Sep 15 2008
Understanding exposures is critical for the protection of human health, but for years scientists and health officials have struggled in their attempts to collect accurate data regarding the exposure of children, emergency responders and military personnel to a wide range of environmental contaminants.
Charles Rodes, Ph.D., director of RTI International's Aerosol Exposure Program. Credit - Jimmy Crawford
Their efforts on the personal level have been hampered by the size, weight and bulkiness of exposure monitoring technology as well as the transient nature of the exposures.
To address this concern, researchers at RTI International have developed a palm-sized, wearable device that measures exposures to a wide range of airborne contaminants and defines how those exposures occurred.
The device, called MicroPEM™, for Micro-miniature Personal Exposure Monitoring, is the size of a cell phone and collects onto filters particle sizes that can be inhaled from the air to characterize contaminant exposure levels in various environments.
The fundamental technology was seeded by an internally-funded RTI research and development project. The resulting MicroPEM™ has a wide range of applications, and is being further enhanced as part of a $1.8 million, four-year grant funded by the National Institutes of Environmental Health Sciences to develop an even smaller sampling and sensing system that can be worn by asthmatic children to define aerosol trigger levels that might increase symptom severity.
"The large size and weight of older systems limits their usefulness in monitoring exposures in populations such as children and emergency responders," said Charles Rodes, Ph.D., director of RTI’s Aerosol Exposure Program. "In many cases, these are the difficult to monitor populations that we need to address for environmental exposures."
MicroPEM's™ small size and quiet operation is facilitated by a very power-efficient design that allows placement of the device in close proximity to individual breathing zones, providing the most accurate exposure estimates in many situations. An active flow system collects and sizes particles in exactly the same aerodynamic manner as the human respiratory system.
"If our military personnel had worn these types of devices during Operations Desert Shield/Desert Storm, we would have been able to more accurately assess the types of airborne contaminants to which they were exposed," Rodes said. "Likewise, this technology would have been valuable in determining the types of exposures experienced by emergency responders in the wake of the terrorist attacks on the World Trade Center towers in New York."
RTI has created different versions of MicroPEM™ designed for collecting samples indoors, outdoors, in automobiles, as well as in personal devices to be worn on individuals that don't interfere with normal daily activities.
"Obtrusive personal exposure monitors get in the way and are simply not worn frequently enough to allow accurate exposure data collection," Rodes said. "The MicroPEM™ is tiny enough to be placed in almost any location and worn by even small children."