is summer and it's the afternoon. Summer because we have the longest days. We also have the warmest temperatures and we have the most sunlight. We have really intense UV radiation here in the summer. And also in the afternoon because the ozone concentrations have to form through time and they form from the reaction of sunlight. And so ozone concentrations often peak here around three or four o'clock in the afternoon. So that's usually the worst time of day for air quality. If you're choosing to go out and exercise, mornings are probably better for you, especially on high air quality alert days. So, second question. When are high or where are high ozone levels a concern? Oh, you guys are good. All of the above. It's true. And I like to highlight this because a lot of people don't think that ozone concentrations are high in Rocky Mountain National Park, but they are and it just highlights that you can't put up a fence and keep out ozone or air pollution in general. You can't put up a fence and keep out any sort of pollution. But even in these seemingly pristine places like Rocky Mountain National Park, we do see high ozone concentrations. And this is in part because Rocky Mountain National Park is downwind of a large power plant in Craig, Colorado. But also Rocky Mountain National Park gets wind, sometimes the wind direction changes. And so you can get wind blowing from Denver and Boulder and up the front range into the National Park. And so we do see high ozone concentrations there as well. So ground level ozone is a concern because it impacts our health. And so it causes a higher rates of asthma and other respiratory diseases, especially in children and in elderly people and other people who have respiratory problems. And so over here on the left, I just wanna highlight this top picture comes from a study that was looking at the effect of ozone on lungs. And this is a lung exposed to air with no ozone. And then here on the bottom is a lung exposed to air with ozone. So you can see the difference between these two lungs. On the bottom, the lung looks swollen and red. This is what ground level ozone can do to your lungs. It makes it swollen and red. It makes it a lot more difficult to breathe. And so this is, like I said, why you don't wanna be out exercising or taking in extra air that has ozone in the afternoons if you can help it. Ground level ozone also impacts our ecosystems and that's what I'm gonna talk about next. But it has direct consequences for a lot of ecological processes. And so I want to talk a little bit about the limits for ozone. And so because ozone is toxic to humans and toxic to plants, the EPA has imposed a limit for ozone. It's one of the criteria air pollutants or one of the seven criteria pollutants, I should say, the EPA regulates. And so they say the limit for ozone is 70 parts per billion over the course of eight hours. And this is actually kind of a tricky metric because it's actually the fourth highest eight hour average above 70 parts per billion over the course of a year that they regulate. And so it gets a little in the weeds. But I also wanna highlight that the standard was updated in 2015 from 75 parts per billion to 70 parts per billion. So we did make some progress in terms of lowering those recommendations or lowering those amounts. But I wanna start with what is a part per billion? Because I imagine that a lot of people don't understand what this is. And so a part per billion, if you think about an Olympic-sized swimming pool, a part per billion is one drop of water in an Olympic-sized swimming pool. So this is a really, really small concentration. And the EPA limit of 70 parts per billion is equivalent to less than a cup of water in an Olympic-sized swimming pool. If you wanna think about this in terms of timescale, one part per billion is three seconds out of a century and the EPA limit would be three and a half minutes out of a century. So it's a really, really small amount of ozone that is toxic to humans and it's also toxic to plants. And so this map shows what the EPA regulates. So this is the exact metric that is calculated or that is regulated by the EPA. And I want to highlight that everything in yellow, orange, or red, these warm colors here, those exceed EPA's limits. So you can see in many parts of the country we have ozone concentrations that are higher than EPA's limits. Ozone concentrations are particularly high in California's Central Valley, so that's one place where air quality is really bad in the nation, but also here in the front range we have bad air quality in many places. And in fact, both Denver and Boulder have been out of compliance with the EPA's standards for over a decade. We have bad air quality here. Just to give you sort of a sense of what concentrations matter, concentrations without humans are closer to 10 parts per billion. There's a lot of variation, but on average, plants start to experience damage around 40 parts per billion. The World Health Organization actually recommends a limit of 50 parts per billion, whereas the EPA limit currently is 70 parts per billion. And last year when I looked, the highest concentration recorded at the Rocky Flats EPA monitoring station was 105 parts per billion. And that was a one hour average of 105 parts per billion. So you can see that we do exceed EPA's limits and we do have high ozone concentrations. And I would say even EPA's limits are potentially not strict enough to minimize human health risk. If you wanna know what ozone concentrations are, you can go look at our air quality exhibit. So this is right as you walk in the front door, you'll see the air quality exhibit. And on this little iPad here, you can see ozone concentrations. So this is ozone in parts per