Increasing evidence supports the significant role of short-range airborne transmission of viruses when in close contact with a source patient. A full-scale ventilated room (Cleanliness: ISO 14644–1 Class 5) and two face-to-face standing breathing thermal manikins were used to simulate a source individual and a susceptible person. Monodisperse particle generation and measurement techniques were used to evaluate the effect of virus-laden droplet nuclei size on short-range airborne transmission risk. We analysed four particle sizes (1.0, 1.5, 2.5, and 5.0 µm) to simulate the transport of exhaled droplet nuclei within an interpersonal distance of 0.5 m. The results indicated that the size distribution of airborne droplet nuclei could significantly influence transmission, with the inhalation fraction decreasing with increasing droplet nuclei size. Additionally, results showed that proximity to the source manikin could influence transmission. Inhalation fraction decreased with increasing interpersonal distance, fitting well with the 1/d rule of droplet nuclei concentration decay. Our findings improve the understanding of the mechanism of the disease transmission.
TangJWBahnflethWPBluyssenPMBuonannoGJimenezJLKurnitskiJLiYMillerSSekharCMorawskaLMarrLCMelikovAKNazaroffWWNielsenPVTellierRWargockiPDancerSJ.Dismantling myths on the airborne transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). J Hospital Infect2021; 110: 89–96.
2.
ShiuEYLeungNHCowlingBJ.Controversy around airborne versus droplet transmission of respiratory viruses: implication for infection prevention. Curr Opin Infect Dis2019; 32: 372–379.
3.
GreenhalghTJimenezJLPratherKATufekciZFismanDSchooleyR.Ten scientific reasons in support of airborne transmission of SARS-CoV-2. Lancet2021; 397: 1603–1605.
4.
MorawskaLCaoJ.Airborne transmission of SARS-CoV-2: the world should face the reality. Environ Int2020; 139: 105730.
5.
AllenJGIbrahimAM.Indoor air changes and potential implications for SARS-CoV-2 transmission. JAMA2021; 325: 2112–2113.
6.
XuCLuoXYuCCaoS-J.The 2019-nCoV epidemic control strategies and future challenges of building healthy smart cities. Indoor Built Environ2020; 29: 639–644.
Organization WH.Transmission of SARS-CoV-2: implications for infection prevention precautions: scientific brief, 09 July 2020. Geneva: World Health Organization, 2020.
9.
QianHMiaoTLiuLZhengXLuoDLiY.Indoor transmission of SARS-CoV-2. Indoor Air2021; 31: 639–645.
10.
SunKWangWGaoLWangYLuoKRenLZhanZChenXZhaoSHuangY.Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2. Science2021; 371: eabe2424.
11.
AllenJGMarrLC.Recognizing and controlling airborne transmission of SARS-CoV-2 in indoor environments. Indoor Air2020; 30: 557–558.
12.
ZhangNTangJWLiY.Human behavior during close contact in a graduate student office. Indoor Air2019; 29: 577–590.
13.
PratherKAMarrLCSchooleyRTMcDiarmidMAWilsonME, andMiltonDK.Airborne transmission of SARS-CoV-2. Science2020; 370: 303–304.
14.
LiYG.Basic routes of transmission of respiratory pathogens – a new proposal for transmission categorization based on respiratory spray, inhalation, and touch. Indoor Air2021; 31: 3–6.
15.
ChenWZhangNWeiJYenH-LLiY.Short-range airborne route dominates exposure of respiratory infection during close contact. Build Environ2020; 176: 106859.
16.
MorawskaLMiltonDK.It is time to address airborne transmission of coronavirus disease 2019 (COVID-19). Clin Infect Dis2020; 71: 2311–2313.
17.
LiuLLiYNielsenPVWeiJJensenRL.Short-range airborne transmission of expiratory droplets between two people. Indoor Air2017; 27: 452–462.
18.
MorawskaLBuonannoG.The physics of particle formation and deposition during breathing. Nat Rev Phys2021; 3: 300–301.
19.
KlompasMBakerMARheeC.Airborne transmission of SARS-CoV-2: theoretical considerations and available evidence. JAMA2020; 324: 441–442.
20.
