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concentration is reached and the less important these factors are in limiting pathogen dispersion distances and exposures. The larger the number of persons to whom pathogens are dispersed, the lower the average exposure, but the greater the chance of affecting more susceptible persons. The development of these criteria for specific pathogens will require dedicated multi-year committee work by individuals from the ASHRAE disciplines and from infectious disease disciplines. It will need to involve collaboration with health agencies as well. Thanks to the leadership of Richard Fox of Honeywell, representatives of TC9.3, TC9.6, TC2.4, the Environmental Health Committee and health scientists and professionals outside of ASHRAE, the scope of ASHRAE’s pathogen research has been defined for the next five years and research is beginning. While ASHRAE is working on new standards, industry spokespersons could recommend some simple-to-implement precautionary measures that passengers might take. Preflight measures could include getting vaccinations as appropriate; being rested before traveling; and taking disinfectant wipes, hand sanitizers and face breathing masks on board. In-flight measures could include ill passengers wearing masks to protect others (airlines might even offer these to coughers); coughing into sleeves for those not wearing masks; refraining from touching one’s face (wearing a mask helps here); periodically sanitizing your hands and surrounding hard surfaces such as the tray table and armrests; refraining from facing nearby passengers when talking; using a face mask to raise the humidity in your breathing zone if nasal passages are dry; wearing a mask if in an aisle seat or near a washroom; and turning on and pointing overhead air vents to make the air jet flow between you and nearby passengers (do not point it at your face and entrain your neighbor’s breath into your breathing zone). This latter measure will help prevent exchange of airborne pathogens with neighboring persons, and will draw airborne pathogens to the floor returns where they can be exhausted or filtered out. Such measures can be simply and easily described by flight attendants as part of the safety instructions given at the beginning of the flight.
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Douglas S. Walkinshaw, Ph.D., P .Eng., owns three companies involved in indoor air quality investigations and ventilation technologies and lives in Bonita Springs, Fla., Ottawa and PEI, Canada.
ASHRAE Journal 73

ASHRAE Journal - April 2010

Table of Contents for the Digital Edition of ASHRAE Journal - April 2010