billion. This is, I actually just put this in, I took this picture of the ozone concentrations earlier today, so you can see that we didn't quite reach that 70 parts per billion concentration today, but we have earlier in the week. You can also toggle up here, so you can go for, this is for the last week, you can look at one month or one year, and you can look at particular matter and the air quality report. I did, from this plot, I did take off the NCAR's Mesa Lab Ozone Monitor because it's in the shop for calibration and it wasn't reading the correct values because it was not calibrated. But we do have an ozone monitor here, so you can come check back and see what the ozone concentrations are actually right here. So like I said, we didn't reach the 70 parts per billion today, but one of my friends sent me this image from his iPhone, from the Weather Channel app from his iPhone, and it shows that Boulder's air quality is unhealthy for sensitive groups today. So just to give you a heads up, if you ever want to look at your air quality app, you can, or if you want to look at the Weather Channel app, it might tell you what the air quality is or if it's going to be unhealthy. So things to keep in mind, there are air quality, there are websites that you can check for air quality as well. And so some of those are on the iPad out there. Okay, so that's a lot of information about ozone air quality, but if you don't remember anything from what I just told you, these are the points that I hope you remember. Ozone is what we call good up high and bad nearby, so it's good in the stratosphere and that it protects earths. It protects earths from sun's harmful UV rays, but it's bad at the ground surface because that's where we breathe it and we interact with it and it's toxic. Small concentrations of ground level ozone can be harmful and so that limit of 70 parts per billion is a very small amount of ozone, but it is still harmful to humans and to plants. Ozone concentrations are highest during summer afternoons so that warm sunny, those warm sunny days are when ozone concentration can be quite warm. And ozone can also be high in pristine location like several national parks, Rocky Mountain National Park is not the only national park that has bad air quality, so keep that in mind. Okay, so I just talked to you a lot about these two pictures here, how humans are changing air quality, but what I'm really excited about and interested in is how that affects plant processes. So I'll move on to the second objective for today is how does ozone impact our ecosystems? So this is a picture of a potato plant that I planted here at Mesa Lab. This is the first year that I planted the ozone bio indicator gardens and I'm gonna talk about those a little bit later, but I planted these gardens in June, actually right on June 4th of 2014 that I went to look exactly two months later when I found is the first signs of ozone damage on these leaves. And so you can see these little spots, these are caused by ozone damage. And when I went to look a few weeks later, the ozone damage had gotten progressively worse and when I went to look a month later in September and see that ozone causes dramatic impacts, visible impacts on this particular variety of potato. And I will say that this is a variety of potato that is known to be very sensitive to ozone, so it's what we call a bio indicator where it biologically indicates that the air is dirty by developing these visible symptoms. Not all plants respond to this extreme, but that's not to say that just because plants don't have visible symptoms does not mean that they're not affected by ozone. So, you just saw a good example of the visible damage that ozone can cause. Can you think of a way that ozone might impact our ecosystems? I can reduce photosynthesis, what does that mean, though? What impact might that have? Okay, more CO2 in our air, it could, yep. Less production, less food, yeah, exactly. These are all big impacts and that's what I'm interested in trying to understand is what are the impacts? So, I'm gonna start by talking about how ozone damage occurs. So, what I'm gonna show you because these are very leaf level responses is a cross-section of a leaf. And so, this is just if you took a leaf and you cut it and you're looking on the inside, so this is blown up quite a bit. And I'm just gonna start with leaf level processes. So, leaves interact with our atmosphere because they take carbon dioxide into the leaf and it gets fixed through biochemical processes into sugars that the plants can use for food and this suite of processes is called photosynthesis. And I want to highlight these stem-model cells right here. So, these are specialized cells and the size of the opening of those cells is called the conductance. And so, these cells open and close in response to a variety of environmental cues like relative humidity or sunlight. And it determines how much carbon dioxide gets in and also how much water is lost from the leaf surface. And so, these cells are meant to optimize the amount of water being lost per amount of carbon dioxide going in. So, the plant wants to get carbon dioxide into the leaf so that it can have food, but it wants to minimize the amount of water that's lost back to the atmosphere. And so, it tries to optimize this stem-model conductance. And so, what I want to highlight here is that the plant, so the inside, there's a couple of things I guess I want to highlight. The inside of the leaf is similar to the inside of our cells where everything is coated in water and so there's all sorts of, there's water in between all of the different cells. And that water is what is evaporating out of the stem-model cell, or yeah, out of the stem-model cells back into