Allergists have traditionally focused on identifiable airborne allergen containing particles such as pollen grains and fungal spores. However, all airborne particles have the potential to carry allergenic proteins. To study the relationship of identifiable aeroallergens and total airborne particles, the following studies were conducted.

The ambient air was sampled from the top of a 5 story building in downtown Kansas City, Missouri, every morning between 0800 and 0900 hours. Total airborne particles were obtained in six size ranges (0.3 - 0.5uM, 0.5 - 1.0uM, 1 - 5uM, 5 - 10uM, 10 - 25uM and > 25uM) using a Climet CI 100 laser light scattering instrument. Particle counts were produced as particles/ ft3 of air and converted to particles/ m3 of air. Spore and pollen collections were made with an Allergenco MK-3 spore trap operating at an inlet velocity of 15 L/ minute. Collection time was either 5 or 10 minutes. Slides were mounted with glycerin jelly containing Calberlas solution for contrast. Pollen grains were identified and counted microscopically at 400X. Spores were identified and counted microscopically at 1000X. Tire particles were identified as irregular black particles without rounded edges having no translucent areas. These particles were similar to particles abraded from automobile tires in the laboratory. The elasticity of numerous large particles judged to be tire particles was confirmed by observing the result of physical pressure applied to the particle. Counting and collection was performed so that the general limit of detection was 7/ m3 of air for pollen grains and 224/ m3 of air for fungal spores and tire particles. Counts were represented as the number of pollen grains, fungal spores, or tire particles/ m3 of air.

Data was collected on 480 mornings between the months of March and November for the years1999, 2000, and 2001. Tire particle count estimates ranged from 53,760 to 341/ m3 of air. Particle counts/ m3 for the measured sizes ranged from: total- 107,183,187 to 1,853,245; 0.3 - 0.5uM- 85,838,433 to 1,702,966; 0.5 - 1.0uM- 55,532,602 to 74,151; 1 - 5uM- 23,275,787 to 39,158; 5 - 10uM- 752,809 to 7,697; 10 - 25uM- 863,965 to 812; >25uM- 288,906 to 0. Total pollen counts ranged up to 3,013/ m3 of air and total spore levels ranged up to 79,360/ m3 of air. There were good correlations between tire particle count and particles in the 5 - 10uM range (0.24) and between tire particle estimates and spore counts (0.21). There were no correlations between particle measurements and pollen counts or particle measurements and spore counts.

We conclude that pollen grains and fungal spores are a small fraction of overall airborne material. Additionally, factors governing total airborne particles are quite different from factors governing airborne pollen grain and fungal spore concentrations.