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Li Y, Frandsen KM, Guo W, Lu Y, Hvelplund MH, Suolang B, Xi Z, Duan M, Liu L. Impact of altitude on the dosage of indoor particulates entering an individual's small airways. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133856. [PMID: 38394896 DOI: 10.1016/j.jhazmat.2024.133856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 02/17/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
The complexity of indoor particulate exposure intensifies at higher altitudes owing to the increased lung capacity that residents develop to meet the higher oxygen demands. Altitude variations impact atmospheric pressure and alter particulate dynamics in ambient air and the human respiratory tract, complicating particulate inhalation. This study assessed the fraction of PM2.5 and PM10 entering small airways. This assessment covered an altitude range from 400 m above sea level to 3650 m, and an in vitro respiratory tract model was used. The experimental results confirmed that with increasing altitude, the penetration fractions of PM2.5 and PM10 significantly increased from 0.133 ± 0.031 and 0.141 ± 0.045 to 0.404 ± 0.159 and 0.353 ± 0.132, respectively. Additionally, the computational fluid dynamics simulation results revealed that among particles with sizes of 0.1 to 10 µm, the 7.5-μm particles exhibited the most substantial reduction in deposition in the upper airway, displaying a decrease of 6.27%. Our findings underscore the health risks faced by low-altitude residents during acclimatization to higher altitudes, as they experience heightened exposure to particulate matter sources.
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Affiliation(s)
- Yifan Li
- Department of Building Science, Tsinghua University, Beijing 100084, China; Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China
| | | | - Weiqi Guo
- Department of Building Science, Tsinghua University, Beijing 100084, China; Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Yiran Lu
- Department of Building Science, Tsinghua University, Beijing 100084, China; Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China
| | | | - Baimu Suolang
- School of Engineering, Tibet University, Lhasa, Tibet 850000, China
| | - Ziang Xi
- Department of Building Science, Tsinghua University, Beijing 100084, China; Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Mengjie Duan
- Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China; Vanke School of Public Health, Tsinghua University, Beijing 100084, China.
| | - Li Liu
- Department of Building Science, Tsinghua University, Beijing 100084, China; Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China.
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Zhang S, Yan Z, Zhang Y, Wu X, Liu L, Yang A, Duan M. Protocol of a randomised controlled trial to assess medical staff's inhalation exposure to infectious particles exhaled by patients during oesophagogastroduodenoscopy and the efficacy of surgical masks in this context. BMJ Open 2023; 13:e068291. [PMID: 36854596 PMCID: PMC9980315 DOI: 10.1136/bmjopen-2022-068291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
BACKGROUND Aerosol-generating procedures such as oesophagogastroduodenoscopy (OGD) result in infectious particles being exhaled by patients. This substantially increases the medical staff's risk of occupational exposure to pathogenic particles via airway inhalation and facial mucosal deposition. Infectious particles are regarded as a key route of transmission of SARS-CoV-2 and, thus, represents a major risk factor for medical staff during the ongoing COVID-19 pandemic. There is a need for quantitative evidence on medical staff's risk of multiroute exposure to infectious particles exhaled by patients during OGD to enable the development of practical, feasible and economical methods of risk-reduction for use in OGD and related procedures. This randomised controlled trial (RCT)-Personal protective EquiPment intervention TrIal for oesophagogastroDuodEnoscopy (PEPTIDE)-aims to establish a state-of-the-art protocol for quantifying the multiroute exposure of medical staff to infectious particles exhaled by patients during real OGD procedures. METHOD AND ANALYSIS PEPTIDE will be a prospective, two-arm, RCT using quantitative methods and will be conducted at a tertiary hospital in China. It will enrol 130 participants (65 per group) aged over 18. The intervention will be an anthropomorphic model with realistic respiratory-related morphology and respiratory function that simulates a medical staff member. This model will be used either without or with a surgical mask, depending on the group allocation of a participant, and will be placed beside the participants as they undergo an OGD procedure. The primary outcome will be the anthropomorphic model's airway dosage of the participants' exhaled infectious particles with or without a surgical mask, and the secondary outcome will be the anthropomorphic model's non-surgical mask-covered facial mucosa dosage of the participants' exhaled infectious particles. Analyses will be performed in accordance with the type of data collected (categorical or quantitative data) using SPSS (V.26.0) and RStudio (V.1.3.959). ETHICS AND DISSEMINATION Ethical approval for this RCT was obtained from the Ethics Committee of Peking Union Medical College Hospital (ZS-3377). All of the potential participants who agree to participate will provide their written informed consent before they are enrolled. The results will be disseminated through presentations at national and international conferences and publications in peer-reviewed journals. TRIAL REGISTRATION NUMBER NCT05321056.
