Environmental contamination of SARS-CoV-2 on surfaces, air-conditioner and ventilation systems

Abstract

Background COVID-19 can be transmitted directly through respiratory droplets or indirectly through fomites. SARS-CoV-2 has been detected on various environmental surfaces, air samples and sewage in hospital and community settings. Methods Environmental samples were collected from a ferryboat during a COVID-19 ongoing outbreak investigation and a nursing home and from three COVID-19 isolation hospital wards and a long-term care facility where asymptomatic COVID-19 cases were isolated. Samples were tested by real-time reverse transcriptase–polymerase chain reaction. Results SARS-CoV-2 was detected on swab samples taken from surfaces of food preparation and service areas, hospital isolation wards, an air exhaust duct screen, air-conditioning filter, sewage treatment unit and air sample during investigations conducted in response to COVID-19 outbreaks on a ferryboat, nursing home, isolation facility and COVID-19 hospital wards. Discussion Food preparation areas and utensils can be contaminated during COVID-19 outbreaks. Respiratory droplets/nuclei from infected persons can be displaced by the air flow and deposited on surfaces. It can be assumed that in the same manner, air flow could transfer and deposit infected respiratory droplets/nuclei from infected persons to the mucous membranes of persons standing against the air flow direction.

Investigation of SARS CoV-2 virus in environmental surface

“…The previous detection of the virus in stools supports this interpretation, as does the fact that stools obtained from the first COVID-19 patient in the United States also proved positive ( Ding et al, 2020 ). The results showed that among the various surfaces studied (bed rail, locker handle, cardiac table, electric switch, chair, toilet seat and flush, air exhaust vent and floor), the most infected samples with the virus were related to floor ( Mouchtouri et al, 2020 ), which confirms the results of the present study. Riddell et al (2020) reveal that SARS-CoV-2 can stay potentially infectious for significantly longer periods than commonly are believed to exist but the scope of their study was limited in terms of evaluating the persistence of virus in different environmental conditions.…”

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

“…The effectiveness of ventilation systems has attracted particular attention during the SARS-CoV-2 pandemic, and various ventilation strategies have been analyzed [67][68][69]. In the EU, ventilation with outdoor air is recommended to dilute contaminants in closed spaces, increase the time required for exposure to an infectious dose of pathogens, maintain the minimum airflow rate per person (7-10 l/person according to American Society of Heating, Refrigerating and Air-Conditioning Engineers ASHRAE) and increase the air exchange rate [70].…”

The detection of SARS‐CoV‐2 in outpatient clinics and public facilities during the COVID‐19 pandemic

“…The contamination of surfaces and objects with SARS-CoV-2 has been proposed as one of the main routes of transmission of the infection. 4,9,13 Several articles have confirmed the contamination of surfaces and objects with SARS-CoV-2 RNA in isolation wards and ICU units housing COVID-19 patients; however, other outpatients' health-care facilities were not thoroughly investigated.…”