We present in Table 1 of this paper a series of free tropospheric radon profiles, obtained in the summer of 1994 on flights originating from Moffett Field, California (37.4 ¿N, 122.0 ¿W). These data were collected with the intent of acquiring a high-quality, statistically significant set of observations, in one season and at one location, suitable for use in the development and validation of three-dimensional global circulation and chemical transport models, as demonstrated in the companion paper <Stockwell, et al., this issue>. The profiles, which extend from the surface to 11.5 kilometers, were obtained on 11 flights flown in the period June 3 to August 16. A series of high-pressure whole-air samples (typically 11 or 12 per profile) were collected as the plane ascended to altitude, and analyzed immediately after each flight in a ground-based laboratory. A thorough discussion of sampling, analysis, calibration, and quality control procedures is provided. ¿ 1998 American Geophysical Union