As nations cut emissions that once fueled urban smog, scientists are discovering unexpected chemistry taking place in the atmosphere.
UC Merced Professor Xuan Zhang is leading a project to uncover how these chemical shifts could affect the air we breathe and the climate. The project is supported by a National Science Foundation CAREER Award.
Zhang is the 43rd researcher from UC Merced to earn a CAREER award from the NSF.
CAREER awards are among the NSF’s most prestigious. They are given through the Faculty Early Career Development Program to recognize untenured faculty members as teacher-scholars. Early-career faculty members are selected based on three factors: the strength of their research proposals; their potential to serve as academic role models in research and education; and their leadership in their field and organizations.
Zhang will receive about $621,000 over the next five years for the project “Dynamics of Peroxy Radicals at Extended Lifetimes: A Key Missing Piece in the Canonical Mechanism.”
The project focuses on peroxy radicals — short-lived molecules formed whenever fuels, plants or fires release volatile organic compounds. Traditionally, scientists thought these radicals quickly disappeared by reacting with nitrogen oxides or hydrogen compounds. But as pollution drops worldwide, the radicals are lingering longer and behaving in ways not captured by current models.
"This project is about understanding how our atmosphere is changing as pollution controls take effect worldwide,” Zhang said. “By studying key chemical reactions in the air, we hope to improve predictions of air quality and climate.”
The research will examine how peroxy radicals generated from aromatic compounds — key pollutants from combustion — transform into different versions of themselves and form highly oxidized organic molecules. These reactions are believed to be important in creating tiny airborne particles that damage lungs and trap heat in the atmosphere.
Findings from the study will feed into large-scale climate models, helping policymakers evaluate the effectiveness of emissions controls and design strategies that protect health and the environment.
Zhang and her lab focus on atmospheric chemistry, including the toxicity and health impacts of organic aerosols, such as on Alzheimer’s disease, atmospheric composition measurement, air pollution, and interactions between air quality and climate. She is a member of the Department of Life and Environmental Sciences in the School of Natural Sciences.
"I’m deeply honored to receive the NSF CAREER award,” Zhang said. “It not only supports my research on atmospheric chemistry but also gives me the chance to mentor students and engage local communities in conversations about air quality and climate.”
The project also carries a strong educational mission, a required part of each CAREER proposal. Six undergraduates will participate in a nine-week bridge program that immerses them in atmospheric research and mentorship at the National Center for Atmospheric Research.
In addition, UC Merced will host summer workshops to help high school teachers incorporate cutting-edge climate science into their classrooms, and the team will produce animations for a YouTube channel aimed at making air chemistry more accessible to the general public.
By combining advanced research with education and outreach, the project not only addresses urgent questions about future air quality but also opens doors for students and communities that are often left out of scientific conversations.
"I see this award as an opportunity to connect atmospheric research with education,” she said. “By linking discoveries about how our air is changing to the classroom, workshops and outreach, we can both improve climate science and empower students and teachers in communities such as Merced that are most affected by poor air quality.”
