University Place

Air Quality in the U.S.

[Tom Zinnen, Outreach Specialist, Biotechnology Center, University of Wisconsin-Madison]

Welcome, everyone, to Wednesday Nite @ The Lab. Im Tom Zinnen. I work here at the UW-Madison Biotechnology Center. I also work for UW-Extension Cooperative Extension. And on behalf of those folks and our other co-organizers, Wisconsin Public Television, Wisconsin Alumni Association, and the UW-Madison Science Alliance, thanks again for coming to Wednesday Nite @ The Lab. We do this every Wednesday night, fifty times a year.

Tonight, its my pleasure to introduce to you Tracey Holloway. Shes a Professor of Atmospheric and Oceanic Sciences here. Shes also with the Nelson Institute for Environmental Studies. She was born in Evanston, Illinois, and graduated from New Trier High School. She got her undergraduate degree in Applied Mathematics at Brown University, then got her PhD at Princeton University in Atmospheric and Oceanic Sciences. Did a post-doc at Columbia and then came here in 2003. Tonight, she gets to talk with us about, Every Breath You Take: The Past and Future of Air Quality in The United States. Please join me in welcoming Tracey Holloway back to Wednesday Nite @ The Lab.

[applause]

[Tracey Holloway, Professor, Civil and Environmental Engineering, University of Wisconsin-Madison]

Thank you, Tom.

Thank you so much. And thank you, Tom, for that lovely introduction.

It is such an honor to be here tonight at Wednesday Nite @ The Lab talking about my favorite topic, which is air quality in the U.S. And I hope that by the end of this evenings talk that you might find it to be a pretty exciting topic too, because even though here in the United States we’ve been regulating air pollution for public health, and visibility, and clean lakes, and healthy plants going back to 1970 on a national scale, and before, back to the late 1800s in individual cities, it’s a topic that a lot of people don’t really think about when they think about environment and energy issues. But really, air quality is fundamental to our public health, to our energy systems, and to our environment. And I think we’ll have a lot of fun tonight digging into some of the issues.

So, Ill start out with kind of a dark, hard to see slide –

[slide with a photo of the actor, John Lithgow playing Winston Churchill,looking out a window in the TV show The Crown]

– but if you look carefully, you’ll see John Lithgow. He’s peering out of a window in London in 1952 on December 7, in one of my favorite mini-series from Netflix, The Crown. And if you watched The Crown –

[Tracey Holloway]

– you may remember, I think it’s Episode 4, which focuses on a major air pollution event in London. There’s a reason that this air pollution event was such a big deal that they devoted a whole episode of The Crown to its discussion. Its because it is really one of the hallmark episodes of air pollution that was a catastrophe for public health in London at that time.

Now, one thing about this extreme air pollution episode in London, which still characterizes air pollution around the world, is that when were thinking about what makes for bad air there are two key issues. One is, whats being emitted? Whats the flux of chemicals into the air? And the other is, what are the weather conditions? You need have a perfect storm, where you have chemicals being emitted into the air and weather conditions that trap those chemicals over a city or a community so they cant just mix away. So, the reason that this air pollution episode occurred in London in December 1952, was because they were already emitting a lot of smoke, sulfur dioxide and other pollutants. This is an actual picture of the London smog –

[slide with a photo of the London smog event in 1952 showing a double decker bus travelling through the fog]

– of 1952. And there was a weather system that came in and trapped the pollution in place.

[slide with a graph showing deaths per day, the amount of sulfur dioxide and the amount of smoke in the air charted by the date in December in London in 1952, showing a large amount of smoke and sulfur dioxide in London on December 6-11, 1952 as well as a large number of deaths]

And we can see from the data from that episode just how definitive this air pollution event was, and the associated public health impacts.

If you look at this figure, which is from data taken in the 1950s during this time, and published shortly thereafter, you see three different lines on the plot. The red dots represent smoke. So, just how much smoke is in the air. And in London in the 1950s, no day was a perfectly clear day, but on average you had about 4-400, a little less than 400 micrograms of smoke per meter cubed.

The blue triangles represent sulfur dioxide, because in London they got a tremendous amount of their electricity, and energy, and lighting, and home heating from coal back in the 1950s. And coal is a fuel that contains sulfur along with carbon and other elements that are naturally occurring in the coal. So, when you burn it, it emits smoke, it emits carbon dioxide, and it emits sulfur dioxide and other – other pollutants. So, when the weather trapped the smoke, it also trapped the sulfur dioxide. So, you see the sulfur dioxide compounds rose exactly in sync with the smoke. But whats different here is the green, that line at the top, the little squares, that these are the number of deaths that occurred in London during this event.

And what the line shows, if you look at the early part of December, is that on your average day in London around 300 people might die. These were people who might have had a heart attack, or gotten sick, or had been hit by a bus, who knows? But what we see is that then as the air pollution builds up, that the number of deaths per day doubles from 300 to 600 and then again to 900, before it slowly begins to come down. And even when the air pollution has cleared back to its standard levels, the average number of people that die each day is still quite a bit higher than it was before the smog. And this is because when people get sick –

[Tracey Holloway]

– during – during a high-pollution episode, they may be sick for a few days before – before they die.