the atmosphere. And the thing that I want to highlight is that these stem-model cells are sort of this joint control over carbon exchange and water loss, but the carbon exchange has another aspect to it where it's getting biochemically fixed. And so, these processes are linked through the stem-model conductance, but then there's another aspect of photosynthesis. And so, I wanted to understand what happens when plants are exposed to ozone. Where does the damage occur? And so, I set up an ozone exposure experiment. That is a picture of me. Both of those are pictures of me. And this is, so this is an experiment that I set up when I was in graduate school. And this is what I call an open-top chamber experiment. And so, these open-top chambers that are built that plants can grow in where I can expose plants to elevated concentrations of ozone. And so, the pipes that are going in to these chambers can introduce air and artificially elevated ozone into these chambers to understand how the plants respond. And then, the lachor, this instrument here, which I forgot to bring. It's, I have one in my office that I was supposed to bring for people to look at. And if you want to look at it, I can bring it down. But this measures carbon and water fluxes in the leaf. And so, this is the part that you clamp onto the leaf and it's attached to this, the body of this instrument. And this is what's reading those changes in carbon and water concentrations as the air moves across the leaf. And that gives us a sense for how much water the leaf is losing and how much carbon the leaf is gaining. And so, what I found was that those ozone, in fact, does damage both processes, both photosynthesis and stomatal conductance. And so, I want to highlight a few things here. First is that this axis is percent of control. And so, this hundred percent line, this is if ozone had no effect, photosynthesis and stomatal conductance would be, the bars would be here at this line. And so, anything that's below this line is the effect that ozone has on both of these processes. So, the green bars are photosynthesis and the blue bars are stomatal conductance. And on average, mean photosynthetic change, so the mean change in the amount of carbon that the plant is gaining is 21%. So, this is a 21% decrease, whereas the mean stomatal conductance change to the amount of water that's being lost is only an 11% decrease. The other thing that I want to highlight before I move on is that 95% of the data that are available are for temperate species. So, we really only understand how temperate species respond to ground level ozone, even though ozone could be and is a problem in many other parts of the world. And so, to go back to our leaf cross-section, ozone enters the leaf in the same way that carbon dioxide does. It's sort of like when humans breathe, we can't control what goes into our mouths when we breathe in the air. Ozone gets into our lungs as well, because we don't filter that out. And similarly, when the plant pours, the stomatal pours are open, the ozone enters the leaf. And so, when it enters the leaf, initially it damages the biochemistry that is part of photosynthesis. And so, this has a direct decrease on the amount of carbon that the plants can take up from the atmosphere. And at the same time, it also decreases the stomatal conductance, but this decreases smaller. And so, you're changing that efficiency. So, you're getting more water loss for the amount of carbon that plants are taking in. And so, that's an important thing to keep in mind is the plants are less optimized to tolerate things like drought stress or other environmental stressors, because they're losing more water for the amount of carbon that they're gaining. And they're decreasing the amount of carbon that they're gaining in general. So, both of those things have big impacts. So, that's a little bit about leaf level processes, but I also wanted to understand how ozone can affect these global scale processes. And it's in part because carbon dioxide and water are both really important greenhouse gases. And so, knowing how ground level ozone affects plant fluxes of those processes could cause changes in climate. And so, that's really what I wanted to understand is how does ozone change these, the carbon and water exchange between the land surface and the atmosphere so that we can better understand what's happening globally, these processes. And so, I'm not gonna say a whole lot about this model, but I use a large scale model to do these, to understand these processes. And that's in part because it's really, really hard to take observations globally. And so, this is the community earth system model, and this is the model that we develop here at NCAR. And this is basically a mathematical representation of how we understand the earth works right now. And so, this is based on state of the art scientific understanding and the mathematical representation of that. And so, this earth system model has different components. So it has an atmosphere, it has land ice, it has sea ice, it has ocean, and it has the land. And so, I'm gonna focus when I'm talking about here, the land. But these are all connected, so all the math equations go through this thing called the coupler. So we get these, so when we solve an equation, for example, for photosynthesis or carbon flux, that can be passed to the coupler and then back to the atmosphere so that we understand then what does that mean for the atmosphere? And so, models are a really useful tool. We don't know everything, they're not absolutely perfect, but they're a really useful tool for being able to understand large scale global processes, for being able to understand what might happen in the future, for being able to understand