 Greetings and thank you for attending this month's Science Seminar presented by the NSF's National Ecological Observatory Network which is operated by Patel. Our goal with this monthly series of talks is to build community among researchers at the intersection of ecology, environmental science, and neon. Today we're excited to have Mike Bell from the National Park Service here to present, but before we turn it over to the speaker, a few logistics. We have enabled optional automated closed captioning for today's talk. If you would like to use it, please find the CC or closed captioning button in your Zoom menu. The webinar will consist of a presentation followed by a Q&A session. As you think of questions, please add them to the Q&A box. We also have a meeting chat. Use this to share links and other items of interest with the group, but add speaker questions to the Q&A. We will facilitate discussion at the end and there will also be opportunity to ask questions over audio. Neon welcomes contributions from everyone who shares our values of unity, creativity, collaboration, excellence, and appreciation as outlined in our Neon Code of Conduct. This applies to Neon staff as well as anyone participating in a Neon event. The full code of conduct is available via a link that I will share in the chat in a moment and is also embedded in the Science Seminars webpage, which I'm showing on my screen, and I will also pop the link in the chat in a moment. This talk will be recorded and made available for viewing on the Neon Science Seminars webpage. You can access those by scrolling down to the list of talks, finding the talk from today, and when the recording is available, there'll be a recording available. You can go ahead and click that and watch the talk at your leisure. To complement our monthly Science Seminars, we host related data-skilled webinars on how to access and use Neon data. Registration for those is available on the same Science Seminars webpage below the list of talks. You can find the list of data-skilled webinars. There are also recordings for those if you didn't get a chance to attend and would like to watch them separately on your own. The next one will be coming up in March. Lastly, if you have ideas for a talk for this seminar series, nominate yourself or a colleague today by filling in the form on the Science Seminars webpage. You can go all the way to the top and here we've got our nominate a seminar speaker. So, without further ado, I'm going to turn it over to Teresa Berlingame to introduce today's speaker. Hello, everyone. My name is Teresa Berlingame. I work for Neon largely with instrument system data quality. I'm introducing Dr. Mike Bell today. He's an ecologist from the National Park Services Air Resource Division where he researches the impact that air pollution has on plants, soils, and waters within federal lands. He previously worked in the field at multiple National Park Service units before getting his PhD in botany from UC Riverside where he studied how desert plank communities change with increasing air pollution from Los Angeles. Today he's going to share how NPS scientists are relating air pollution data across the country to make risk assessments of sensitive species and ecosystems within NPS units and discuss how this data is used to guide conservation and management decisions. Thank you for joining us. Take it away. Awesome. Thank you, Teresa. All right. Well, everyone, thank you everyone for joining. So, I'm with the National Park Service Air Resource Division. A lot of my colleagues who are working on doing this work with are with the U.S. Forest Service and the U.S. EPA. So, it's a very collaborative process. With that being government agencies, the views expressed in this presentation are those of the authors and don't necessarily reflect the views or policies of the agency. So, to start off, I wanted to give a little bit of information about the National Park Service Air Resource Division. Mostly because I feel like most people don't know that we exist because I didn't know we existed prior to applying for this job here. Basically, our goal is we are one of 10 National Science Offices in the National Park Service. And our goal is to allow visitors to breathe easy, see far, and let nature thrive. We do this by monitoring air pollution across the country, calculating pollution levels where ecosystem harm is occurring, and synthesize this data to understand general risk of the parks. And so, we work across the entire U.S., across the entire Park Service. And to really provide that expertise to parks that might have an air pollution issue that they don't have the local expertise to. Within this, the results and the information that we provide, as well as the other National Science Offices are really to guide management actions. And then within ours is review permits for new pollution sources that are coming outside of the parks, and then informed policy and regulations that the EPA is developing to reduce future air bluits. And as I mentioned at the beginning, we do this in a very broad interagency collaboration. So, each of these federal agencies have slightly different missions, but we're all trying to use the same data so that at least we have the same numbers that we're applying appropriately. So, the Forest Service and the Fish and Wildlife Service have similar, but different missions and responsibilities with a part of their goal being to preserve natural resources. The EPA is more focused on the science of this and developing