Gas and aerosol measurements at Barrow, Alaska during the spring of 1986 confirm the inverse relationship between particulate excess bromine (xBr) and O3. In addition to this inverse xBr--O3 relationship, several other factors were found to be important in understanding the springtime variability of O3 at Barrow. They are (1) O3 concentration variability associated with NOx chemistry at high pollutant levels or transport of primary pollutant O3 from lower latitudes, (2) displacement of air masses of high O3 content with air masses low in O3 but high in sea salt, suggesting potential roles of sea salt in O3 fluctuations, and (3) when pollutant levels were low, advection of air that can cause gradual change in O3 with more rapid inversely related fluctuations of O3 and xBr superimposed. Under the conditions of factor 3 the trend and anticorrelation each accounted for about one quarter of the variance in O3, suggesting a role for other compounds or low level reactive nitrogen species and gas-particle interaction in the photolytic O3 destruction process. ¿ American Geophysical Union 1990