So, this – I really like using this graph when I am teaching in classes and giving public talks, because the basic idea here is that we know air pollution is bad for peoples health because we can see it in the data.

Now, in many parts of the world, thankfully, the relationships are not this extreme. Theres a lot of things that determine when kids go to the hospital with an asthma attack, or when someone reports a – a heart attack in their – in the hospital records. But statisticians, epidemiologists compare these health records with air pollution records to kind of back out what is the risk of air pollution. And individual air pollutants in individual cities have different risk factors, but the basic idea ties back to the same idea shown here from 1952 in London.

So, moving forward from the smog of 1952 in London, we continue to see episodes of bad air pollution in the United States, but we also see great improvements. In many ways air quality is an environmental success story. The air has been getting cleaner and cleaner, and especially in the U.S., where we have some of the most aggressive air pollution regulations in the world. What I am showing here is –

[slide with a photo of smog in New York City in 1988]

– 1988 in New York City.

[new slide of smog in Milwaukee in 2014]

Heres 2011 in Milwaukee.

[new slide of smog in Pittsburgh in 2014]

Heres 2014 in Pittsburgh.

Now, whats notable about all of these pictures is that you can see the pollution in the air. And anytime you can see air pollution youre really dealing with whats called particulate matter, or P.M.

Most gases, really every gas thats in the atmosphere at typical concentrations, is invisible to the eye. So, anytime youre seeing air pollution, its liquids or solids that are suspended in air. And these could be made of directly emitted smoke from a barbecue –

[Tracey Holloway]

– or windblown dust, but they also are often made of chemically formed particles, so that that sulfur dioxide cooks up to make sulfate particles. Invisible nitrogen oxides cook up to make nitrate particles. And these chemically formed particles and the directly emitted particles both contribute to the haze that we see. But just like in London, we dont see this kind of pollution every day in most parts of the U.S. It really depends on whether the weather conditions are in place to trap the air pollutants or cook them up.

When thinking about air quality, here in the U.S. we think about two big categories of pollutants. One category is called air toxics, and these are also known as hazardous air pollutants. Air toxics include about 187 different chemicals that are associated with cancer, neurological disease, birth defects, and other issues. For these pollutants theres no safe level, so theyre regulated mostly on an industry-by-industry basis to minimize the health risks.

But there are six pollutants that are really the ones that you think of when you think of air quality, both in the United States and around the world. These are the most wanted pollutants if you were to imagine them on the wall of the F.B.I. And these include carbon monoxide, lead, nitrogen dioxide, ozone, particles, the ones that you can see, and sulfur dioxide. And I wont go into the levels here except to say that since 1970 –

[slide with a table of the six most wanted pollutants with the name, type, average time, E.P.A. limit level and form and their associated statistics]

– the E.P.A. has set a limit for each of these six pollutants. Thats, kind of, like a class where theres a – a failing – a level where theres a passing and a failing grade. And every county in the United States has – that measures air pollution has the pollution compared with this pass/fail level, and its determined to be either passing or failing the standard. So, if you’ve ever lived in a place where you had to take your car to be emissions tested, that has been because it was a county that was failing in the ozone standard. Not every county thats failing the ozone standard has vehicle testing, but it’s pretty typical.

[Tracey Holloway]

My parents live in Chicago and theyve been taking their car to be emissions tested for many years. I lived in New Jersey; emissions tested. My sister lives in California, emissions test. All of those are above the federal standard for ozone.

Depending on the pollutant, the impacts of a county failing the standard may be different. It may affect how industries can file for permits, or how power plants can expand their facilities. So, these are really big issues that affect a wide range of industries in Wisconsin and across the United States.

The policies that weve had in place though, are really working. Air pollution has been coming down, down, down. This plot shows –

[slide with a graph with the year on the y axis and amounts of pollutants on the x axis showing the decrease in the amount of pollutants since 1990]

– going back to 1990. And the dash line is showing the pass/fail limit for each of the pollutants.

And what you see is that today every single pollutant, on average, is below the- the line. Were in the clear in most areas on average for everything. Now, there are still select counties that are above the standards for P.M.2.5, the tiniest of the particles for ozone, and to a lesser degree for sulfur dioxide, and some of the other pollutants. But overall, it is a clear downward trend. And since 1990, lead has decreased 99% in the air, mostly due to unleaded gasoline –

[Tracey Holloway]

– becoming the norm. Sulfur dioxide has decreased over 80% since 1990, mostly due to scrubbers on coal-fired power plants – plants, and a growing role of natural gas for electricity generation. Carbon monoxide has gone down by nearly 80% due to cleaner burning cars and trucks. And really, you could – we could go through the list. Theyre all going down, down, down.

Another way to look at how air is getting cleaner in the United States is to compare with satellite data.

[slide with a satellite photo of the United States showing Nitrogen Dioxide levels and its concentrations in the U.S. with Chicago, Los Angeles and New York City identified on the map]

Now, satellite data is one of my favorite sources of data. Im not sure if everybody has a favorite source of data, but mine is satellites. And – and what youre seeing here is a yearly average of NO2, one of these invisible gases, taken over the United States in the year 2005.

