Ozone (O3) is still a major environmental and health concern despite the pollution control efforts by the U.S. Environmental Protection Agency. While many people may be chronically exposed to moderate levels of [O3] in suburban areas, little is known about the temporal and spatial characteristics of [O3] in these urban to rural transitional regions. This paper reports on a study of the vertical and temporal variation in ozone over a suburban neighborhood. Measurements were made under sunny skies and calm to light winds in a suburban residential neighborhood of Greater Lafayette, Indiana. In all, 38 soundings were made over 19 days during the period from mid-August through mid-October of 1994. Sixty-three percent of the soundings exhibited a local maximum in the [O3] profile. This local maximum occurred most often when the local surface winds brought air from agricultural areas into relatively stationary air commonly found under high pressure conditions. Correlations were also made between the local maximum and measures of local traffic, canopy temperatures, and the [O3] at 155 m. Implications of these results on the estimation of O3 flux by micrometeorological methods are discussed.