A classic lake breeze circulation cell that formed on the western shore of Lake Michigan on 4 September 1974 is studied in great detail. Wind measurements are made with surface anemometers and serial pibals, with air trajectories monitored via tetroons. Aircraft measurements map the thermal internal boundary layer and small and large aerosol distributions. Recirculation of pollutants is indicated from analysis of the tetroon data. Aerosol measurements suggest size sorting of small versus large particles as they are transported through the complex three-dimensional flow. These wind data also form the basis of a kinematic diagnostic study of mesoscale pollution transport in coastal areas, to be reported in a subsequent paper. Abstract A classic lake breeze circulation cell that formed on the western shore of Lake Michigan on 4 September 1974 is studied in great detail. Wind measurements are made with surface anemometers and serial pibals, with air trajectories monitored via tetroons. Aircraft measurements map the thermal internal boundary layer and small and large aerosol distributions. Recirculation of pollutants is indicated from analysis of the tetroon data. Aerosol measurements suggest size sorting of small versus large particles as they are transported through the complex three-dimensional flow. These wind data also form the basis of a kinematic diagnostic study of mesoscale pollution transport in coastal areas, to be reported in a subsequent paper.