Now the reason I show 2005 is because this data is from a satellite called the Aura satellite. The Aura satellite was launched by N.A.S.A. in 2004, around the summertime. And each satellite contains lots of different instruments. And one of the instruments on board Aura is called Omi, O-M-I. And Omi measures a whole bunch of different gases and particles in the atmosphere. But NO2 is especially useful because the images are pretty clear, as you can see, thats not too noisy, and because NO2 is emitted by cars, trucks, power plants, forest fires. Anything that burns emits NO2.

So, when we see these patterns in NO2, it’s a really good tracer of other types of air pollutants, a lot of different types, and also human activity and energy use. So, what you see here in 2005 is you can very clearly see the major cities, Chicago, New York, Los Angeles. You can see in Indiana and Ohio the high levels of NO2 associated with electricity production. A lot of U.S. power plants are located in the Ohio River Valley, and these power plants are a major source of NOx. You also see some power plants in the western United States, where otherwise it’s pretty clear; theres a lot fewer people out there. And some interesting patterns like, you may not be able to quite make it out, but in southern Idaho there’s a line that stretches across from east to west, and that runs right parallel with trains and – burning diesel fuel – and with a major highway where theres a lot of trucks and cars.

But whats great about this is that weve had – these satellites take a snapshot of the entire Earth every single day. And so, this is showing what the Earth – what the U.S. looked like in 2005, and heres what it looked like just five years later in 2010. I could show you 2015 and it would look even cleaner. In fact, over the ten-year period between 2005 and 2015, many cities in the US had 40% or more of a –

[Tracey Holloway]

– reduction in NO2. And this is really due to cleaner cars, cleaner trucks, cleaner power plants, cleaner energy.

To give you an idea of how the U.S. compares with other countries in terms of our clean energy, one way to think about it is how clean our cars have to be. This and the next couple of plots are taken from an International Energy Agency report that Ill show you at the end of this talk.

But if youve ever – if youve ever dreamed about importing a sports car from Europe, you might have had it cross your mind, that you cant just go to Europe, buy a car, and bring it to the U.S. And the reason is that here in the U.S., we have some of the tightest vehicle emissions standards in the world. That is why our air is getting so clean. This is ranking –

[slide with a table of Emissions and fuel sulfur standards in selected regions, with a list of countries and their related emissions standards for a variety of vehicles]

– many major countries in terms of their – how clean their standard is for light-duty vehicles, that means cars and small trucks. And the U.S. and Canada have, you know, something stricter than the strictest rule in Europe. Europe, Japan, Korea, Australia are in the same zone. Turkey, China, Russia, Brazil, Argentina. And then India is less strict. Mexico, Indonesia, South Africa, and Saudi Arabia. So, every country sets their own policies on how clean they want their car engines to be. And the U.S., we’re one of the cleanest.

[new slide with an illustrated map of the world showing, Mandated sulfur levels in diesel transport fuel, with countries color coded by the amount of diesel fuel sulfur levels, green being the lowest and red being the highest – the U.S., Canada and Australia are the greenest]

Another way to look at this, that was looking at light-duty vehicles especially, but diesel is used for trucks and buses. In many parts of the world, diesel is used as a – a common fuel for cars and electricity production. But one of the questions is, how much sulfur is allowed to exist in the fuel? And in the U.S., we have some of the lowest allowed sulfur diesel levels, especially compared to other parts of the world.

[new slide with an illustrated map of the world showing, energy-related P.M.2.5 emissions by sector – buildings, industry, transport and other – and by region]

And all of these rules and others contribute to relatively small energy emissions. Here now we’re looking at particles, kind of the smoke that you’ve seen coming sometimes out of trucks or off a barbecue. And you see that in the United States our little pie is quite small compared to many – to the rest of the world. Now thats interesting because in the U.S. we use a lot of energy. We use about twice as much energy as the average –

[Tracey Holloway]

– person in Germany, about five times as much as the average person in China. And so, that we could be using so much energy and yet having clean air is really the evidence of this big investment that the U.S. has made.

And theres different ways of counting up the benefits of this investment in clean air. And one is by thinking about how many people didnt die, or didnt get asthma, or didnt check into the emergency room because of policies that were put in place. And the first binding policies for the U.S. were in 1970, but there was a big sweeping addition in 1990, the 1990 Amendments to the Clean Air Act. And this is –

[slide with a table of things that the 1990 Clean Air Act Amendments have prevented and will prevent including adult mortality, infant mortality, ozone mortality, bronchitis, heart disease, asthma, E.R. visits, lost school days and lost workdays and their associated numbers]

– you dont have to pay attention to the numbers, but the kind of benefits that you expect to see from these investments in clean air. You expect infant and adult mortality to go down. You expect chronic bronchitis to go down. Heart disease to go down, asthma down. Emergency room visits are going down. Fewer days lost of school; fewer days lost at work. And thats exactly what we find.

But the funny thing about air quality –

[Tracey Holloway]

– is that its very hard to know who specifically benefited. And I think this is one of the reasons why people dont – arent as aware of the benefits of air pollution control is because when somebody has dirty water, you know who had the dirty water. You can see it. You can probably turn on their tap and measure it. Its very clear the specific person who benefited from clean water or was adversely impacted by dirty water.