policy and using that science that will help all lands and people within the U.S. And the BLM has a mixed mission that allows for some commercial uses like grazing oil and gas that generally have a negative effect on air pollution as well as some for conservation. So, the core questions I'm asking today and hopefully answering is how is nitrogen and sulfur air pollution harming sensitive resources? How do we then use this to influence management policy? And then what I'm really excited about with this group is to figure out how we can integrate NEON and other data sources into this analysis, both in the application of what we know, as well as generating new data moving forward. So, while most people think of national parks as these clean and pristine places, the air pollution levels that we're seeing, the threats from outside from air pollution sources are still causing significant damage to the parks. We have a variety of cars and agriculture. We can see the smog and then fossil fuels all kind of negatively impacting the visitor experience. So, this is a piece of EPA propaganda that I love to share that they really highlight the fact that, look, we've had a 300% increase in the GDP since the Clean Air Act was signed in 1970 and along with that a 78% decline in air pollution. So, we are seeing significant declines but my question always like what would happen if we actually tried to reduce some of these numbers, like in reduce our energy consumption or individual vehicle miles travel, we could have even a greater effect on some of this stuff. So, while this is great, the technology has improved and we're removing a lot of pollutants from the air, we had this opportunity to do better. And that decline in those criteria air pollutants is having an effect. We're seeing soils recovering, we're seeing fish return to streams where they were absent after long periods of acid rain. We're seeing tree species respond, forests regenerate, two levels that they hadn't been at since pre-industrial or since like the peak acid rain in the 70s and 80s. So, the first question is how much pollution is there? The National Park Service currently monitors pollution, some kind of air pollution in 67 parks. In addition, we have a set of special studies like when we know a new pollution source is coming in, like a big oil and gas development is happening, we'll do more refined studies in those areas to understand the risk of what's going on. Additionally, we collaborate with the National Atmospheric Deposition Program that currently has five different networks. Looking at a lot of it is either wet or dry deposition. The largest network has 261 sites that are currently active and collecting basically that wet deposition from every precipitation event that happens. A lot of this work that I'm going to be explaining today comes from this coordinated research through the NDP through the science subcommittees that exist there. And with that, the main one I am involved with is the critical loads of atmospheric deposition where we're trying to figure out how ecosystems respond at these deposition sites and at the areas between them. So, we have these 261 sites, but we need to know what's happening in between those as well. So, another science committee, the Total Deposition Science Committee at NDP has been developing these measurement model fusion products that take chemical transport models and modify them using that precipitation. So, they're a little more refined and hopefully a little more accurate so that we can do these analyses outside of the monitoring sites. You can see on the top row of figures on the left we have nitrogen on the right we have sulfur and sulfur deposition was extremely high in 2000-2002. Nitrogen deposition pretty much the entire east coast while on the bottom we have the most recent deposition maps available and you'll see with these regulations put on fossil fuel burning in the southeast, we have that steep decline in sulfur pollution and while you see some of that decline matched on the nitrogen side, you also see a lot of areas where no change has occurred. That's like in the agricultural hot spots of the U.S. because those pollutants aren't currently regulated from an atmospheric perspective. So, we have all this pollution, whoops this one is going into the sky, what happens when it comes down? So, mostly today I'm going to be talking about nitrogen pollution just because I'm limited in time but also have a lot of these same responses happening for sulfur, the sulfur pollution as well. So, one thing is you have a change in biogeochemical cycle. Add a bunch of nitrogen to the soil, to the water. It is eutrophying elements, causes things generally to grow faster, often bad things grow faster, so you have increased growth which leads to changes in mortality and shifts in species composition. Nitrogen especially causes leaf tissue, leaf chemistry to change, which can make the leaves more likely to be eaten by herbivores, pests, etc. So, we're seeing a lot of these, both small short-term changes as long as these long-term community composition shifts that are harder to overcome with time, especially with like annual plant species. And so, in identifying the rate of deposition at which any of these changes are occurring, we're using this concept of the critical load. So, this is the threshold of deposition below which this ecological harm does not occur. And generally we have four different responses that we see from deposition. The first is we have a decrease in risk. So, as