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Affiliation(s)
- Shengyu Zhang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhiyu Yan
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- 4+4 M.D. Program, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yuheng Zhang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xi Wu
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Li Liu
- Department of Building Science, Tsinghua University, Beijing, China
- Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing, China
| | - Aiming Yang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Mengjie Duan
- Department of Building Science, Tsinghua University, Beijing, China
- Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing, China
- Vanke School of Public Health, Tsinghua University, Beijing, China
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Ren J, Tang M, Novoselac A. Experimental study to quantify airborne particle deposition onto and resuspension from clothing using a fluorescent-tracking method. BUILDING AND ENVIRONMENT 2022; 209:108580. [PMID: 34848915 PMCID: PMC8620412 DOI: 10.1016/j.buildenv.2021.108580] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/10/2021] [Accepted: 11/10/2021] [Indexed: 05/22/2023]
Abstract
The rapid spread and high level of morbidity of the SARS-CoV-2 virus during the COVID-19 pandemic has attracted considerable attention worldwide. Recent studies have shown that clothing is one of the vectors for the transport of airborne particles, including bioaerosols. This study developed a method that can both quantify the deposition of particles onto clothing and the resuspension of particles from clothing using a fluorescent-tracking technology and found that electrical tape can be used as a fluorescent particle collector on irregular clothing surfaces. Results show that 0.07%-6.61% of the fluorescent particles (FPs) previously loaded on the room flooring surfaces moved to the occupant's clothing during the 20-min sampling periods; the percentage depended on the type of activity and the range is for: office work, walking, and vacuuming. Furthermore, both the flooring type (carpet or vinyl composition tile) and flooring condition (clean or dirty) had significant effects on particle resuspension and transport to the occupant's clothing. The average particle deposition factor for carpet flooring was 2.7 (±1.4) times that for vinyl composition tile flooring, while the average particle deposition factor for dirty flooring was 2.4 (±1.6) times that for clean flooring. A multiple regression analysis shows that the activity type had the largest effect on the particle transport among all experimental variables. An additional experiment performed in a full-scale house shows that 46.8% of FPs formerly seeded on clothing resuspended from clothing and dispersed around the house during the 1-h period of light walking at a speed of 60 steps/min.
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Affiliation(s)
- Jianlin Ren
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Mengjia Tang
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, USA
| | - Atila Novoselac
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, USA
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Xu J, Wang C, Fu SC, Chao CYH. The effect of head orientation and personalized ventilation on bioaerosol deposition from a cough. INDOOR AIR 2022; 32:e12973. [PMID: 34888956 DOI: 10.1111/ina.12973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
Head orientations directly determine movement directions of exhaled pathogen-laden droplets, while there is a lack of research about the effect of the infected person's head orientations on respiratory disease transmission during close contact. This work experimentally investigated the effect of different head orientations of an infected person (IP) on the bioaerosol deposition on a healthy person (HP) during close contact. Also, the effectiveness of PV flow in reducing bioaerosol deposition on the HP under the IP's different head orientations was investigated. Bacteriophage T3 was employed to represent viruses inside the cough-generated aerosols. The bioaerosol depositions on different locations of the HP's upper body (chest, shoulder, and neck) and face (chin, mucous membranes, cheek, and forehead) were characterized by a cultivation method. Results showed that the IP's different head orientations resulted in significantly different deposition density on the HP. PV flow could reduce the bioaerosol deposition remarkably for most cases investigated. The effectiveness of PV flow in reducing deposition on the HP was significantly affected by the IP's head orientations. Findings suggest that changing head orientations can be a control measure to reduce the bioaerosol deposition. Personalized ventilation can be a potential method to reduce the bioaerosol deposition on the HP.
