Barbara J. Finlayson-Pitts

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. After completing a postdoctoral fellowship at UC Riverside, she worked as a professor of chemistry at California State University, Fullerton from 1974 to 1994. In 1994, she joined the chemistry department of the University of California, Irvine.

Finlayson-Pitts' research focuses on developing a molecular-level understanding of the fundamental kinetics, mechanisms, and photochemistry of gaseous reactions of particles. She is particularly interested in how reactions occur in different layers of the atmosphere, and at the interfaces of different layers. In addition to her work on the troposphere and stratosphere, she studies interactions at the interface between air and water, where gases meet liquids. Reactions that occur at the surface between layers may differ from the reactions that occur within each layer.

In the atmosphere, emitted gases and particles may react further to form new chemical species. Some compounds may not react within the troposphere, but will break down and participate in further transformations in the higher stratosphere. The inorganic chemistry of oxides of nitrogen and sulfur in the gas phase are better understood than the interactions of nitrogen and sulfur oxides with organic compounds. Finlayson-Pitts and her colleagues have done important work on understanding the chemistry of the troposphere, in particular, the conversion of nitric oxide (NO) to nitrogen dioxide (NO₂) in air and the subsequent formation of ozone, nitric acid, and organic nitrates.{{cite book |author=Consensus Study Report |title=The future of atmospheric chemistry research : remembering yesterday, understanding today, anticipating tomorrow|chapter=Chapter 3 Understanding Today |date=2016 |publisher=National Academies Press |isbn=978-0309445658 |pages=48–50 |chapter-url=https://www.nap.edu/read/23573/chapter/5 |access-date=16 October 2018|doi=10.17226/23573}}

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.{{Cite journal|last1=Raff |first1=J. D. |last2=Njegic |first2=B. |last3=Chang |first3=W. L. |last4=Gordon |first4=M. S. |last5=Dabdub |first5=D. |last6=Gerber |first6=R. B. |last7=Finlayson-Pitts |first7=B. J.|title=Chlorine activation indoors and outdoors via surface-mediated reactions of nitrogen oxides with hydrogen chloride|url=http://www.pnas.org/content/106/33/13647.full.pdf|journal=Proceedings of the National Academy of Sciences |date=20 July 2009 |volume=106 |issue=33 |pages=13647–13654 |doi=10.1073/pnas.0904195106|pmid=19620710 |bibcode=2009PNAS..10613647R|pmc=2713392|doi-access=free }}

Finlayson-Pitts and her team examined reactions between nitrogen dioxide (NO₂) and dinitrogen pentoxide(N₂O₅), two common compounds created from fossil fuel combustion prevalent in the atmosphere, and gaseous hydrogen chloride (HCl), which has reached concentrations of a few parts per billion in polluted air. The authors of the study proposed N₂O₅ exists as an asymmetric dimer, NO₂⁺NO₃⁻. They also hypothesized water molecules promote the ionization of N₂O₅ to NO₂⁺NO₃⁻.When NO₂ reacts with HCl (in the form of NO₂⁺NO₃⁻), it creates ClO and HNO₃, and when N₂O₅ reacts with HCl, it forms ClNO₂ and HNO₃.

The team said the creation of the chlorine nitrogen compounds could have negative implications for the reliability and lifetime of electronics that are susceptible to corrosion when the reaction takes place in doors. Light absorption crosses into section in near ultraviolet and overlaps strongly not only with solar radiation but also with that from fluorescent lights, causing smog. The chlorine-containing molecules also react with nitrogen monoxide (NO) to produce ozone.

In a 2010 paper, Finlayson-Pitts detailed the role of halogens in reactions of the lower atmosphere. She found that chlorine ions in the air help ozone formation, while bromine ions aide ozone destruction. Both ions are common in the troposphere due to cycles between seawater and gaseous phases.{{Cite journal |last=Finlayson-Pitts |first=Barbara J. |title=Halogens in the Troposphere |journal=Analytical Chemistry |date=February 2010 |volume=82 |issue=3 |pages=770–776|doi=10.1021/ac901478p|pmid=20041651 }}

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 also helped author a 2012 study published in the Proceedings of the National Academy of Sciences which concluded that new models may be needed to address secondary organic aerosols.{{cite journal |last1=Perraud |first1=V. |last2=Bruns |first2=E. A. |last3=Ezell |first3=M. J. |last4=Johnson |first4=S. N. |last5=Yu |first5=Y. |last6=Alexander |first6=M. L. |last7=Zelenyuk |first7=A. |last8=Imre |first8=D. |last9=Chang |first9=W. L. |last10=Dabdub |first10=D. |last11=Pankow |first11=J. F. |last12=Finlayson-Pitts |first12=B. J. |title=Nonequilibrium atmospheric secondary organic aerosol formation and growth |journal=Proceedings of the National Academy of Sciences |date=30 January 2012 |volume=109 |issue=8 |pages=2836–2841 |doi=10.1073/pnas.1119909109|url=http://www.pnas.org/content/109/8/2836.full.pdf |pmid=22308444 |pmc=3286997|bibcode=2012PNAS..109.2836P |doi-access=free }}

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.

Finlayson-Pitts and the team she worked with found that secondary organic aerosols actually attach themselves more tightly to organic particles in the air. Because of this, previous models underestimate the amount of fine particles, which are linked to both lung and heart disease, in the air.{{cite news |last1=Barringer |first1=Felicity |title=Scientists Find New Dangers in Tiny but Pervasive Particles in Air Pollution |url=https://www.nytimes.com/2012/02/19/science/earth/scientists-find-new-dangers-in-tiny-but-pervasive-particles-in-air-pollution.html |access-date=16 October 2018 |work=The New York Times |date=February 18, 2012}}

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.{{cite web |last1=Rosenzweig |first1=Efrat |title=Every Breath You Take |url=https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=115198&org=NSF |website=National Science Foundation |access-date=16 October 2018|date= July 13, 2009}}

Barbara J. Finlayson-Pitts married James Pitts (1921–2014) in 1970. James Pitts was also a chemist.{{cite news|url=http://www.latimes.com/local/obituaries/la-me-james-pitts-20140626-story.html|title=James Pitts dies at 93; his research led to cleaner air in California |last=Barboza |first=Tony |date=2014-06-25|work=Los Angeles Times|access-date=2014-07-18}} He followed her to the University of California, Irvine in 1994, where the two collaborated on research and co-authored books and other publications.

• 1993 Fellow of the American Association for the Advancement of Science
• 1999 "Service Through Chemistry" Award, Orange County Section of the American Chemical Society
• 2004 American Chemical Society Award for Creative Advances in Environmental Science & Technology
• 2007 Richard C. Tolman Award, Southern California Section of the American Chemical Society{{cite web |title=2007 Barbara Finlayson-Pitts, UC Irvine |url=https://scalacs.org/?page_id=1054 |website=Southern California Section of the American Chemical Society |access-date=16 October 2018|date = 2012-07-17}}
• 2009 Coalition for Clean Air Carl Moyer Award for Scientific Leadership and Technical Excellence
• 2017 Garvan–Olin Medal, American Chemical Society
• 2019 Royal Society of Chemistry Environment Prize {{Cite web|url=https://www.rsc.org/ScienceAndTechnology/Awards/EnvironmentPrize/2019-Winner.asp|title=RSC Environment Prize 2019 Winner|website=www.rsc.org|access-date=2019-06-20}}

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Category:21st-century American chemists

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Category:21st-century American women scientists