At the community forum last night with Rep. Ellison and Paulsen, many of you saw our page that shows the impact of the proposed RNAV tracks on Minneapolis schools. This chart takes into consideration the modern metrics that are used in pretty much the rest of the world when evaluating the impact of aircraft noise.
If we lived anywhere in Europe, for instance, the FAA would need to account for the fact that every school in SW Minneapolis is subjected to noise that has been proven to have a significant effect on the reading scores of students.
55 dB of average noise instead of 65 dB: every major agency in the developed world – except for the FAA and the Department of Defense, uses 55 dB of average noise as the point at which noise becomes problematic in a residential area. And yes, every other includes even the Environmental Protection Agency. Making the FAA use 55 dB requires Congress to order them to do so, which of course they can do.
CNEL – Community Noise Equivalent Level, instead of DNL, or Day Night Level. This gives extra consideration to the evening hours, between 7 pm and 10 pm, when calculating average noise. Why? Because there is a good chance you are sitting on your deck trying to have a conversation with your family while grilling at that time. Like DNL, CNEL is a rather odd logarithmic average derived from a model. But if you are going to use a rather odd logarithmic average derived from a model, the least we can do is use the right one. CNEL is approved for use in California, and is similar in approach to Lden, which is used in Europe. We can have it here if our legislators just ask for it.
N70 – A super simple metric that us regular folk can relate to: It just counts the number of times a plane goes over your head that is at least 70 decibels. Why 70? Because that’s loud enough to stop your conversation. For reference, that’s about as loud as vacuum cleaner.
Part II of our video series gives you a lot more background on this topic.
ps: I should mention that the original map of schools was sent anonymously to us by someone in the community. Thank you to whoever you are – It made the job of creating this chart much easier!