Ascospores are traditionally associated with rainfall events and Cladosporium spores are associated with the following periods of dry weather. To examine this relationship of airborne ascospores and periods of wet weather we conducted the following studies.

Airborne spores were collected during the months of March thru October from 1998 to 2002 in Kansas City. Spores were collected on silicon grease coated glass slides using an Allergenco MK-3 or Burkard spore trap device. Slides were stained and preserved with Calberlas stain in glycerin jelly and counted microscopically at 1000x. Counts were generated to represent airborne spore concentrations at 4-hour intervals. Spore numbers were entered into an Access database and counts were displayed as spores per cubic meter of air. Weather data was obtained from an Automated Weather Source weather station located adjacent to the urban collector.

During this 5 year period, there were74 days when Ascospore counts exceeded 20000 per cubic meter of air and Cladosporium counts did not. There were 43 days when Cladosporium counts exceeded 20000 per cubic meter of air and Ascospore counts did not. And there were 10 days when both Ascospore counts and Cladosporium counts exceeded 20000. During these 5 years there were 16 occasions when rainfall was associated with high Ascospore levels that were directly succeeded by high Cladosporium events.

Data collected over these 5 years support the conclusion that Ascospore releases are associated with rainfall events and that Cladosporium releases were high in the succeeding dry period.