Authors: 1David Deglau and 1Shirley Klimkiewicz

1Johns Hopkins University Applied Physics Lab, Laurel MD


The utilization of odor detection canines (ODCs) in the detection of person-borne (PB) threats is a continuously evolving field. The influence of many variables such as traffic flow, time of day, and temperature, among others, on a canine’s performance during a PB scan are not yet fully understood. One such variable that has received increased interest from Law Enforcement Agencies (LEAs) recently is the influence of airflow on detection efficiency. Whether a PB scan is being conducted indoors or outdoors, it is reasonable to expect that the speed and direction of airflow relative to pedestrian traffic might impact odor drift from its source. While smoke pens are regularly used to establish the general direction of airflow in an operational scenario, this tool has several shortcomings, including the inability to simulate odor drift from a specific hide configuration (e.g., inside backpack, strapped to ankle, etc.) and challenges in visualizing dynamic airflow (i.e., airflow from a stationary backpack versus being carried). Given the limited understanding of the impact of airflow on detection in PB scenarios, currently used search patterns have not been optimized and may lead to reduced detection efficiency. Under the direction of the Department of Homeland Security Science and Technology Directorate, our team has developed an Airflow Visualization Kit with the objective of aiding canine trainers and handlers in understanding the impact of airflow on ODC detection. Central to the kit is a hand-held fogging device equipped with a remote control that enables visualization of dynamic airflow. The kit is augmented by accessories and tubing attachments that allow the user to simulate odor drift from commonly encountered hide configurations in PB scenarios. Besides informing airflow from hide configurations, use of the handheld fogger enables more thorough characterization of the baseline airflow conditions in an operational environment. Compared to a smoke pen, the amount of fog that can be continuously released from the fogging device allows the user to observe the airflow for a longer distance. Furthermore, this device enables the user to understand the influence of pedestrian traffic flow on airflow and consequentially odor drift. Our airflow visualization studies with simulated operational environments have shown that localized airflow created by pedestrian traffic can overcome the baseline airflow of the environment in certain scenarios, demonstrating the need for enabling technology beyond the smoke pen. Furthermore, we have observed that pedestrian traffic can have different effects on airflow emanating from a simulated odor source depending on the location (e.g., differences in height, depth, or concealment). Our use of the Airflow Visualization Kit in simulated PB scenarios has revealed several facets of airflow that are not currently considered to be widely understood by operational teams, warranting additional study. Two kits are currently deployed with LEAs, and feedback from end-users has stated that the kit is beneficial in helping trainers and handlers visualize and understand airflow. As we continue testing and revisions to the accompanying user guide, it would be beneficial to present our research to the community so that we may incorporate additional feedback and recommendations from potential end users.