9421079 Dickerson Bordered by two of the Earth's major industrial regions, the North Atlantic Ocean (NAO) is one of the remote areas of the Earth most likely impacted by air pollution. The overlying marine troposphere is also an ideal laboratory in which to study the chemical and meteorological mechanisms leading to the long-range transport of pollution, and the consequent perturbation of the radiative properties and oxidizing capacity of atmosphere. The overall goal of this work is: To understand the role of anthropogenic emissions and natural processes in the ozone budget and oxidizing capacity of the troposphere over the North Atlantic Ocean. The primary data set for this project will be collected in the spring of 1996 when we conduct a carefully planned airborne experiment with the University of Wyoming King Air supported by surface intensive experiments and ozonesonde launches from the US east coast and Bermuda. The King Air has the payload and range to carry the essential instruments on flight paths near fronts and out to Bermuda. Its crew is also experienced with research in convective conditions. This work will be supplemented with collaborative surface measurements made on Bermuda, and in Maryland by the NOAA Air Resources Laboratory. Detailed meteorological guidance for the field programs will be provided by colleagues. For example, the ozonesonde launches will be triggered by forecasts of interesting transport conditions. Flights will coordinate as far as possible with other experiments conducted in our area at the same time. We will work with the NOAA Aeronomy Lab and their P-3 flights to assure that compatibility of analytical methods, and share results. We will incorporate experimental results into global, hemispheric, and regional models to show the large-scale impact of anthropogenic emissions. Initial model results will, in turn, help direct the next phase of experiments.