With air its different. We just saw in London in 1952 that the number of deaths went from about 300 a day to 900 a day. But if you were to a – find one person who died, would that person maybe have died anyway? Its really hard to say. My sister lives in Los Angeles, and after moving to the Los Angeles, developed asthma. Would she have developed it anyway or not? Its really hard to tell. Now, we would – the – the idea that more people in Los Angeles have asthma, and that you are at higher risk when youre exposed to higher levels of air pollution, that is a fact. But pinpointing the specific people its – is different. Its more of a statistic population way to. We know that theyre saved, we just dont know who they are.

And when you translate these benefits into dollars, the benefits are huge. This is really because in the U.S. we value, we spend a lot to be safer, we spend a lot to be healthier. Well pay more for a safer car; well, you know, invest – well eat kale and invest in expensive vitamins to be a little healthier. And anything that we can do thats going to extend our life, and improve the quality of our life is something that we put a lot of money in. And if you add up all the money that we put into each increment of improved living, it ends up being about $6 million per person. And so, the value of avoiding death –

[slide with a bar graph showing the year on the x axis and the dollar amount in billions on the y axis with the costs as one tiny amount and the benefits as a huge amount]

– is, in the U.S., ballpark $6 million. So, when we can avoid the adverse impacts of air pollution, that adds up very quickly to high amounts of money.

Now, to put this in sort of a news-you-can-use framework, another statistic that I like came from a study at the Harvard School of Public Health. They looked at different cities across the United States and controlled for smoking, and income, and access to healthcare.

[Tracey Holloway]

And looked at how long did the people live in those cities. They found that for the cities that had, Im going to say 10 units, and Ill come back to the units in a second, but for every 10 units cleaner air that one city had over another, the people in the cleaner city lived about seven months longer.

Now, this 10 units, right now the standard for our – our annual average P.M.2.5 is 12 micrograms per meter cubed. So, when we are saying 10 units on average, its 10 micrograms per meter cubed, meaning that if it went from 22 micrograms to 12 micrograms, that on average people would live seven months longer. And it is not uncommon in many parts of the world to have P.M.2.5 in the hundreds of micrograms per meter cubed. So, here in the U.S. if a city, or if a – if a monitor anywhere reads higher than 35, its sort of a ding, ding, ding, thats too high, period. But on a day-in-day-out basis we want it to actually be lower than 12.

To get this level of clean air we spend a lot of money, on average about $50 billion a year. And that often comes in the form of how much youre paying for your electricity, how expensive your car is. Thats why you cant go to Germany and pick a car and bring it back here. But the benefits are in our health.

So now, I want to bring you into my lab here at the University of Wisconsin-Madison, because I work with a team of students and professional researchers to tackle some of these questions. What we are interested in knowing is, what controls air pollution? How do different energy strategies lead to clean air? How can we use satellite data and other new tools to do better science and have better information to give to decision-makers? And how do all of these complex weather and energy and chemistry processes feed together?

And what I think is really exciting about this is that it lets me works with students from all across the campus, from Engineering to Public Health, from Geography to Chemistry. And its a lot of fun but its also a really effective way of tackling some of these complex crosscutting issues.

So, my lab at the University is in the Institute for Enzyme Research. There’s actually –

[slide with a photo of Tracey and some of her students in front of the doors of the Institute for Enzyme Research at 1710 University Ave. in Madison]

– no enzymes used in our research at all. But here on campus, like many universities, buildings were sometimes named for what they were first used for, or what theyre mostly used for, and were very happy to have the Enzyme Institute as our home.

[new slide of Tracey and her students in front of the doors of the Institute for Enzyme Research, now making goofy gestures]

We do a lot of goofing around, but actually this was a bit of a old picture –

[new slide with individual photos of the 15 students now working for Tracey in a grid]

– and now my lab, it has about – about 15 or 16 people in it, most of whom are undergraduates. In this picture, which is actually omitting some of the students in my lab who dont yet have their pictures up on our website, most of the top two rows are undergraduates. I have two – three graduate students, a professional researcher who does the computer modeling and scientific data analysis, Monica Harkey, a PhD in History who helps with our communications and outreach and writing, Daegan Miller, and then me.

[slide with the words Research idea (from scientist) in the upper left and a red arrow pointing downward at 45 degrees to the words Research Publications on the lower right]

So, one way that I like to think about research is, where does the idea come from? And the typical approach in science is for a scientist, a professor, a researcher in a lab to be sitting and just have that eureka moment, Aha!, or to come up with just some question out of thin air to spend their time studying. This is typical, where the research idea comes from a scientist, they do the work, they publish it in peer-reviewed journals that are really not very easy to read.

[new slide that animates on a yellow arrow emanating down and to the left at a 45-degree angle from the bottom of the words Research Publication to the words, Document & Share Success]

And if theyre lucky, maybe its covered by a press release, or covered in a news magazine to reach the public.

