cord-016897-t71f10kv	2013	We discuss the risk of transmitting these procedures and the strategies for mechanical ventilation in future airborne epidemics with special consideration given to the issue of protecting health care workers (HCWs). In contrast to the situation regarding severe acute respiratory syndrome (SARS) or tuberculosis prevention in HCWs, little attention has been given to the importance of HCWs personal protective equipment (PPE) (gowns, gloves, masks) for prevention and management of infl uenza. There is also potential for NIV to reduce the need for intubation in patients with infl uenza pneumonia or chronic respiratory disease, facilitate extubation, and widen the provision of ventilator support outside the intensive care unit (ICU). Evaluation of droplet dispersion during non-invasive ventilation, oxygen therapy, nebulizer treatment and chest physiotherapy in clinical practice: implications for management of pandemic infl uenza and other airbone infections Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review
cord-102746-rimpulm0	2020	Calculations with these equations provide a straightforward way to determine the airborne lifetime of emitted droplets after accounting for the decrease in droplet size from water evaporation. At a relative humidity of 50%, droplets with initial radii larger than about 50 microns rapidly fall to the ground while smaller, potentially-virus containing droplets shrink in size and remain airborne for many minutes. Second, for each relative humidity, how much time does it take for water evaporation to reduce a virus-containing droplet to a size that leaves it floating in air for a sufficiently long time to allow direct transmission of the virus to another person? Determining whether or not a virus-containing droplet will remain airborne to cause an infection requires determination of the rate of evaporation of water, which is a more complex problem and is different for different size regimes.
cord-103945-q3ry13vp	2020	By modelling the evaporation and settling of droplets emitted during respiratory releases and using previous measurements of droplet size distributions and SARS-CoV-2 viral load, estimates of the evolution of the liquid mass and the number of viral copies suspended were performed as a function of time from the release. By modelling the evaporation and settling of droplets emitted during respiratory releases and using previous measurements of droplet size distributions and SARS-CoV-2 viral load, estimates of the evolution of the liquid mass and the number of viral copies suspended were performed as a function of time from the release. The Lagrangian framework, given in Sec. 2(a), is considered in one (vertical) dimension and droplet clouds for two exhalation modes, speaking and coughing, are released at the height of the emitter''s mouth (1.5 m) and then let settle by gravity while evaporating in ambient air.
cord-129086-ra2njvcz	2020	However, in more recent times, the focus has shifted towards the theoretical investigations of fluid flow mechanisms involved in the virus-laden particles prevention by facemasks. 44 While these experimental studies are essential for the broad characterization and design evaluation of respiratory facemasks, further theoretical and numerical methods and algorithm-based investigations provide a better insight into the facemask''s fluid flow dynamics and the droplet leakage through the facemask openings. The computational fluid flow models have shown their potentials in an improved prediction of the spreading of respiratory virus-laden droplets and aerosols, sensitive to the ambient environment, and crucial to the public health responses. The results revealed that the small droplets travel a larger distance and remain suspended in the air for a longer time under the influence of airflow, supporting the mandatory use of facemasks to prevent the virus. In recent years, the respiratory droplets flow behavior through the facemasks has typically well-predicted using the computational fluid dynamics (CFD) techniques.
cord-148354-3nl3js2x	2020	We simulate the aerodynamic flow through the mask and the spatial spread of droplet ejecta resulting from respiratory events such as coughing or sneezing. We present the viral load in the air and deposited around the person, and show that wearing even a simple cloth mask substantially decreases the extent of spatial spread of virus particles when an infected person coughs or sneezes. 30 Here, we employ Computational Fluid Dynamics (CFD) simulations to address the influence of homemade face masks on the turbulent clouds that result due to sneezing events, and on the lateral extent of spread of ejecta. When an infected person not wearing a mask sneezes or coughs, virus particles in the large droplets rapidly drop to the floor. Our simulation results conclusively demonstrate that wearing even just a simple cotton mask has a dramatic influence on the air flow and spread of ejecta after a respiratory event.
