Noise Pollution Maps Offer a Nightmare Feast for the Senses

Silence. For more than half the world’s population estimated to be living in urban areas, the manifestation of that word today is likely only possible with some assistance from noise-canceling headphones. Absent technology, our ears are otherwise pervaded with a soundscape of cars, horns, planes, construction, and other textured nuances of city living.

As acoustic ecologist Gordon Hempton once said, noise pollution creates dumb environments. 

"Noise pollution is basically defined as the presence of simple information that makes it impossible to hear all the other more delicate—and often more important—information," he told Guernica. "Noise pollution creates, if you will, dumb environments. Our industrial areas, many of our downtown urban areas, are dumb acoustic environments. Very simple, very loud, often unhealthy."

On that last point, the World Health Organization has classified noise as the second largest environmental cause of health problems, just after impacts from air pollution. In one report, excessive noise was linked to an increase in blood pressure, hypertension, heart disease, and even cognitive impairment in children. 

Mapping Our 'Dumb Environments'

In an effort to provide some context of noise pollution impacting urban environments, a Brussels-based data scientist named Karim Douïeb has turned to creating interactive maps. Initially starting with the city of Brussels, he's since released "noisy maps" for London, Paris, and New York City. Each provides a visualization and sonification map of a city's multi-layered soundscape based on available noise-level data.

"Classical colored maps don’t do enough justice to the research published in static noise reports," Douïeb told Nightingale. "I wanted to make the noise data more tangible and leverage this type of research by improving its impact. I couldn't think of a better and simpler way than using sounds to explain a situation about noise."

While your eyes can quickly pinpoint noisy hotspots on Douïeb's maps, taking your mouse and hovering over the areas in question presents an audible representation of the intensity of noise pollution present. For instance, dark gray lines in Brussels trace busy traffic corridors, where average decibels exceed 75 dB. Similar levels of noise pollution exist on the New York City map, in particular near congested hotspots like JFK International Airport or downtown Queens. Central Park, meanwhile, offers a more ear-friendly experience of less than 40 dB.

"The experience is personalized," added Douïeb. "You explore the cities, find your neighborhood or places you have been in the past, and realize how noisy they are compared to other parts of the cities."

According to the CDC, noise above 70 dB "over a prolonged period of time may start to damage your hearing." Other prevalent city sounds, such as an approaching subway train (100 dB) or standing beside or near sirens (120 dB), can cause hearing loss or even pain or ear injury after only a few minutes of exposure.

Tracking Noise Across the U.S.

While Douïeb's maps are unique in their addition of audio, he's not the only one interested in tracking our increasingly noisy world. Since 2016, the U.S. Department of Transportation has been modeling noise levels across the U.S. generated by road, aviation, and, more recently, rail noise pollution with its National Transportation Noise Map. The idea behind the map, which models worse-case impacts from transportation noise, is to gauge trends and better inform policymakers looking to "prioritize noise-related transportation investments."

According to the 2018 data, more than 74 million Americans were exposed to a 24-hour average noise level of an office (40-49 dB), with 1.7 million of those experiencing consistent noise pollution approaching 80 dB (or the equivalent sound of a garbage disposal). As for the rest of us, 97% of the U.S. population is exposed to some level of noise pollution from road, train, and aviation. It's no wonder that Hempton estimates that there are only 10 to 12 naturally quiet places left in the whole continental U.S.

"Now, when you're in a quiet place, what is the listening horizon?," he told On Being. "If you ask a person that lives in a city, they might take a wild guess and say, Oh, you can listen for a mile. Right? They know it's a trick question, so they're going to pick something really big: You can listen for a mile. You ask somebody in the country: Oh, you can listen for three or four miles. And I've heard sounds 20 miles away: if you do the math, that is the size of 1,276 square miles. Do you know what it's like to listen to 1,276 square miles when the sun is rising?"