1981 Member, Panel on Multidimensional Aspects, NASA/WMO Stratospheric Workshop.

1982 Chair, 2nd Symposium on the Composition of the non-urban Troposphere.

1983-4 Member, Global Tropospheric Chemistry Panel, National Academy of Science.

1983-4 Member, Exec. Committee, Global Tropospheric Experiment(GTE)/NASA.

1986 - 1998 Member, Exec. Committee, Atmospheric/Ocean Chemistry Experiment (AEROCE).

1987 Member of the Review Panel of the Tropospheric Research Program NASA Langley Research Center.

1993-95 Member, AMS Committee on Atmospheric Chemistry.

1994-96 Eos Editor with special responsibility for Atmospheric Science.

1997-2000 Associate Editor for the Journal of Geophysical Research [Atmospheres]

1999-2000 Member, Committee on Atmospheric Chemistry, National Academy of Science.