And this from 2009
DoD and FAA guidelines define noise-sensitive land uses in areas where the DNL is 65 decibels (dB) or higher to be non-compatible with aircraft operations. Noise-sensitive uses below DNL 65 dB are considered to be compatible “without restrictions.” FAA policy regards noise to be so intrusive on one side of that pencil-thin line on a map that Federal funding is provided to sound insulate or possibly acquire residences and other noise-sensitive structures, such as schools, churches and hospitals; but outside that line on the map the Federal guidelines suggest that noise sensitive development is perfectly acceptable without restriction. Clearly, it is not the intent of Federal policy to communicate that noise stops at that boundary, and a number of forward thinking communities have effectively addressed this circumstance by establishing buffer areas between these non-compatible and fully compatible areas, where if noise-sensitive development is permitted, it is allowed to occur only “with restrictions.” Where such airport buffer zones have been established between noise-sensitive land use areas and areas regarded as fully compatible for noise sensitive development without restriction, controversy over aviation noise impacts has been substantially reduced. Supplemental metrics that show how many events comprise DNL at various dB levels, and how much time out of the day those events are present, helps to identify and communicate the benefits of establishing and maintaining a buffer zone between the non-compatible and fully compatible areas around an installation.
The Federal government adopted DNL because it is the best single system of noise measurement that can be uniformly applied in measuring noise in the communities and around airports, and for which there is a relationship between projected noise and surveyed reaction of people to the noise. While the Federal agencies have accepted DNL as the best metric for land use compatibility guidelines, reducing the description of noise exposure to a single value of DNL may not help the public understand noise exposure. Simply looking at the location of their home on a DNL contour map does not answer the important questions: how many times airplanes fly over, what time of day, what type of airplanes, or how these flights may interfere with activities, such as sleep and watching television.
Even the navy says we are getting too much noise!This is from THE NAVY AICUZ Manual!
And this from 2009