Short-term disturbances in the carbon dioxide record at Mauna Loa Observatory have been observed since measurements were begun in 1958. These variations are easily recognized and documented on the CO2 record and must be deleted if only the baseline data are to be analyzed. By use of a simple wind analysis technique it was shown that the probable source of these CO2 disturbances since 1976 is venting in the crater of the Mauna Loa volcano during southerly flow.