AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Measurements of Changes in the Fluorescence and Viability of Biological Particles Exposed to Outdoor Conditions in the Washington D.C. Metro Area
JOSHUA SANTARPIA, Don Collins, Yong-Le Pan, Shanna Ratnesar-Shumate, Crystal Glen, Andres Sanchez, Steven Hill, Carlos Antonietti, Jill Matus, Nathan Taylor, Christopher Bare, Sean Kinahan, Elizabeth Corson, Danielle Rivera, Mark Coleman, Chatt Williamson, Sandia National Laboratories
Abstract Number: 294 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract Biological aerosols are studied for many reasons, including their effects on cloud properties as both cloud condensation and ice nuclei. Predominantly, however, biological aerosols are studied for their effects on human, plant and animal health. This can range from allergy to disease and is often concerned with detection and measurement of bioaerosols used as biological weapons. A variety of methods have been used to study atmospheric bioaerosols. One of the most often used of these techniques is the natural fluorescence of biological particles when excited by ultraviolet light. In October, 2012 we examined the changes in the fluorescence spectra and viability/infectivity of biological aerosol particles seeded into a chamber that exposed them to ambient conditions in Adelphi, MD for periods of several hours. The Captive Aerosol Growth and Evolution (CAGE) chambers used in this study employ a rotating drum constructed with an exterior FEP Teflon film, to allow sunlight to penetrate, and an inner ePTFE membrane to allow ambient trace gasses to permeate the drum, while still containing the biological particles being studied. Biological aerosol particles were sampled with a TSI UV-APS (ex. 355 nm), a Single Particle Fluorescence Spectrometer (ex. 351 and 263 nm) and AGI-30 impinger. The data indicate that significant changes in both fluorescence and viability/infectivity of both Bacillus thuringiensis var. kurstaki spores and MS2 bacteriophage particles occurred during replicate experiments. Solar intensity, relative humidity and ozone concentration were measured locally, and other meteorological data and air quality measurements were retrieved from a local Maryland Department of Environmental Quality monitoring site. The observed changes in these particles appear to be due to a combination of factors, rather than any single factor. These observations indicate that biological aerosol properties may be significantly changed by aerosol processes, and that these changes may affect measurement by UV-LIF.