The freezing behavior of particle mixtures

Associate Professor of Chemistry and Mechanical Engineering Ryan Sullivan published findings in the journal Atmospheric Chemistry and Physics titled “A new multi-component heterogeneous ice nucleation model and its application to Snomax bacterial particles and a Snomax-illite mineral particle mixture.”

In this paper, Sullivan and his students—Mechanical Engineering graduate student, Hassan Beydoun, and Chemistry graduate student, Michael Polen—investigate the freezing behavior of biological ice nucleating particles (INP) mixed with mineral dust particles to examine how these mixtures could potentially impact the abundance of ice nucleating particle surfaces in the atmosphere.

“This is one of the first methods that allows us to predict the temperature at which a cloud droplet will freeze when it contains a mixture of different types of ice nucleating particles,” says Sullivan, explaining the importance of the study.

This is one of the first methods that allows us to predict the temperature at which a cloud droplet will freeze when it contains a mixture of different types of ice nucleating particles.

Ryan Sullivan, Associate Professor, Chemistry and Mechanical Engineering

“We wanted to answer the burning question of whether putting bacterial material onto dust particles changes the overall ice nucleation properties of the mixed particle. The answer is no—the freezing properties are still governed by the properties of the individual components, even when mixed.”

Understanding the freezing behavior of different particles is important because researchers can use that information to predict how particles might interact with each other in the atmosphere and how these interactions might contribute to a net cooling or net warming effect on the planet.

Overall, this information will help researchers have a better understanding of how human activities and particle emissions alter cloud physics and change the global climate.

Read the article: Beydoun, H., Polen, M., and Sullivan, R. C.: A new multicomponent heterogeneous ice nucleation model and its application to Snomax bacterial particles and a Snomax–illite mineral particle mixture, Atmos. Chem. Phys., 17, 13545-13557, https://doi.org/10.5194/acp-17-13545-2017, 2017.

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Lisa Kulick
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