People, Noise, People

by Nick Miller

So when I started my career in acoustics, the Noise Control Act of 1972 had just passed, the “Levels Document” was being researched by the heavies of acoustics, and the concept of Ldn (DNL to some of you) was being proposed.  Passing through the work room, Ted Schultz (God rest his soul) was pasting up some report or other: “Hi Meatball.  Did you know the architect thought building this wall in the shape of a sine wave would reduce the traffic noise?  Good thing it was built of bricks, long and tall.”

It was the early days of trying to understand acoustics.  The concept of Ldn and setting some sort of compatibility level was pretty innovative and a good start, it seemed to me.  I carefully read and marked up Appendix D of said “Levels Document.”

Then came the public meetings and field work.  Measuring aircraft taxi noise levels in Jeffries Point (East Boston) under the watchful eye of several residents, Mary Ellen Welch says, “But it can’t be Ldn 65.  That number is just too small.  The aircraft make much more noise than that.”  And so began my struggles of trying to figure out how to 1.) explain Ldn and 2.) relate noise levels to the way people reacted.

But now the International Civil Aviation Organization (ICAO ) Committee on Aviation Environmental Protection (CAEP) has issued a report recommending that rather than counting the number of people exposed to significant noise as measured by DNL, the focus should be on specific health effects or outcomes.  More significantly for us in the U.S., the Federal Aviation Administration (FAA) is considering whether DNL 65 and percent highly annoyed is the best way to characterize impact, and is planning an international forum to discuss noise research needs.  Finally (and here I have to pause and take a deep breath as well as cross my fingers), the FAA and the National Park Service (NPS) seem like they’re about to cooperatively work on figuring out how aircraft noise affects park visitors.

To many of us on the front lines of aircraft noise assessment, these developments are a wonder and welcome beyond words (well, not beyond words, but pretty welcome anyhow).  The motivations for these thoughtful, long needed efforts are probably many – maybe partly the effort of specific personalities, maybe Vision 100 and its requirement for the creation of a plan to design the Next Generation Air Transportation System that reduces the impact of aviation on community noise.  Well, whatever the motiviation, it’s great to think that the time has finally come to update and upgrade the ways we examine and reduce the effects of aircraft noise on people.  “O frabjous day!  Callooh!  Callay!”  I’ll keep you posted.

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