cord-191527-okxzqzl1	2020	An end-to-end system model which considers the pathogen-laden cough/sneeze droplets as the input and the infection state of the human as the output is proposed. An end-to-end system model which considers the pathogen-laden cough/sneeze droplets as the input and the infection state of the human as the output is proposed. This model uses the gravity, initial velocity and buoyancy for the propagation of droplets and a receiver model which considers the central part of the human face as the reception interface is proposed. This model uses the gravity, initial velocity and buoyancy for the propagation of droplets and a receiver model which considers the central part of the human face as the reception interface is proposed. Furthermore, the probability of infection for an uninfected human is derived by modeling the number of propagating droplets as a random process. Furthermore, the probability of infection for an uninfected human is derived by modeling the number of propagating droplets as a random process.
cord-208426-wz3jan5d	2020	Using realistic air flow simulation, we model droplet dispersion from coughing and study the transmission risk related to SARS-CoV-2. Notably, numerical methods, such as Computational Fluid Dynamics (CFD) based on Reynolds Averaged Navier-Stokes (RANS) turbulence models 31 produce high resolution flow fields and concentration data, 32 which not only compensate for slow instrumental speeds of analytical techniques, 25 but are also adaptable to different environments and scenarios, such as passengers in an aircraft cabin, 33 and more recently, a cough dispersion study in an outdoor environment under significant wind speeds, 34 whose results are useful in integrated transmission modeling. As detailed in the Supplementary Information, the model cough is inclined downwards at an average of 27·5°, 37 follows a characteristic air flow pattern 33,37 at breath temperature of 36°C, and emits a cluster of droplets with a standard size distribution 11, 38 and viral loading 39 
cord-253252-s8fm5rfa	2020	This review paper intends to outline the literature concerning the transmission of viral-laden droplets and aerosols in different environmental settings and demonstrates the behavior of droplets and aerosols resulted from a cough-jet of an infected person in various confined spaces. There have been myriads of hypotheses corroborating that certain threshold levels of humidity, temperature, sunlight, and ventilation will speed up the virus-laden droplet and aerosol transmission, aggravating the spread of the SARS-CoV disease (Morawska, 2006) . Nevertheless, the effectiveness of the use of masks for the control of SARS-CoV-2-laden aerosol transmission from an infected person to a susceptible host is uncertain and not fully conceivable. Researchers have speculated that both droplets and aerosols generated from non-violent and violent expirations of SARS-CoV-2-infected people may be responsible for the nonnosocomial and nosocomial transmission of COVID-19 disease.
cord-254894-ta7hebbg	2020	In this paper, we discuss the processes of droplet generation by exhalation, their potential transformation into airborne particles by evaporation, transport over long distances by the exhaled puff and by ambient air turbulence, and final inhalation by the receiving host as interconnected multiphase flow processes. (ii) A first-order mathematical framework that describes the evolution of the cloud of respiratory droplets and their conversion to droplet nuclei, as a function of time, and (iii) A simple description of the inhalability of the aerosols along with the corresponding evaluation of the effectiveness of different masks based on existing data reported to date.
cord-255084-qav7yb0p	2018	The approach is featured with a continuity equation being explicitly solved for water vapor, which allows comprehensively considering the effects of inhomogeneous humidity field on droplets evaporation and movement. The study also revealed that due to the droplet size reduction induced by evaporation, both the number density of airborne droplets and mass concentration of inhalable pathogens remarkably increased, which can result in a higher risk of infection. Apart from that, many other factors including the mass of exhaled droplets, the ambient temperature and humidity could have significant effects on the process of droplet evaporation, resulting in different time-size correlation and droplet dispersion trajectories. Comparatively, the time-dependent size of the 112-μm droplets was not significantly affected by the inhomogeneous humidity field, probably because the travelling speed of this group of droplets was larger than that of vapor dispersion (refer to Figs.
