1
|
Liu F, Luo Z, Qian H. Impact of thermal stratification on airborne transmission risk of SARS-CoV-2 in various indoor environments. BUILDING SIMULATION 2023; 16:1-14. [PMID: 37359828 PMCID: PMC10166632 DOI: 10.1007/s12273-023-1021-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 03/08/2023] [Accepted: 03/22/2023] [Indexed: 06/28/2023]
Abstract
There exist various vertical temperature gradients in different-type buildings. A holistic understanding of the impact of different temperature-stratified indoor environments on infection risk is necessary. In this work, the airborne transmission risk of SARS-CoV-2 in different thermally stratified indoor environments is assessed using our previously developed airborne infection risk model. Results show that the vertical temperature gradients in office building, hospital, classroom, etc. are within the range of -0.34 to 3.26 °C/m. In large space such as coach station, airport terminal, and sport hall, the average temperature gradient ranges within 0.13-2.38 °C/m in occupied zone (0-3 m); in ice rink with special requirements of indoor environment, the temperature gradient is higher than those in the above indoor spaces. The existence of temperature gradients causes multi-peaks of the transmission risk of SARS-CoV-2 with distancing, and our results show that in office, hospital ward and classroom, the second peak of the transmission risk is higher than 10-3 in most contact scenarios, while most being lower than 10-6 in large spaces like coach station and airport. The work is expected to provide some guidance on specific intervention policies in relation to the types of indoor environments. Electronic Supplementary Material the Appendix is available in the online version of this article at 10.1007/s12273-023-1021-5.
Collapse
Affiliation(s)
- Fan Liu
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, China
| | - Zhiwen Luo
- Welsh School of Architecture, Cardiff University, Cardiff, UK
| | - Hua Qian
- School of Energy and Environment, Southeast University, Nanjing, China
| |
Collapse
|
2
|
Daniell H, Nair SK, Guan H, Guo Y, Kulchar RJ, Torres MD, Shahed-Al-Mahmud M, Wakade G, Liu YM, Marques A, Graham-Wooten J, Zhou W, Wang P, Molugu SK, de Araujo WR, de la Fuente-Nunez C, Ma C, Short WR, Tebas P, Margulies KB, Bushman FD, Mante FK, Ricciardi R, Collman RG, Wolff MS. Debulking different Corona (SARS-COV-2 delta, omicron, OC43) and influenza (H1N1, H3N2) virus strains by plant viral trap proteins in chewing gums to decrease infection and transmission. Biomaterials 2022; 288:121671. [PMID: 35953331 PMCID: PMC9290430 DOI: 10.1016/j.biomaterials.2022.121671] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 12/13/2022]
Abstract
Because oral transmission of SARS-CoV-2 is 3–5 orders of magnitude higher than nasal transmission, we investigated debulking of oral viruses using viral trap proteins (CTB-ACE2, FRIL) expressed in plant cells, delivered through the chewing gum. In omicron nasopharyngeal (NP) samples, the microbubble count (based on N-antigen) was significantly reduced by 20 μg of FRIL (p < 0.0001) and 0.925 μg of CTB-ACE2 (p = 0.0001). Among 20 delta or omicron NP samples, 17 had virus load reduced below the detection level of spike protein in the RAPID assay, after incubation with the CTB-ACE2 gum powder. A dose-dependent 50% plaque reduction with 50–100 ng FRIL or 600–800 μg FRIL gum against Influenza strains H1N1, H3N2, and Coronavirus HCoV-OC43 was observed with both purified FRIL, lablab bean powder or gum. In electron micrographs, large/densely packed clumps of overlapping influenza particles and FRIL protein were observed. Chewing simulator studies revealed that CTB-ACE2 release was time/dose-dependent and release was linear up to 20 min chewing. Phase I/II placebo-controlled, double-blinded clinical trial (IND 154897) is in progress to evaluate viral load in saliva before or after chewing CTB-ACE2/placebo gum. Collectively, this study advances the concept of chewing gum to deliver proteins to debulk oral viruses and decrease infection/transmission.
