Validated Diffusive Monitors: Meeting the Challenge of Personnel Monitoring

Kirollos, Kirollos* (K&M Environmental, Inc., Virginia Beach, VA)
Mihaylov, Gueorgui (K&M Environmental, Inc., Virginia Beach, VA)
Chapman, Kimberly (K&M Environmental, Inc., Virginia Beach, VA)

Personnel monitors are devices designed to determine the exposure of airborne toxic substances within the breathing zone or other appropriate exposed body areas of workers. There is no doubt that handheld and area monitors have great need and applications in the workplace. However, the simplicity, light weight and low cost of personnel diffusive monitors make them highly advantageous over active samplers and area monitors in determining personnel exposures to toxic gases and vapors in the workplace. Three types of personnel monitors are described. Two types are colorimetric direct-read devices for monitoring hydrides, hydrogen chloride, hydrogen fluoride, acetone and 19 other contaminants. A new coating technology is used to fabricate the sensor. The color forming ingredients are encapsulated in a thin uniform layer on an inert surface to insure stability, color uniformity and accuracy. The intensity of the color developed in the sensor is directly proportional to the exposure dose. The third type is an organic vapor monitor for sampling over 120 volatile organics. The monitor operates by sorption / desorption process followed by standard analytical methods for the determination of exposure. The monitors are validated using a protocol based on the NIOSH Protocol for the Evaluation of Passive Monitors. The monitors were tested at concentrations from 1/10 to at least 10 times their corresponding permissible exposure limits. Relative humidities ranged from 10% to 90%, temperatures ranged from 10 to 35 degrees celsius and face velocities ranged from 5 to 160 cm/sec. At ambient conditions, the monitors showed overall accuracies better than +/-25% at the 95% confidence level.

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