nitrogen or sulfur pollution increases along the x-axis there, the ecosystem component that we're looking at decreases. One of the most sensitive species that I'll talk about later is lichen species communities because they pull all of their nutrients directly from the air. They're very sensitive to these changes, so any change in pollutants generally causes a quick decline in species richness. The second is an increasing. And I have this two different critical loads marked here with the circles, one at the bottom. So, this is like generally if you have like an invasive species in an area, that stark increase is you want to prevent before that exponential growth occurs. So, kind of setting it before large increases. While if these are more gradual increases of native species that aren't really showing ecological harm, we'll often either not set a critical load or set it at this higher level where we haven't like really reached that level at which things start to decline yet. The last is a threshold response. And so, this we have this initial increase in growth or survival with increasing deposition and then you start to decline. And we go back and forth with this one between setting it at the highest level which kind of marks that maximum growth conditions for a species and setting it at that level that's more equal to that initial growth space. And I think as we're advancing a lot of our sort of load applications to correlate with climate change, carbon storage and all those things, we're really we're really more interested in this kind of endpoint of like at what point are we reducing carbon storage past what it is and also looking at the benefits of carbon storage as potential offsets. And the last is when there's no relationship to nitrogen or sulfur and then we have to move over the graphs to make this a little clearer. But when we combine the expected level of response to those deposition maps, we can calculate a critical load exceedance. And so this is when deposition is greater than the critical load. The critical load is said to be an exceedance. So this increases the risk that harm will occur to that ecosystem component. And for most of these, we have a dose-response relationship so that the higher the exceedance, the more intense the response. And just to note is like we'll become apparent in some of the future slides. As with the previous slide, these critical loads occur at different levels of sensitivity based on the ecosystem, based on the species itself, etc. So first, so now with that, we're going to identify these different sensitive ecosystems. So the eight different categories that we have currently been classifying critical loads are alpine ecosystems, aquatic lakes. We generally use more mountain lakes that don't have upstream sources of pollutants. So it's pretty apparent that any changes are being caused by atmospheric deposition. We have herbaceous communities as a whole, then looking at herbaceous species individually. We have lichen community, specifically here, we're going to be looking at nitrogen sensitive lichens. We have tree individual tree species growth, individual tree species survival over time, and then micro-risal fungi changes in micro-risal fungi communities. So the point of this talk is going to be more of the outputs that we're generating rather than how the critical loads were set. So really, this is kind of all the data that goes into these different models. I just kind of want to highlight that most of these relationships are showing a decreasing response at some point in the relationship to nitrogen, while some of them are showing this increasing response. So for each of these, we are identifying the community at which they're happening. So within these closed vegetation, these are forested communities, lichen are generally occurring in forested communities. These are alpine lake responses. These are individual herbaceous species responses and individual tree responses. And we take those responses and we overlay those with either land cover data of where a forested or grassland, shrubland area occurs, or when we have data points within parks or within federal land areas, we can put species points directly onto the deposition map to show where the harm is occurring. And generally for the purpose of this talk, when you're looking at these maps, red equals bat. So that's where harm is occurring. Blue equals good. So that's where the deposition isn't high enough to cause harm. And then the yellow areas are kind of that, the edge of that transition. And so those those areas are really important to this so that we, because you can have potentially the most impact there, preventing ecosystem from starting to climb or reducing pollution so that we can allow for these ecosystems to recover. So now we're taking that national data and moving it more towards the local space. So the dots here are of class one areas within the US. Class one areas have special protections under the Clean Air Act that kind of give these federal agencies teeth and pushing back against the EPA and against these polluters in that these areas need to be protected from harm from any new pollution source that comes into effect. I'm going to zoom in on Iraqi Mountain National Park and kind of show these how kind of how these two different datasets look up close. On the left here we have the critical load nitrogen for a decline in insensitive lichen species richness. And this is basically a single value over the forest. And you can see that most of the area