Barbara J. Finlayson-Pitts

Barbara J. Finlayson-Pitts is a Canadian-American atmospheric chemist. She is a professor in the chemistry department at the University of California, Irvine and is the Director of AirUCI Institute. Finlayson-Pitts and James N. Pitts, Jr. are the authors of Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications. She has been a member of the National Academy of Sciences since 2006 and is the laureate for the 2017 Garvan–Olin Medal. In 2016 she co-chaired the National Academy of Science report "The Future of Atmospheric Chemistry Research".

Finlayson-Pitts investigates the chemistry of the upper and lower atmosphere and ways in which chemical reactions in the atmosphere are involved in air pollution and climate change. She and her team work to develop a molecular-level understanding of gaseous reactions of particles in different layers of the atmosphere, and at the interfaces between layers. They also study the interface between air and water.

Education Finlayson-Pitts received a Bachelor of Science from Trent University in Peterborough, Ontario, in 1970. She earned her master's and PhD in chemistry from the University of California, Riverside in 1971 and 1973, respectively.

Finlayson-Pitts served as the lead author of a 2009 study published in the Proceedings of the National Academy of Sciences that found that burning fossil fuels releases nitrogen oxides, which interact with gaseous hydrogen chloride to form smog-forming compounds. The study also found water vapor enhances the reaction.

Chloride, which is many times more abundant than bromine, reacts with nitrogen and oxygen-containing compounds in both the aqueous and gas phases to form a variety of molecules that scatter light, including HCl, Cl2, ClNO2, ClO, and OClO. Finlayson-Pitts worked with scientists from UCI and the Pacific Northwest National Laboratory in Richland, Washington, to research the processes leading to secondary organic aerosol formation. More specifically, they studied particle formation under the simultaneous oxidation α-pinene by ozone and NO3 radicals using an aerosol flow system. α-Pinene is emitted by vegetation in varying quantities, depending on temperature and light conditions. The reaction of α-pinene with NO3 radicals in the atmosphere creates low-volatility particles, generating secondary organic aerosols. These particles were previously thought to condense into tiny droplets of liquid and then dissipate as those drops of liquid evaporate.

Her research group has received funding from the National Science Foundation and the Department of Energy. They are a part of Atmospheric Integrated Research for Understanding Chemistry at Interfaces (AirUCI), a collaboration from across the University of California-Irvine. AirUCI examines how air quality and climate change are affected by processes that occur at the atmosphere's air-water interface, and focuses on the impacts of energy use, air pollution, and air quality on human health. He followed her to the University of California, Irvine in 1994, where the two collaborated on research and co-authored books and other publications. 2009 Coalition for Clean Air Carl Moyer Award for Scientific Leadership and Technical Excellence 2025 L'Oréal-UNESCO For Women in Science Awards, Laureate for North America.