cord-255770-gbhjke93	2020	A general consensus exists on coronavirus diffusion by droplet transmission, especially the aerosolization during hospital procedures like intubation or bronchoscopy might represent a big concern, exposing other patients and healthcare staff to an increased risk of infection. Sore throat with or without fever, sneezing, hoarseness may be prodromic symptoms of a COVID-19 infection in the incubation period. Direct contact of droplet spray produced by coughing, sneezing, or talking involves relatively large droplets containing organisms and requires close contact usually within 1 m. Moreover, the total number of droplets generated during sneeze is also larger than that of other respiratory activities. The high-speed airflow and corresponding turbulence produced by sneeze may also lead to a large number of droplets, that is, the number of the droplets generated by sneeze is about 18 times larger than that of cough. SARS-CoV-2 viral load in upper respiratory specimens of infected patients
cord-258304-86gqxajw	2020	title: Droplets and Aerosols generated by singing and the risk of COVID-19 for choirs The results of detailed particle tracking (in supplementary video) reveals that the maximum velocity of droplets expelled, specifically for certain syllables such as ''do'', ''fa'' and ''ti'', is approx. Figure 2c shows the velocity distribution of droplets that are visible while the subject was singing syllable ''sol'' & ''la'' and the direction in which these droplets are moving. Nevertheless, the droplets observed do not appear to be settling down rapidly and without adequate ventilation, these droplets can potentially saturate the indoor environment which can likely explain the very high attack rates of COVID-19 seen in choirs in the US and Europe (almost 87% in Skagit County, Washington) [1] . We note the present study only provides visual evidence of the droplets and aerosols expelled during singing and compare the associated velocities and directions with speaking and coughing.
cord-263644-rg00br0d	2017	This study investigated the emission strength of three types of airborne bacteria, namely Staphylococcus epidermidis, Escherichia coli, and Pseudomonas alcaligenes, during toilet flushing in a custom‐built toilet under a controlled environment. The pathogens emitted by the first flush were calculated, with the correlations between airborne pathogen emissions and droplet concentration (HP, r=0.944, P<.001; LP, r=0.803, P<.001, HT, r=0.885, P<.05) and bacterial size (HP, r=−0.919, P<.001; LP, r=−0.936, P<.001; HT, r=−0.967, P<.05) in the different conditions then tested. A significant association between bacterial emission strength at different degrees of flushing energy and flushing systems was reported in a recent study focusing on the initial droplet size distribution generated by flushing an experimental toilet system with various flushing mechanisms. Parameters such as water pressure, tank height, and bacterial size were varied, and the correlations between airborne droplet concentration and bacterial emission strength were investigated.
cord-271822-ohkki0ke	2020	We use qualitative visualizations of emulated coughs and sneezes to examine how materialand design-choices impact the extent to which droplet-laden respiratory jets are blocked. We outline the procedure for setting up simple visualization experiments using easily available materials, which may help healthcare professionals, medical researchers, and manufacturers in assessing the effectiveness of face masks and other personal protective equipment qualitatively. 7 The rationale behind the recommendation for using masks or other face coverings is to reduce the risk of cross-infection via the transmission of respiratory droplets from infected to healthy individuals. 8, 9 The pathogen responsible for COVID-19 is found primarily in respiratory droplets that are expelled by infected individuals during coughing, sneezing, or even talking and breathing. Various studies have investigated the effectiveness of medical-grade face masks and other personal protective equipment (PPE) in reducing the possibility of cross-infection via these droplets.
cord-274083-6vln3erl	2020	Drying of the droplet is predicted by using a diffusion-limited evaporation model for a sessile droplet placed on a partially wetted surface with a pinned contact line. We consider diffusion-limited, quasi-steady evaporation of a sessile droplet with a pinned contact line on a partially wetted surface (Fig. 2) . The mass lost rate (kg/s) of an evaporating sessile droplet is expressed as follows: 12 where H and θ are relative humidity and static contact angle, respectively. (8) and (10) Second, we present the effect of ambient temperature, surface wettability, and relative humidity on the drying time of the droplet. To determine the likelihood of the droplet and the virus on the surface, we find the mean and standard deviation of the probability density function (PDF) of the normal distribution of the droplet drying times for different cases of ambient temperature, contact angle, and relative humidity.
