Human Research Study of Particulate Propagation Distance From Human Respiratory Function

Abstract

Background Airborne viral pathogens like SARS-CoV-2 can be encapsulated and transmitted through liquid droplets/aerosols formed during human respiratory events. Methods The number and extent of droplets/aerosols at distances between 1–6ft [0.305–1.829m] for cases of a participant wearing no face covering, a cotton single-layer cloth face covering, and a three-layer disposable face covering were measured for defined speech and cough events. The data includes planar particle imagery to illuminate emissions by a light-sheet, and local aerosol/droplet probes taken with Phase Doppler Interferometry and an Aerodynamic Particle Sizer. Results Without face coverings, droplets/aerosols were detected up to a maximum of 1.25m [4.1ft±(0.22ft–0.28ft)] during speech, and up to 1.37m [4.5ft±(0.19ft–0.33ft)] while coughing. The cloth face covering reduced maximum axial distances to 0.61m [2.0ft±(0.11ft–0.15ft)] for speech, and to 0.67m [2.2ft±(0.02ft–0.20ft)] while coughing, respectively. Using the disposable face covering, safe distance was reduced further to 0.15m [0.50ft±(0.01ft–0.03ft)], measured for both emission scenarios. In addition, the use of face coverings was highly effective in reducing the count of expelled aerosols. Conclusions The experimental study indicates that 3ft [0.914m] physical distancing with face coverings is equally as effective at reducing aerosol/droplet exposure as 6ft [1.829m] with no face covering.

A Novel Framework for Modeling Person-to-Person Transmission of Respiratory Diseases

“…Respiratory particles produced by infected individuals may carry airborne pathogens, and the surface deposition and inhalation of these particles are the primary mechanisms by which many contagious diseases, including SARS-CoV-2, are transmitted [ 28 ]. There are three primary routes of exposure, in general, for respiratory particles from an infectious individual to a susceptible individual: (1) respiratory particle emission and fomite deposition on surfaces [ 29 ]; (2) respiratory particle emission and direct deposition to mucous membranes or inhalation in close contact situations [ 30 , 31 ]; and (3) respiratory particle emission and inhalation of the suspended airborne particles [ 32 ]; this paper and model framework focuses solely on the third route of exposure.…”

Entwicklung konkreter Handlungsoptionen für die sichere Öffnung und den Betrieb von Freizeitdestinationen unter Pandemiebedingungen

“…Zu Beginn der Jahres 2021 musste teilweise immer noch auf Erfahrungen aus der Influenza-Pandemie von 1918 zurückgegriffen werden [ 25 , 36 ]. Es zeigt sich zunehmend im Rahmen der SARS-CoV-2-Pandemie, dass die Anwendung der AHA+L + A-Formel [ 8 , 14 , 31 ], insbesondere das Tragen von Masken sowie Abstand [ 3 , 33 , 40 ] und die Etablierung umfassender SARS-CoV-2-Impfprogramme [ 9 ] wirksame Interventionen darstellen. Die breite Anwendung von SARS-CoV-2-RATs bei asymptomatischen Bevölkerungsteilen wird teilweise kontrovers diskutiert [ 26 ].…”

“…Elementarer Bestandteil einer erfolgreichen Überwindung der SARS-CoV-2-Pandemie ist eine hohe Maßnahmen-Compliance innerhalb der Bevölkerung [ 4 ]. Insbesondere das Tragen von Masken sowie Abstand spielen dabei eine kritische Rolle [ 24 , 33 ]. Unsere Ergebnisse zeigen, dass ein konsequentes Besuchermonitoring ein entscheidendes Instrument zur Überprüfung der Akzeptanz der Maßnahmen auf Seiten des Publikums ist.…”

The effect of relative air humidity on the evaporation timescales of a human sneeze

“… 56 Second, experimental investigations from the authors have confirmed the high sensitivity to the saliva fluid properties 57 and provided an assessment of safe social distance for human speech and coughing as a function of three types of face coverings. 58 These investigations form the foundation for the present study, which builds upon these findings and is targeted to expand the data to sneezes, while considering the sensitivity to the key ambient parameter, which is the air humidity.…”