These scientists think peace and quiet should be a human right

Noise pollution is terrible for your health, but they want to find a solution.

Step onto the streets of New York or any other major city and you will be greeted with a barrage of noise. It might come from car horns, sirens, barking dogs, jackhammers, or any number of other sources. But whatever you’re hearing, it’s unlikely you can escape it. And if you live in the city, even in your apartment you might be besieged by noisy neighbors or music from the restaurant you live above.

By now, we have started to realize that this state of affairs is very, very bad for our health. Epidemiological studies have shown that noise keeps us from getting a good night’s sleep, boosts our risk for heart disease and hypertension and dementia, spikes our stress hormones, is linked with memory and reading comprehension problems in kids, and causes hearing problems.

And yet we still tend to view quiet as a luxury. “People just have this general attitude that noise is just a nuisance…even the people who are victims of noise also kind of take that stance,” says Erica Walker, an exposure scientist at Harvard University who studies how people are affected by noise. “It’s a sacrifice that we have to make because we choose to live in these place that are close to everything, it’s something that we can put up with, it’s something that we can get used to over time.”

But it doesn’t have to be this way. Walker and other researchers are investigating how cities can turn down the volume. First, we must understand the scope of our noise problem. That means creating maps of how noise fluctuates across a city, figuring out when it happens, and identifying what kinds of spaces offer city dwellers some much-needed respite.

“It’s not a problem that we can’t overcome, it’s just that we’re going to have to be smarter about how we’re going to define it and what we’re going to do to mitigate it,” Walker says

Describing the din

Walker first realized how harmful city noises can be when she moved into an apartment in Boston below a family with very boisterous children. “Above me were these kids that used to run around all day; it was just incredibly annoying and disruptive,” she says. Frustrated, she began to read up on the impacts of being constantly exposed to unwanted noise. “I saw that this problem was way, way, way bigger than just me dealing with my noisy neighbors upstairs.”

Walker decided to investigate what qualities make city noises so harmful. She has measured noise levels around the greater Boston area and surveyed residents to create a map of the city’s soundscape. She’s found that noise ordinances are rarely enforced, and the World Health Organization’s recommendation that noise levels stay below 55 decibels during the day and 40 decibels at night doesn’t hold in the real world. “During my time measuring sound in the city, I’ve never seen sound levels that are remotely like that,” Walker says. “It’s always way over.”

Erica Walker has measured noise levels around the Boston area. Noise and the City

She’s also discovered that loudness is only part of the picture. “Noise is extremely complex. But the way we describe it, the way we regulate it is extremely superficial,” she says.

Other characteristics of noise can also affect our long-term health and emotional wellbeing. These include the frequency of a sound, how long it lasts, how unpredictable it is, and how people feel about it. “I asked people what they found most bothersome about noise and people were like, ‘it’s something I can’t control, if I tell someone no one will do anything about it,’” Walker says. “It’s just feeling imprisoned by this thing that is just so multifaceted.”

Another pattern Walker noticed was that poorer communities tended to be both louder and have greater amounts of low-frequency sounds than other areas. When Walker talked to residents of East Boston—which is near an airport and home to two major highways—people reported that they weren’t just bothered by the noise they heard, but the noise they felt.

“If you’re standing in from of a bus and it passes by you, you hear some of it but you also can feel some of it reverberating in your chest,” Walker says. These kinds of low-pitched noises can be deceptive because they don’t seem very loud to our ears.

“It’s really insidious because it just permeates through the environment pretty much unchallenged; it can penetrate walls, it can travel long distances,” Walker says. As an experiment, she and her colleagues exposed people to low-frequency noise—and saw changes in their heart rate that indicated their bodies were under stress.

Walker also has created an app called NoiseScore that people can use to report noises in their community and how it made them feel. This will give people a way to see what the sound climate is like in their community, she says. And by creating maps of a city’s soundscape, Walker says, we can identify problem areas in need of better noise-control measures.

Being in the moment

Few places throb with noise like New York.

The city actually has been at the forefront of efforts to curb noise pollution for decades, says Juan Bello, a sound researcher at New York University. New York was the first city in the United States to enact a noise code. However, it’s also the largest city in the country and densely packed with people.

“There is a lot of activity in the city per square mile in a way that is unusual for most American cities,” Bello says. “So noise is part and parcel of life in New York City.” And in recent years, its streets have become even noisier because the city has been going through a massive construction boom, he points out.

Noise is tricky to deal with because, unlike water or air pollution, it leaves no traces behind in the environment. “The main problem is the transience of the event,” Bello says. When people complain about evening construction noise, it can take days for the city to send an inspector to the site—by which time, the noise has probably stopped. “The vast majority of those complaints don’t lead to any violation being issued.”

