A Technique for Individual Noise Exposure Assessment

Abstract

Instrumentation and methodologies were developed in a feasibility study to measure noise exposure, at the ear, of a person as he went about his usual daily activities. Two physiological parameters, heart rate, and peripheral vasoconstriction at the earlobe, were also monitored during the same measurement period. The instrumentation consisted of a small, portable package consisting of (1) a subminiature electret microphone worn on the ear, (2) standard EKG chest leads for measuring heart rate, (3) a photoplethysmo-graph sensor mounted on the earlobe for measuring peripheral vasoconstriction, (4) circuitry to convert the microphone signal into a dc voltage proportional to the A -weighted noise level, and (5) a subminiature four-channel cassette tape recorder. Each of the five persons who participated in the experiment were instrumented early in the morning, wore the device for the entire day, and removed it at night (leaving it in the bedroom until it was picked up the next morning). Each person also kept a log of location and activity during the day. Representative results of the pilot study are illustrated by synchronized time history records of the noise levels and physiological responses. The technique could be adapted to allow the measurement of noise exposure and physiological response under a wide variety of circumstances in the field. [The study was supported by the Department of Transportation and the Environmental Protection Agency.]