01/15/2016

Freezing Sea Spray Aerosols to Study Their Natural State

A new method preserves sea spray aerosols for studying their natural structure.

The Science

Scientists can now trap sea spray aerosols in their natural state and accurately characterize their particle structure using a new microscopy approach.

The Impact

This approach will enable scientists to more easily investigate the influence of sea spray aerosols on climate and the environment.

Summary

Sea spray aerosols are a highly complex mixture of sea salt and organic components that are generated through wave action and bubble bursting where the air and sea meet. Obtaining detailed information about the structure and composition of these aerosols is crucial for understanding their role in cloud formation and their influence on climate. However, studying sea spray aerosols using conventional electron microscopy requires high-vacuum conditions that alter aerosol structure and prevent scientists from characterizing the natural configuration of these particles in the atmosphere. To address this problem, a team of researchers from the University of California, San Diego; Department of Energy’s (DOE) Environmental Molecular Sciences Laboratory (EMSL); and University of Iowa developed a new approach that used cryogenic transmission electron microscopy. This approach involved flash freezing sea spray aerosol particles to preserve their natural configuration and then studying their structure with electron microscopy. The researchers used the environmental transmission electron microscope and scanning/transmission electron microscope at EMSL, a DOE user facility. Using this unique approach, the team of researchers was able to detect mixed salts and soft materials characterized by distinct biological, chemical, and physical processes. The researchers also demonstrated this approach could be used to study chemical and morphological changes that occur when particles are exposed to various environmental conditions, such as changing humidity. The ability to trap aerosols under environmentally relevant conditions will open new avenues for addressing many important questions about the chemical complexity and structure of aerosol particles and how they impact climate and the environment.

Principal Investigator(s)

James Evans
Environmental Molecular Sciences Laboratory
[email protected]

Funding

This work was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Biological and Environmental Research, including support of the Environmental Molecular Sciences Laboratory, a DOE user facility; the National Science Foundation; and National Institutes of Health.

References

Patterson, J. P., D. B. Collins, J. M. Michaud, J. L. Axson, C. M. Sultana, T. Moser, A. C. Dommer, J. Conner, V. H. Grassian, M. D. Stokes, G. B. Deane, J. E. Evans, M. D. Burkart, K. A. Prather, and N. C. Gianneschi. 2016. “Sea Spray Aerosol Structure and Composition Using Cryogenic Transmission Electron Microscopy,” ACS Central Science 2(1), 40-47. DOI: 10.1021/acscentsci.5b00344.