drivers of change and also testing other hypotheses if we find something that is interesting in the model, we can see if that, does that actually happen in reality? So this is a really, really useful tool for a lot of reasons. And so I use the model in this case to try and understand both complex interactions, so other functions within our ecosystems and also how to scale a leaf level response or a plant level response to understanding global scale processes. So what I'm showing you first is this decrease in photosynthesis. So this is due to ozone and so all of the colors on this map represent a percent decrease because all the numbers are negative, so it's a percent change. And this is a direct decrease in carbon gain because photosynthesis is the amount of carbon that the plants take up. And so there's a couple of things that I want to highlight here. This is significant because it reduces the amount of carbon that's stored in our ecosystem. So if plants are taking less carbon dioxide out of our atmosphere, that means that there's more carbon dioxide staying in our atmosphere and that can contribute to climate change, to global warming. Second thing I want to highlight is that regions with the largest reductions in photosynthesis are regions that are agricultural hotspots. And so these are regions where you're getting a decrease in photosynthesis which means a decrease in crop productivity. And so I highlighted a few regions here like the Eastern United States like parts of Europe and parts of Southeast Asia. And so these are important agricultural regions that are having a, where ozone is having a large impact on the productivity of crops and other vegetation in those ecosystems. So the second thing that I want to highlight is that there's also a decrease in transpiration due to ozone. And so that's what you see here is, again, this is the same scale bar. So any of the colors are an actual decrease in the amount of water that is lost back to our atmosphere through plants. And so there's a couple of things that are significant here. One is that it reduces the evaporative cooling and it can increase surface runoff and I'll get to that in a minute. But because it reduces evaporative cooling that can also be an indirect effect that warms our climate because we're getting that less of that evaporative cooling. And the second thing, this is something that I mentioned is I want to highlight, if you look at the Eastern United States, for example, you can see that there's a, you know, 20% decrease in carbon gain but only a 10% to 15% decrease in water loss. And so I'm highlighting this because this is showing the fact that the carbon and water exchange is less optimized. So there's a decoupling of the amount of carbon that is going in and the amount of water that's going off. And ozone is making these plants less optimized at conserving water for the amount of carbon that they gain. And so this is also a direct negative response or a direct negative effect on plants. Okay, so like I said, models can be really useful for understanding other ecosystem processes. And so I wanted to explore how ground level ozone might affect hydrology. And so the reason that I'm interested in looking at this is because plants can get water from the soil. So they take water out of the soil into their roots. And so the water travels from the roots through the stems and into the leaves. So that's represented by these blue arrows here. And then it evaporates through the stomata and that's the process of transpiration. And so if you have ozone that is decreasing this process, so it's decreasing the amount of transpiration, what happens to the amount of water that's in our soil? What do you guys think? It's gonna increase. Yeah, and that's exactly what I saw. So we see an increase in surface runoff because plants are transpiring less. And so this is changing hydrology. And so one region of interest that you can focus on is in the Mississippi River Valley, for example, and in the Mississippi basin, we get an increase in runoff. So because there's an increase in the amount of water that's in the soil. And so runoff is the flow of water over the land that's not absorbed by the soil. And ozone is causing increases in this. So this could lead to additional more flooding in these regions or other impacts or consequences. So this is a direct effect that I wouldn't really be able to measure very easily. And so this is where models are really useful because they can help us to understand that these processes might be happening. And so this highlights that we need additional research in this area as well to try and understand how these processes are happening and what the consequences are beyond just carbon gain and water loss back to the atmosphere. So other processes like hydrology. Okay, so that was again, a lot of information. If you remember anything, I want you to remember that ozone can damage leaf level processes. It globally decreases carbon gain and water loss, especially in agricultural regions. And it can also change hydrology, including things like increasing surface runoff. We're not done with the ecosystem impacts though, because next I wanna talk about the ozone bio indicator gardens. And so these are gardens where we can use plants as indicators of local air pollution. And I've already shown you some photos from this, but I wanna talk in a little bit more detail about this particular project. So I helped plant four gardens in Boulder County. Caterina Lapina was the other person who was really instrumental in getting these gardens planted. And she was a postdoc at Sea Boulder. She's moved on from a career perspective and hasn't had much involvement with the ozone gardens more recently, but she was very