Ragweed pollen concentrations were measured at 5 levels from 1.5 to 108 M. on a meteorology tower at Brookhaven National Laboratory. Samples were taken over an 11 year period using both the rotoslide and the slide-edge cylinder samplers. Vertical pollen profiles showed great variability from day to day but, when averaged over pollen seasons or longer periods, little systematic change in height was found. These results suggest that long-term patient exposure at upper levels of tall buildings would be similar to that at ground level in the absence of nearby pollen sources.