Effects of Meteorological Conditions on Spore Plumes

Micah Burch, Bachelor’s Student, Biology, Estelle Levetin

 

Fungal spores are an ever-present component of the atmosphere, and have long been known to trigger asthma and hay fever symptoms in sensitive individuals. The atmosphere around Tulsa has been monitored for airborne spores and pollen with Burkard Spore Traps. The main sampling station is on the roof of a building at the University of Tulsa, and two additional samplers are located south of Tulsa at Mesonet meteorological stations. One of these stations is located in an agricultural field, and the other is located in a pasture. During routine analysis of Burkard slides for airborne spores, some days were found which exhibited exceptionally high spore concentrations with average daily concentrations above 50,000 spores/m³ of air. This study involved the examination of the hourly spore concentrations for three days which have very high spore concentrations.

 

The spore concentrations from these three days from each of the sampling stations were analyzed using the 12-traverse method. The hourly concentrations of Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, other, and total spores were determined and then correlated with meteorological data including temperature, rainfall, wind speed, dew point, air pressure, and wind direction. At every site each of these days exhibited a phenomenon in which spore concentrations increased dramatically over a very short period of time, and we called this phenomenon a spore plume. Spore plumes for these days occurred around midday, and spore concentrations were seen to increase from lows around 20,000 total spores/m³ of air to highs over 170,000 total spore/m³ of air in two hours. Although the diurnal rhythm for spore release also reaches its peak for total spores near midday, spore plumes exhibit total concentrations up to ten times higher than those found in a normal diurnal rhythm.

 

Multiple regression analysis of the data indicated that increases in temperature, wind speed, dew point, and air pressure correlated with the sudden increase in total spore concentrations, but no single weather variable predicted the appearance of a spore plume. The proper combination of changes in these meteorological parameters that result in a spore plume may be due to the changing weather conditions associated with thunderstorms, as each of the three days exhibiting spore plumes near midday experienced thunderstorms later that evening. It is believed that spore plumes can occur in a wide variety of areas, and are not confined to the air around Tulsa. Days exhibiting spore plumes or extremely high spore concentrations such as the ones in this study may have an important clinical significance, because other studies have shown that sensitization to certain spore types can occur during exposure to high spore concentrations.