instrumental in helping to get these gardens planted. She's an atmosphere chemist. So between her expertise in the atmosphere chemistry and mine in the ecosystem impacts and understanding plant responses, we made a great team for planting these gardens. And so we have a garden at the front entrance that you probably walked past. We have another garden at CU's Mountain Research Station. We have a garden at the CU Natural Museum of Natural History. And I think that this is the last year that they're gonna have that garden there. And so if you wanna see it, go see it this year. And then we have another garden on the cafeteria patio. And so you can see these gardens range in shape and size. Some of them are in planter boxes. Some of them are planted directly in the ground or in much, much larger planter boxes. And so these are four of the gardens that we have in Boulder. But one of the things that I've been doing is coordinating a national or international really network of ozone bio indicator gardens. And so this is our national network. And you can see that we have several gardens. So we have two new gardens coming online. One at Denver University and one in Fort Collins. But then we also have one at the University of Colorado in Colorado Springs. And so we have several gardens in Colorado. There's one in South Dakota. There's a cluster of gardens in the St. Louis area. And then there's gardens along the Eastern Seaboard including this Appalachian Highlands Science Learning Center is affiliated with the Great Smokies Mountain National Park. And this garden is the longest running garden that we have. It's been running for more than 15 years now. So that's pretty exciting. And so I'm coordinating this network so that we can better understand how ozone is affecting plants in all of these different locations. At the gardens, we plant specific kinds of bio indicator plants. And so as I mentioned earlier, bio indicator plants are plants that can biologically indicate that the air is dirty by developing specific signs of damage. And so these plants basically they serve as kind of analogous to a canary in a coal mine where they can biologically indicate that the air is dirty before we might feel the impacts of that air. And so at our gardens in Boulder, we plant four different species of bio indicator plants. We plant the cut leaf cone flower which is native throughout Colorado and actually our cut leaf cone flower. We got special permits to be able to collect seeds in some plants from Rocky Mountain National Park where they were showing visible signs of damage in Rocky Mountain National Park. So that's where our cut leaf cone flowers come from. We also have common milkweed which is not the species of milkweed that's native here. It's native to the East Coast. The kind of milkweed we have here is called showy milkweed and it's not a bio indicator. It still can be damaged by ozone but it does not bio indicate in the same way as common milkweed. We also have two agricultural varieties. So we have a specific variety of snap bean that is sensitive and we have a specific variety of potato that's sensitive. And if you're interested in knowing more bio indicators the National Park Service actually compiled a comprehensive list of bio indicators and so you can look at that list online if you're interested. So the ozone damage develops by, it starts off as stipples and so this is the cover sheet of our data collection worksheets and I'll talk a little bit more about data collection in a minute. But we have to think about how to identify ozone injury on plants because it is a very specific kind of damage and you can easily be confused with other kinds of damage on leaves. And so ozone damage starts as stipples and so these are, it's described on our sheets but these are just small dot like areas that are either tan or red or brown or purple or black. I often think they look really shiny like pencil lead or something. They're typically separate and uniform in size but they can merge and cover more of the leaf surface as the ozone exposure continues and so these are examples of stippling in our garden. So here's on the snap bean, some of these brown spots and I should say that snap bean are actually, they're hard because they seem to have a threshold response and so they go from having no ozone damage to having pretty extreme ozone damage in a very short period of time. The cut leaf cone flower, I'm not sure how easily you can see this but there's some dots right there that are stippling. The potato has stippling right here and then this is the stippling on the milkweed and just to give you a reference, this here is my thumb so you can see that these dots are actually really, really small because my thumb looks pretty big in this picture and also in this picture. So it just gives you a sense for how small some of the damage can be and it can be really tough to find at first. So examples in our garden, these are the cut leaf cone flower and again I'm not, it's not very easy to see on these leaves and the damage is pretty minor on these leaves over here but on this other side you can see that there's some damage in here and there's some damage up here and then you can see sort of more extensive damage and I mean this is in early June so I've already started seeing just the start of stippling on our cone flowers in the garden in front so if you wanna come back when there's, I think it's gonna be dark by the time we leave but if you come back you can actually start, you can see just the start of the stippling on the top surfaces of the leaves and who knows, if our ozone concentrations and air quality continues to be bad we might be seeing damage like this in later in June. These are examples from potato and