is in exceedance while there's a small area that is right around that critical load. Then on the right here, these are individual plot locations for herbaceous species surveys from which we then put the individual critical loads into these sites. And most of them you see are blue so they have not expected to shift the community dynamics while there's a couple hot spots with sensitive species that would allow directed management in these areas or maybe potential revisits to the sites of those species that are there are of importance. We then pull all the data together and we provide each park with a quick summary of the potential risk of to their site. And so here is like a this is kind of what we were working with initially which looked at the different critical loads relative to the total nitrogen deposition. And if it's red here the lower threshold just it means that every area in the park is going to be in exceedance. If it's blue that means it's above the highest threshold of deposition that's when you don't have to worry about. And yellow is like likely some areas of the park are in exceedance. We then pull all that together and we have this summary of critical load data. So if you have a regional biologist or someone from a monitoring network they can kind of pull out the parks they're interested in get a general overview of what's going on very quickly. One of the new tools let's see if I can do that. I just put some links in the chat where you can look at kind of some of the stuff that we're talking about if you're getting bored here I just want to put a putter about. We have our conditions and trends page which overall from the air resource division shows the current condition of different air pollutants in each national park and the trend of how that pollute the concentration or the amount of deposition of that pollutant is changing over time. So the this ecosystem response is a new component to the conditions and trends where we're using that model data to look at the maximum median and minimum deposition over time. In Iraqi you can see it's kind of the recent models are showing the maximum is kind of increasing while the minimum deposition seems to be slowly decreasing over time. So a lot of that has to do with the elevation range at the park where you're with at higher elevations you're getting more precipitation and thus more deposition. Then we advance those those previous figures into these that fair and poor benchmark. So where before you're saying some of the park might be in exceedance of that this this kind of gives you that that better reference of how much of each area is in decline. So of all of the alpine area like all of it seems to be above the lower benchmark while most of it is below the higher. While mycorrhizal communities you'll see only a small area is above the that lower benchmark even smaller above the higher. So you can kind of get a better sense of the broader range. I didn't put them in here but I put two other links in the chat as well that one is for mapping of the critical load so you can actually see the spatial distribution of the exceedances so you can really understand of the area that you're interested in has an exceedance you can even zoom into neon sites or anywhere else in the U.S. because all of the data sets are eventually going to be included in there. The third link is to these critical load summary reports. So if you're interested in exactly the amount of area the number of the the list of species that are occurring within these herb occurrences or tree growths and the number of them that we have all of that like very refined data is in there. So those are from more of the expert person rather than the higher level manager who's just kind of interested if anything is happening. Okay then we are taking all of that together and kind of evaluating the the parks or the in this case the class one areas in totality. So the first on the left is like where we have the most data and we had those eight different critical load categories so the highest number here is eight and then there's a handful where we have either zero one. Given that one of those eight is alpine areas as well as having aquatic resources you'll see the highest numbers around the Rocky Mountains and the Cascades and Sierras the West just because of those some of these components just don't don't have the opportunity to exist. We then look at the total condition of each of those resources so we can kind of get a sense of like where what parks are being most impacted by air pollution what and then where can we dive in to figure out what's going on what additional information we need to assess the like what like what is happening on the ground what like is it are there management actions or policy implications or policy actions that we can take to reduce harm to parks. Summarizing some of this data looking at the different class one areas we have some data on critical loads currently for almost all class one areas there's a handful of Fish and Wildlife Service sites and a couple of National Park Service sites where we don't a lot of these are more of the coastal areas that just are outside of the range of most of these larger data sets. We then have the count of critical loads and the the count of exceedances and again you'll see the Fish and Wildlife Service has the lowest number mostly that's because their air program hasn't had a biologist in place for a while who's been interested or has had the ability to pool data from those refuges they don't have a