Experiments comparing volumetric spore collection data averaged into daily, 10-day, or seasonal counts were conducted at various locations within the city of Manhattan, Kansas, USA, and surrounding countryside in 1976–1979. At any given time, differences in number of airspora per m3of air at two or more locations were comparatively great. However, as average numbers were computed for longer periods of time, differences between sites became progressively less. On a daily basis, mean concentrations for the four spore groups during 1976 were significantly different 32% of the possible comparisons between three sites. When 10-day means were compiled for the 100 days sampled at four sites during 1977, significant differences occurred in only 5% of the possible comparisons. For the entire 30 day period of 1976 and 100 day period of 1977, there were no significant differences in mean spore concentrations between any of the sites for any of the four spore groups.