But my group and I –

[new slide with how Traceys research progresses with the same words, Research idea (from scientist) now joined by the words, Problem statement (from stakeholder) as two smaller red arrows pointing to a bigger/longer red arrow that led to the words, Research Plan & Two-way dialog that then led to a small orange arrow pointing lower to the words, Research Publication, that then follows to the words, Document & Share Success by a yellow arrow as before]

– tend to take a more applied approach to re-research. We figure if were gonna – theres so many important questions out there in the world that need to be answered, why should we just be dreaming up questions out of the blue? So, we like to work with users, whether at the Department of Natural Resources, or the E.P.A., whether at private companies or non-profits, whether cities, or countries – counties, or countries that we engage with and ask them, what do you need to know? What would be helpful to you? And working with different people who actually are working in air and energy fields, finding out what are the open questions –

[Tracey Holloway]

– that really need to be answered, using that to develop a research plan, yes, writing the research publications, but also thinking about what are useful outcomes for other audiences? Not everybody needs a research paper written. Some people like to have data given that they can analyze, images for a report, a – a finding that can help them make a decision. So, we try to deliver the research in traditional means, but also means that can reach new audiences.

Once we document the success, we try to share the work –

[new slide with the words, Stakeholder Outcomes next to the words, Research Publications now also emanating by a small orange arrow from the words, Research plan & Two-way dialog to the words, Document & Share Success by a small yellow arrow and a new green arrow leading from those words to the words, Building Awareness, Engagement]

– that were doing, building awareness –

[new slide that animates on two new purple arrows, one leading from the words, Build Awareness, Engagement back to the words, Problem Statement (from stakeholder) and another from the words, Build Engagement, Awareness back to the words, Research idea (from scientist)]

– forging new relationships, getting new questions. A cycle.

[new slide with a magenta oval with the words, Direct Measurements, on top of and partially covering a larger blue oval below]

And the- there are three tools in our toolbox that we use to answer these questions. But before I begin talking about the tools in the toolbox, Ill just give one example of this kind of –

[Tracey Holloway]

– cycle of question and answering.

I spoke at a meeting for the Western U.S. states a couple of years ago, and I was talking about satellite data and how effective it could be for answering different air pollution problems. And the reason I was talking about satellite data is because for the past few years Ive been involved with efforts at N.A.S.A. to make satellite data more usable by different communities. Theres been hundreds of millions of dollars invested in advanced satellite technology, but often it isnt getting used by all of the people who could use it.

So, in 2011 N.A.S.A. set up a team called the Air Quality Applied Sciences Team, or A.Q.A.S.T., and I was the deputy leader of A.Q.A.S.T. And A.Q.A.S.T. was trying to be a front door to connect N.A.S.A. with the people who are interested in air quality, air pollution issues. Because if you were somebody who worked on air pollution and you thought I want to use satellite data, who do you turn to? Its really hard to know, where is the front door? So, A.Q.A.S.T. was trying to be that front door and part of that was going and talking to potential users who would be interested in this and meeting them where they are already working.

So, I was very happy to go out to Denver, Colorado, and give a talk to Western U.S. states who were meeting on a, you know, once-every-couple-of-years basis to trade information, share insights, learn from each other.

And at that meeting, in the elevator, I met a air quality manager from a major city in the Western United States. And he said, You know, I really liked your talk. Im thinking maybe we could start using satellite data. I said, Yeah, great idea! So, I actually went out to visit about three months later, and I gave a talk to he and his colleagues. And they were interested. They had not heard about how satellite data could be used for air quality before – and – but that got him thinking. He said, You know, I’m not sure. And without getting into all the details, he said, Ive run the numbers. Ive looked at some of the data you showed me, and Im just not sure that it will work for our city. And I looked at his numbers and I said, You know what, I think youre right. Its really – we need to look into how the satellite data really should be used in your city. And we dont want to be over-selling. I mean, the whole point is to try to get good science into the decision process. If its not the right tool, well, lets go back to the drawing board, lets try to improve it, but if it doesnt work it doesnt work. And who knows better than somebody where his whole life is focusing on air pollution in that city?

So, actually Ive come back to Wisconsin, and Im working with undergraduates to help address the specific questions that he pointed out and keeping him in the loop as were doing that. So, just as an example of the loop. And the students love it because they really want to work on questions that matter.

I think a lot of students dont like the idea of research because it sounds esoteric. It sounds, kind of, like youre just working on one little project at a lab bench. But actually, a lot of the research, not just in my group but all across the University of Wisconsin, is addressing some of the biggest problems that are facing humanity. And so, these students to be looped into it in a way that they can clearly see. Theyve heard that it was a problem, they can see how their work is going to contribute, and then theyre excited to get to work.

So, there are three toolboxes that air quality and health managers use for looking at air pollution. And if these are the three toolboxes that the professionals use, theyre the three toolboxes that I want myself and my students to use so that were best able to interact with the groups who do this for a living.

So, one approach is direct measurements. And just to show you what were talking about –

[slide with a photo of some large air monitoring equipment in a field]

– were talking about instruments that are out on the ground, across the United States that are actually measuring whats in the air. Here in Madison, Wisconsin, our main monitoring site is a big trailer behind East High School. But there are monitors across the state, and Ill show you a map.

[new slide with an illustrated map of the United States titled Current P.M.2.5 Air Quality Index, with air monitoring stations represented by green and yellow dots]

This is actually a map of monitors that measure P.M.2.5, those tiny particles that are bad for our health. And you can see from this map that there are a lot of monitors in the eastern U.S., and a lot of monitors in California and the Pacific Northwest. The – the Great Plains has fewer monitors. But this plot is taken from one of my favorite websites which is airnow.gov, airnow.gov. And it is put up by the E.P.A. to show you what is in the air, now.