cord-274781-tmc31aa6	2020	We find that, in the absence of gravity, there are two distinct behaviors for the droplets: small droplets cannot go further than a specific distance, which we determine analytically, from the source before getting pulled into the sink. The transport of inertial particles in fluid flows occurs in many problems arising in engineering and biology, such as the build-up of microplastics in the ocean 1 and respiratory virus transmission through tract droplets. 17 Such a flow could represent the trajectories of water droplets emitted from coughing, sneezing, [2] [3] [4] or breathing and in the presence of extraction, such as an air-conditioning unit or air current. We are interested in where the flow field changes direction, since this indicates the maximum distance the droplets emitted at the source can travel before moving toward the sink. We model the situation as a point source emitting droplets of various sizes in the presence of gravitational forces and compute the maximum horizontal distance traveled by these droplets.
cord-275303-8mj8gjv9	2020	
cord-276649-3zl3pm79	2020	We outline the following recommendations: pull the face mask down partially and keep the mouth covered, only allowing nasal access during nasoendoscopy; avoid nasal sprays if possible; if nasal sprays are used, procedurists should be in full personal protective equipment prior to using the spray; withdrawal of swabs and scopes should be performed in a slow and controlled fashion to reduce potential dispersion of droplets when the capillary bridge of mucus breaks up. We outline the following recommendations: pull the face mask down partially and keep the mouth covered, only allowing nasal access during nasoendoscopy; avoid nasal sprays if possible; if nasal sprays are used, procedurists should be in full personal protective equipment prior to using the spray; withdrawal of swabs and scopes should be performed in a slow and controlled fashion to reduce potential dispersion of droplets when the capillary bridge of mucus breaks up.
cord-290277-ndfoppoq	2020	World Health Organization (WHO) has issued guidelines for contact and droplet precautions for Healthcare Workers (HCWs) caring for suspected COVID-19 patients, whilst the US Centre for Disease Control (CDC) has recommended airborne precautions. We aimed to review the evidence for horizontal distance travelled by droplets and the guidelines issued by the World Health Organization (WHO), US Center for Diseases Control (CDC) and European Centre for Disease Prevention and Control (ECDC) on respiratory protection for COVID-19. We aimed to review the evidence supporting the rule of 1 m (≈3 ft) spatial separation for droplet precautions in the context of guidelines issued by the World Health Organization (WHO), US Center for Diseases Control (CDC) and European Centre for Disease Prevention and Control (ECDC) for HCWs on respiratory protection for COVID-19. Interim Infection Prevention and Control Recommendations for Hospitalized Patients with Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
cord-291836-dlsas702	2020	
cord-293097-poh1y6o7	2020	This concept is assessed using four major parameters such as population density, climate severity, the volume of indoor spaces, and air-conditioning usage which affect the infection spread and mortality using the data available for various states of India. Hence the major objective of the present work is to propose the mechanism of virus spread under various climates and the indoor environment conditions maintained through the existing theory of respiratory droplet drying. Further, it is aimed to perform a statistical study on the dependence of mortality and infection in the Indian States with respect to four major parameters such as population density, climate severity, volume of indoor spaces, and air-conditioning usage based on monthly data for March and April. In an environment with low humidity and low temperature, due to combined high heat and mass transfer potential leads to fast drying and size reduction of the respiratory droplets and the virus is almost active in all the locations.