SametJMPratherKBenjaminGLakdawalaSLoweJ-MReingoldAVolckensJMarrLC.Airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): what we know. Clin Infect Dis2021; ciab039,https://doi.org/10.1093/cid/ciab039 (accessed 28 February 2021)
21.
DrossinosYStilianakisNI.What aerosol physics tells us about airborne pathogen transmission. Aerosol Sci Technol2020; 54: 639–643.
22.
DingJYuCWCaoS-J.HVAC systems for environmental control to minimize the COVID-19 infection. Indoor Built Environ2020; 29: 1195–1201.
23.
FennellyKP.Particle sizes of infectious aerosols: implications for infection control. Lancet Respir Med2020; 8: 914–924.
24.
YanJGranthamMPantelicJde MesquitaPJBAlbertBLiuFEhrmanSMiltonDKConsortiumE.Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community. Proc Natl Acad Sci U S A2018; 115: 1081–1086.
25.
BakeBLarssonPLjungkvistGLjungströmEOlinA.Exhaled particles and small airways. Respir Res2019; 20: 14.
26.
LiuYNingZChenYGuoMLiuYGaliNKSunLDuanYCaiJWesterdahlD.Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals. Nature2020; 582: 557–560.
27.
ChiaPYColemanKKTanYKOngSWXGumMLauSKLimXFLimASSutjiptoSLeePH.Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients. Nat Commun2020; 11: 1–7.
28.
Van DoremalenNBushmakerTMorrisDHHolbrookMGGambleAWilliamsonBNTaminAHarcourtJLThornburgNJGerberSI.Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. N Engl J Med2020; 382: 1564–1567.
29.
AlsvedMMatamisABohlinRRichterMBengtssonP-EFraenkelC-JMedstrandPLöndahlJ.Exhaled respiratory particles during singing and talking. Aerosol Sci Technol2020; 54: 1245–1248.
30.
LeeBU.Minimum sizes of respiratory particles carrying sars-cov-2 and the possibility of aerosol generation. Int J Environ Res Public Health2020; 17: 6960.
31.
DuguidJ.The numbers and the sites of origin of the droplets expelled during expiratory activities. Edinb Med J1945; 52: 385.
32.
LoudonRGRobertsRM.Droplet expulsion from the respiratory tract. Am Rev Respir Dis1967; 95: 435–442.
33.
PapineniRSRosenthalFS.The size distribution of droplets in the exhaled breath of healthy human subjects. J Aerosol Med1997; 10: 105–116.
34.
ChaoCYHWanMPMorawskaLJohnsonGRRistovskiZHargreavesMMengersenKCorbettSLiYXieX.Characterization of expiration air jets and droplet size distributions immediately at the mouth opening. J Aerosol Sci2009; 40: 122–133.
35.
MorawskaLJohnsonGRistovskiZHargreavesMMengersenKCorbettSChaoCYHLiYKatoshevskiD.Size distribution and sites of origin of droplets expelled from the human respiratory tract during expiratory activities. J Aerosol Sci2009; 40: 256–269.
36.
AsadiSWexlerASCappaCDBarredaSBouvierNMRistenpartWD.Aerosol emission and superemission during human speech increase with voice loudness. Sci Rep2019; 9: 1–10.
37.
AsadiSBouvierNWexlerASRistenpartWD.The coronavirus pandemic and aerosols: does COVID-19 transmit via expiratory particles?Aerosol Sci Technol2020; 54: 635–638.
38.
HartmannALangeJRotheudtHKriegelM.Emission rate and particle size of bioaerosols during breathing, speaking and coughing. DepositOnce2020; 226493262. DOI: 10.14279/depositonce-10331 (accessed 8 October 2020)
39.
LiLNiuMZhuY.Assessing the effectiveness of using various face coverings to mitigate the transport of airborne particles produced by coughing indoors. Aerosol Sci Technol2021; 55: 332–339.
40.
MürbeDKriegelMLangeJSchumannLHartmannAFleischerM.Aerosol emission of adolescents voices during speaking, singing and shouting. PLoS One2021; 16: e0246819.
41.
