Epidemiology and Infection

Other viruses

The risk of airborne influenza transmission in passenger cars

L. D. KNIBBSa1 c1, L. MORAWSKAa1 and S. C. BELLa2a3

a1 International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia

a2 Thoracic Medicine, The Prince Charles Hospital, Brisbane, Australia

a3 School of Medicine, The University of Queensland, Brisbane, Australia

SUMMARY

Travel in passenger cars is a ubiquitous aspect of the daily activities of many people. During the 2009 influenza A(H1N1) pandemic a case of probable transmission during car travel was reported in Australia, to which spread via the airborne route may have contributed. However, there are no data to indicate the likely risks of such events, and how they may vary and be mitigated. To address this knowledge gap, we estimated the risk of airborne influenza transmission in two cars (1989 model and 2005 model) by employing ventilation measurements and a variation of the Wells–Riley model. Results suggested that infection risk can be reduced by not recirculating air; however, estimated risk ranged from 59% to 99·9% for a 90-min trip when air was recirculated in the newer vehicle. These results have implications for interrupting in-car transmission of other illnesses spread by the airborne route.

(Accepted April 16 2011)

(Online publication May 09 2011)

Correspondence:

c1 Author for correspondence: Dr L. D. Knibbs, International Laboratory for Air Quality and Health, Queensland University of Technology, 2 George St, Brisbane, 4001, Australia. (Email: luke.knibbs@qut.edu.au)

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