My research interests are in the sources, transport, and transformation of atmospheric trace gases in the global atmosphere. This work has a primary focus on trace gases and aerosols associated with the formation and destruction of ozone in the atmosphere. The research involves development and application of advanced trace gas sampling and measurement techniques. My research group investigates the distributions and trends of a large variety of halocarbons (both natural and man-made), hydrocarbons, and photochemical oxidation products of these species (such as organic nitrates). The research extends from studies of sub-surface distribution of trace gases in the polar firn record to studies of urban and regional chemical distributions of short-lived tropopsheric gases to measurement of halocarbons in the stratosphere up to 32 km altitude. The research platforms include tropospheric and stratospheric aircraft (C-130, P-3B, ER-2, WB-57), high altitude balloons, oceanographic research ships, and land and island-based experiments.