central database of plots available but otherwise we have four to five critical loads for National Park Service and Forest Service sites and currently the Park Service sites are slightly cleaner like having less harm than Forest Service. Same thing for critical loads of sulfur and we're seeing fewer critical load exceedances overall and that's mostly because that's steep decline in sulfur deposition that I highlighted earlier. So how are we using this data specifically? A lot of it as I mentioned we provide that science scientific expertise to MPS units and then we inform policy and we then help reduce the risk from new sources. We do that in part through that the MPS is going through a resource stewardship strategy development process where in the past like air pollution is something we would come in when a new source is outside of the boundary or just like in case of an emergency or someone came to us but with this we're able to kind of build risk from air pollution into their 10-year plan of managing the park. One thing that's been great by having these tools available is linking to connecting with park managers and biologists to have a place for them to put their data. A lot of times in the past when we say hey we're working on this big project can you do you have any data on x, y, or z there would be a little hesitation because the park service has been challenged in the past of having the resource to do something with it so it takes a lot of time to pull together and there's not often anything that comes back to power and now that we have this tool in place and it's like hey if you give us the data we can plug it right into this this tool and you'll have an output of which of these species which of this data is being responsive to your then just by prioritizing those areas and species that are at risk we can prioritize active management restoration mitigation and then work with local stakeholders to minimize emissions and potentially new sources of pollution. So I'm going to go through a couple of case studies. The first is a Great Smoky Mountains National Park. This was a collaboration with Sarah Goose University where they modeled the deposition level at which these stream the red streams here are those that are in exceedance of the of the critical low that have a pH low just low enough that fish and other invertebrates aren't able to survive in the waters and so we're looking to determine the level of deposition that would support healthy fish populations and the recovery of other aquatic invertebrates. So we're starting with looking at the long-term deposition of the site going from 2000 to 2015 and so when this was started we're at about 7.8 kilograms per hectare per year and based on current regulations in place we are expected by 2030 to get down to 6.2 which is still significantly above this natural background that we expect to be around one where these ecosystems evolved. So from that we set up these target looks like how can we get down to about 3.1 kilograms per hectare which is a 60 reduction from those initial levels and if we did that like this is based on that modeling you would see about 57 of those streams recovered by 2018. So this was a big undertaking bringing in the states in the areas and trying to get everyone on the same page so that those sources outside of the park were involved in the process and knew the value not only to people but also the culture and ecosystems around Rocky Mountain. I'm sorry Great Smoky Mount Sash Park and the exciting thing here is that within the five six years after we've actually significantly dropped below this target line and we're doing better than expected. So I think this is I can't say it's 100% aligned with just our actions but it's nice that when you're setting this glide slope of a long-term recovery to get below it early see it's not as much of a stress to respond later. The next is at Rocky Mountain National Park kind of a similar issue where but here we have emissions coming in from the Greeley or Collins area that you have a lot of cattle a lot of agriculture there that handful of times a year you have these east east to west storms come in blow all of that pollution from the valley up into Rocky Mountain National Park and causes additional deposition. So here we look at all the critical loads so here we have the x-axis is nitrogen again the y-axis is kind of that level all of the different ecosystems that you can see and you can see that with our current deposition you have a lot of areas that are in exceedance and we are trying to move to this target load where most of these ecosystems are not going to be impacted and a lot of this is based on these like the diatoms in the Alpine Lakes that are most sensitive to pollution and so here we started meeting with farmers we started meeting with the local communities and tried to develop a a set of best practices in an early warning system so if the forecast called for one of these storms it was coming through what actions could farmer state to reduce their emissions from their sites that would then blow to the river. So this started in about 2006 and between 2006 and 2012 we were looking right on the glide slope or making good progress and then had a couple of big rain years had some just things outside of our control that seems that led to kind of an increase in deposition miss that slope started coming down again and then we're going back up and so this one's a little less obviously successful but the relationships that we've built and the connections