That’s why Bello and his colleagues are placing sensors around New York to capture noise in real time. So far, they have planted about 50 of the book-sized devices around Manhattan, Brooklyn, and Queens to record 10-second snippets of sound. “You can actually go back in time and locate occurrences that justify those complaints,” Bello says. He’s examined complaints about after-hours construction in areas with sensors. About 95 percent of the complaints matched up to a noise violation occurring at the time they were lodged.

a sensor
A sensor designed by Juan Bello and his colleagues. The spikes are intended to deter pigeons. NYU Photo Bureau – Hollenshead

Bello and his colleagues are training an algorithm to recognize what might be making different noises the sensors have picked up. Eventually, it will be able to tell you that a noise is louder than what’s permitted in a particular area, and whether it came from a jackhammer, pile driver, or truck backing up.

“It will give you information about what is going on, but it doesn’t allow you to really recover the sound that was captured in the first place,” Bello says. “That’s mostly to protect privacy to make sure that this thing cannot be used to eavesdrop.”

In the next few months, Bello and his team hope to use the sensors to track construction sites and other areas with recurring noise complaints. Ideally, he says, the technology will eventually help these sites control their own noise output. “Just giving violations is not going to solve the problem,” Bello says. Instead, the city could ask the managers of a construction site to install sensors and use them track whether they are making too much noise. “This is what would then become a regular part of the process of any major construction site in the city,” Bello says.

Like Walker, he and his team also hope to develop an app that would allow city dwellers to check on their own neighborhood’s soundprint. People could use it to scope out an area where they’re thinking of renting an apartment, he says. “You’ll have more information about what it is like to live there, what is the noise environment.”

Seeking quiet

Quelling urban noise pollution isn’t just about defining what makes an area noisy; it’s also important to figure out how to make a place feel peaceful and quiet.

“It should be a right to have access to quiet spots,” says Antonella Radicchi, a soundscape scientist and architect at the Technical University of Berlin. She is trying to find out what people look for in everyday quiet areas—public places within a city where residents can relax, read, walk, and chat within walking distance from the buildings where they live or work.

Radicchi has created a map of quiet spaces in Berlin by interviewing people about their favorite haunts and collecting their impressions through an app she developed called Hush City. With the app, people can report a quiet space, fill out a questionnaire about how it makes them feel, and take a picture and brief audio recording of the area. They can also browse quiet spaces shared by other users. Hopefully, she says, these maps will help city officials figure out how best to preserve quiet areas and make it easier for residents to find one nearby.

It turns out that there are several ingredients that most quiet areas seem to have in common, Radicchi has learned. They tend to be found in secluded streets, small parks or city squares, and along waterways like rivers and canals. People generally describe these areas as secure, clean, and well landscaped. They also aren’t completely silent; people actually preferred being able to hear human voices and natural sounds like birdsong. “This feeling of being part of a community is very important and it’s a characteristic of these areas,” Radicchi says.

She’s now started to gather reports on quiet spaces from people around the world, including the United States, United Kingdom, Italy, and Spain. In collaborating with researchers in Granada, she’s observed that people in the Spanish city seem to value the same features as those in Berlin. “It seems that when we look for a quiet spot in our daily routine we all look for something similar,” Radicchi says.

Quiet areas around New York rated by Hush City users. Antonella Radicchi

In the past, cities have rarely relied on residents’ feedback when estimating how noisy different neighborhoods are. The European Commission requires its member states to create noise maps for major cities and release them to the public. However, cities only are required to measure features like traffic or industrial noise. This leads to some major blind spots.

One such area is Reuterkiez, a rapidly gentrifying neighborhood in Berlin. “If you look at the noise map of Berlin…the neighborhood is very quiet,” Radicchi says. But she discovered that, while some people rated the area’s central square as a quiet area, others complained that the nightlife had become overly noisy. So many cafes, restaurants, and bars had popped up in recent years that the area no longer felt residential—a problem city officials had been unaware of.

By gathering this kind of intel from people who live near quiet areas, cities can decide what actions to take to protect them. For Reuterkiez, one step could be to restrict the number of licenses granted to eating establishments, Radicchi says, but the best solution will look different for every neighborhood.

Fighting back

Our cities weren’t designed with noise in mind. This is particularly true in neighborhoods where homes are sprinkled among restaurants, stores, and bars, or wedged between highways, buses, and airports.

“We spend a lot of money in building noise barriers, but what if we thought about the sonic environment from the very beginning?” Radicchi says.

Going forward, cities could change their zoning laws so new apartments are built in locations where less noise can reach them, Walker suggests. “It actually needs to be part of the city’s planning fabric.”

And in the meantime, there are some inexpensive ways that cities can cut down on noise pollution for all their residents, such as planting more trees and bushes. Not only does greenery absorb noise, but it also makes us healthier and happier. Cities can also subsidize soundproof windows, install noise-absorbing pavement on the streets, and prevent traffic from passing through certain streets in the evening, Walker says.

It’s also up to individual city dwellers to pay attention to how much noise we’re making. We don’t really think about honking or blasting our music as polluting the environment like we would littering, but we should. “Sometimes we don’t make the connection,” Bello says. “We want people to see this as throwing the candy wrapper out of the window.”

Of course, he and other sound researchers don’t expect—or want—to transform New York or Berlin or Boston into hushed mausoleums. “There will always be some noise,” Bello says. “It’s an unavoidable fact of life in the city. We think we can help to make it a little better.”