Particulate matter plays significant roles in the chemistry and physics of the lower atmosphere. In combination with sunlight, these particles can initiate interesting chemistry. The Laboratory of Atmospheric Physical Chemistry uses creative new experiments to explore the effect of aerosols in the atmosphere in the presence of solar radiation. These experiments can be summarized in the following projects:
Heterogeneous Photochemistry
Have you ever wondered how sunlight can spark chemical reactions in the air we breathe? In this project, we study light-driven chemistry on aerosol surfaces—how light interacts with chemicals stuck to the surface of tiny airborne particles called aerosols. These reactions can change the composition of our atmosphere and play a key role in environmental processes like air pollution and climate.
Our team uses a variety of tools to explore these surface reactions, including vibrational spectroscopy, quartz crystal microbalance (QCM), computational chemistry, and solar simulators that mimic sunlight in the lab. Our experiments help us understand how light and surfaces together can promote the formation of reactive molecules such as HONO (nitrous acid), which influences the nitrogen cycle and affects the chemistry of the atmosphere.
We investigate several types of aerosols, from natural ones like sea spray and mineral dust to man-made particles and lab-created models that mimic them. This research combines hands-on lab work, instrumentation, and environmental relevance—perfect for students curious about chemistry at the Earth’s surface.
Interested in helping uncover the daytime chemical pathways that shape our atmosphere? Join us and be part of this exciting exploration.
Aerosol Dissolution
What happens to airborne particles once they are part of rain, fog, or clouds? In this project, we study how tiny particles like volcanic or industrial ash can dissolve in atmospheric water—a process that transforms their chemical makeup and affects how they interact with the environment.
We focus especially on how sunlight influences the release (or leaching) of metals like iron and copper from these particles into water. By examining both light and dark conditions, we can learn how the composition of the particles controls which metals dissolve, in what form, and how quickly. These processes have important implications for atmospheric chemistry, nutrient cycles, and even human health.
In our lab, we use advanced aqueous reactors that simulate the thin layer of water found on humid aerosols, allowing us to mimic conditions in clouds or fog. We combine this with techniques like colorimetry, electron microscopy, atomic absorption spectroscopy, surface area analysis, and X-ray methods to study the particles and the water they dissolve into.
Curious about how particles change as they travel through the sky? Join us to explore the hidden chemistry of the atmosphere’s liquid layers.
Computational Chemistry
How do molecules behave on the surface of atmospheric particles—and how can we predict that behavior? In this project, we use quantum chemistry and computer modeling to explore chemical reactions that occur on aerosol surfaces. These reactions can be difficult to observe directly, so theoretical tools help us see what’s happening at the molecular level.
We use quantum mechanical methods to simulate how atmospheric trace compounds, like nitrates, bind to particle surfaces such as titanium dioxide. The image above corresponds to energy minimized structures of nitrates adsorbed onto titanium dioxide particles. These models allow us to predict how the molecules might interact, what the most stable configurations are, and how their spectroscopic signatures might change once they’re adsorbed.
We also draw from environmental and engineering approaches, using simplified box models to interpret the results of our experiments and explore how particle chemistry affects the larger atmosphere. This combination of molecular modeling and system-level analysis provides an interdisciplinary perspective, ideal for students interested in chemistry, physics, or environmental and chemical engineering.
Excited by the idea of using theory and modeling to solve real-world atmospheric problems? Join us and help uncover the chemistry happening at the surface of our sky.
Plasma Chemistry
Plasma—the fourth state of matter—is all around us, from lightning to the northern lights. In the lab, we use plasma to explore how highly reactive species, like free radicals and atomic oxygen, interact with the surfaces of atmospheric particles.
Using a custom-built plasma reactor known as The Cube, we simulate how hydroxyl radicals (OH) and atomic oxygen react with organic molecules that are stuck to mineral dust surfaces. These experiments help us understand real atmospheric processes, but they also reveal new ways to modify and reuse hydrocarbons—offering insights into sustainable chemistry and materials science.
We also study how ozone reacts with organic coatings on aerosol surfaces, especially how these reactions transform volatile molecules into more hydrophilic compounds that help form clouds. By combining techniques from our plasma and photochemistry experiments, we’re investigating how aerosols are processed in the atmosphere and how these changes impact air quality, climate, and sustainability.
Are you curious about using cutting-edge tools to explore atmospheric chemistry and sustainable materials? Join us and help discover how surface reactions drive change in the environment—and in the lab.