cord-298227-av1ev8ta	2020	
cord-298461-tyhtdawb	2020	
cord-301721-31a2q3ad	2020	In this paper, we discuss the processes of droplet generation by exhalation, their potential transformation into airborne particles by evaporation, transport over long distances by the exhaled puff and by ambient air turbulence, and final inhalation by the receiving host as interconnected multiphase flow processes. But as the puff of air and the droplets move forward, the droplet Reynolds number rapidly decreases for the following reasons: (i) as will be seen in section 4.1 the puff velocity decreases due to entrainment and drag, (ii) as will be seen in section 4.2.1 the droplet diameter will decrease rapidly due to evaporation, (iii) as will be seen in section 4.2.2 the time scale τ V on which the droplet accelerates to the surrounding fluid velocity of the puff is quite small, and (iv) very large droplets quickly fall out of the puff and do not form part of airborne droplets. It should again be emphasized that the temperature difference between the puff fluid containing the droplet nuclei cloud and the ambient air may induce buoyancy effects, which for model simplicity will be taken into account as part of turbulent dispersion.
cord-306861-qcctchsk	2020	Using a validated computational model, the transport, evaporation, hygroscopic growth, and deposition of multi-component droplets were simulated in a simplified airway geometry. Numerical results indicate that the droplet/particle-vapor interaction and the heat and mass transfer of the mucus-tissue layer must be considered in the computational lung aerosol dynamics study, since they can significantly influence the precise predictions of the aerosol transport and deposition. If the more realistic thermal boundary (Chen, 11 al., 2018; Wu, et al., 2014) and indoor air conditions (McFadden Jr, et al., 1985) are 12 considered, higher inhalation flow rate also has a stronger cooling effect on the 13 mucus-tissue layer, which further affects the mucus evaporation. Therefore, the 14 transport, hygroscopic growth, and deposition of multi-component droplets have not 15 been investigated under different inhalation flow rate conditions, when employing the 16 more realistic thermal boundary conditions.
cord-307264-l13gyl94	2020	Calculations with these equations provide a straightforward way of determining whether emitted droplets remain airborne or rapidly fall to the ground, after accounting for the decrease in droplet size from water evaporation. Calculations with these equations provide a straightforward way of determining whether emitted droplets remain airborne or rapidly fall to the ground, after accounting for the decrease in droplet size from water evaporation. At a relative humidity of 50%, for example, droplets with initial radii larger than about 50 μm rapidly fall to the ground, while smaller, potentially virus-containing droplets shrink in size from water evaporation and remain airborne for many minutes. At a relative humidity of 50%, for example, droplets with initial radii larger than about 50 μm rapidly fall to the ground, while smaller, potentially virus-containing droplets shrink in size from water evaporation and remain airborne for many minutes.
cord-307768-xx46w6dc	2017	title: From single-molecule detection to next-generation sequencing: microfluidic droplets for high-throughput nucleic acid analysis Recent applications of such technologies to genetic analysis have suggested significant utility in low-cost, efficient and rapid workflows for DNA amplification, rare mutation detection, antibody screening and next-generation sequencing. 2003) , with the relative concentration of each reagent being defined by the Fig. 1 a Physical and chemical variables in droplet-based experiments: (1) Temperature can be controlled over wide ranges, enabling PCR in emulsions; (2) Hydrophobic substrates or ligands can be delivered through the oil phase into aqueous droplets; (3) Watersoluble components can be delivered through nanoscale droplets or swollen micelles, allowing the regulation of biochemical processes; (4) Internal pH can be altered, for example, by the delivery of acetic acid; (5) Photocaged substrates and ligands can be introduced into the droplets during emulsification and photoactivated at later times. Two recent studies describing single-cell RNA sequencing methods using droplet-based microfluidics [termed Drop-seq (Macosko et al.
