The airborne transmission of infection between flats in high-rise residential buildings: Particle simulation

摘要

Severalcaseclustersoccurredinhigh-riseresidentialbuildingsinHongKonginthe2003SARS(the severe acuterespiratorysyndrome)epidemic,whichmotivatedaseriesofengineeringinvestigations into thepossibleairbornetransportroutes.Itissuspectedthat,drivenbybuoyancyforce,thepolluted air thatexitsthewindowofthelowerfloormayre-entertheimmediateupperfloorthroughthe window onthesameside.Thiscascadeeffecthasbeenquantifiedandreportedinapreviouspaper,and it isfoundthat,bytracergasconcentrationanalysis,theroomintheadjacentupstairsmaycontainupto 7% oftheairdirectlyfromthedownstairsroom.Inthisstudy,aftervalidationagainsttheexperimental data fromliteratures,EulerianandLagrangianapproachesarebothadoptedtonumericallyinvestigate the dispersionofexpiratoryaerosolsbetweentwoverticallyadjacentflats.Itisfoundthattheparticle concentrationintheupperflooristwotothreeordersofmagnitudelowerthaninthesourcefloor. 1.0 mm particlesdisperselikegaseouspollutants.Forcoarseparticleslargerthan20.0 mm, strong depositiononsolidsurfacesandgravitationalsettlingeffectgreatlylimittheirupwardtransport