Trouble is, those lowest-decibel readings (along with the highest—think jackhammer or ambulance siren), are frequently discarded in noise studies, which tend to weigh only the mid-range levels that most people hear. Walker hypothesizes that this approach may not be painting the most accurate picture of how urban noise affects real people, which is why she’s using a wide variety of collection methods that factor in the full spectrum of noise readings.

“We shouldn’t just throw out components that we think they don’t hear, we should consider the whole spectrum,” Walker says. “And we should ask the community what they’re bothered by. If you’re going into a community and you’re monitoring noise, you need to ask them, what’s bothering you? Then you can make connections between noise and health.”

Which is why Walker has become such a voracious surveyor. She’s currently surveying in every Boston neighborhood, in multiple languages, asking residents to rank certain city noises—a car idling or subway rumbling, for instance—on a 10-point scale of how bothersome or stressful they are. She says she’s been surprised how many respondents are willing to complain while at the same time say they’ve gotten used to the noise around them. Still others, she says, are in denial that their neighborhoods have a noise problem.

When all the surveys are collected, Walker plans to create a “perceived noise map,” which compares the perceptions of Boston residents to the readings she’s taken with her decibel meter. Eventually, a noise value could be assigned to every residence in Boston.

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Walker’s research is in some ways a throwback to a golden era of noise research that reached its height in the U.S. in the 1970s, during the Nixon administration. The Noise Control Act of 1972 authorized the Environmental Protection Agency to study the effects of noise for the first time and set up the federal Office of Noise Abatement and Control.

“We now have the authority to come to grips with an environmental problem that affects millions of people,” then-EPA Administrator William D. Ruckelshaus said at the time.

Over roughly the next decade, several landmark epidemiological studies documented the human toll that noise—especially airplane noise—can take. Then came Ronald Reagan’s massive deregulation and dismantling of the Environmental Protection Agency. The federal noise abatement office closed in the early 1980s, and noise regulation returned to cities and states. With it went much of the funding for noise research, says David Sykes, who runs the nonprofit Acoustics Research Council, which focuses on policy-level analysis of noise issues. He expresses surprise and delight about Walker’s work in Boston.

“The fact that she’s actually doing an epidemiological study is very, very rare,” he says. “What she’s doing is very courageous. It’s not a path you would chase if you were trying to get a tenured appointment somewhere.”