Boston University professor Jeffrey Geddes wants to better understand our air and how it is changing, with a focus on how natural sources of emissions interact with emissions from human activities, such as burning fossil fuels.
Geddes, an assistant professor of earth and environment, was recently awarded almost $1 million in federal research grants to study the issue and what it means for improving air quality.
The World Health Organization estimates that nine out of 10 people worldwide breathe air containing high levels of pollutants.
To support his research, Geddes has received two grants with related but separate goals: a National Science Foundation grant of $693,000 over five years and a National Aeronautics and Space Administration grant of $280,000 over three years.
In an interview last week, Geddes outlined his research plans and what he hopes to achieve. (The interview has been edited and condensed.)
What are the goals for each of these grants, specifically?
The NSF grant will focus more on modeling work. The outcome will be gathering a better understanding of how natural systems change from year to year and how those changes impact the atmosphere and atmospheric composition. The NASA work will be more focused on establishing new observations that help us understand air quality in the Boston region and on improving how we use satellites to look at air quality.
What are some of the shortcomings of measuring air quality with satellites?
Satellites don’t sample as many individual spots. It’s just one big footprint that covers a large area. What I’m doing is filling in that footprint with smaller measurements.
What kind of measurements will you be taking around Boston?
I’m going to be focused on a couple of small reactive molecules. The first is nitrogen dioxide. The other is formaldehyde. Nitrogen dioxide is a really good indicator of combustion-related pollutant emissions. Formaldehyde is a really good indicator for organic emissions, both from human systems but also natural systems. What we’re trying to get at is what the variability is across the city of Boston in terms of what we measure from human sources and what might be caused by natural emissions.
What is known about how natural emissions and emissions caused by human activities interact?
There are specific pollutants, like ozone, that can form in the atmosphere from chemistry, as opposed to being directly emitted. Natural systems like forests emit organic molecules naturally, and these organic molecules are reactive. The problem is that natural emissions can also lead to the formation of pollutants when they’re mixed with anthropogenic [human-generated] emissions. If trees are emitting what they’re emitting completely in the absence of what we emit, it wouldn’t be as large of a problem.
How is a better understanding of that interaction going to lead to better air quality?
If we understand how the biosphere is going to change and impact the atmosphere, we can tailor our response. So, say, one year we’re going to reduce anthropogenic emissions by 20 percent, and we should see an improvement in air quality. But the next year, the background emissions from the biosphere might be higher. Maybe it means that, actually, we needed to decrease our emissions by 40 percent to account for the fact that there are these interactions.
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