The reduction in concentation of CCl4, CFCl3, and CF2Cl2 that has been reported for irradiated air samples at atmospheric pressure is reinterpreted in terms of known atmospheric electron and ion chemistry. According to this reinterpretation, the oss of these compounds that is observed at high irradiation levels, when scaled down to ionization levels appropriate to the atmosphere, supports the conclusion that ion reactions in the lower atmosphere do not constitute a significant tropospheric sink for CCl4, CFCl3, or CF2Cl2, which is contrary to the conclusion originally associated with these observations.