Collapse
|
3
|
Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes. Proc Natl Acad Sci U S A 2022; 119:e2203086119. [PMID: 35727979 PMCID: PMC9245670 DOI: 10.1073/pnas.2203086119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Respiratory droplets are widely recognized as the primary vehicle in viral respiratory disease transmission. Accurate information on their number and size distributions is important for appropriate mitigation strategies, for quantitative modeling of airborne disease transmission, and for evaluating the relative importance of droplets originating from saliva versus airway lining fluid. A straightforward experimental setup using inexpensive, readily available components is developed for simultaneous characterization of larger particles by video analysis of laser light scattering and monitoring of smaller sizes by an optical particle counter. Measurements indicate that in a healthy volunteer, the airborne mass of speech aerosol far exceeds that generated by breathing, even when accounting for faster sedimentation of the larger particles. Accurate measurements of the size and quantity of aerosols generated by various human activities in different environments are required for efficacious mitigation strategies and accurate modeling of respiratory disease transmission. Previous studies of speech droplets, using standard aerosol instrumentation, reported very few particles larger than 5 μm. This starkly contrasts with the abundance of such particles seen in both historical slide deposition measurements and more recent light scattering observations. We have reconciled this discrepancy by developing an alternative experimental approach that addresses complications arising from nucleated condensation. Measurements reveal that a large volume fraction of speech-generated aerosol has diameters in the 5- to 20-μm range, making them sufficiently small to remain airborne for minutes, not hours. This coarse aerosol is too large to penetrate the lower respiratory tract directly, and its relevance to disease transmission is consistent with the vast majority of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections initiating in the upper respiratory tract. Our measurements suggest that in the absence of symptoms such as coughing or sneezing, the importance of speech-generated aerosol in the transmission of respiratory diseases is far greater than generally recognized.
Collapse
|
4
|
Stadnytskyi V, Anfinrud P, Bax A. Breathing, speaking, coughing or sneezing: What drives transmission of SARS-CoV-2? J Intern Med 2021; 290:1010-1027. [PMID: 34105202 PMCID: PMC8242678 DOI: 10.1111/joim.13326] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/05/2021] [Indexed: 12/19/2022]
Abstract
The SARS-CoV-2 virus is highly contagious, as demonstrated by numerous well-documented superspreading events. The infection commonly starts in the upper respiratory tract (URT) but can migrate to the lower respiratory tract (LRT) and other organs, often with severe consequences. Whereas LRT infection can lead to shedding of virus via breath and cough droplets, URT infection enables shedding via abundant speech droplets. Their viral load can be high in carriers with mild or no symptoms, an observation linked to the abundance of SARS-CoV-2-susceptible cells in the oral cavity epithelium. Expelled droplets rapidly lose water through evaporation, with the smaller ones transforming into long-lived aerosol. Although the largest speech droplets can carry more virions, they are few in number, fall to the ground rapidly and therefore play a relatively minor role in transmission. Of more concern is small speech aerosol, which can descend deep into the LRT and cause severe disease. However, since their total volume is small, the amount of virus they carry is low. Nevertheless, in closed environments with inadequate ventilation, they can accumulate, which elevates the risk of direct LRT infection. Of most concern is the large fraction of speech aerosol that is intermediate-sized because it remains suspended in air for minutes and can be transported over considerable distances by convective air currents. The abundance of this speech-generated aerosol, combined with its high viral load in pre- and asymptomatic individuals, strongly implicates airborne transmission of SARS-CoV-2 through speech as the primary contributor to its rapid spread.
Collapse
Affiliation(s)
- V Stadnytskyi
- From the, Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - P Anfinrud
- From the, Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - A Bax
- From the, Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
5
|
Dabiri D, Conti SR, Sadoughi Pour N, Chong A, Dadjoo S, Dabiri D, Wiese C, Badal J, Hoogland MA, Conti HR, Taylor TR, Choueiri G, Amili O. A Multi-Disciplinary Review on the Aerobiology of COVID-19 in Dental Settings. FRONTIERS IN DENTAL MEDICINE 2021; 2. [PMID: 35574425 PMCID: PMC9098049 DOI: 10.3389/fdmed.2021.726395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The COVID-19 pandemic pushed dental health officials around the world to reassess and adjust their existing healthcare practices. As studies on controlled COVID-19 transmission remain challenging, this review focuses on particles that can carry the virus and relevant approaches to mitigate the risk of pathogen transmission in dental offices. This review gives an overview of particles generated in clinical settings and how size influences their distribution, concentration, and generation route. A wide array of pertinent particle characterization and counting methods are reviewed, along with their working range, reliability, and limitations. This is followed by a focus on the effectiveness of personal protective equipment (PPE) and face shields in protecting patients and dentists from aerosols. Direct studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are still limited, but the literature supports the use of masks as an important and effective non-pharmaceutical preventive measure that could reduce the risk of contracting a respiratory infection by up to 20%. In addition to discussing about PPE used by most dental care professionals, this review describes other ways by which dental offices can protect patients and dental office personnel, which includes modification of the existing room design, dental equipment, and heating, ventilation, and air conditioning (HVAC) system. More affordable modifications include positioning a high-efficiency particulate air (HEPA) unit within proximity of the patient’s chair or using ultraviolet germicidal irradiation in conjunction with ventilation. Additionally, portable fans could be used to direct airflow in one direction, first through the staff working areas and then through the patient treatment areas, which could decrease the number of airborne particles in dental offices. This review concludes that there is a need for greater awareness amongst dental practitioners about the relationship between particle dynamics and clinical dentistry, and additional research is needed to fill the broad gaps of knowledge in this field.
