Apple Watch Data Shows the World Got Half As Noisy During Lockdown

Exposure to environmental noise for thousands of U.S. residents plunged by almost 50 percent in the early months of the COVID-19 pandemic, research suggests.

Data from a project analyzing the impact on hearing health by sound exposure suggests social distancing measures in California, Florida, New York and Texas were linked to a reduction in personal environmental noises of roughly three decibels (dBA).

"This represents a substantial and health-relevant reduction in exposure," researchers' noted in a paper published this month in Environmental Research Letters.

"While the impact of a 3 dBA reduction in sound exposure on sound-related health impacts such as ischemic heart disease, hypertension and cognitive performance has not been sufficiently characterized, a 3 dBA reduction in average sound levels over 70 dBA is associated with a lower risk of noise-induced hearing loss," it added.

"The COVID-19-related reduction in sound exposures among study participants likely represents a meaningful reduction in overall risk of sound-related health effects."

The data was compiled and released by researchers at University of Michigan's School of Public Health as part of the Apple Hearing Study. As part of the partnership, the tech giant grant grants the team access to noise metrics from volunteer Apple Watch users.

Researchers—who obtained more than 500,000 daily noise readings from 6,000 participants before and during the pandemic—said it was one of the largest such studies to date.

It found that daily average sound levels dropped by approximately 3 decibels during the time that local governments started to enforce stay-at-home orders and urged residents to socially distance in March and April, when compared to January and February.

Average noise exposure levels "dropped dramatically" after lockdowns started in early March in New York, California and later on in Texas and Florida, the team said.

After lockdown

Rick Neitzel, associate professor of environmental health sciences at UM's School of Public Health, author on the joint study released last week, said the exposure reduction could have a "great effect on people's overall health outcomes over time."

"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.

"After lockdowns, when people stopped physically going to work, the pattern became more opaque. Daily routines were disrupted and we no longer saw a large distinction in exposures between the traditional five working days versus the weekend."

Data suggested the largest drop in environmental exposure was recorded over weekends. Close to all of the participants' time spent above the 75 dBA threshold—roughly the equivalent of an alarm clock ringing—reduced between Friday and Sunday,

Researchers said the data will be shared with the World Health Organization (WHO) as a contribution toward its Make Listening Safe initiative. Ultimately, they said, the research will help to better understand how everyday exposure to sounds can impact on hearing.

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File photo: Customers try Apple Watch devices in the Apple Marunouchi store in Tokyo, Japan. Exposure to environmental noise for thousands of U.S. residents plunged by almost 50 percent in the early months of the COVID-19 pandemic, data suggests. Tomohiro Ohsumi/Getty