we've made both within the community and within the park and has been really valuable and like spreading the word of the connectedness of our actions and not just be this is happening here the parks are protecting over there but we're all in the same like world we're in the same ecosystem and it's made it a lot easier for us to communicate kind of around the topics and help advance the science even more both in the transport and deposition of pollutants. The next is a more that direct to EPA method so every there's I think it's every five years they're supposed to reevaluate the science to make sure that the current national ambient air quality standards are still protective of human health and the environment and this is like where this is based off the Clean Air Act and setting these numerical increments of pollution both for new sources modified sources as well as looking like and using the data to determine that causal relationship between pollution and welfare so a lot of this work goes into filling these boxes in the integrated science assessment the policy is based off of when I first started here back in 2015 there was a lot more hashed lighter colors that they're showing that these relationships were more suggestive or likely causal but based on the research and based on the guidance from the EPA of like hey this isn't strong enough yet we've been able to show that there are these causal relationships between nitrogen sulfur deposition especially and ecosystem responses. So recent rulemaking the recent updates to the NACs were actually were released last week and there's some disappointment that even though all these boxes are green you'll see on the bottom for nitrogen like nitrogen concentrations there was no secondary standard set to highlight the fact that these things were occurring but I don't know why I'm going from the bottom up but sulfur for the first time set a secondary standard that is different from the primary standard for a criteria pollution so it's exciting that they're taking a step forward unfortunately the standard they set it at is currently below any level of that position that we see in any class one area or any park so we're getting there but not quite and then lastly the primary standard for PM 2.5 is being decreased from 12 to 9 and this is going to be hugely beneficial for human health but also a huge component of PM 2.5 are these ecommonia agricultural emissions that will result in a will likely result the client in nitrogen so it is a secondary effect to PM but should have should improve general so we're excited and supportive of those things happening and then lastly it's like so when there is a new pollution source coming out we work with the park to pull together data and kind of identify what is at risk and how things are at risk so quickly there was in Alaska a natural gas pipeline that was being posed outside of Denali National Park and the pipeline was going to be along the eastern side of the park our NNEP site here is in one of the cleaner areas there was kind of a way from where this pipeline was going to have an impact so we use these deposition models kind of highlight what the the current level of deposition is and then with the park biologists identified the lichen species that are occurring there those that are potentially likely to be impacted by deposition and so in conversation in the permitting process we kind of highlight it's like hey we have an endangered lichen it exists in this community these are the critical loads and we are able to use that data to convince them or assist in their decision making to put additional controls on the facility so that less pollution would go to the park and there would be less of an impact on these lichen species potentially so this is like well I was really excited and when I first signed up to give this talk I was hoping to collaborate in advance and pull together a little more data from the neon sites but alas life and other projects got in the way so I did a quick analysis of all this data from the different sites within the contiguous US and hope that we can use this as like a guiding structure for future collaborations getting more information on the onsites so first just pulled the deposition data on sites there are many of them that are kind of above this 7 to 10 threshold that we often think of is when large shifts in ecosystems start to occur and then pulled critical load data from overlapping from the neon polygons as well as for some of them where we had species data having a buffer around the spot just to pull in some of our our nearby data that were species are likely to occur at the neon site as well and I think most importantly the herbaceous species presence in trees like I assume that all of your sites have vegetation in plants this is our data set is is is pretty sparse in the western US so it's pretty clear that those are likely going to be missing and then trees I'm sure existed a higher number than we have here but yeah so like just pulling out we had really good data on on these more consistent data sets across us and in general we were seeing higher conditions for these higher critical loads of herbaceous species and lower for the more sensitive ligands and mycorrhizal species and trees were we're looking at trees and herbs from what we had were pretty good so the looking at the looks putting those conditions map the most uh healthiest sites relative to air pollution were these southwestern sites for the most part and in some of the plains when you