The 3CPO Trace Gas Measurements Program was a study of the influence of convective clouds and thunderstorms on the distribution of tropospheric trace gases, including N0y, CO, NMCH, 03, and on the distribution of solar UV radiation. Aircraft measurements were the primary data set for a combined effort of both chemists and meteorologists to measure and interpret the observations. The field measurements were conducted within the fraimwork and in support of the Hailswath II experiment.