snap bean and so these typically emerge from the ground later so the damage occurs later and in fact I actually haven't planted the snap bean seeds yet because we were still having snow just a couple of weeks ago as many of you know but on July 2nd in this particular year, 2015 I didn't see any damage, July 24th I just started to see the signs of damage on the potato and the snap bean and then by September 3rd you can see that the damage was pretty extensive on both of these plants. How do we know what ozone damage looks like? It's through these controlled chamber experiments like I showed you earlier and so when we blow artificially, or blow artificially high ozone concentrations at plants in half of the chambers and keep the other half of the chambers relatively ozone free or at low ozone concentrations we can compare what the leaves look like in the development of the damage and so this is a picture of a tulip poplar leaf from this particular ozone exposure experiment that I ran and the other thing that I wanna highlight so this damage is starting to look pretty severe but like I said, it's stipples it's usually on the top surface of the leaf and the other important part is that it doesn't cross the leaf veins and so you can see how green these veins look they're standing out because the ozone damage doesn't really occur on the leaf veins and so that's another indication if you have damage that is crossing the leaf veins it's likely not ozone damage and it's something else and just to give you examples these are examples of things that are not ozone damage so over here on the right this is the potato leaf and if you look at these spots the first thing for me as I'm a little bit experienced when I look at these, these spots look too light compared to the other ozone damage that I've seen on the potato and if you look more closely the damage is kind of irregular and it actually looks like it's chewed out of that leaf surface and that's because this is damage caused by a leaf miner bug. Over here on the left this one confused me because these are regular dot-like symptoms but again, knowing what I know about what ozone damage looks like these looked a little too black to me compared to other ozone damage that I've seen on milkweed leaves which is what this is and then the other thing that was characteristic I looked in here and there's ozone damage it looked like there was damage on the central vein of this leaf and that to me was kind of a signal that this is probably not ozone damage and in fact when I got closer to the leaf and I rubbed those spots they rubbed off, ozone damage shouldn't rub off these rubbed off because they're insect poop so it looks quite similar and these can be really tricky even for me and I have to look very closely a lot of times at the damage we're going to work on a project this summer using purple glasses and so it's a purple film that you can look through and that highlights damage even more easily on the leaf surface and so we're going to try to see if it only highlights insect damage or if it also highlights ozone damage so that's a new project that could happen soon. So I mentioned that we are collecting data at these gardens and we're doing this through citizen science and so this is a really exciting project. This is the worksheet that we're using to collect data and just a few weeks ago we finally got this online so it's not just a paper worksheet anymore but you actually can access it online and so we ask, what we ask visitors to do is to look at one of these kinds of plants in our garden it doesn't have to be the same exact plant but just the same species and then we ask people to randomly choose 10 leaves on this plant and for each of those 10 leaves to categorize how severe that ozone injury looks on a scale of one to six and so one means that there's no damage and six means that there's damage on 76 I should say, till 100% of the leaf and so we're asking people just to categorize 10 leaves of any particular species of plant and then what we have been doing some basic data analysis with this so far and so this is from our citizen science data collection and this is actually data from the Purchase Knob Garden which is the garden affiliated with Great Smokies National Park in North Carolina and I should say that I worked with I've been working a lot with Dorit Hamerling who used to be a project scientist here at NCAR and now she's a professor at Colorado School of Mines and we hired three summer interns so these are high school students from the area who helped conduct this data analysis and so this was a really fun project to get to work on with these students they were fantastic and so what I wanna highlight is here is the proportion of leaves that are injured and so this scale bar, the width of these color bands is basically the number of leaves that might be damaged so out of every 10 leaves that you looked at what proportion of them showed some kind of injury and then the different colors are the score the injury score and so these correspond with the categories that I just talked about where this light green color is no damage and this bright red color is 76 to 100% of the leaf was covered so there's two primary things that I want to highlight from this particular data collection so the first is looking at the year 2010 because it's a little bit easier and what I wanna highlight is that ozone injury accumulates through time and so this is the leaf a particular leaf does not recover a plant might recover but a particular leaf does not recover so once it has the ozone damage like I said it doesn't rub off and it doesn't go away it stays on that leaf until the leaf dies and so this damage accumulates through time and what you see in 2010 is