Measurements of NO2, HNO3, and PAN, as well as O3 were made in March 1985 at Alert, N.W.T., Canada. The observations show that PAN is by far the dominant NOy species at this Northern location at the onset of spring. Surface loss of HNO3 and possibly O3 seemed to occur over the snowy surface, but no loss of PAN was apparent. The observations are further evidence for the importance of PAN as a major carrier of the oxides of nitrogen in the clean troposphere. Although concurrently measured light hydrocarbons would appear to be sufficient for local formation of PAN, it is suggested that this did not take place but rather that long range transport from more southerly regions was responsible for the observed PAN levels.