Development and application of a long dynamic range nitrous oxide monitoring system

The laboratory and field evaluation of a nitrous oxide monitor for an extremely wide range of cumulative exposures are reviewed. The passive sampling behavior and high analyte capacity show it to be useful for short-term and full workweek exposure monitoring. The monitor has application for both area and personnel surveillance. The principal criterion is for an accurate report of exposure time of the monitor. Application of the monitor to real workplace environments--with and without a reference method--demonstrated the ability of workweek monitoring as a valuable and potentially superior way of documenting exposure stress of employees. Environmental factors such as humidity and temperature variation are shown to have acceptably small effects on both short- and long-term exposure data; barometric pressure affects the data in a predictable manner. Paired dosimeters show good agreement in the workplace environment throughout the range of 6-40 cumulative hours of exposure. In both hospital and dental operating suites, work logistics and work group relationships were readily traceable on a week-by-week basis during a continuous weekly monitoring program. Source emissions and appropriate worker and work area exposure relationships were clearly evident, with appropriate reduction of all exposures as a result of an abbreviated work schedule. The ability to effectively track employee and area exposure excursions in an integrated weekly manner leads to a whole series of new applications and concepts of industrial hygiene surveillance. Such approaches could effectively replace the speculative statistical approaches currently in use with actual data on a cost effective basis.