NaDos Personal Exposure Monitor

NaDos is a wearable personal exposure monitor (PEM) and near-real-time environmental chemical exposure monitor with higher sensitivity (<10 micrograms/m3) than a PID and extremely high specificity to naphthalene vapor concentrations in the breathing zone of the wearer. NaDos provides GPS position and time stamped time histories of exposure to naphthalene vapor.

The NaDos personal exposure monitor is a fully integrated, battery powered, instrument weighing about 1lb and small enough to be worn by personnel working in hazardous environments. The NaDos detector was originally developed with high detection specificity for naphthalene vapor because of the wide range of health hazards association with naphthalene inhalation, but it is capable of measuring a wide range of HOVs including benzene, toluene, xylene, naphthalene, anthracene, etc. with a real time limit of detection less than 10 micrograms/m3. The performance of the instrument has been demonstrated across a range of naphthalene concentrations from 10 micrograms/m3 to over 100 mg/m3.  Accuracy and performance was found to meet or exceed the National Institute for Occupational Safety and Health recommended acceptance criteria of ± 25% of the true concentration, >95% of time.  To deliver this accuracy in a real world environment, the monitor accurately removes the effects of both humidity (0–95% RH) and temperature (0°C to >45°C).

NaDos accurately quantifies the amount of naphthalene in jet fuel vapors, while showing zero concentration for the synthetic jet fuel Syntroleum which is devoid of naphthalene. The monitor also accurately predicts naphthalene concentration in the presence of benzene, toluene, ethyl-benzene, and xylene confusants and vice versa.

Sponsored ongoing field studies have been focused upon naphthalene exposure in U.S. Military jet fuel handlers. Furthermore, a wide range of applications have been identified as needing a wearable monitor for naphthalene exposure including: in home tobacco smoke and vapor intrusion; first responders for wildfires; urban structure fires; military burn-pits; oil/fuel spills; workers in and around petroleum, coal-tar-pitch/asphalt sealers, etc. Yet, a major promising feature of the device is its real time nature giving highly specific, high sensitivity, real time data which is a superior predictor of human health outcomes. Hopefully this type of analysis will someday revolutionize dosimetry by providing a minute by minute, GPS stamped concentrations of analytes for the creation of 4D personnel exposure monitoring.

Personal Exposure Monitoring

Why are personal exposure monitors needed to detect, differentiate, quantify, and log naphthalene and other volatile organic compounds (VOCs) with high sensitivity and chemical specificity?  There is a rapidly increasing awareness of the health risks of inhaling jet fuel vapors by DOD personnel engaged in or around jet fueling operations.


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