The size distribution of SARS-CoV-2 genetic material in airborne particles sampled in hospital and home care environments occupied by COVID-19 positive subjects

• Published in: The Science of the total environment Vol. 892; p. 164642
• Main Authors: Cvitešić Kušan, Ana, Baranašić, Jurica, Frka, Sanja, Lucijanić, Tomo, Šribar, Andrej, Knežević, Jelena, Buonanno, Giorgio, Stabile, Luca
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.09.2023; Published by Elsevier B.V
• Subjects: aerosols; airborne transmission; Airborne virus transmission; COVID-19 infection; data collection; environment; exposure scenario; hospitals; Indoor air; nose; oxygen; particle size; Particle size-distribution; risk; Risk assessment; RNA; Severe acute respiratory syndrome coronavirus 2; Submicrometric particles; therapeutics; viruses; Submicrometric particles; Airborne virus transmission; Particle size-distribution; Risk assessment; Indoor air
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.164642

Characterizing the size distribution of airborne particles carrying SARS-CoV-2 virus is essential for understanding and predicting airborne transmission and spreading of COVID-19 disease in hospitals as well as public and home indoor settings. Nonetheless, few data are currently available on virus-laden particle size distribution. Thus, the aim of this study is reporting the total concentrations and size distributions of SARS-CoV-2- genetic material in airborne particles sampled in hospital and home environments. A nanoMOUDI R122 cascade impactor (TSI, USA) was used to collect size-segregated aerosol down to the sub-micron range in home and in three different hospital environments in presence of infected patients in order to provide the concentration of airborne SARS-CoV-2 genetic material for each particle size range at different sampling locations. Providing one of the largest datasets of detailed size-fractionated airborne SARS-CoV-2 RNA to date, we found that 45.2 % of the total sub- and super-micrometric fractions were positive for SARS-CoV-2 with its genetic material being present in 17.7 % of sub-micrometric (0.18–1 μm) and 81.9 % of super-micrometric (>1 μm) fractions. The highest concentration of SARS-CoV-2 genetic material in total suspended particles (5.6 ± 3.4 RNA copies m−3) was detected in the room occupied with patients with more severe COVID-19 symptoms collected during the patients' high flow nasal oxygen therapy. The highest concentration at certain particle size fraction strongly depends on the sampling environment. However, the contribution of SARS-CoV-2 genetic material was in favour of super-micrometric compared to sub-micrometric particle size range. The evaluation of the individual risk of infection was carried out on the basis of the obtained data considering a hypothetical exposure scenario. The obtained results indicate the necessity of the protective masks in presence of infected subjects, especially while staying for longer period of time in the hospital environments. [Display omitted] •Airborne SARS-CoV-2 RNA was detected in the hospital and home care environments.•Fine resolution of airborne SARS-CoV-2 RNA size-distribution was reported.•SARS-CoV-2 was detected in 45.2 % of the total sub- and super-micrometric fractions.•SARS-CoV-2 was detected in 17.7 % of sub-micrometric (0.18–1 μm) fractions.•Evaluation of the risk of infection was carried out on basis of the measured data.