The experiments revealed that in open air, simulants decayed 10 to 1,000 times faster than in laboratory settings. These data indicate that laboratory tests underestimate the rate of agent decay that occurs outdoors, and on their own, laboratory tests are not sufficient in understanding the decay process outdoors.
To learn how biological threat agents decay upon interacting with variables in the open air, the Defense Threat Reduction Agency’s Chemical and Biological Technologies Department (DTRA CB) developed a new, state-of-the-art test apparatus, the Captive Aerosol Growth and Evolution System (CAGES).
“Due to various challenges posed by outdoor testing, it was generally assumed by scientists that biological threat agents aged and decayed at similar rates indoors as they did outdoors. Our goal was to test this theory,” said Richard Mathieson, Science & Technology Manager, DTRA CB.
“We have a great deal of data about bio threat degradation testing from laboratory settings. What we don’t have is results of testing in the natural environment,” said Mathieson. “ For obvious reasons, it is difficult to test live biological threat agents outdoors.”
The research was performed at the Sandia National Laboratory, National Strategic Research Institute, and the Army Research Laboratory. Researchers evaluated the combination of open-air factors that most affect the rate of agent decay. They also compared data collected in laboratory studies to data collected in outdoor experiments.
The experiment took place in two locations: Albuquerque, New Mexico, and Houston, Texas. Differing air quality in the two test cities offered differing pollutant levels that can interact with aerosolized biological agents. In both cities, researchers quantified how components of the atmosphere would affect an agent’s makeup and response.
Outdoors tests performed within the rotating drum chambers of CAGES contained simulants representing biological threat agents and would expose them to different atmospheric conditions and compositions. Afterwards, aerosol samples were taken from the chambers to study their physical and chemical properties. Meanwhile, laboratory tests were used to conduct indoor aerosol testing that mimicked real-world, aging conditions in the indoors to compare against the outdoor decay data.
Data gathered through these experiments may transform the way DTRA CB examines the aging and decay of biological threat agents in the future. Improved, fundamental knowledge of agent decay provides more accurate data to the modeling community, and ultimately, to the warfighter who needs to operate in a contaminated environment.
Article adapted from story by DTRA Public Affairs
