Real-Time Personal Monitors.
NIOSH research on real time personal monitors was reviewed. Real time monitoring devices were described. A real time monitoring device was described as a miniature colorimeter that continuously monitors the color change in a sensor resulting from exposure to an analyte and converts it into an electrical signal. The signal was fed into a data storage device. Real time monitoring research completed to date was discussed. Four prototype devices have been constructed for testing using ammonia (7664417) and mercury (7439976) vapor in clean air as analytes. The results for ammonia at concentrations of approximately 17 and 35 parts per million (ppm) and flow rates of 0.16 to 0.70 milliliters per minute were discussed. When tested for 4 hours, sensors exposed to ammonia at higher flow rates reached saturation first. The magnitude of the response at saturation appeared to be related to the chemical and electrical properties of the sensor. Up to saturation, each sensor had a linear range of operation which was proportional to the product of flow rate times concentration. Plots of sensor response versus ammonia concentration indicated that the responses were acceptable, even though the plots were not absolutely linear. Preliminary testing for interfering compounds indicated that strongly acidic and alkaline solutions have no detectable effect on the color indicating layer, although amines appear to cause positive interferences. The authors conclude that the real time monitors under development can apparently monitor ammonia for 4 hours at concentrations near the NIOSH recommended standard, 35ppm, with a reasonable degree of specificity. Quantitative testing of mercury vapor will begin soon.
NIOSH-Author; Occupational-exposure; Laboratory-testing; Equipment-design; Equipment-reliability; Industrial-hygiene; Measurement-equipment; Nitrogen-compounds; Air-samples; Colorimetry; Analytical-instruments;
The Changing Nature of Work and Workforce, Proceedings of the Third Joint US-Finnish Science Symposium, Frankfort, Kentucky, October 22-24, 1986, NIOSH, Cincinnati, Ohio