cord-312236-8eaqn8eu	2007	
cord-312708-9ywu6r2t	2020	OBJECTIVE: The otolaryngology community has significant concerns regarding the spread of SARS-CoV-2 through droplet contamination and viral aerosolization during head and neck examinations and procedures. RESULTS: There were no fluorescein droplets or splatter contamination observed in the measured surgical field in any direction after myringotomy and insertion of ventilation tube. 7 As a result, the American Academy of Otolaryngology-Head and Neck Surgery has issued a position statement to limit elective procedures requiring interaction with upper airway mucosal surfaces or those with increased risk of aerosolization, which may include otologic procedures such as myringotomy and mastoidectomy. Since the upper respiratory tract harbors a high viral load, 3 otolaryngologists are vulnerable to SARS-CoV-2 transmission while performing head and neck procedures that utilize suction and powered instrumentation, such as the surgical drill, especially if they are doing so without appropriate protective personal equipment.
cord-313636-kcjnjq52	2020	title: Identifying the extent of oral fluid droplets on echocardiographic machine consoles in COVID-19 era The aim of this study was to identify the extent of oral fluid droplet spread on echocardiographic machine consoles, after observers were speaking in English or Japanese. Two observers without surgical masks repeated the words "inhale, exhale, hold" (the words often used during examinations) in English and Japanese, in front of echocardiographic machine (EUB-7500, Hitachi Medical Corporation, Japan) after ingesting the liquid with volunteers lying on your left side echocardiography. It was also important that no droplets were detected on the console when surgical masks were worn in this setting, although it is unlikely that examinations would be performed with either the sonographer/cardiologist scanning or the patient not wearing a mask in the current COVID era. To the best of our knowledge, this is the first report to assess the spread of the droplets generated by speech on the surface of an echocardiographic machine using visualized methods.
cord-315130-8g2ih8zl	2020	
cord-316129-mjg3un0l	2020	title: Aerosol and droplet creation during oscillatory motion of the microkeratome amidst COVID-19 and other infectious diseases METHOD: In an experimental setup, flap creation was performed on enucleated goat''s eyes (n = 8) mounted on a stand using One Use-Plus SBK Moria microkeratome (Moria SA) to assess the spread of aerosols and droplets using high-speed shadowgraphy. The maximum distance traversed was ∼1.8 m and ∼1.3 m assuming a constant airflow (setting of refractive surgery theater) and decaying jet condition (setting of an operating theater with air-handling unit), respectively. The maximum distance traversed was ∼1.8 m and ∼1.3 m assuming a constant airflow (setting of refractive surgery theater) and decaying jet condition (setting of an operating theater with air-handling unit), respectively. 13, 14 Therefore, we quantified the aerosol and droplet generation during flap creation using the Moria One Use-Plus SBK microkeratome (Moria SA) and assessed their trajectory using high-speed shadowgraphy and fluid mechanics principles.
cord-318187-c59c9vi3	2020	
cord-318835-sd9hbocg	2020	title: Utility of patient face masks to limit droplet spread from simulated coughs at the slit lamp 3 Herein, we aimed to investigate how various scenarios of masks worn by patients can reduce the spread of respiratory droplets onto the examiner during a slit-lamp examination using a simulated patient cough. This simulation demonstrates that the use of slit-lamp breath shields and standard PPE for the examiner may reduce but does not eliminate the projection of droplets onto the examiner''s field, chest, shoulders, and arms (Fig. 1) . In the simulation involving the improperly positioned surgical mask, droplets were identified on the shoulders, arms, and gloves of the examiner as well as the slit lamp, floor, and walls. Our findings suggest that the use of a properly fitted mask on the patient as an adjunct to the current standard PPE used by the examiner, and the breath shield is essential for limiting droplet dissemination during slit-lamp examinations.
cord-319822-h1zm94p4	2020	My thesis is supported and described on the basis of a physicist''s model which studies the droplets behavior when emitted by the respiratory apparatus of an infected person, symptomatic or not. The intermediate dimensioned droplets are proved to be changed into aerosol, losing their water content and becoming seriously contagious, but in their initial phase they could be easily caught by a simple surgical mask. This habit, There are non doubts about the fact that expiratory particles transmit the pandemic, but we must make a coarse distinction among droplets and their dynamic evolutions when emitted by infected people. These droplets have a substantial viral load, they are quite numerous, some thousands of them can contain just one single virion each and they are probably the most contagious and dangerous elements[14]; if not stopped on time, they constitute the real element of airborne infection [15] .