get higher in the mountains you're getting more deposition more known ecosystems that are sensitive so you see some declines the midwest here is where we're seeing that higher deposition load and then along the ablations in the east also more in the mountains so seeing like having this list of the these are the sites with poor condition that had the most critical loads that I had so with that I'm hoping to develop some collaborations with NEON as well as other partners to expand the data that we're using these analyses maybe develop some first for application of like hey where do these species occur then use that data to develop new models especially for species that didn't have a lot of points for and hopefully new critical loads that can help us be more protect park resources etc in the future so yeah I want to include data from the NEON surveys I can give a more accurate representation of what's going on then compare compare that long-term data looking at how species and communities are responding at these sites of varying deposition to see if it matches like all this data is going to be outside of our current data set so we can like really test and confirm what we've been saying and then hopefully integrate that into into these models in the future so that I will take any questions if you want to email me directly emails here this is a picture of me searching for air pollution at the bottom of the Grand Canyon by collecting like in a couple of years ago so it's the nice thing about air touching everything is you get to go to cool places to look for it so thank you very much and look forward to the questions fascinating that was so cool to see where the NEON sites fall even though it was very preliminary everything you say yeah great thank you so much Mike I can start with the chat here it looks like there are already a handful of questions let me expand on that a little bit so I can see it better um the first question that came in was what are all of the pollutants that are being monitored by the NPS oh goodness um we we do it like there's a lot of there's nitrogen there's sulfur and white deposition as well as base cations etc we do visibility through particulate matter look at various stages we have expanded our purple air monitoring it's like a cheap and easy particulate monitoring in parks ozone is another big one looking both at the human health effects of peak ozone levels as well as the the continuous mid to high level ozone for vegetation impacts mercury has been increasingly important over the years both in looking at mercury within bio indicators both in insects up into fish and then we have been expanding and interested in micro plastics and PFAS and pesticides and other toxics that are coming in as well um so we have a very broad measurement program monitoring program uh some more expensive than others great thanks Mike felt like that one was a little bit of a pop quiz that earlier you thought it was out my boss they want to see what if I knew what was going on all right the next one here uh how do you decide the critical load thresholds for different pollutants does it vary with tree species versus herbs and does it vary across ecosystems and or parks if I go back to this the other way um okay um so basically we develop these models that integrate local conditions temperature precipitation soil ph etc and looking look at responses with nitrogen and sulfur across them so in this case there's nine like this is 71 of I think they're up to 145 different tree species that show different types and levels of responses this is I think 350 herbaceous species in each one of these the different type of response so you have different levels of sensitivity where they start declining different rates of decline and um so yeah each of them kind of responds individually some of them will have like a temperature and like temperature by nitrogen precipitation by nitrogen response so we're able to quantify that critical load when um ground conditions or environmental conditions are changing too so it's like it's an ever-expanding data set that as we do more of these analyses gets more complex and how and where we're applying all the data okay thank you um let's see are these data publicly available as shape or CSV files and if yes where can they be accessed yes um let's see I'll put it in the chat in a little bit when I can when I get my screen back um but yeah the through the entity and the critical loads of atmospheric deposition program we've developed a national critical load database and so this is a mix of shape and CSV files that um have all like we we try to get as much of the published data um into it as fast as possible we um have been suffering through staffing issues and or behind a couple of years so not all of this is in there yet but we're hoping to have everything I presented here and there shortly additionally the the mapping website that I put in the chat should have access to downloadable files for at least leggings, trees, and aquatic data that we'll be getting the rest of it in there soon. Awesome thanks I think definitely relate to uh too much data not enough time yeah and then let's see one more here it says uh sorry I may have missed this at the beginning but do the critical loads only include wet deposition or are you also measuring dry deposition with these numbers if it's only wet does that mean what does that mean for dryer sites? One of the challenges of critical load science is that we've pulled this they've been developed over the last 10-15 