that by September you had hardly any of the plants this little stem shows some of the light green but hardly any of the leaves had no damage most of the leaves had at least some ozone damage the other thing that I want to highlight is that ozone damage varies by year and so in 2009 it was a low ozone year and so you can see that the colors stay brighter green than in 2010 when there's a high ozone year and so in 2010 by August you had at least a large fraction of the leaves with at least some ozone damage whereas in August of 2009 for most of the leaves almost 90% of the leaves had no damage and so this just shows you that year to year variation is important because ozone concentrations do change from year to year and that also the ozone damage does accumulate through time so plants in our ozone gardens can help to visually identify air pollution and the impact that it has on our leaves and it helps to raise awareness about ozone pollution which is really important in a place like Colorado's Front Range where we have bad air quality and I just wanted to highlight the damage increases through time and can be linked to ozone concentrations that said this is still very much a work in progress questions that I really want to know the answer to are things like what ozone levels cause damage so connecting that damage with the ozone concentrations how quickly does it develop do most plants or do different types of plants respond differently which I think that they do and where do we see the most damage the reason that I say this is a work in progress is because we have very little funding for this project and actually for any of my ozone work in general I don't really have any funding to work on these things so the ozone gardens are continuing on a shoestring budget and by the citizen scientists who help us collect data but we don't always have funding for ozone monitors or for putting in new gardens or for hiring students to help us do the data analysis and so those are constraints but we are continuing to do this and so ideally we're going to continue to collect data frequently at existing gardens because the damage accumulates through time we need to understand that accumulation of damage through time and how that happens it's not enough just to look at the plants late in the season and say oh they have ozone damage because that doesn't tell us much about how that damage occurs and at what ozone concentrations it starts and how rapidly it develops in conjunction with those ozone concentrations. I would also really like to add more garden locations and ozone monitors at each of those locations this will give us a larger sample size and it can allow us to better connect ozone damage with ozone levels. Ozone monitors are expensive and so it's hard for gardens to get the garden project itself if you wanna plant a garden is not that expensive to do but the monitors are really expensive and so not all of our gardens have ozone monitors. I think it's really important though because after we start to get a better sense for what the ozone concentrations are with the development of this damage we can start to plant gardens without necessarily needing the ozone monitors and those can be used as a community tool so that people can actually go look at the gardens and say okay our air quality is bad and we know that because there have been these studies that have linked the air quality with this visible damage and we have this level of visible damage. So that's ultimately what I'm hoping for this project it's gonna take many years to get there but I hope that we can get there. And last is to continue the project for many years because like I said there's year to year variability and so trying to understand that variability and how that manifests as ozone damages is going to be really important especially at those same locations. Okay, so that's a lot of information about ozone damage and how it happens on plants and what it means for our ecosystems but it's not all doom and gloom. There are things that we can do and so that's what I want to talk about last just wrapping up and so I wanna highlight that less air pollution is beneficial for our health and so there is this article that just came out a couple weeks ago I heard it on NPR as I was listening to the radio says when LA's air got better kids asthma cases dropped and so when we reduce air pollution directly impacts human health and it's beneficial for our health. Less air pollution is also beneficial for our ecosystems so less ozone can let plants grow more and that also allows them to store more carbon and so in this example with this polluted air these plants are not growing as well whereas if we have cleaner air the plants can grow more and they can store more carbon and so cleaner air benefits earth's climate because more carbon is being stored in our ecosystems rather than in our air so it has this double benefit of improving both our ecosystems and our climate and our health and so there's all of these benefits to reducing air quality and so I want to highlight that really there have been a lot of successes in the past so EPA's regulations have helped to decrease ozone concentrations in both places and what this figure shows is these ozone concentrations through time and so this is from the 1980s through 2017 and over that time period there's a 32% decrease in the national average ozone concentration and so this is really I think it's it makes me really happy to see that these regulations can have this impact because we need to keep doing this we need to keep decreasing our ozone concentration this black line is the national standard currently at 70 parts per billion and you'll notice that nationally average we're just starting to hit