THESIS
2014
xv, 163 pages : illustrations ; 30 cm
Abstract
Outbreaks of infectious respiratory diseases have become an important issue
worldwide and have drawn people's attention studying them with a view to providing
better means for prevention. Pathogens causing infectious respiratory diseases are
normally carried by the expiratory particles and they can be transmitted through
airborne and droplet modes. However, due to the complicated transport
characteristics, it is a challenging task to investigate the transmission of infectious
respiratory diseases. In this research, disease transmissions were studied according
to the different pathways. Exposure levels of susceptible people were estimated by
the model developed and subsequently input into the risk model to quantify the
probability of acquiring infection for a certain type of dis...[
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Outbreaks of infectious respiratory diseases have become an important issue
worldwide and have drawn people's attention studying them with a view to providing
better means for prevention. Pathogens causing infectious respiratory diseases are
normally carried by the expiratory particles and they can be transmitted through
airborne and droplet modes. However, due to the complicated transport
characteristics, it is a challenging task to investigate the transmission of infectious
respiratory diseases. In this research, disease transmissions were studied according
to the different pathways. Exposure levels of susceptible people were estimated by
the model developed and subsequently input into the risk model to quantify the
probability of acquiring infection for a certain type of disease. Experiments were
conducted to study the aerodynamic properties of pathogen-laden particles in test
chamber using particle image velocimetry techniques. A case study of a previous
disease outbreak was conducted to demonstrate the applicability of proposed
method.
Infectious respiratory disease transmission was studied according to different
pathways. For the indirect contact transmission route, the results indicated that
human behavior has a relatively higher impact on the disease transmission than that
of the ventilation rate. By comparing the infection risk using three selected diseases,
it was found that the infection risk could be reduced by 3 orders of magnitude if the
proper surface materials in indoor environments were used. Besides indirect contact transmission of disease, airborne expiratory particles could serve as carriers for virus
pathogens, as well as for bacterial pathogens. Results of respiratory disease infection
risk assessments indicated that the airborne route contributes higher infection risks
than the indirect contact route does in indoor environments. When considering
bacterial pathogens via the airborne route, the results could be substantially
different if the aerodynamic particle diameters were ignored. This research also
demonstrates the applicability of the proposed exposure model and risk model
integrated with the aerodynamic particle diameters.
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