years or so the quality of our deposition information is better today than it was 15 years ago so some of the original ones were just based on wet deposition those were going to be more of your okay kind of those aquatic sites where we were seeing very obvious responses at the beginning more recently we've based them off of these total deposition measurements so it is incorporating usually modeled dry deposition which is has some uncertainty inherent in certain bees itself I'm combining that with measured and modeled wet deposition so we are getting a better sense of the total amount that's coming down it's like one of the big questions I have and I'm I'm really interested in pursuing especially with climate change in the next couple years is uh how the timing of deposition and time like aligning with timing of precipitation is impacting the response of the ecosystem so I did a lot of my work in joshua tree in southern california if you have no rain from june to november when the highest deposition is occurring you kind of just get this layer of nitrogen on the surface and then once the first rain comes like is all that nitrogen actually being bioavailable is it being processed in minted as gases is it washing off into the the rivers etc so we're really trying to refine some of these analyses to get that temporal component involved as well right thank you um it looks like that was all that was in the q&a but there is one in the chat from sam simpkin um great talk mic what do you think the prospects are for a knock secondary standard in the next five years or so and then I'd also personally like to tack on if you could um add a little bit more definition to the difference between a primary and secondary standard okay yeah the primary standards are said to protect human health and so those are required by law like based on the most recent science what level of pollution causes people to get second dying basically so we're getting like each of those most years they get a little bit stronger as the science gets a little bit clearer that what we're currently doing is still causing a lot of hurt secondary standards are meant to protect human welfare and they they can be said at the same level of primary and welfare is a very expansive definition going from how people enjoy uh the outdoors and how that contributes to our our life to um just other secondary impacts of pollution um etc so one of the big challenges in setting a secondary standard that relates to ecosystem health is that EPA is currently unwilling to consider a deposition based standard their interpretation of the clean air act is that it needs to be aligned with concentrations in the atmosphere and because of these this variation in wet dry deposition variation deposition rates from one ecosystem to another you it's a lot more challenging to relate a single concentration to these impacts and so we've been trying to advance that like there's people within the air resources division who are looking at that question how can we better relate concentrations to deposition with a single value across all of these data product see that one of the problems with this last assessment is a lot of this data you'll see is from 2017 to 2019 and the cutoff for references included in this last analysis I think was 2017 because partly this is pandemic delays partly it's just the way things are but it yeah I feel like we're getting closer I mean I feel like they a moved the goalposts every time where 10 years ago they were just like oh do x y and z we did x y and z and they're like nah maybe you need to do a b and c is we did a b and c and like oh well now we have this whole deposition concentration issue so um I think it's going to happen but one of the big challenges and one of the things I'm interested to see with the sulfur secondary standard is there because a secondary standard hadn't previously been set we don't like it isn't clear how they would enforce it um so I'm hoping that this allows for some of those early questions to be asked like if this is an exceedance how how would this be implemented what um what's like the the consequence of exceeding it and then I don't know I'm always helpful I wouldn't do this work but I didn't feel like we weren't we didn't have a chance to make a difference but as um with the case studies that I showed I think one of the biggest one of the most important things for us to do really is develop these relationships with the local communities and sources the more people care and understand and see that relationship between both of our consumptive actions and our daily um movements mobile actions the more likely that we're going to be able to develop the ground swell the to make shifts and improve the quality of the air so great thank you um well that was all the questions we have and we're near the end of our hour so I'm going to let uh Sam take it from here for some closing notes great yeah thank you for a wonderful seminar that was extremely interesting especially thinking about giving us food for thought how the neon data might contribute to these efforts so we look forward to learning more about that in the future like please keep us keep us in dialogue um our next science seminar is going to be Tuesday March 12th where we're going to hear about leveraging neon airborne sensing data to better understand how ecosystems are responding to disturbances so please join us for that um and in the meantime take care thanks again for a great seminar bye thank y'all for having me dutch y'all soon