Hongwan Li1, Sripriya Nannu Shankar1, Chiran T. Witanachchi1, John A. Lednicky2,3, Julia C. Loeb2,3, Md. Mahbubul Alam2,3, Z. Hugh Fan4,5, Karim Mohamed5, Arantzazu Eiguren-Fernandez6, Chang-Yu Wu This email address is being protected from spambots. You need JavaScript enabled to view it.1

1 Department of Environmental Engineering Sciences, University of Florida, USA
2 Department of Environmental and Global Health, University of Florida, USA
3 Emerging Pathogens Institute, University of Florida, USA
4 Department of Mechanical & Aerospace Engineering, University of Florida, USA
5 J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, USA
6 Aerosol Dynamics Inc., Berkeley, California, USA

Received: May 7, 2021
Revised: August 19, 2021
Accepted: September 1, 2021

 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.210106  

Cite this article:

Li, H., Shankar, S.N., Witanachchi, C.T., Lednicky, J.A.,  Loeb, J.C., Alam, M.M. Fan, Z.H., Mohamed, K., Eiguren-Fernandez, A., Wu, C.Y. (2021). Environmental Surveillance and Transmission Risk Assessments for SARS-CoV-2 in a Fitness Center. Aerosol Air Qual. Res. 21, 210106. https://doi.org/10.4209/aaqr.210106


  1. The first environmental sampling study of SARS-CoV-2 in a fitness center in the US.
  2. No SARS-CoV-2 RNA detected by rRT-PCR analyses of all air and surface samples.
  3. Up to 94% reduction of airborne transmission predicted following CDC guidance.
  4. Predicted infection risk lowered by filtration, UV and low air recirculation.
  5. Low infection risk possible in fitness centers that follow CDC guidance.


Fitness centers are considered high risk for SARS-CoV-2 transmission due to their high human occupancy and the type of activity taking place in them, especially when individuals pre-symptomatic or asymptomatic for COVID-19 exercise in the facilities. In this study, air (N = 21) and surface (N = 8) samples were collected at a fitness center through five sampling events from August to November 2020 after the reopening restrictions were lifted in Florida. The total attendance was ~2500 patrons during our environmental sampling work. Air samples were collected using stationary and personal bioaerosol samplers. Moistened flocked nylon swabs were used to collect samples from high-touch surfaces. We did not detect SARS-CoV-2 by rRT-PCR analyses in any air or surface sample. A simplified infection risk model based on the Wells-Riley equation predicts that the probability of infection in this fitness center was 1.77% following its ventilation system upgrades based on CDC guidelines, and that risk was further reduced to 0.89% when patrons used face masks. Our model also predicts that a combination of high ventilation, minimal air recirculation, air filtration, and UV sterilization of recirculated air reduced the infection risk up to 94% compared to poorly ventilated facilities. Amongst these measures, high ventilation with outdoor air is most critical in reducing the airborne transmission of SARS-CoV-2. For buildings that cannot avoid air recirculation due to energy costs, the use of high filtration and/or air disinfection devices are alternatives to reducing the probability of acquiring SARS-CoV-2 through inhalation exposure. In contrast to the perceived ranking of high risk, the infection risk in fitness centers that follow CDC reopening guidance, including implementation of engineering and administrative controls, and use of personal protective equipment, can be low, and these facilities can offer a relatively safe venue for patrons to exercise.

Keywords: COVID-19, Airborne transmission, Inhalation exposure, Risk assessment, Biohazard risk

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