Collapse
Affiliation(s)
- Darya Dabiri
- Department of Dentistry, Division of Pediatric Dentistry, University of Toledo, Toledo, OH, United States
- Correspondence: Darya Dabiri,
| | - Samuel Richard Conti
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Niloufar Sadoughi Pour
- Department of Mechanical, Industrial and Manufacturing Engineering (MIME), University of Toledo, Toledo, OH, United States
| | - Andrew Chong
- Department of Cariology, Restorative Sciences & Endodontics, University of Michigan, Ann Arbor, MI, United States
| | - Shaahin Dadjoo
- Department of Orthodontics and Dentofacial Orthopedics, The Eastman Institute for Oral Health, University of Rochester, Rochester, NY, United States
| | - Donya Dabiri
- Department of Dentistry, Division of Pediatric Dentistry, University of Toledo, Toledo, OH, United States
| | - Carol Wiese
- Department of Dentistry, Division of Pediatric Dentistry, University of Toledo, Toledo, OH, United States
| | - Joyce Badal
- Department of Medicine, University of Toledo, Toledo, OH, United States
| | | | - Heather Raquel Conti
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| | - Travis Roger Taylor
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, United States
| | - George Choueiri
- Department of Mechanical, Industrial and Manufacturing Engineering (MIME), University of Toledo, Toledo, OH, United States
| | - Omid Amili
- Department of Mechanical, Industrial and Manufacturing Engineering (MIME), University of Toledo, Toledo, OH, United States
| |
Collapse
|
6
|
Li B, Wang D, Lee MMS, Wang W, Tan Q, Zhao Z, Tang BZ, Huang X. Fabrics Attached with Highly Efficient Aggregation-Induced Emission Photosensitizer: Toward Self-Antiviral Personal Protective Equipment. ACS NANO 2021; 15:13857-13870. [PMID: 34313425 DOI: 10.1021/acsnano.1c06071] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Personal protective equipment (PPE) is vital for the prevention and control of SARS-CoV-2. However, conventional PPEs lack virucidal capabilities and arbitrarily discarding used PPEs may cause a high risk for cross-contamination and environmental pollution. Recently reported photothermal or photodynamic-mediated self-sterilizing masks show bactericidal-virucidal abilities but have some inherent disadvantages, such as generating unbearable heat during the photothermal process or requiring additional ultraviolet light irradiation to inactivate pathogens, which limit their practical applications. Here, we report the fabrication of a series of fabrics (derived from various PPEs) with real-time self-antiviral capabilities, on the basis of a highly efficient aggregation-induced emission photosensitizer (namely, ASCP-TPA). ASCP-TPA possesses facile synthesis, excellent biocompatibility, and extremely high reactive oxygen species generation capacity, which significantly outperforms the traditional photosensitizers. Meanwhile, the ASCP-TPA-attached fabrics (ATaFs) show tremendous photodynamic inactivation effects against MHV-A59, a surrogate coronavirus of SARS-CoV-2. Upon ultralow-power white light irradiation (3.0 mW cm-2), >99.999% virions (5 log) on the ATaFs are eliminated within 10 min. Such ultralow-power requirement and rapid virus-killing ability enable ATaFs-based PPEs to provide real-time protection for the wearers under indoor light irradiation. ATaFs' virucidal abilities are retained after 100 washings or continuous exposure to office light for 2 weeks, which offers the benefits of reusability and long-term usability. Furthermore, ATaFs show no toxicity to normal skin, even upon continuous high-power light illumination. This self-antiviral ATaFs-based strategy may also be applied to fight against other airborne pathogens and holds huge potential to alleviate global PPE supply shortages.
Collapse
Affiliation(s)
- Bin Li
- Center for Infection and Immunity, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, Guangdong, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519000, Guangdong, China
- Key Laboratory of Tropical Diseases Control, Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
| | - Dong Wang
- Center for AIE Research, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, Guangdong, China
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Michelle M S Lee
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Wei Wang
- Center for Infection and Immunity, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, Guangdong, China
| | - Qingqin Tan
- Center for Infection and Immunity, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, Guangdong, China
| | - Zhaoyan Zhao
- Center for Infection and Immunity, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, Guangdong, China
| | - Ben Zhong Tang
- Center for AIE Research, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, Guangdong, China
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Xi Huang
- Center for Infection and Immunity, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, Guangdong, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519000, Guangdong, China
- Key Laboratory of Tropical Diseases Control, Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
- The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan 511518, Guangdong, China
| |
Collapse
|