Six-day measurement of size-resolved indoor fluorescent bioaerosols of outdoor origin in an office--颗粒学报PARTICUOLOGY

Xie, Y., Fajardo, O. A., Yan, W., Zhao, B., & Jiang, J. (2017). Six-day measurement of size-resolved indoor fluorescent bioaerosols of outdoor origin in an office. Particuology, 31, 161-169. https://doi.org/10.1016/j.partic.2016.09.004

Six-day measurement of size-resolved indoor fluorescent bioaerosols of outdoor origin in an office

Yangyang Xie ^{a 1}, Oscar A. Fajardo ^{c 1}, Weizhuo Yan ^c, Bin Zhao ^{a b *}, Jingkun Jiang ^{c d *}

a Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China
b Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
c State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
d State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China

10.1016/j.partic.2016.09.004

Volume 31, April 2017, Pages 161-169

Received 10 March 2016, Revised 29 August 2016, Accepted 18 September 2016, Available online 4 January 2017, Version of Record 9 March 2017.

E-mail: binzhao@mail.tsinghua.edu.cn; jiangjk@tsinghua.edu.cn

Highlights

• Indoor/outdoor size resolved fluorescent bioaerosol concentrations were measured continuously.

• Correlations of indoor/outdoor bioaerosol concentrations showed concentration-attenuation and time-lag.

• A two-parameter model was proposed and verified.

• Penetration and deposition factors of bioaerosols are close to the values for normal particles.

Abstract

Indoor airborne bioaerosols of outdoor origin play an important role in determining the exposure of humans to bioaerosols because people spend most of their time indoors. However, there are few studies focusing on indoor bioaerosols originating from outdoors. In this study, indoor versus outdoor size-resolved concentrations and particle asymmetry factors of airborne fluorescent bioaerosols in an office room were measured continuously for 6 days (144 h) using a fluorescent bioaerosol detector. The windows and door of this room were closed to ensure that there was only air infiltration; moreover, any human activities were ceased during sampling to inhibit effects of indoor sources. We focused on fine particles, since few coarse particles enter indoor environments, when windows and doors are closed. Both indoor and outdoor fluorescent bioaerosol size distributions were fit with two-mode lognormal distributions (indoor R² = 0.935, outdoor R² = 0.938). Asymmetry factor distributions were also fit with lognormal distributions (indoor R² = 0.992, outdoor R² = 0.992). Correlations between indoor and outdoor fluorescent bioaerosol concentrations show significant concentration-attenuation and a time lag during the study period. A two-parameter, semi-empirical model was used to predict concentrations of indoor fluorescent bioaerosols of outdoor origin. The measured and predicted concentrations had a linear relationship for the studied size fractions, with an R² for all size fractions of larger than 0.83.

Graphical abstract

Keywords

Fluorescent bioaerosols; Indoor air; Outdoor air; Waveband integrated bioaerosol sensor (WIBS); Particle size distributions; Concentrations

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