that line so we can do this I know that there's a lot of industry out there that says we can't do it but we can and if we do it's better for our health and it's better for our ecosystems so we need to keep doing this but we still do have work to do Denver is ranked 12th in the nation for the worst ozone air quality this is just a picture of the haze in Denver just illustrating that we really do need to keep making progress that national average is not we don't always see a decreasing trend everywhere and in Colorado's front range we're actually seeing increases in ozone concentrations and so we need to keep that in mind so just to sort of bring us back to these ozone concentrations again concentrations without humans are about 10 parts per billion plants experience damage starting around 40 parts per billion there's a lot of variation in that EPA's limit is 70 and we have high ozone concentrations here so like I said 105 parts per billion for a one hour average last year recorded at Rocky Flats that's not acceptable we need to do better so things that we can do take action so there's a lot there's several easy things that you can do some of these are very similar to reducing our climate impact and others are maybe not as intuitive and so there are things like drive less and use public transportation tune your car properly inflate your tires and if you can use electric or fuel efficient cars so those are things that we often think about okay you wanna reduce your impact on climate it's also gonna reduce your impact on air pollution things that are maybe a little less intuitive are things like refueling your car in the evening and don't top off because that smell of gasoline that you get especially when you top off that releases the VOCs into the air and so that can contribute to air pollution but refueling in the evening and the same thing doing yard work in the evening we do those things in the evening because remember the ozone requires sunlight to form and so if we're doing these things in the evening and the emissions are happening in the evening it has the air has time to dissipate so the air quality can improve before the morning and it's not going to accumulate whereas if you do these things in the morning or the middle of the day that's the peak time for ozone to be generated in our atmosphere and so that's when you don't wanna do these activities similarly don't idle your car for more than 30 seconds and also choose low VOC paints, carpets and other products you've probably seen some of these labels if you've painted your house recently or anything you've probably seen low VOC paints and Boulder tries to I think that they have tried to regulate so that we have to use low VOC paints in the city and maybe even in the county so those are positive actions that we can take to reduce our air quality also need to raise awareness because some of these things like I said aren't intuitive I mean I'm guessing that most of you didn't realize that refueling in the evening would reduce our impact on air quality and so if we help to make other people aware that ozone is a problem it's bad at the ground level it's bad for us and it impacts both our health and our ecosystems and that there are things that we can do I think that once people start to know and get on board we can really have a big impact because the more of us that are doing these things the larger the impact we're gonna have the last thing that I will say about this particular thing is a lot of these the regional air quality council has done a lot of work to try and develop some of these actions and they have additional programs in the area for example they have one where you can bring in your gas powered lawn mower and get money back so that you can go purchase an electric powered lawn mower so if you want to know more about those problems I recommend you visit the regional air quality council website they call themselves RAC R-A-Q-C I always get that one confused so check those out because they have a lot of good programs that are also gonna help reduce your impact okay so if you don't remember anything else from this talk at all I want you to remember ozone is a toxic air pollutant it can hurt plants by causing visible symptoms it decreases the amount of carbon stored in our ecosystems and it can reduce crop yields and I want to highlight that we are making progress but we still need to do more to reduce our impact so that we can improve our health and our ecosystems if you would like to get involved you can help collect data at the gardens you can come to NCAR's noon tour to learn how and those are Monday, Wednesday, Fridays at noon and so that if the tour guide is willing they will show you how to collect the data from the gardens and they can point out the symptoms on the leaves and then you can visit the garden on your own as well and use our online data collection form but please remember with this data collection form that it's just available as of last week and so remember that we're still in the testing phase there might be some glitches so please be patient with us in that context but if you have a public space and want to plant a garden, get in touch unfortunately we don't have seeds that we can provide to everybody to grow one in your backyard but the other thing that I will say is these cut leaf cone flowers they're native here to Colorado they're also native throughout most of the US and so if you see those plants you can go and look and see if they have spots on them because they are bio indicators and so that's one way of getting out into your own ecosystems and looking for ozone damage outside of just these bio indicator gardens so that's all I have for you today but I am more than happy to answer questions