Improved characterization of potential aeroallergens is much needed by medical clinicians. Primary aims of the study are to apply modern techniques of air spora study to accomplish the following: 1. To characterize qualitatively the air spora, mainly fungi and pollens, of major regions of Pennsylvania; 2. To provide quantitative volumetric data on air spora; 3. To characterize circadian (daily) and seasonal periodicities of individual kinds of spores. Methods will include use of efficient volumetric (Hirst) spore traps, operating 24 hours a day and providing time-related deposits of air spora. Counts and identifications will be by microscopic inspection of spores. Traps will be situated ca. 100 ft. above ground to assess general air spora concentration in the area, and will be located to provide data representative of three different regions. Weather data will be studied to determine relations of comparative climatology and phenological events and zones of valid application of sampling site data.