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Size‐resolved fluorescent biological aerosol particle concentrations and occupant emissions in a university classroom
Author(s) -
Bhangar S.,
Huffman J. A.,
Nazaroff W. W.
Publication year - 2014
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/ina.12111
Subject(s) - aerosol , particle (ecology) , environmental science , fluorescence , environmental chemistry , atmospheric sciences , chemistry , meteorology , ecology , physics , biology , optics
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 μ m 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 ( N F ) 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 N F source strengths of 2 × 10 6 particles/h/person, and 9 × 10 4 particles per metabolic g CO 2 . During transitions between lectures, occupant activity was more vigorous, and estimated mean, per‐person N F emissions were 0.8 × 10 6 particles per transition. The observed classroom peak in FBAP size at 3–4 μ m is similar to the peak in fluorescent and biological aerosols reported from several studies outdoors.