Between April 22 and May 11, 1992, ten flights of the University of Wyoming King Air were made during the maximum in tropospheric ozone over the central North Pacific Ocean in conjunction with the spring intensive of the second Mauna Loa Observatory Photochemistry Experiment. During the first week of flights, an episode of remarkably large total reactive nitrogen, NOy (~2 ppbv) persisted in the 5--9 km altitude region for 3--4 days. Backtrajectory calculations combined with the trace gas and aerosol measurements confirm that its source was due primarily to export from northern latitude continental surface regions. The total amount of odd nitrogen transported over Hawaii during this event was estimated to be 1--2% of the annual emissions from subsonic aircraft or from stratospheric input. Throughout the measurement program layers of elevated O3, NOy, condensation nuclei (CN), and other species were frequently found between the onset of the marine boundary layer temperature inversion and 4--5 km altitude. Structure and strong gradients within these layers contribute to the daily variations seen at the 3.4 km elevation of the Mauna Loa Observatory during the nighttime downslope flow. The dryness of these low-altitude layers and the calculated air mass trajectories indicate that export from northern latitudes occurred mainly with subsidence to the Hawaii region rather than from transit just above the boundary layer inversion. There was no evidence of recent stratospheric input to the altitude region sampled below 9 km. However, the observations cannot distinguish whether O3 input from the stratosphere occurred earlier in the air mass histories at higher latitudes. Fine vertical scale anticorrelations between CN and O3 or NOy were also often observed particularly in the last week of the program when NOy mixing ratios were more typical of the remote troposphere. These features are attributed to new particle formation near the tops of cloud convection episodes and they illustrate the importance of such processes in contributing to the detailed layering and dilution of some chemical species in the free troposphere during this time of year. Mean and median profiles for many of the title species are given for high and low-to-moderate NOy categories.¿ 1997 American Geophysical Union