1965, graduate, Universidad Nacional Autónoma de México; 1972, PhD in Physical Chemistry, University of California, Berkeley. 1975-82, Assistant and Associate Professor, University of California, Irvine; 1982-89, Senior Research Scientist, Jet Propulsion Laboratory, Caltech; since 1989, Professor and Institute Professor, MIT. Member: National Academy of Sciences, US; Institute of Medicine, US. Recipient of awards: Tyler Ecology and Energy Prize (1983); Nobel Prize in Chemistry (1995); UNEP Sasakawa Prize (1999). Expertise: atmospheric chemistry and stratospheric ozone depletion.