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Affiliation(s)
- Jingcui Xu
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Cunteng Wang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Sau Chung Fu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Christopher Y H Chao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- Department of Building Environment and Energy Engineering, Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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Negative Ion Purifier Effects on Indoor Particulate Dosage to Small Airways. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:ijerph19010264. [PMID: 35010523 PMCID: PMC8751072 DOI: 10.3390/ijerph19010264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/13/2021] [Accepted: 12/24/2021] [Indexed: 12/13/2022]
Abstract
Indoor air quality is an important health factor as we spend more than 80% of our time indoors. The primary type of indoor pollutant is particulate matter, high levels of which increase respiratory disease risk. Therefore, air purifiers are a common choice for addressing indoor air pollution. Compared with traditional filtration purifiers, negative ion air purifiers (NIAPs) have gained popularity due to their energy efficiency and lack of noise. Although some studies have shown that negative ions may offset the cardiorespiratory benefits of air purifiers, the underlying mechanism is still unclear. In this study, we conducted a full-scale experiment using an in vitro airway model connected to a breathing simulator to mimic inhalation. The model was constructed using computed tomography scans of human airways and 3D-printing technology. We then quantified the effects of NIAPs on the administered dose of 0.5-2.5 μm particles in the small airway. Compared with the filtration purifier, the NIAP had a better dilution effect after a 1-h exposure and the cumulative administered dose to the small airway was reduced by 20%. In addition, increasing the negative ion concentration helped reduce the small airway exposure risk. NIAPs were found to be an energy-efficient air purification intervention that can effectively reduce the small airway particle exposure when a sufficient negative ion concentration is maintained.
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Wang L, Deng Y. The Need for Ocular Protection for Health Care Workers During SARS-CoV-2 Outbreak and a Hypothesis for a Potential Personal Protective Equipment. Front Public Health 2020; 8:599757. [PMID: 33282819 PMCID: PMC7690622 DOI: 10.3389/fpubh.2020.599757] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/19/2020] [Indexed: 02/05/2023] Open
Abstract
SARS-CoV-2 is a coronavirus with high infectivity and has caused dramatic pressure on health systems all over the world. Appropriate personal protection for medical staffs is critical. For ocular protection, there is ongoing hot debate and concern for potential ocular transmission of SARS-CoV-2. Ocular manifestations and positive detection of viral RNA in ocular samples were only reported in very small number of patients infected with SARS-CoV-2. However, health care workers need to face patients more closely and have higher risk of aerosol contamination. Thus, appropriate ocular protection for medical workers is still recommended by organizations such as WHO and American Academy of Ophthalmology. Although eye goggles provide excellent protection and are mandatory for medical practitioners with high risk of exposure, they are not ideal for common clinical practice, because they can disturb vision due to extensive formation of water droplets and frequently cause moderate to severe discomfort after longtime wearing, which have been reported to interfere with working status. For the majority of medical workers who don't deal with high risk patients, they are not advised to wear goggles in daily practice. However, they also face the risk of infection due to the presence of asymptomatic carriers. Especially in situations with high risk of ocular exposure, such as close physical examination, eye surgery, dental clinics and surgery, ocular protection may be needed. Griffithsin has been shown to directly bind to spike proteins and has anti-viral activity against a broad spectrum of viruses, including coronavirus. Griffithsin is found to inhibit the entry of SARS-CoV at relatively low concentration and is stable and non-toxic. SARS-CoV-2 and SARS-CoV share the same entry receptors and their spike proteins are similar in conformation. We hypothesize that contact lenses containing nanoparticles loaded with griffithsin may provide sufficient ocular protection for medical staffs without high risk of exposure during the outbreak period of SARS-CoV-2. If proven effective, griffithsin-loaded contact lens can be considered as a supplementary ocular protective equipment for medical workers who can tolerate well. The daily disposable contact lens should be applied as needed and refrain from extended wearing in order to reduce potential side effects.
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Affiliation(s)
- Lixiang Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yingping Deng
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
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Chemicals inhaled from spray cleaning and disinfection products and their respiratory effects. A comprehensive review. Int J Hyg Environ Health 2020; 229:113592. [PMID: 32810683 DOI: 10.1016/j.ijheh.2020.113592] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/20/2020] [Accepted: 07/03/2020] [Indexed: 12/13/2022]
Abstract
Spray cleaning and disinfection products have been associated with adverse respiratory effects in professional cleaners and among residents doing domestic cleaning. This review combines information about use of spray products from epidemiological and clinical studies, in vivo and in vitro toxicological studies of cleaning chemicals, as well as human and field exposure studies. The most frequent chemicals in spray cleaning and disinfection products were compiled, based on registrations in the Danish Product Registry. The chemicals were divided into acids, bases, disinfectants, fragrances, organic solvents, propellants, and tensides. In addition, an assessment of selected cleaning and disinfectant chemicals in spray products was carried out. Chemicals of concern regarding respiratory effects (e.g. asthma) are corrosive chemicals such as strong acids and bases (including ammonia and hypochlorite) and quaternary ammonium compounds (QACs). However, the evidence for respiratory effects after inhalation of QACs is ambiguous. Common fragrances are generally not considered to be of concern following inhalation. Solvents including glycols and glycol ethers as well as propellants are generally weak airway irritants and not expected to induce sensitization in the airways. Mixing of certain cleaning products can produce corrosive airborne chemicals. We discuss different hypotheses for the mechanisms behind the development of respiratory effects of inhalation of chemicals in cleaning agents. An integrative assessment is needed to understand how these chemicals can cause the various respiratory effects.