cord-324444-t697xw4y	2020	However, given that asymptomatic individuals, not wearing masks within the public, can be highly contagious for COVID-19, prevention of environmental droplet contamination (EnDC) from coughing/sneezing/speech is fundamental to reducing transmission. When used as double-layers, textiles were as effective as medical mask/surgical-cloth materials, reducing droplet dispersion to <10cm, and the area of circumferential contamination to ~0.3%. The synchronized implementation of EDBs as a community droplet reduction solution (i.e., face covers/scarfs/masks & surface covers) could reduce EnDC and the risk of transmitting or acquiring infectious respiratory pathogens, including COVID-19. defibrinated sheep blood, placed on a need droplets to facilitate their expulsion, transmission and EnDC 12 , we first validated a rapid 116 spray-simulation model of droplets (mimicking a sneeze) using a bacterial-suspension to quantify 117 the extent by which widely-available household textiles reduced the ejection/long-distance flight of 118 .
cord-325205-8yug5jjx	2020	This paper employs computational multiphase fluid dynamics and heat transfer to investigate transport, dispersion, and evaporation of saliva particles arising from a human cough. For a mild human cough in air at 20 °C and 50% relative humidity, we found that human saliva-disease-carrier droplets may travel up to unexpected considerable distances depending on the wind speed. 4. The numerical modeling approach to capture the complex varying space and time scales, e.g., both heat and mass transfer considerations, modeling of mass and phase changes due to droplet evaporation, coalescence, breakup, and turbulent dispersion in interaction with the bulk flow field. A human cough: saliva droplet''s disease-carrier particles cannot travel more than 2 m in space at approximately zero wind speed. This study shows that, when a person coughs, the wind speed in an open space environment significantly influences the distance that airborne disease-carrier droplets travel.
cord-334166-vll4s0xq	2020	RESULTS: The use of a negative pressure mask technique resulted in a 98% reduction in the fine particulate aerosol simulation, and eliminated larger respiratory droplet spread during simulated ESS, including during external drill activation. CONCLUSIONS: As global ENT services resume routine elective operating, we demonstrate the potential use of a simple negative pressure mask technique to reduce the risk of viral exposure for the operator and theatre staff during ESS. A few studies have sought to investigate this concern in a simulated setting and have demonstrated significant droplet spread during endoscopic sinus surgery, particularly when using powered drills 15, 16 . This proof of concept study demonstrates that a negative pressure mask can effectively reduce both fine droplet nuclei aerosol and larger droplet spread during endoscopic sinus surgery using powered instruments. This study demonstrates the effectiveness of a simple negative pressure mask in reducing droplets and respiratory nuclei generated during endoscopic sinus surgery, thus reducing potential exposure for both operator and theatre staff.
cord-335874-mtfe9uq1	2008	
cord-353170-fiadxpar	2020	Common sense would dictate this instinctively reduces the dispersion of aerosol and droplets and thus the spread of contact and airborne infections. Common sense would dictate this instinctively reduces the dispersion of aerosol and droplets and thus the spread of contact and airborne infections. On impact with smooth surfaces droplets disperse to smaller sizes and can aerosolise. One suggestion is the use of facemasks to help reduce the risk of inadvertent droplet dispersion (2) .  Droplets produced by coughing or sneezing carry a higher viral particle load and can be reduced by wearing a surgical mask in turn helping reducing infection transmission  The SNAP device is an effective and safe method of providing access to the nasal cavity during nasoendoscopy whilst also providing a barrier of a surgical mask to protect against droplet dispersion  Reducing the exposure to pathogens for all healthcare works facilitates a return of
cord-356118-7yuzl5he	2010