CAREER: Reactions of Volatile Organics in Aerosol Articles as a Source of Persistent Free Radicals

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

WIth support from the Environmental Chemical Sciences Program in the Division of Chemistry, Eric P. Vejerano at the University of South Carolina will study the formation of environmentally persistent free radicals (EPFRs) in secondary organic aerosols (SOA). EPFRs are a recently identified class of stable and persistent pollutants that contribute to some of the adverse health effects of atmospheric particulate matter.

Knowledge gaps on understanding the sources, nature, and formation of EPFRs remain, for instance, the contribution of atmospheric processing of organic contaminants in forming EPFRs. This project will investigate the formation of EPFRs when volatile organic compounds (VOCs), such as those released by plants and from human-related activities, react with atmospheric oxidants (e.g., ozone) to form particles.

Also of interest are subsequent reactions that may result in the loss of EPFRs after their formation. The project will utilize a suite of analytical methods to probe changes in the particles and characterize size distributions and concentrations. The broader impacts of this project include providing knowledge of the classes of chemicals responsible for forming EPFRs, which integrates research on EPFRs with atmospheric chemistry.

Concepts and results from the project will be incorporated in developing publicly accessible electronic and online educational tools for K-12 students. Additionally, this project will equip undergraduate students with scientific and technical skills through research participation and give them insight to science, technology, engineering, and mathematics (STEM) career paths.

The PI seeks to cultivate excellence through diversity and is engaged in training students from groups underrepresented in chemistry. Specifically, the PI is actively training early career female and African-American students tol strengthen diversity, equity, and inclusion in chemistryresearch.

The atmospheric processes leading to the conversion of VOCs to SOA are a potentially significant contributor to EPFRs, since many anthropogenic and biogenic VOCs and their oxidation byproducts have similar chemical structures to those known to form EPFRs from primary emission sources. Mass spectrometry will be used to determine chemical identities and electron paramagnetic resonance spectroscopy to measure EPFR formation and identify possible chemical structures.

Diverse chemical classes of VOCs will be tested in their ability to form EPFRs using a potential aerosol mass chamber to explore structure-EPFR relationships. In addition, the impact of seed particles, temperature, irradiation, and humidity that regulate the formation and loss of EPFRs via subsequent atmospheric processes will be explored. The objectives of this career-development plan are therefore to: (1) conduct a lab-scale chamber study to understand the impact of atmospheric processes in the transformation of VOC to SOA that subsequently form EPFRs; (2) determine the factors that affect the formation and loss of EPFRs; and (3) integrate the research outcomes in implementing educational and outreach programs to improve science education on the research topic by developing electronic and online educational tools for K-12 students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.