Public officials and scientists are looking at what kinds of noise most annoy us—and what kinds can make us feel better.
Boston’s Southwest Corridor Park runs through the South End and several other neighborhoods where residents think noise levels are lower than they really are.
By Adrienne Roberts
Sept. 16, 2018 10:03 p.m. ET
Public officials and scientists are increasingly absorbed in the study of how sound affects our health. Negative effects, such as stress from the roar of traffic, are getting most of the attention. But sound experts also are looking at ways that sound can be engineered to both soothe spirits and serve safety needs.
Much of the concern is driven by the increasingly urban, and noisy, environments in which so many people live. A World Health Organization study in 2011 made the case that at least one million West Europeans could expect to lose on average about a year of good health over the course of their lives due to traffic noise. Traffic noises cause high blood pressure, interrupt sleep and increase stress, the study found.
Noise at street level in New York City was found to average about 73 decibels in a 2015 study published in the journal Environmental Health. The Environmental Protection Agency has found that outdoor noise levels above 55 decibels can be dangerous to one’s health, and that chronic exposure to noise levels above 70 decibels can lead to hearing loss and health problems.
As a result, some researchers are gathering data that they hope can help bring urban noise to a healthier level. Erica Walker, for one, a researcher in the Boston University School of Public Health, is attempting to compile detailed sound maps of cities around the world, starting with Boston. She has recorded sound levels across the city and interviewed residents about what noises and neighborhoods are the worst.
Ms. Walker says that with her research, she also wanted to “take a step back and peel back the layers of what is noise.”
“I found that there are components of sound we don’t regulate and don’t measure,” she says. For instance, Ms. Walker has found that sound frequency—the speed of the vibration that determines the pitch of the sound—is what bothers residents the most, such as when people waiting at a bus stop can feel the reverberations when a bus passes by.
Ms. Walker has designed an app, called NoiseScore, that she hopes will help her measure detailed noise levels in cities around the world. In addition to measuring noise levels, the app shows the precise location and gives users the ability to report the event with photographs, video and descriptions of the noise. While the app is still in the pilot phase, Ms. Walker says she envisions the data it gathers being used by city officials around the world to better understand and manage noise in their cities and to improve residents’ health.
For instance, in Boston neighborhoods with lots of parks and trees, residents report less noise and related stress than they do in some other neighborhoods—even when measured noise levels aren’t much different. In response, Ms. Walker says, Boston and other cities could plant trees and take other inexpensive measures to make residents happier and more relaxed.
In New York City, where noise is one of the most frequent complaints on the city’s 311 hotline, scientists at New York University’s Center for Urban Science and Progress, or CUSP, are measuring noise levels in Manhattan, Queens and Brooklyn using small recording devices installed on buildings. More than 50 sensors have been installed so far.
Justin Salamon, a senior research scientist at CUSP working on the project, says that while New York has a fairly advanced noise-control program compared with other cities, it is difficult to enforce noise violations. By the time the city’s Department of Environmental Protection sends an inspector to the scene of a complaint, he says, the noise is often gone.
The sensors can help remedy this, Mr. Salamon says, by constantly measuring noise levels and recording sounds. The sounds are fed into computers that use machine learning to identify the sources of noises, whether it is a dog barking or a construction worker drilling. The scientists plan to create a real-time noise map with the data to better identify hot spots and make it easier for the city’s environmental protection officials to uncover and resolve problems.
Some smaller cities, meanwhile, are attempting to improve residents’ health and quality of life by creating “soundscapes.”
Rex Parris, mayor of Lancaster, Calif., hired the U.K.-based sound consultant Julian Treasure to create a composition of music and bird sounds to play on speakers along a mile of the city’s main street. Mr. Parris says people initially thought he was “mentally deranged” but have since warmed to the sounds. Next, he plans to install a trolley on the same street and remove vehicles so that traffic noise doesn’t interfere with the audio.
Efforts elsewhere to reduce noise caused by traffic include experiments by the states of Texas and Arizona with different types of highway pavements in a bid to reduce tire noise.
Sound innovations by the auto industry itself, meanwhile, could contribute to public safety and health. Because electric vehicles are silent when traveling at low speeds, they sometimes pose a danger to cyclists and pedestrians. Regulations in the U.S. and elsewhere are expected soon to require that electric and hybrid vehicles make noise. Thus, automotive engineers and designers are trying to create an appropriate and unique sound.
Nissan Motor Co. hired the composer Joel Beckerman, founder of the firm Man Made Music, to create a sound for its electric vehicles. Mr. Beckerman, whose client list includes AT&T Inc. and “The CBS Evening News,” ultimately created a sound that he says has warm, inviting and musical qualities—a sound that is recognizable as a vehicle but not unpleasant to pedestrians.
He says when he was designing the sound, he was thinking both about the noisy city landscape of today but also a quieter future.
The vehicle of tomorrow, he says, should “enrich the aural environment.”
Ms. Roberts is a reporter for The Wall Street Journal in Detroit. She can be reached at firstname.lastname@example.org. Appeared in the September 17, 2018, print edition as ‘Scientists Put Sound Under the Microscope.’
This editor’s note: consider loading the app, Decibel X, for either iPhone or Android and check volumes any time you wish.