1 Influence of cabin conditions on placement and response of contaminant detection sensors in a commercial aircraft Sagnik Mazumdar Qingyan Chen, Ph.D. Air Transportation Center of Excellence for Airliner Cabin Environment Research (ACER) School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-2088 Potential causalities due to airborne disease transmission and risk of chem-bio terrorism in commercial airliner cabins can be reduced by fast responses. Fast responses are only possible by using sensors at appropriate locations in the cabins. Cost, size and weight factors restrict the number of sensors that could be installed inside a cabin. Since release locations and seating patterns of passengers can impact airborne contaminant transports, this study first addressed this impact by using a validated Computational Fluid Dynamics (CFD) program in a four-row mockup of twin-aisle airliner cabin. It was observed that occupancy patterns and release locations have little influence on longitudinal contaminant transports though localized variations of contaminant concentrations may exist. The results show that response time of the sensors is considerably reduced with the increase in number of sensors. If only a single sensor is available across a cabin cross-section then it should be placed at the middle of the ceiling. A cabin model of a fully occupied twin-aisle airliner with 210 seats was also build to study the diverse contaminant distribution trends along cabin length. The results reveal that seating arrangements can make cross sectional airflow pattern considerably asymmetrical. Similar airflow patterns make the longitudinal contaminant transport in the business and economy classes alike. The presence of galleys greatly affected the longitudinal transport of contaminants in a particular cabin section. The effects due to galleys were less significant if a multipoint sampling system was used. The multipoint sampling system can also reduce the number of sensors required in a cabin. INTRODUCTION Nearly two billion people travel on commercial airliners each year 1 . The increasing mobility of people has also augmented the potential risk of airborne disease transmission. In March 15, 2003 Air China Flight 112 from Hong Kong to Beijing five people died from SARS after most likely contracting the disease from an infected passenger on the same flight 2,3 . Hence with growing mobility the chances for disease to be transmitted between passengers during the flights have become an important public health issue 4 . Heightened fears of chemical and biological attacks by terrorists have made matters worse. Based on the analysis on Air China passengers the mean incubation period of SARS was found to be 4 days. The incubation periods of some biological agents like Cholera can be as low as 4 hours and can spread rapidly with high lethality without treatment 5 and hence can create a major pandemic. Moreover some chemical agents can kill passengers immediately. Sagnik Mazumdar is a Ph.D. candidate, Qingyan (Yan) Chen is a professor in the School of Mechanical Engineering, Purdue University, West Lafayette, IN. Mazumdar, S. and Chen, Q. 2008. “Influence of cabin conditions on placement and response of contaminant detection sensors in a commercial aircraft,” Journal of Environmental Monitoring, 10, 71-81.