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. and Zhang, Y. (2020). The Microbial Activity in PM2.5 in Indoor Air: As an Index of Air Quality Level. Aerosol Air Qual. Res. 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 an important cause of indoor pollution, and the microorganisms adhering to PM2.5 adversely affect on human health. People spend approximately 90% of their day indoors. Most research has focused on the concentration and influencing factors, with less attention paid to the correlation between microbial activity and air quality. In this study, we used a modified fluorescein diacetate hydrolysis method to measure the indoor and outdoor microbial activity in PM2.5 during three seasons in Beijing. The microbial activity indoors and outdoors ranged from 0.155 to 5.388 ng m-3 and 0.091 to 5.740 ng m-3 sodium fluorescein, respectively, which were not significantly different; however, the indoor air was affected by the outdoor environment to some extent. During the observation period, the microbial activity under excellent air quality, good air quality and slight pollution decreased as follows: autumn > winter > summer. In summer and autumn, the microbial activity was highest under excellent air quality conditions, and in summer, the activity under both excellent and good air quality conditions was obviously higher than that under slight pollution. We observed different variations in microbial activity in rooms that were closed or ventilated, and inferred that the indoor microbial activity was closely associated with the ventilation status. Overall, 20 minutes of ventilation can achieve better air exchange when the air quality is excellent. However, the ventilation duration should be appropriately reduced under polluted conditions. This study provides a new insight for indoor air quality evaluations from the perspective of microbial activity.

Keywords: Fluorescein diacetate; Season; Pollution level; Ventilation.

Aerosol Air Qual. Res. 20 :-. https://doi.org/10.4209/aaqr.2020.03.0101  

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