Evaluating the Potential for Use of Smartphones as Noise Dosimeters

Research Trainee: Benjamin Roberts, MPH, PhD Student, Department of Environmental Health Sciences at the University of Michigan

Faculty Sponsor: Richard Neitzel, PhD, CIH, Assistant Professor of Environmental Health Sciences at the University of Michigan

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Benjamin Roberts, PhD

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Professor Neitzel

Smart devices (phones, tablets, and other devices) have become prevalent in modern society. These devices are sophisticated computers that have the ability to use both internal and external sensors to capture environmental and personal exposure information. Almost all smart devices contain a microphone that can be used with an application (“app”) to measure a person’s noise exposure. However, there is limited information on the accuracy of using these apps to measure noise in the workplace.

This study’s aim was to evaluate the accuracy of a particular smart device (the Apple iPod), equipped with a sensitive external microphone, to measure fluctuating noise and full-shift noise in the workplace. To accomplish this, four iPods were each paired with a traditional noise dosimeter and exposed to randomly generated noise in a controlled laboratory setting. The devices recorded the sound level in A-weighted decibels (dBA) every second. The measurements made by each pair were compared and the mean difference was calculated. Additionally, 15 maintenance and 14 office workers each wore an iPod and dosimeter for up to five days while working. Their daily exposure was measured, and a statistical model was used to determine the systematic difference in measurement made by the iPods compared to the dosimeter.

An example the noise dosimeter and iPhone microphone placed on a worker in experiment 2.

An example the noise dosimeter and iPhone microphone placed on a worker in experiment 2.


In the laboratory setting the iPods and dosimeters had fairly good agreement, with the majority of the one-second recorded measurements having less than a 2.0 dBA difference, the criteria used by the American National Standards Institute to classify a type 2 sound level meter. In the workplace the iPods measured noise levels that were on average 1.7 dBA higher than the dosimeters. The results from this research suggest that, in certain situations when sound measurement equipment is unavailable due to cost or technical limitations, certain smart devices could be used to make fairly accurate noise measurements. However, it is important to note that the measurement quality will still depend on the skill of the user, so measurements should be interpreted with caution.

Project Abstract