[Tracey Holloway]

And so, I pulled this plot off just about two hours ago, and this is showing that across most of the U.S., the monitors are showing green. We are well below the threshold for health damaging P.M.2.5 according to the standards. But in the eastern United States the dots are yellow. This is the moderate zone, showing that – that were above –

[return to the Current P.M.2.5 Air Quality Index slide]

– whats considered good for a yearly average, but were still below the – the red-light zone for a – for a daily limit. So, were between 12 and 35 in the yellow.

There are no orange dots that I can see on the plot, but there is one red dot in the unhealthy zone, which means its actually quite high above 35, and that looks to be somewhere in California and probably is due to a local fire.

I had a colleague once who said that the reason he liked studying air pollution was because every day was –

[Tracey Holloway]

– a science experiment. And I feel that way often when I look at the data on airnow.gov, but when were trying to see how healthy our air is overall, the question isnt what it is today, what it is this evening, but the question is, if we look across the year, how many days did he get really high? And on the days that it got high, how high did it get?

And here is –

[slide with an illustrated map of Wisconsin showing, Preliminary 8-Hour Ozone Design Values from 2014-2016, with ozone values indicated by colored dots relating to the amount of ozone present]

– a plot of ozone. Now, this is a different pollutant. This is an invisible gas in the atmosphere, but it has many of the same health impacts as P.M.2.5. And what you are seeing here is, first of all, the location of ozone monitors across Wisconsin. And its a – what youre – its a – what youre looking at is a metric called the Design Value. Thats kind of nerdy, but its showing on the fourth-highest day how high was the ozone, on average, across these three years. Because just like in baseball where you have three strikes and youre out, in – for ozone, it is four strikes and youre out. So, they don’t pay attention to the highest, the second highest, the third highest. Okay, those are, you can – you can take those strikes. But the fourth highest is the one they zoom in on to determine whether we are passing or failing the federal allowed standard for ozone.

And what this plot is showing is the green dots are where this average fourth highest value is below 65. And that is well in the green zone because the standard, I should focus on that, thats at the lower-left corner. The current standard for ozone is 70 parts per billion. Seventy is the pass/fail limit. Now, this was just implemented in 2015 and is not yet being enforced. Were still in the process of – of regulating based on the 2008 standard of 75. And one of the reasons why the – why the newer standard isnt being enforced is that you need three years of data, and that was just passed in 2015.

So, but this is color-coding, and you can see whether its passing the 70 or the 75. The green is in the clear for both standards, and thats across the northern part of the state, and most of the inland art of the state. But as you get close to Lake Michigan, we see quite a few dots that are between – that are red, that are between 71 and 75, meaning that all those dots that are red are failing the new standard, although they would have passed the old standard. And then there are a few dots at Sheboygan and at Chiwaukee Prairie that are higher than 75, meaning that they would be failing even the old and the new.

This idea that the standards are getting tighter and tighter and –

[Tracey Holloway]

– pose new challenges for industry to meet these air quality regulations is something that there are a lot of people who could argue about that, because on the one hand, its improving public health, on the other hand, it is very expensive to meet these regulations and poses costs to industries that are having to pay high electric bills or buy fuel or things like that.

But from a – kind of, leading us to the – to the, back to why I love satellites, here we have –

[return to the 8-Hour Design Values ozone map of Wisconsin]

– a lot of great data, but there is much more of the state that doesnt have a dot than does have a dot. Most of the U.S. –

[return to the slide of Current P.M.2.5 Air Quality Index]

– has no monitor –

[return to the 8-Hour Ozone Design Values map of Wisconsin]

– most of Wisconsin has no monitor.

[new slide of an illustrated anthropomorphic fallen tree saying Hello? Can anybody hear me?]

And so, just like if a tree falls in the forest, and no one is there to hear it does it make a sound? When you have a county with no air pollution monitor, and its a high air pollution event, it does not register. Nobody knows –
[Tracey Holloway]

– about it. So, when it comes to satellites, they can fill in the gaps. Theyre not as good as ground-level monitors for many different reasons. One is that they’re mostly once-a-day measurements rather than all-day. They dont measure all the different pollutants. They dont see the surface where were breathing, they, kind of, see more the column. But when youre – when youre choosing between having no information from a measurement source or a satellite data, they can really be a nice complement.

And actually, here at Wisconsin, we are a hot-spot of satellite data to study the atmosphere. And not just air pollution.

[slide with a photo of the satellite and radar array on the roof of the Atmospheric Sciences building on the U.W.-Madison campus]

The whole idea of studying weather and atmospheric processes with satellites is something that was developed here at Wisconsin with Verner Suomi and continues to be a huge strength of the university on a global scale with our Cooperative Institute for Meteorological Satellite Studies.

[new slide with an illustrated map of the Earth from space and illustrations of all the weather satellites currently orbiting the Earth including, Aura, Parasol, Calipso, CloudStat and Aqua]

When were thinking about air quality, theres a collection of satellites that are producing information that we can use.

[slide with a list of the members of the Health and Air Quality Applied Sciences Team and their associated universities and government agencies]

And I mentioned A.Q.A.S.T., that was the Air Quality Applied Sciences Team. Just this past summer in 2016, N.A.S.A. launched the Health and Air Quality Applied Sciences Team, or H.A.Q.A.S.T. And this is a national team of researchers now trying to connect satellite data and other N.A.S.A. tools with health and air quality stakeholders.

