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Title: Fluorescence spectra and biological activity of aerosolized bacillus spores and MS2 bacteriophage exposed to ozone at different relative humidities in a rotating drum

Biological aerosols (bioaerosols) released into the environment may undergo physical and chemical transformations when exposed to atmospheric constituents such as solar irradiation, reactive oxygenated species, ozone, free radicals, water vapor and pollutants. Aging experiments were performed in a rotating drum chamber subjecting bioaerosols, Bacillus thuringiensis Al Hakam (BtAH) spores and MS2 bacteriophages to ozone at 0 and 150 ppb, and relative humidities (RH) at 10%, 50%, and 80+%. Fluorescence spectra and intensities of the aerosols as a function of time in the reaction chamber were measured with a single particle fluorescence spectrometer (SPFS) and an Ultra-Violet Aerodynamic Particle Sizer® Spectrometer (UV-APS). Losses in biological activity were measured by culture and quantitative polymerase chain reaction (q-PCR) assay. For both types of aerosols the largest change in fluorescence emission was between 280 and 400 nm when excited at 263 nm followed by fluorescence emission between 380 and 700 nm when excited at 351 nm. The fluorescence for both BtAH and MS2 were observed to decrease significantly at high ozone concentration and high RH when excited at 263 nm excitation. The decreases in 263 nm excited fluorescence are indicative of hydrolysis and oxidation of tryptophan in the aerosols. Fluorescence measured with the UV-APSmore » (355-nm excitation) increased with time for both BtAH and MS2 aerosols. A two log loss of MS2 bacteriophage infectivity was observed in the presence of ozone at ~50% and 80% RH when measured by culture and normalized for physical losses by q-PCR. Viability of BtAH spores after exposure could not be measured due to the loss of genomic material during experiments, suggesting degradation of extracelluar DNA attributable to oxidation. The results of these studies indicate that the physical and biological properties of bioaerosols change significantly after exposure to ozone and water vapor.« less
 [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [3] ;  [4]
  1. Johns Hopkins Univ., Baltimore, MD (United States). Applied Physics Lab; Univ. of Maryland, Baltimore, MD (United States)
  2. US Army Research Lab, Adelphi, MD (United States)
  3. Johns Hopkins Univ., Baltimore, MD (United States). Applied Physics Lab
  4. Univ. of Maryland, Baltimore, MD (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Quantitative Spectroscopy and Radiative Transfer
Additional Journal Information:
Journal Volume: 153; Journal Issue: C; Journal ID: ISSN 0022-4073
Research Org:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES Bioaerosols; Spectroscopy; Bacillus; Bacteriophage; Ozone; Relative humidity