dc.contributor.author	Pan, Jin	en
dc.contributor.committeechair	Marr, Linsey C.	en
dc.contributor.committeemember	Duggal, Nisha	en
dc.contributor.committeemember	Vikesland, Peter J.	en
dc.contributor.committeemember	Schmale, David G. III	en
dc.contributor.department	Civil and Environmental Engineering	en
dc.date.accessioned	2022-06-02T08:00:36Z	en
dc.date.available	2022-06-02T08:00:36Z	en
dc.date.issued	2022-06-01	en
dc.description.abstract	The emergence of coronavirus disease 2019 (COVID-19) has resulted in more than 300 million cases and 5 million deaths worldwide and innumerable economic losses. COVID-19 is acknowledged to transmit via air, but whether it is capable of transmitting via contaminated surfaces, also known as fomites, remains controversial. The overarching goal of this study was to investigate the presence and stability of SARS-CoV-2, the virus that causes COVID-19, on indoor surfaces and masks, and to provide insight into the possibility of fomite transmission. Since most transmission occurs indoors where humans spent 90% of their time, we first focused on quantifying the contamination level of SARS-CoV-2, including both viral RNA and viable virus, on commonly touched surfaces and in the heating, ventilation, and air cleaning (HVAC) systems in two university dormitories. Although we found up to 104 gene copies per ~10×10 cm2 on surfaces, we did not detect any viable virus, suggesting that the possibility of transmission via indoor surfaces is low. As universal masking has been recommended as an effective practice to prevent transmission of SARS-CoV-2, we shifted our focus to masks, both their effectiveness at filtering the virus from the air and their potential to serve as fomites. We evaluated the effectiveness of 11 face coverings for material filtration efficiency, inward protection efficiency on a manikin, and outward protection efficiency on a manikin. Masks made of filter materials, such as vacuum cleaner bag and HVAC filters, achieved a high material filtration efficiency whereas common textiles like cotton and acrylic usually showed the worst performance. The material filtration efficiency was generally positively correlated with either inward or outward protection effectiveness, but stiffer materials were an exception to this relationship as they did not fit as closely to the manikin's face and thus leaked substantially. Subsequently, we analyzed the survival of aerosolized SARS-CoV-2 in saliva on masks. Results suggested that the virus lost infectivity within one hour on an N95 respirator, surgical mask, polyester mask, and two types of cotton masks but not on a nylon/spandex mask. This study also highlighted the importance of applying virus in aerosols of realistic sizes when analyzing the stability of SARS-CoV-2 on surfaces.	en
dc.description.abstractgeneral	The emergence of coronavirus disease 2019 (COVID-19) has resulted in more than 300 million cases and 5 million deaths worldwide and innumerable economic losses. Researchers are debating if COVID-19 can transmit via surfaces contaminated with SARS-CoV-2, the virus that causes the disease. The goal of this study was to investigate whether SARS-CoV-2 is present and remains viable on indoor surfaces and masks, and to provide insight into the possibility of transmission via contaminated surfaces. Since most transmission occurs indoors where humans spent 90% of their time, we first focused on quantifying number of SARS-CoV-2 on commonly touched surfaces and in the heating, ventilation, and air cleaning (HVAC) systems in two university dormitories. Although we found a high concentration of SARS-CoV-2 genes on surfaces, we did not detect any viable virus, suggesting that the possibility of transmission via indoor surfaces is low. As universal masking has been recommended as an effective practice to prevent transmission of SARS-CoV-2, we shifted our focus to masks. We evaluated the effectiveness of 11 face coverings regarding their ability to trap viruses, protect wearers from inhaling viruses, and prevent infected individuals from expelling viruses into the surrounding air. Masks made of filter materials, such as a vacuum cleaner bag and HVAC filter, trapped the most viruses whereas common textiles like cotton and acrylic usually performed worst. It is also crucial that masks fit closely to the wearer's face to achieve better protection. Subsequently, we analyzed the ability of SARS-CoV-2 in aerosols, microscopic particles such as those exhaled by an infected person, to survive on different types of masks. Results suggested that the virus died within one hour on a majority of the masks. This study also highlighted the importance of applying aerosols of realistic sizes instead of large droplets when analyzing the survival of SARS-CoV-2 on surfaces.	en
dc.description.degree	Doctor of Philosophy	en
dc.format.medium	ETD	en
dc.identifier.other	vt_gsexam:34855	en
dc.identifier.uri	http://hdl.handle.net/10919/110397	en
dc.language.iso	en	en
dc.publisher	Virginia Tech	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	SARS-CoV-2	en
dc.subject	mask	en
dc.subject	airborne transmission	en
dc.subject	fomite transmission	en
dc.title	Presence and Stability of SARS-CoV-2 on Indoor Surfaces and Masks	en
dc.type	Dissertation	en
thesis.degree.discipline	Civil Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Doctor of Philosophy	en

Presence and Stability of SARS-CoV-2 on Indoor Surfaces and Masks

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