Im the leader of this national team, and there are 12 other researchers from across the U.S. and a wide range of institutions. Were actually meeting next week in Seattle at the University of Washington in Seattle, where a big part of our mission is to hear from –

[Tracey Holloway]

– potential users who could use satellite data, who might use satellite data, who are using satellite data, and trying to say, What are your research questions? And how can we answer those questions?

Outreach has been a big part of our activities with A.Q.A.S.T. and H.A.Q.A.S.T. We have been doing research on those trends in NO2 that I showed you earlier, how its going down in the U.S., but up in many other countries. And, actually, one of my colleagues from A.Q.A.S.T, Bryan Duncan –

[slide with a screen grab of the C.N.N. website story, N.A.S.A. data shows nationwide air improvement — but still more needed, featuring a photo of Bryan Duncan talking to a C.N.N. reporter in front of a satellite map of the U.S.]

– was on C.N.N. a couple of years ago talking about this.

[new slide with a screen grab of a Discovery Channel article where President Obama explains how pollution affects our planet featuring a video with and animation of one of the satellites in action]

And we were, actually, really thrilled that the Discovery Channel then picked up on some of this research with NO2 and asked former President Obama to discuss how air pollution in the U.S. compared with other countries. And he did so by talking almost exclusively about satellite data. Because satellites see the entire world, you really can compare different areas in an apples-to-apples fashion. And if you are interested in that 60-second Discovery clip, you can find it at tinyurl.com/obamaNO2.

[new slide featuring four line graphs, one from 2007 and one from 2011, showing average summertime NO and NO2 values over time in urban, suburban and rural areas using the OMI component of the Aura satellite]

Im going to talk for just a few seconds about an example of the kind of research that Im doing here with an undergraduate named Elise Penn. And one of the things we were interested in is how representative the satellite data was of NO2 on the ground. We see that its going down. Thats great news. But the problem is the – the – the best satellite thats up there, on the Aura sat – the best instrument up there, the OMI instrument on the Aura satellite only passes over in the early afternoon.

And if you look at NO2 at the surface, what we find is that that early afternoon time period is the minimum NO2. What youre looking at here is the hours of the day from midnight to midnight and you can just look at the top two panels. I should have removed the – the lower ones. But if you look at the top two panels, you see that in the urban areas, the red line, it goes up in the morning, down, then up. Same happens in suburban, same happens in rural. And thats – thats really mostly due to rush hour traffic combined with the way that the atmosphere moves during the day.

So, the OMI satellite instrument passes over in the early afternoon.

[new slide of an updated line graphs of average summertime NO2 values for two years, 2007 and 2011, in urban, suburban and rural settings using the GOME-2 satellite instead of the OMI component of the Aura satellite]

But we were wondering if maybe by comparing with another satellite, this one from the European Space Agency, we might be able to see the change in NO2 over the course of the day.

[new slide of an illustrated map of the U.S. showing Morning to Midday NO2 columns comparing the OMI to the GOME-2 satellites]

And when we took the difference between these two products, what we saw was really remarkable. We could see rush hour traffic in the satellite data. And its not super obvious from – especially with the color schemes that youre seeing right here, but in many cities what we see is a bulls-eye, where the satellite that is in the morning shows higher NO2 in the suburbs, and the satellite in the afternoon shows higher NO2 in the center of the city. We see this in Phoenix, we see it in San Diego, we see it in Chicago, in Philadelphia, and Houston. And –

[slide animates in a close-up look at NO2 data from Chicago in a smaller box]

– you can zoom in on these individual cities. We also see that power plants, especially in the summertime in the Western U.S., are higher in the afternoon when these power plants are cranking to meet that air-conditioning demand.

[slide animates to give a very detailed look at NO2 values in Phoenix]

[new slide titled, Cities among the Top 20 for Commuter-Adjusted Population, showing bar graphs of eight cities with their populations divided by non-workers, workers living and working in the city, workers commuting in and workers commuting out and their associated data]

And what we found is that, actually, if we looked at the cities that we saw where the rush-hour traffic patterns popped up in in the satellites, these were the same cities that the U.S. Census Bureau finds have the most commuters commuting from the suburbs to the inner-city. So, that was pretty cool, that this pattern that popped up with the satellites is something that is consistent with what we would expect from rush-hour traffic, but its something we would not –

[Tracey Holloway]

– have been able to see with monitor data because there arent enough monitors. So, that was one kind of neat study that we did.

But the third tool in our toolbox is computer models. Tom mentioned that my undergraduate major is applied math. And in applied math, some people focus a lot on statistics, but other people focus on calculus. And Im a calculus person. I love calculus. And one of the reasons I love calculus is because that it is the science of change. What is a derivative, but it is showing change? And if you want to look at how things are changing in time, it is the derivative with respect to time. But if youre trying to solve equations that have derivatives, it becomes really complicated, and most of the time you cant solve it with a pencil and paper. You need a computer.