HamiltonFGregsonFArnoldDSheikhSWardKBrownJMoranEWhiteCMorleyABzdekBReidJMaskellNDoddJW.Aerosol emission from the respiratory tract: an analysis of relative risks from oxygen delivery systems. medRxiv Preprint 2021. DOI: 10.1101/2021.01.29.21250552 (accessed 20 Aril 2021).
42.
GregsonFKAWatsonNAOrtonCMHaddrellAEMcCarthyLPFinnieTJRGentNDonaldsonGCShahPLCalderJDBzdekBRCostelloDReidJP.Comparing aerosol concentrations and particle size distributions generated by singing, speaking and breathing. Aerosol Sci Technol2021; 55: 681–691.
43.
SayampanathanAAHengCSPinPHPangJLeongTYLeeVJ.Infectivity of asymptomatic versus symptomatic COVID-19. Lancet2021; 397: 93–94.
44.
LindsleyWGBlachereFMBeezholdDHThewlisRENoorbakhshBOthumpangatSGoldsmithWTMcMillenCMAndrewMEBurrellCN.Viable influenza A virus in airborne particles expelled during coughs versus exhalations. Influenza Other Respir Viruses2016; 10: 404–413.
45.
BerlangaFde AdanaMROlmedoIVillafruelaJSan JoséJCastroF.Experimental evaluation of thermal comfort, ventilation performance indices and exposure to airborne contaminant in an airborne infection isolation room equipped with a displacement air distribution system. Energ Build2018; 158: 209–221.
46.
OlmedoIBerlangaFVillafruelaJDe AdanaMR.Experimental variation of the personal exposure in a hospital room influenced by wall heat gains. Build Environ2019; 154: 252–262.
47.
YangJSekharSCheongKRaphaelB.Performance evaluation of a novel personalized ventilation–personalized exhaust system for airborne infection control. Indoor Air2015; 25: 176–187.
48.
HeQNiuJGaoNZhuTWuJ.CFD study of exhaled droplet transmission between occupants under different ventilation strategies in a typical office room. Build Environ2011; 46: 397–408.
49.
LiXNiuJGaoN.Co-occupant's exposure to exhaled pollutants with two types of personalized ventilation strategies under mixing and displacement ventilation systems. Indoor Air2013; 23: 162–171.
50.
XuCLiuL.Personalized ventilation: One possible solution for airborne infection control in highly occupied space?Indoor Built Environ2018; 27: 873–876.
51.
AiZHashimotoKMelikovAK.Airborne transmission between room occupants during short-term events: measurement and evaluation. Indoor Air2019; 29: 563–576.
52.
NielsenPVBuusMWintherFVThilageswaranM.Contaminant flow in the microenvironment between people under different ventilation conditions. ASHRAE Trans2008; 114: 632–638.
53.
OlmedoINielsenPVRuiz de AdanaMJensenRL.The risk of airborne cross-infection in a room with vertical low-velocity ventilation. Indoor Air2013; 23: 62–73.
54.
OlmedoINielsenPVRuiz de AdanaMJensenRLGrzeleckiP.Distribution of exhaled contaminants and personal exposure in a room using three different air distribution strategies. Indoor Air2012; 22: 64–76.
55.
BjørnENielsenPV.Dispersal of exhaled air and personal exposure in displacement ventilated rooms. Indoor Air2002; 12: 147–164.
56.
LiXNiuJGaoN.Spatial distribution of human respiratory droplet residuals and exposure risk for the co-occupant under different ventilation methods. HVAC&R Res2011; 17: 432–445.
57.
LiuSNovoselacA.Transport of airborne particles from an unobstructed cough jet. Aerosol Sci Tech2014; 48: 1183–1194.
58.
PascalPOesterléB.On the dispersion of discrete particles moving in a turbulent shear flow. Int J Multiphase Flow2000; 26: 293–325.
59.
XuJCWangCTFuSCChanKCChaoCYH.Short-range bioaerosol deposition and inhalation of cough droplets and performance of personalized ventilation. Aerosol Sci Tech2021; 55: 474–485.
60.
UekiHFurusawaYIwatsuki-HorimotoKImaiMKabataHNishimuraHKawaokaYImperialeMJ.Effectiveness of face masks in preventing airborne transmission of SARS-CoV-2. mSphere2020; 5: 00620 e00637.
