Size-resolved fluorescent biological aerosol particle concentrations and occupant emissions in a university classroom
Article first published online: 25 APR 2014
© 2014 The Authors. Indoor Air Published by John Wiley & Sons Ltd
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
How to Cite
Bhangar, S., Huffman, J. A. and Nazaroff, W. W. (2014), Size-resolved fluorescent biological aerosol particle concentrations and occupant emissions in a university classroom. Indoor Air. doi: 10.1111/ina.12111
- Article first published online: 25 APR 2014
- Accepted manuscript online: 21 MAR 2014 10:56AM EST
- Manuscript Accepted: 14 MAR 2014
- Manuscript Received: 19 NOV 2013
- Alfred P. Sloan Foundation
- Coarse particles;
- Time-resolved measurement;
- Indoor air quality;
- Human activity
This study is among the first to apply laser-induced fluorescence to characterize bioaerosols at high time and size resolution in an occupied, common-use indoor environment. Using an ultraviolet aerodynamic particle sizer, we characterized total and fluorescent biological aerosol particle (FBAP) levels (1–15 μm diameter) in a classroom, sampling with 5-min resolution continuously during eighteen occupied and eight unoccupied days distributed throughout a one-year period. A material-balance model was applied to quantify per-person FBAP emission rates as a function of particle size. Day-to-day and seasonal changes in FBAP number concentration (NF) values in the classroom were small compared to the variability within a day that was attributable to variable levels of occupancy, occupant activities, and the operational state of the ventilation system. Occupancy conditions characteristic of lecture classes were associated with mean NF source strengths of 2 × 106 particles/h/person, and 9 × 104 particles per metabolic g CO2. During transitions between lectures, occupant activity was more vigorous, and estimated mean, per-person NF emissions were 0.8 × 106 particles per transition. The observed classroom peak in FBAP size at 3–4 μm is similar to the peak in fluorescent and biological aerosols reported from several studies outdoors.