Mirna Alameddine This email address is being protected from spambots. You need JavaScript enabled to view it.1, Oluchi Okoro1, Loïc Wingert2, Geneviève Marchand2, Benoit Barbeau1

1 Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, QC, H3C 3A7, Canada
2 Department of Chemical and Biological Hazard Prevention, Institut de Recherche Robert-Sauvé en Santé et Sécurité du Travail, Montréal, QC H3A 3C2, Canada 

Received: January 20, 2023
Revised: August 28, 2023
Accepted: August 28, 2023

 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.230018  

Cite this article:

Alameddine, M., Okoro, O., Wingert, L., Marchand, G., Barbeau,.B. (2023). Impact of the Contamination Method on the Disinfection of N95 Respirators: Drops versus Aerosols. Aerosol Air Qual. Res. 23, 230018. https://doi.org/10.4209/aaqr.230018


  • More efficient contamination by deposition of drops than aerosols on coupons of FFR.
  • Better inactivation in coupons contaminated by drops deposition than by aerosols.
  • Highest resistant spores fraction in artificial saliva with mucin (drops, aerosols).
  • Level of inactivation significantly impacted by the contamination method.


The recent surge in the use of filtering facepiece respirators (FFRs) during the SARS-CoV-2 pandemic triggered economic and environmental concerns with regards to their safe reuse and/or disposal. Their decontamination through ultraviolet (UV) irradiation has proven efficient in bench tests. Nevertheless, no study has yet investigated to what extent the decontamination method’s performance was impacted by the contamination method. In this study, Bacillus subtilis spores were inoculated in three suspensions used to contaminate coupons of FFRs via aerosols nebulisation or 2 µL drops deposition. The contaminated coupons were then exposed to UV irradiation in a monochromatic UVC lamp collimated beam reactor. The results revealed that contamination and decontamination were more efficient for drops (maximum 0.72 log losses and 3 log inactivation at 150 mJ cm-2) than for aerosols (maximum 2.47 log losses and 1.75 log inactivation at 150 mJ cm-2). Inactivation was greater in coupons contaminated using artificial saliva, followed by phosphate buffer solution, and finally artificial saliva with mucin which also presented the highest fraction of resistant spores, based on kinetic modeling. Disinfection was determined sensitive to the method of contamination (p < 0.001). However, the composition of the contaminating suspension was the most important performance predictor for decontamination by UV irradiation (p = 9.2 × 10-10).

Keywords: Filtering facepiece respirators, UV irradiation, Artificial saliva, Kinetic modeling

Share this article with your colleagues 


Subscribe to our Newsletter 

Aerosol and Air Quality Research has published over 2,000 peer-reviewed articles. Enter your email address to receive latest updates and research articles to your inbox every second week.

77st percentile
Powered by
   SCImago Journal & Country Rank

2022 Impact Factor: 4.0
5-Year Impact Factor: 3.4

The Future Environment and Role of Multiple Air Pollutants

Aerosol and Air Quality Research partners with Publons

CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit
CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit

Aerosol and Air Quality Research (AAQR) is an independently-run non-profit journal that promotes submissions of high-quality research and strives to be one of the leading aerosol and air quality open-access journals in the world. We use cookies on this website to personalize content to improve your user experience and analyze our traffic. By using this site you agree to its use of cookies.