During the early months of the COVID-19, exposure to environmental noise dropped by nearly half, according to researchers at the University of Michigan. The team analyzed data from the Apple Hearing Study, a partnership with Apple designed to track noise exposure and its impact on hearing health.
The noise exposure data was collected by volunteer Apple Watch users in Florida, New York, California, and Texas. The data included more than a half million daily noise levels measured before and during the pandemic.
When local governments announced stay-at-home orders in March and April, the daily average sound levels dropped by approximately three decibels compared to January and February.
“That is a huge reduction in terms of exposure and it could have a great effect on people’s overall health outcomes over time,” said study co-author Professor Rick Neitzel. “The analysis demonstrates the utility of everyday use of digital devices in evaluating daily behaviors and exposures.”
The four states represented in the study issued different guidelines in response to the pandemic, which showed through the data.
“California and New York both had really drastic reductions in sound that happened very quickly, whereas Florida and Texas had somewhat less of a reduction,” said Professor Neitzel.
At first, the largest drop in noise exposure occurred on the weekends. Nearly 100 percent of the participants reduced their time spent above the 75 dBA threshold between Friday and Sunday. This is a sound level that is roughly as loud as an alarm clock.
“But after the lockdowns, when people stopped physically going to work, the pattern became more opaque,” said Professor Neitzel. “People’s daily routines were disrupted and we no longer saw a large distinction in exposures between the traditional five working days versus the weekend.”
The findings will help researchers gain a better understanding of what personal noise exposures are like for Americans of various ages and locations, or for those who have or do not have hearing loss.
“These are questions we’ve had for years and now we’re starting to have data that will allow us to answer them,” said Professor Neitzel. “We’re thankful to the participants who contributed unprecedented amounts of data. This is data that never existed or was even possible before.”
The study is published in the journal Environmental Research Letters.