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. 2021 Apr:195:110847.
doi: 10.1016/j.envres.2021.110847. Epub 2021 Feb 6.

SARS-CoV-2 and indoor/outdoor air samples: a methodological approach to have consistent and comparable results

Angelo Robotto  1 , Paola Quaglino  1 , David Lembo  2 , Marcello Morello  1 , Enrico Brizio  3 , Luisella Bardi  1 , Andrea Civra  2
Affiliations

SARS-CoV-2 and indoor/outdoor air samples: a methodological approach to have consistent and comparable results

Angelo Robotto et al. Environ Res. 2021 Apr.

Abstract

Since the beginning of coronavirus disease 2019 (COVID-19) pandemic, large attention has been focused on the relationship between SARS-CoV-2 diffusion and environment. As a matter of fact, clear evidence of the transmission of SARS-CoV-2 via respiratory aerosol would be of primary importance; at the same time, checking the presence of SARS-CoV-2 in wastewater can be extremely useful to control the diffusion of the disease. Up to now, many studies report SARS-CoV-2 concentrations in indoor/outdoor air samples or water/wastewater samples that can differ by order of magnitude. Unfortunately, complete information about the scientific approach of many studies is still missing, relating to: samplers and sampling materials performances, recovery tests, measurement uncertainty, robustness, detection and quantification limits, infectivity of captured virus, virus degradation during sampling, influence of sample pre-treatments (included freezing) on results, effects of inhibitors, sample alterations due to manipulation, validation of methods and processes, quality assurance according to ISO/IEC 17025 requirements. Based on the first experiences focused on the presence of SARS-CoV-2 in environmental samples such as air quality filters or impingers collection solutions, the present study describes a coherent preliminary approach to SARS-CoV-2 indoor and outdoor air sampling in order to overcome the evident lack of standardization. Three aspects are highlighted here: the first solution to assure quality and consistency to air sampling relies on the development of recovery tests using standard materials and investigating sampling materials, sampling techniques, sampling durations, sample conservation and pre-treatments; secondly, in order to overcome the shortcomings of every single sampling technique, coupling different samplers in parallel sampling could be an efficient strategy to collect more information and make data more reliable; finally, with regards to airborne virus sampling, the results could be confirmed by simplified emission and dilution models.

Keywords: Air quality filters; Airborne transmission; Bioaerosol; Environmental virology; SARS-CoV-2.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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