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  • May Monthly Faculty Highlight- Tracey Holloway

May Monthly Faculty Highlight- Tracey Holloway

May 22, 2019

Photo of Tracey Holloway

While awards and appointments attract much of the news attention, the Atmospheric and Oceanic Sciences department has a large variety of work going on behind the scenes. As part of a new Monthly Highlights series, the AOS news page will be featuring different faculty and student projects once a month. These highlights will be showcasing published papers, community outreach events, field campaigns, Q&As on climate change and weather phenomenon, and other topics as they come up.

In early March, Professor Holloway's research group published a paper in the Environmental Science & Technology journal. Titled “The air quality-related health benefits of energy efficiency in the United States”, Holloway and her team discerned that reducing energy costs and consumption could have tangible benefits for human health. Given that air pollution is one of the biproducts of energy production, improving energy efficiency could both reduce costs for consumers and reduce the risks of asthma attacks and respiratory diseases.

The press release for the paper can be found here.


What was the overarching goal of your research for this paper?

My research group uses atmospheric science methods to address policy-relevant research question. We have published a number of studies examining how energy system change impacts air quality and health. For example, we have quantified how air pollution would change due to more solar energy, changing transportation systems, and changing building energy use. In this case, we looked at the potential air quality benefits of energy efficiency.

All of these questions require advanced atmospheric models, because air quality depends on day-to-day weather variability and chemical processes.

In fact, it is relatively uncommon to quantify air quality impacts of energy use, because it depends on weather and atmospheric chemistry. Most energy analysts do not work with atmospheric models, and most atmospheric scientists don’t tackle energy issues. Air quality is one of the many cool topics at the energy-meteorology interface.

What methods did you use to gather your data?

For this paper, we worked with the American Councils for an Energy Efficient Economy (ACEEE). They are experts in energy policy, and we took their recommendation for the energy scenario of a 12% summertime energy savings.

Reducing electricity use 12% doesn’t mean that every power plant is working 12% less. Rather, some power plants are turned off entirely, others may crank down just a little. To determine which power plants turn on and off with an energy scenario, we used a model called the AVoided Emissions and geneRation Tool (AVERT), developed by the EPA.

AVERT calculates the changes in emissions of sulfur dioxide and nitrogen oxides associated with the change energy scenario. We combine these power plant emissions with other sources of chemicals into the atmosphere, from cars and trucks, industry, and natural sources like trees and soils.

We calculate weather over our study area - in this case the United States - with the Weather Research and Forecasting Model (WRF).

Then, we combine weather from WRF and emissions from AVERT and other sources into the atmospheric chemistry model used by my group, called the Community Multiscale Air Quality model, or CMAQ. CMAQ is developed and maintained by the EPA and is used around the world as a state-of-the-art chemical transport model.

The output from CMAQ tells us what chemicals are in the air, and how they change in time and space.

When we know what is in the air, and how it is changing, then the last step is to evaluate public health. We use another model, that is based on health risk functions and population data, called the Benefits Mapping Tool or BenMap. AVERT, CMAQ, and BenMap were all created by EPA to support air quality and health assessment of energy systems.

So we aren’t the only ones using these models, but we were the first to evaluate how energy efficiency could benefit public health and make the air cleaner.

Were there any outcomes that particularly surprised your team? Alternatively, was there anything your team was expecting to find but did not?

We were surprised at how big the health benefits were for energy efficiency. We found that saving $1 in energy (through efficiency or conservation), actually saves about $1.50 — the $1 for not paying for the energy itself, and an extra 50 cents in terms of health benefits.

These health benefits are primarily in the form of longer life expectancy. The EPA values each life at about $8 Million, so reducing the risk of death across the whole population quickly adds up in terms of benefits. To understand where they get this number, think about the cost of health care — A heart transplant is well over a million dollars. The EPA calculates the cost of saving a life by extrapolating the amount we are willing to pay to live longer.

What do you consider the most valuable piece of information that your team discovered?

I think it’s important to show the “win win” opportunities in energy. Energy efficiency saves money, reduces carbon emissions, reduces multiple air pollutants, and benefits public health.

None of these benefits are surprising, but we have shown quantitatively where, when, and how much air quality is affected.

This same approach can be used for any energy policy or technology change. To me, using atmospheric models to support energy planning is a powerful example of using science to inform policy options.

Are you working on any other projects that focus on the intersection of human health and environmental concerns?

Yes. Since I study air quality, pretty much everything I do relates to public health. As an example, I am leading the NASA Health and Air Quality Applied Sciences Team (HAQAST), a $15 Million national initiative to connect NASA data with public health and air quality information needs.

In the press release, you spoke about bridging the gap between researchers and policymakers. Are you working on any other projects that keep this philosophy in mind?

The HAQAST team I lead connects researchers and policymakers around NASA data. For example, the Clean Air Act regulates air pollution across the U.S., and science is a huge part of air pollution management. But, the Clean Air Act was written in 1970…way before satellites could “see” chemicals in the air. So HAQAST works with cities, states, federal agencies, non-profits, and companies to understand what questions they have that NASA data could answer.

Research is about asking and answering innovative questions. There are a lot of exciting research questions that have evolved from asking experts on other fields “what do you need? what questions are you struggling with?”

Working with a lot of different people, and listening to their ideas and requests, has led to some really exciting science with real-world applications.


If you have any suggestions for a Monthly Highlight, please send an email to studenthelp@aos.wisc.edu.