[slide with three colored ovals on top of a larger blue oval, the top magenta oval is labelled Direct Measurements, to its left is a cyan oval labelled Computer Models and to its right is a green oval labelled Satellite Observations]

So, the whole idea of computer models to study the atmosphere is based on the idea that we can use physics and chemistry to write differential equations, as theyre called, equations with a derivative, and then use computers to solve them.

[new slide with an illustration of a green car emitting emissions to a cloud marked Chemistry which is next to a cloud labelled Wet & Dry Deposition that has particles emitting from it to a circular arrow titled Mixing/Transport/etc. Additionally, there is an arrow coming in from the lower left bottom that is labelled Input – Emissions & Weather and another arrow pointing right from the middle top labelled Output – Concentrations]

And the kind of chemistry and physics that are in these computer models are the emissions of chemicals into the air, how weather patterns move them around, specific chemical reactions that occur, rainout. And – and what we are interested in is how do all of these chemical – these processes combine to create high or low levels of air pollution at a particular place on a particular day.

[new illustration of a red car driving away from an industrial plant with both the car and the plant releasing NOx – oxides of nitrogen and VOC – volatile organic compounds – and ozone into the air with the equation that NOx + VOC + Heat + Sunlight = ozone.]

I havent talked very much about all the different chemical processes that go into play, but as one just quick example, we talked about ozone in Wisconsin, and how were passing the standards in some places and not in other places. But ozone is not directly emitted. It cooks up in the atmosphere from two big ingredients, NOx and VOCs. So, to understand where the ozone is going to be high and where its going to be low, we need to take a count of chemical reactions involving NOx and VOCs reacting with hydrogen, and oxygen, and sunlight. And its really fun chemistry but its hard to do without a computer model.

[new slide asking the question, what if cities had solar PV such that 20% of Eastern U.S. electricity came from solar? – along with two line graphs plotting the hours of the day on the x axis and the ratios of solar to base electricity with the lower graph showing the difference from the base.]

And just as one example of the kind of questions that we have answered with these computer models is one study that is just tying up right now from a graduate student of mine, David Abel. And we worked with the National Renewable Energy Laboratory to answer a basic question, how much would solar electricity improve our air?

And surprisingly, it is really hard to figure out how energy efficiency, wind energy, or solar will really play out in terms of cleaner air and public health. So, we worked with the National Renewable Energy Laboratory to use some of their fancy electricity models, and used those to calculate what power plants are going to change their generation, when and where, if we had more solar. Then we translated that into changes in sulfur dioxide and nitrogen oxides. We spent some time to look at how much of the change was coming from changes in coal versus natural gas, and where and when these are occurring.

[new slide showing, Greatest Particulate Mass reductions in the Mid-Atlantic, with two illustrated maps of the eastern U.S., one showing the current state of P.M. in this area and the other showing what the P.M. would be in a transition to solar showing great reduction in P.M.]

And then we dumped them into our computer model with the weather and the chemistry included, so that we could figure out where these little particles in the air cooked up, in this case looking at P.M.2.5. And the first thing we want to do is look at what is the business-as-usual case. Create a computer model that has everything included, compare it with observations to make sure we are in the right zone of reality. But once we have a computer model that looks right, then we can use it to test things that we could never test in real life.

So, we took our computer model and then we just waived our magic wand and poof, 20% solar electricity across the Eastern U.S. And we found that it decreased P.M.2.5 pretty much everywhere across the Eastern U.S. and in some places over 10% on average. Some places almost 15%. But what we’re really interested in is not just whats happening on average, but what about those dirty days?

[Tracey Holloway]

Is solar electricity making the dirtiest days cleaner? And what we found is, yes, the greatest benefits from solar happen on the dirtiest days. So, we looked here at a few different cities, Indianapolis, Columbus, –

[slide with a graph of Solar benefits most on high-P.M. days showing the decrease in P.M.s in a variety of cities with a transition to 20% solar energy]

– Philadelphia, Chicago, and New York. Each one showed a somewhat different relationship between the benefits of solar and the reductions in particulate matter, which are mostly in the zone of five to 15%. But it was promising to see that, at least in our computer model, putting in solar energy doesnt just make the clean days cleaner, but it really targets those dirty days –

[Tracey Holloway]

– that are bad for public health.

So, as we wrap up, I wanted to leave you with a few resources. If youre as excited as I am about air pollution and want to go further, some great online resources that may be of interest.

[slide with screen grabs from four websites dealing with air pollution, Our Nations Air, the Wisconsin D.N.R. website, the International Energy Agency report and Tracey’s own website]

One is Our Nations Air, which is a 2016 report from the E.P.A. and thats where some of those figures that I talked about showing how air pollution had gone down in the United States. Another is a report from the International Energy Agency that talks about global energy and air pollution and how different countries compare.

Here in Wisconsin, the Department of Natural Resources puts out an air trends report and has one that just came out at the end of 2016, talking about how air is in Wisconsin. And I added the URL of that report there since it may be of particular interest. And finally, I have – Ive written a lot of different things on my webpage, but one that may be of interest is in the – in a blog out of Arizona State University called U.G.E.C., the Urbanization and Global Environmental Change, on whats next for air quality in the United States?

[return to the slide of the satellite data from the Aura satellite showing the reduced NO2 pollution in the U.S.]

And Ill end with my favorite plot. And its really been a pleasure talking to you this evening. Thank you very much.

[applause]