Hanlin Chen, Rui Du This email address is being protected from spambots. You need JavaScript enabled to view it., Weishan Ren, Sujian Zhang, Pengrui Du, Yongtao Zhang

College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China

Received: June 12, 2020
Revised: August 1, 2020
Accepted: August 12, 2020

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.2020.03.0101  

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Cite this article:

Chen, H., Du, R., Ren, W., Zhang, S., Du, P., Zhang, Y. (2021). The Microbial Activity in PM2.5 in Indoor Air: As an Index of Air Quality Level. Aerosol Air Qual. Res. 21, 200101. https://doi.org/10.4209/aaqr.2020.03.0101


  • Microbial activity was used to evaluate indoor air quality.
  • The variation of microbial activity in PM5 was discussed.
  • In winter with excellent air quality, ventilation for 20 minutes is recommended.


Bioaerosols are a major source of pollution in indoor environments, where people spend approximately 90% of their time, and the microorganisms adhered to PM2.5 adversely affect human health. However, most research has focused on the concentration of these aerosols and the factors that influence it rather than the correlation between microbial activity and air quality. Thus, this study used a modified technique of fluorescein diacetate (FDA) hydrolysis to evaluate the activity of microorganisms in the PM2.5 during three seasons (summer, autumn and winter) in Beijing. 0.155–5.388 ng m3 and 0.091–5.740 ng m3 of sodium fluorescein, a marker of microbial activity, were measured indoors and outdoors, respectively; thus, no significant difference in concentration between the two environments was detected, but the indoor activity was affected by outdoor conditions to an extent. The most active season was autumn, followed by winter and summer. Furthermore, the highest activity in summer and autumn was observed during conditions of excellent air quality, and in summer, the activity during conditions of good air quality also obviously exceeded that during conditions of slight pollution. Additionally, the microbial activity in a room varied according to the room’s ventilation (or lack thereof), suggesting a strong association between these parameters. In general, when the air quality was excellent, 20 minutes of ventilation achieved the optimal air exchange, but this duration should be reduced during polluted conditions. Our results provide new insights into evaluating the indoor air quality based on the microbial activity.

Keywords: Fluorescein diacetate, Season, Pollution level, Ventilation

Aerosol Air Qual. Res. 21 :200101 -. https://doi.org/10.4209/aaqr.2020.03.0101  

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