Urban Acoustics and the Policy of Noise

Photo: TheMostAlive.com

DAVID MENI, CHAPTER PRESIDENT

Urban acoustics is much more than a really excellent band name. It’s an emerging field of study that incorporates elements of urban planning and acoustic ecology—the study of sound’s impact on society and human functions. The study of urban sound planning has grown in popularity in parts of Europe but has yet to be holistically addressed in many American cities, even as new trends of mixed-use development  make acoustic considerations more important.

While it may at first seem to be a trivial issue, acoustics can have an impact on everything from local economics to human psychology. Because of these intersectional issues, it’s important that cities take seriously those policies having to do with urban acoustics, take efforts to eliminate the socioeconomic disparities of noise pollution, and encourage creative use of sound design in new development projects and urban planning.

Now, before I get labelled as a grumpy “get off my lawn” type that doesn’t like loud noises, let me explain some of the current literature on noise pollution and acoustic ecology and how it impacts life in cities.

The World Health Organization and the EPA have established guidelines for community noise exposure: “Individuals [should] not exceed an 8-hour daily average level of 75 decibels or a 24-hour daily average of 70 decibels over a 40-year exposure period.” Seventy to seventy-five decibels is about as loud as a vacuum cleaner or a busy street; the New York Subway gets as loud as 105 decibels.

The public health impact of noise pollution, particularly in cities, is actually quite surprising. By 2050, there may be as many as 50 million people in the US with hearing impairment; younger generations have a rate of impaired hearing 2 1/2 times higher than that of their parents and grandparents, in large part due to the louder environments they live in. Sustained traffic noise in urban environments has been linked to everything from hypertension to sleep deprivation.

Urban acoustics even has an impact on economics. A Hofstra University study found a striking inverse relationship between noise levels and property value in residential areas, with a decrease in property value of 0.62% per decibel. Highways have an even greater impact; just the adjacent noise of a highway like the SE Freeway in DC can reduce property values 8-10%.

It’s important to note that the point of urban acoustic design is not meant to just make everything quiet. The type of noise is just as important to study as the volume—a coach bus and a crowded coffee shop are around the same decibel level. Good public spaces make use of noise as a cue for activity, and well-planned urban acoustic spaces can even go as far as providing the perfect natural acoustics for street musicians.

Soundscape mapping is an important tool for studying these kinds of relationships, but the practice is underutilized in the United States as a resource for planning. Below is an example of a soundscape map of a neighborhood in Seoul, South Korea, which shows trends of activity over the course of day.The crowd-sourced tool Sound Around You is a fun exploration of natural recordings, from birds chirping to squeaky metro escalators.

Photo: acoustics.asn.au

There are clear connections between the impacts of noise and the development trends of American cities, particularly as the automobile became ubiquitous in the 20th century. There’s no doubt that noise pollution is partially to blame for the 20th century phenomenon of over-zoning—the practice of so rigidly dividing residential, commercial, and industrial zones that they can no longer reinforce each other or create a sense of community. The desire to separate loud commercial and recreational space from residential areas led to this stark separation of land use seen in development of the last 40-50 years.

This trend introduces a disparity in noise pollution, which the American Public Health Association put the issue quite succinctly:

“Generally, the public cannot control the main sources of noise, such as transit, industry, and air, which means that the public is powerless to reduce associated health impacts without government intervention. Low-income minority communities are exposed to more environmental noise pollution than other populations, potentially contributing to socioeconomic gaps in public health and education.”

Even if you live in a city, it’s likely that you want to come home to some peace and quiet. But this tranquility often comes at a cost, and, without proper intervention and planning, can be relegated to a luxury. Low-income and minority communities are often not given a voice when high-noise land use (like a freeway) is placed near (or through) them, posing all the health risks, economic damages, and impediments to community growth mentioned above.

With the recent rise of New Urbanism and trends towards zoning for mixed-use, reduced sprawl, and greater density, urban acoustic design has become more important than ever.

If investments are made to advance urban acoustic planning, developments can more comfortably accommodate increased density.

A great example about how intentional acoustic design can encourage diverse and high-density are the plans for The Wharf development on DC’s Southwest Waterfront. Specifically, one building of the mixed-use plan contains both a 6,000 seat concert hall and residential units (the apartments effectively encase the concert hall). The site developers are working with a team of acoustic engineers to sufficiently soundproof the space—the concert hall can rock on while people upstairs can go about their business in peace.

Currently, there are two clear policy applications for urban acoustic design:

First, municipalities should seek to remedy the existing racial and income disparity in noise pollution. While nearly every locality has a noise ordinance, most are poorly enforced in the areas that need it most. To this end, more state and federal funding should be made available for the study of current urban soundscapes and methods of lessening the impact of noise pollution on public health and community development.

Second, American cities should embrace the range of new possibilities opened up by the continued advancement of acoustic design in built spaces. Developers both public and private can involve acoustic design earlier on in the development process, and acoustic considerations and their impacts on human behavior should be given greater consideration in urban planning.

Robust acoustic design can be an effective tool to fight increased sprawl in new developments and help make our cities more diverse.

Increased attention to the policy and practice of urban acoustic design can go a long way to improve the life of our cities. Well designed acoustic spaces can positively impact public health and local economies, as well as create novel ways to increase density and mixed-use development.