Can you tell me a little bit about how you got to Carleton?

The most amusing part of it is I applied to Carleton as an undergraduate and I thought “no chance will I ever live in Minnesota for four years.” So I didn’t even really pursue it after I got in. I went to a similar small liberal arts college, Haverford, and then I went to grad school at Berkeley which is near where I am from, and was a TA for a class that was 50% larger than the college I had just graduated from. And that confirmed for me my interest in small liberal arts colleges. That eventually became my plan, to try to get back to such a place.

After a postdoc, this position was available the year that I was applying, and it was a clear top choice for me! It’s really great that it worked out. After my undergraduate I did my PhD, which was five years, and then my two-year post-doc, which is when I got involved in atmospheric chemistry.

Were you immediately involved in the ENTS program then?

Yeah! I came in saying “Who is this group? I’m interested in being a part of it!” Exactly what that involvement has looked like has ebbed and flowed a little bit. [The program] was a very different thing back in that time period. I came here in the fall of 1998. It was a concentration, there was a director here who was here on a not-meant-to-be-permanent position. ENTS lived in a temporary building.

What have been some of the different research projects you’ve been a part of, either within ENTS or Chemistry?

Pretty much everything has been derived from wanting to understand particulate matter. What are the aerosol particles that are either emitted by something or transformed in some process? The one that is most directly related to ENTS in an active way is my connection to [Professor] Tsegaye [Nega]’s stove project which is really interesting and really fun. [Professor Nega ran an off-campus program in Ethiopia that focused on designing and implementing a cookstove project]. I have no particular knowledge of “how to design a stove” or the community connections, that’s something that I think is really fantastic and has no overlap with most of what I’ve ever done.

I had a student researcher last summer working 100% on stove stuff, she took 8 stoves that Tsegaye had as prototypes and she built a little mock-kitchen, a tent structure surrounded by tarps outside to try to do the best job we could modeling an Ethiopian kitchen, and she ran all 8 stoves doing two different tests. One was a carefully controlled water-boiling test and the other was a controlled cooking test using a recipe for Ethiopian lentils. We were using little air monitors as well as the instrumentation that is a mainstay in my lab, [instrumentation] which gets much more detailed information about the particles emitted. It was a really productive summer!

We know things about each stove, like the ratio of the smoke inside the kitchen and outside, and interesting things about the composition of what the particles actually are, so we can tell the efficiency of the combustion of each stove. That’s been super fun and we were working closely with Tsegaye, the stove-master, he was helping us learn how to use the stoves and helping think about what was important to know about each stove and being the executive chef!

Other projects that have been class-based, I had a group of students for a year on and off in all three seasons measuring particle concentrations at [Northfield] Middle School because that’s the transportation hub of the schools. All the buses bring everyone to the Middle School and redistribute them. And also there are plenty of cars that come to drop off their kids. So I had students do a project where they went during the transportation core time and compared the concentrations of particulate matter at the school to a control site like a mile away to try to get an idea of whether this is an issue, something we should think about.

There are places in the country where there are anti-idling ordinances that have been considered and there are places where they’ve been implemented. As far as I’m aware, no one has considered it here. We were asking the question, is this something that maybe should be thought about? The students working on the project wrote some articles, we were trying to present at a level where middle schoolers could get something out of it. So they talked about what are the health effects of the particles, and if we were to pass an ordinance how would we do it? And what are examples of people who have done it? How has it worked? What are the political consequences of it? Economic consequences of it? That was a fun project!

We have an ongoing project to just measure what’s in the air in Northfield. Most studies in the literature focus on urban air or really clean rural air. We’re in a middle ground that hasn’t been probed much. We’re going by season, measuring for a week in each season and we’ve done that for a few years at this point. We’re seeing things now that we can actually pick out, like the turkey farm, so that’s been fun!

So what are some of the big questions you like to ask in your research? What is it and where does it come from?

Those are pretty big. We want to know what is in the air and we want to try to understand what are the emission sources of the actual particles that we’re sampling or what are the emission sources of the things that are reacting with the particles and transforming them and turning them into what we are seeing. There are things that live in the air for a while and end up being transformed from how they are emitted. There are also particles that form from reactions in the air so you can’t trace those back to their original source, because there isn’t one. But you try to figure out what the characteristics are of those.

The utility of asking these questions are (1) the health effects, to understand what’s out there so that people who do health tests can use real or relevant samples and (2) to understand the climate effects. Knowing the chemical makeup helps us to know whether they’re going to reflect light, absorb light, nucleate clouds efficiently, not nucleate clouds efficiently, all those kinds of things that have a direct impact on climate.

What do you think the role is of atmospheric chemistry within the ENTS department or Environmental Studies in general?

It’s a very specific niche, but the atmosphere mediates so much of climate, so much of what happens in the Earth’s climate system that without a detailed understanding of it, we cannot predict what’s going to happen to it. You’ve looked at the International Panel on Climate Change graphs where the biggest error bar, the largest uncertainty, is the aerosol effects. We understand the greenhouse gases, what they do, and where they are emitted, with some caveats, it’s not perfect. But particles, not so much. They’re too complex and there’s too many uncertainties about all the things that they do. It’s really just an area where we need to learn more.

If we want to be able to predict predict future impacts on the climate in order to either think about what the impact of what we are doing is or how we should address things or what would be good future policy changes in the future or how should we react to expected changes, all of those things that we like to think about in terms of climate, this is an area that we need to understand. I don’t have any grand notions that everyone in ENTS should be doing exactly what I’m doing, but I think this is a core component of understanding the environment and especially focusing on climate.

My last question is what’s your favorite thing about teaching or researching at Carleton?

The students. It’s easy! The opportunities to work with interesting people thinking about interesting things, both from students and the faculty side, being able to get involved in things that people are interested in that I might not have known about or vice versa, having something I want to do and being able to get other people involved in those things.

So you ended up in Minnesota even after the initial hesitation?

Yes and with no regrets! It’s one of those great ironies. You should never say “I’ll never do that!” Because you will probably do that thing, is what I found out.