This paper discusses several extended sets of measurements of stratospheric NO2 near 20 ¿N and in the region 40¿ N--70¿ N. The principal concern at high latitude is with the relation between the NO2 column abundance and quasi-horizontal flow patterns in the stratosphere near 30 km. It appears that NO2 can serve as a tracer of such flow, particularly at higher latitude in winter when the flow is rapid in comparison with the rate of photochemical readjustment. When polar air, originally low in NO2, is delivered to lower latitude, one observes a drop in NO2 abundance; the drop is less the lower the latitude of observation owing to the greater time available for NO2 to be released from the polar night storage species. A study of total ozone column abundance and the flow at 100 mbar indicates a close relation between them similar to that for NO2 at higher altitude.