Researchers from the Civil, Architectural and Environmental Engineering Department have formulated a system for efficiently sampling a decontaminated area following a bioterrorism attack.
Dealing with the threat of bioterrorism is just one of the many issues facing emergency preparedness agencies in the post-Sept. 11 world. Researchers in Drexel University’s College of Engineering are helping to answer important questions that will shape the way responders handle bioterrorism threats in the future. Most recently, research from Drexel’s Department of Civil, Architectural and Environmental Engineering offered findings that will advise the timing of reoccupying a building where there has been a bioterrorism attack.
Dr. Charles Haas and Dr. Patrick Gurian, professors in the College of Engineering, along with doctoral students Tao Hong and Yin Huang recently co-authored a PLoS One (Public Library of Science) article entitled “Prioritizing Risks and Uncertainties from Intentional Release of Selected Category A Pathogens.” The article offers an efficient method for responders to assess risk from pathogens, such as anthrax and smallpox, following the decontamination process and assess the risk of sending people back into it.
"Bioterrorism continues to be a potential area of terrorist activity,” Gurian said. “Past bioterrorism attacks in the United States revealed that the U.S. lacked guidelines for a quick response to bioterrorism agents.”
The current approach to decontamination is to clean up the building until no pathogens can be detected. The researchers suggest, however, that whether or not pathogens are found depends greatly upon how extensively the buildings are tested. What Haas and Gurian’s team aimed for was a more efficient way to determine when it is safe for people to return to a contaminated building.
In this thrust, the group developed a mathematical formula to calculate the level of sampling and testing necessary to effectively mitigate a health risk in returning to the building. This could help speed the re-occupancy of buildings that do not present substantial residual risks, while allowing resources to be focused on those areas where significant residual risk is present.
“To ensure that sampling efforts are sufficient to achieve targeted levels of human health protection requires a way to link residual contamination to human health risk,” Gurian said. “It is this link between environmental concentrations and human health risk that is provided by this paper.”
The formulae devised by the researchers takes into account various environmental aspects such as ventilation rate, re-aerosolization rate, frequency with which occupants touch contaminated surfaces, and concentration of pathogen, as well as the type of biological agent used in the attack. The end result is a framework of testing that offers a threshold number of negative samples necessary to statistically suggest that the building has been decontaminated.