John H. Seinfeld

Louis E. Nohl Professor and Professor of Chemical Engineering
B.S., University of Rochester, 1964; Ph.D., Princeton University, 1967. D.Sc.h.c., University of Patras; Carnegie Mellon University; Clarkson University. Assistant Professor, Caltech, 1967-70; Associate Professor, 1970-74; Professor, 1974-; Nohl Professor, 1979-. Executive Officer for Chemical Engineering, 1974-90; Chair, Division of Engineering and Applied Science, 1990-2000.

Dual Affiliation with Division of Engineering and Applied Science

Assistant: Martha Hepworth

Increases in the levels of greenhouse gases, such as carbon dioxide, and airborne particulate matter, aerosols, are impacting the Earth's climate. Understanding the chemical and physical processes that govern the dynamics and distribution of gases and aerosols in the atmosphere and their effects on climate and air quality represents one of the grand challenges of science in the 21st Century. That the increase of greenhouse gases attributable to human activities is causing a steady rise in the Earth's global mean temperature is unequivocal.

The ability to forecast future climate based on scenarios of energy consumption and other activities is hampered by uncertainties in two major climate factors. Aerosols, on the whole, partially offset the global warming due to the increase of greenhouse gases, but the complex life cycle of aerosols in the atmosphere is still incompletely understood. This uncertainty translates into an uncertainty of the effect of aerosols on climate. Second, clouds are a large source of uncertainty in climate models, and the most uncertain aspect is the extent to which changes in aerosol levels have influenced cloud amounts and precipitation and will do so in the future.

Our research is broadly aimed at improving our understanding of the physics and chemistry of atmospheric aerosols, at scales ranging from the urban to the global atmosphere. This improved understanding will lead to more accurate representations of these processes in urban, regional, and global atmospheric models. We focus on the fundamental processes of aerosol formation and growth in the atmosphere. Of these, both the most important and the most uncertain are those involving the organic fraction of the atmospheric aerosol, which can be as large as 90% in some regions. Aerosol formation and evolution processes involve detailed gas-phase atmospheric chemistry and gas-particle interactions. The interaction of aerosols with atmospheric water is key to much of their behavior. We also focus on developing and evaluating the representation of aerosol-cloud-precipitation interactions in atmospheric models. Our research is broadly divided into three strongly overlapping areas:

  • Laboratory chamber studies of the formation and evolution of atmospheric organic aerosols.
  • Airborne field measurement of atmospheric aerosols and clouds.
  • Urban, regional, and global modeling of air quality and climate.
Selected Awards: 
Wallace Memorial Fellow, Princeton University (1966-1967); Donald P. Eckman Award, American Automatic Control Council (1970); Camille and Henry Dreyfus Foundation Teacher-Scholar Grant (1972); Curtis W. McGraw Research Award, American Society for Engineering Education (1976); Allan P. Colburn Award, American Institute of Chemical Engineers (1976); Thirty-Second Institute Lecturer, American Institute of Chemical Engineers (1980); Public Service Award, NASA (1980); National Academy of Engineering (1982); William H. Walker Award, American Institute of Chemical Engineers (1986); Fellow, Japan Society for the Promotion of Science (1986); George Westinghouse Award, American Society for Engineering Education (1987); Special Creativity Award, National Science Foundation (1988); Service Through Chemistry Award, Orange County Section of American Chemical Society (1988); Distinguished Alumnus Award, College of Engineering and Applied Science, University of Rochester (1989); Fellow, American Academy of Arts and Sciences (1991); Award for Creative Advances in Environmental Science and Technology, American Chemical Society (1993); Fellow, American Institute of Chemical Engineers (1995); Fuchs Award, International Aerosol Research Assembly (1998); Fellow, American Association for the Advancement of Science (1999); Warren K. Lewis Award, American Institute of Chemical Engineers (2000); Nevada Medal (2001); Haagen-Smit Clean Air Award, State of California Air Resources Board (2003); Fellow, American Geophysical Union (2004); Atmospheric Environment Haagen-Smit Award, 2004; ASLI Choice Award, “Atmospheric Chemistry and Physics”, Atmospheric Science Librarians International, 2006; Aurel Stodola Medal, Swiss Federal Institute of Technology (2008); Doctor of Science honoris causa, University of Patras (2002), Carnegie Mellon University (2002), Clarkson University (2009), Tyler Prize (2012), National Academy of Sciences (2013).
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