Abstract
The American Conference of Governmental Industrial Hygienists, the American National Standards Institute, and the Occupational Safety and Health Administration limits for workers exposed to radiofrequency (RF) radiation specify a time-weighted average over any 6-minute period within the workday. Researchers at the National Institute for Occupational Safety and Health are conducting epidemiologic studies of male and female workers exposed to RF radiation at or near a frequency of 27.12 MHz. These studies require the characterization of the workers' exposure to RF radiation. Exposure data need to be collected over at least 6-minute periods and analyzed to make valid comparisons with present and past exposure standards. Field survey instruments used to measure RF radiation in the near field usually have a volt meter-type output, e.g., 1 volt is a full scale reading. These instruments can record a single maximum reading during a measurement period, but they are not capable of repeated data storage over time to give a 6-minute average exposure. To store survey data over selected time periods, two different data loggers were interfaced with the RF survey instruments. The data loggers were interfaced with MS-DOS™ microcomputers using proprietary and in-house software to allow for subsequent analysis of the stored survey data. Using this system, max/min, average, cumulative, and histogram plots were generated for selected 6-minute periods. If more sophisticated analyses are necessary, these data can be transferred to a larger statistical analysis software package. Each data logger has advantages and disadvantages for measurement of RF radiation from industrial sources. Electromagnetic interference, sampling frequencies, data representation and accessibility, and cost factors must be weighed against the intended use of the data logger.