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Xu C, Wei X, Liu L, Su L, Liu W, Wang Y, Nielsen PV. Effects of personalized ventilation interventions on airborne infection risk and transmission between occupants. BUILDING AND ENVIRONMENT 2020; 180:107008. [PMID: 32834416 PMCID: PMC7260576 DOI: 10.1016/j.buildenv.2020.107008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/30/2020] [Accepted: 05/23/2020] [Indexed: 05/03/2023]
Abstract
The role of personalized ventilation (PV) in protecting against airborne disease transmission between occupants was evaluated by considering two scenarios with different PV alignments. The possibility that PV may facilitate the transport of exhaled pathogens was explored by performing experiments with droplets and applying PV to a source or/and a target manikin. The risk of direct and indirect exposure to droplets in the inhalation zone of the target was estimated, with these exposure types defined according to their different origins. The infection risk of influenza A, a typical disease transmitted via air, was predicted based on a dose-response model. Results showed that the flow interactions between PV and the infectious exhaled flow would facilitate airborne transmission between occupants in two ways. First, application of PV to the source caused more than 90% of indirect exposure of the target. Second, entrainment of the PV jet directly from the infectious exhalation increased direct exposure of the target by more than 50%. Thus, these scenarios for different PV application modes indicated that continuous exposure to exhaled influenza A virus particles for 2 h would correspond with an infection probability ranging from 0.28 to 0.85. These results imply that PV may protect against infection only when it is maintained with a high ventilation efficiency at the inhalation zone, which can be realized by reduced entrainment of infectious flow and higher clean air volume. Improved PV design methods that could maximize the positive effects of PV on disease control in the human microenvironment are discussed.
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Affiliation(s)
- Chunwen Xu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
| | - Xiongxiong Wei
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
| | - Li Liu
- Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an, 710055, China
- Corresponding author. Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China.
| | - Li Su
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an, 710055, China
| | - Wenbing Liu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
| | - Yi Wang
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an, 710055, China
| | - Peter V. Nielsen
- Department of Civil Engineering, Aalborg University, Aalborg, 9000, Denmark
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Zimmerman K, Kearns F, Tzekov R. Natural protection of ocular surface from viral infections - A hypothesis. Med Hypotheses 2020; 143:110082. [PMID: 32679424 PMCID: PMC7346787 DOI: 10.1016/j.mehy.2020.110082] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 07/04/2020] [Indexed: 01/08/2023]
Abstract
A pandemic outbreak of a viral respiratory infection (COVID-19) caused by a coronavirus (SARS-CoV-2) prompted a multitude of research focused on various aspects of this disease. One of the interesting aspects of the clinical manifestation of the infection is an accompanying ocular surface viral infection, viral conjunctivitis. Although occasional reports of viral conjunctivitis caused by this and the related SARS-CoV virus (causing the SARS outbreak in the early 2000s) are available, the prevalence of this complication among infected people appears low (~1%). This is surprising, considering the recent discovery of the presence of viral receptors (ACE2 and TMPRSS2) in ocular surface tissue. The discrepancy between the theoretically expected high rate of concurrence of viral ocular surface inflammation and the observed relatively low occurrence can be explained by several factors. In this work, we discuss the significance of natural protective factors related to anatomical and physiological properties of the eyes and preventing the deposition of large number of virus-loaded particles on the ocular surface. Specifically, we advance the hypothesis that the standing potential of the eye plays an important role in repelling aerosol particles (microdroplets) from the surface of the eye and discuss factors associated with this hypothesis, possible ways to test it and its implications in terms of prevention of ocular infections.
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Affiliation(s)
- Keith Zimmerman
- Department of Ophthalmology, University of South Florida, Tampa, FL, USA
| | - Fiona Kearns
- Department of Chemistry, University of South Florida, Tampa, FL, USA
| | - Radouil Tzekov
- Department of Ophthalmology, University of South Florida, Tampa, FL, USA; Department of Pharmaceutical Sciences, University of South Florida, Tampa, FL, USA; Department of Medical Engineering, University of South Florida, Tampa, FL, USA.
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