All of our previously published atmospheric N2O mixing ratio data must be divided by 1.07 to correct for an error that we have recently discovered in our 1975 N2O primary standard. This problem was uncovered during intercomparison of our electron-capture, gas-chromatographic measurement technique for N2O with a newly developed infrared absorption technique (Connell et al., 1980). The salient features of this intercomparison, the subsequent recalibration of our standards for N2O, CFCl3, and CF2Cl2, and the consequences of the correction required for our N2O data are summarized here.