Four Points for Aviation’s Consideration as the Noise Storm rises

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Noise exposure is becoming ‘the new secondhand smoke’

Generic, National Noise Initiative coming

Aviation should get ready


Noise is “the new secondhand-smoke issue,” said Bradley Vite, who pushed for regulations in Elkhart, Ind., that come with some of the nation’s steepest fines. “It took decades to educate people on the dangers of secondhand smoke. We may need decades to show the impact of secondhand noise.”

The Environmental Protection Agency has said that noise below an average of 70 decibels over 24 hours is safe and won’t cause hearing loss. The National Institute for Occupational Safety and Health says anything below an 85 won’t cause hearing loss for workers exposed to loud machinery.

But those levels are way above recommendations made by the European Union. In 2009, the E.U. set noise guidelines of 40 decibels at night to “protect human health.” And it said steady, continuous noise in the daytime — such as the noise on highways — should not exceed 50 decibels.

“We’re in active denial” about the effects of noise, said Rick Neitzel, director of environmental health policy at the University of Michigan in Ann Arbor. “We’re far, far behind what Europe is doing.”

When it mapped noise across the country last year, the Department of Transportation found that 97 percent of the population is subjected to man-made noise. A recent study of 290 national park sites found that 67 percent had significant human-caused noise, said Rachel Buxton of Colorado State University in Fort Collins.

Aircraft noise fell by 95 percent from 1970 to 2004 as plane engines got quieter, according to the Federal Aviation Administration. But local battles over airport and airplane noise continue for communities in flight paths. In the national parks, “the biggest culprit is aircraft — the planes overhead — and then road traffic and sounds from industrial sources like oil and natural gas drilling,” said Buxton, who participated in the study of national park noise.

What does this mean for aviation? While the Post article tangentially, and surprisingly positively, mentions airplane noise, it makes it clear that federal regulators, EPA and NIOSH, are participating in this generalized examination of noise exposure. Historically, they have been advisers in setting aircraft noise levels, but this new initiative may permit them to take a more central role in setting protections for the general populace.

Clearly, the aviation industry needs to be prepared for this new public awareness.

  1. Administrator Huerta, in 2015, commissioned “a multi-year effort to update the scientific evidence on the relationship between aircraft noise exposure and its effects on communities around airports.” Even then the study’s stated methodology appeared to have flaws.

  1. But as noted in the Post article, the concentration of the aircraft flight patterns, aviation may want to reassess its own standards over these narrow corridors. Here are some thoughts which may lead to a new standard which addresses the unusual noise impact of RNP and NextGen

→ What can be gleaned from looking at these noise patterns? There is both good news and bad news.

  • The environment on a macro basis is better off; because the generalized area of impact is significantly decreased.
  • There is also BAD NEWS on a micro basis; in that the precision of the RNP technology and implementation CONCENTRATES THE NOISE IN A SMALLER AREA. The residents in these areas may be experiencing substantial increases over their historic noise levels (+10 points on the scale equals a doubling of the loudness). Further, the RNP addition to the noise may not reach the FAA’s long standing threshold of 65 dBA; so a NEPA review may find this “new impact” to be acceptable.
  • What sets the DNL “energy average” apart from a mathematical average is that for every increase of 10 dBA in a noise level, the energy is increased by a factor of 10. For example, an event of 70 dBA contains 10 times the energy of an event of 60 dBA or one hundred times the energy of an event of 50 dBA.
  • What needs to be done?
  • The predicted noise levels of select Environmental Assessments (perhaps Phoenix) need to be verified by actual noise measurements within the new PBN flight corridors to determine why the reaction to noise impact is so much greater than the predicted noise impact.
  • If the predicted noise impact is found to be accurate through physical noise measurements, then the threshold for significant impact needs to be evaluated and adjusted to account for factors such as aircraft operation frequency and differing community tolerance for noise.
  • As illustrated above the issue of frequency may not have a significant impact on the DNL value but certainly appears to be having an impact on community tolerance of noise. The current FAA threshold of significance (1.5 Db at 65 DNL and above) does not account for the significant increase in frequency that occurs under the new PBN corridors.

  1. There is clearly a rising expectation of communities for lower noise levels. Though objective, engineering data shows that the exposure has been reduced as this FAA quote indicates:

“In 1975, there were about 200 million people flying in the United States, with about 7 million people exposed to what is considered significant aircraft noise.  Since then, an FAA study conducted in 2015 showed that the number of people flying in the United States had almost quadrupled, yet the number of people exposed to aircraft noise had dropped to around 340,000, or a 94% reduction in aircraft noise exposure. “

The intense anger of local groups signals a strong political movement which does not give much credibility to the existing accepted noise numbers.

The science of human response to noise is denominated “psychoacoustics” :

sound waves produce unconscious activity within the brain. If you think of sound waves (including spoken words), you really have to think about them as aural units of measurement. Each of these units enters into the ear and then into the brain where both psychological and physiological changes can be observed. Obviously, we know that a song that makes us nostalgic is going to produce certain psychological shifts in perception.”

While this discrepancy between measured and perceived noise may be frustration, perception is a reality with which must be dealt in public policy debates.


  1. This phenomenon has been exacerbated by recent scientific discoveries, which may have identified some correlation between certain sounds and “noise rage.” The phenomenon is called misophonia literally “hatred of sound.”

In 2000 scientists defined misophonia as a “condition in which negative emotions, thoughts, and physical reactions are triggered by specific sounds.” Other labels include “select sound sensitivity syndrome” and “sound-rage.” Misophonia has not been classified as an auditory, neurological, or psychiatric condition; so far, no standard diagnostic criteria have been defined. Neither the DSM-IV nor the ICD-10 has included misophonia listed in their referenced problem. Unfortunately, there is little research on its prevalence or treatment.

Misophonia (and its related conditions–phonophobia and hyperacusis) can be remediated. The techniques for addressing inordinate reaction to noise must be researched. While Stage 5 is being implemented, FAA, industry and the medical profession should sponsor such research.







These are complex, evolving issues which may influence the coming noise exposure debate.  It is not yet validated whether the increased local noise complaints are valid, whether the NextGen corridors do have increased impacts or whether “misophonia” should be discarded as an outlier. What should be understood NOW by aviation is that the past policies and even measurements may have to be rethought. Preparation will be critical to be effective in balancing aircraft noise and citizen impact.





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1 Comment on "Four Points for Aviation’s Consideration as the Noise Storm rises"

  1. Kim vanriper | March 7, 2019 at 9:46 am | Reply

    Living in a home which recently has been impacted in the Mesa area in Phoenix, we are seeing hundreds of flights overhead daily at well under 3000msl, where before, not a plane was in sight. (We are around 13 miles from the airport) Through communication with aviation officials I have been informed that there is simply no data to support any increase in noise in this area. On the ground the reality is one cannot speak on the phone while outside, and literally hundreds of planes pass above daily making it a variable nightmare. There are no sound stations nearby, so my thoughts are that the noise is simply not being accurately measured, or measured with parameters which is not reflective of true micro area impact. Very little ambient noise here, and a giant corridor north of here which boasts no homes (salt river) yet planes are directed over residential areas now, which saw little prior impact. I’m not sure perception has changed as much as may be credited. 500-1000 ft of altitude difference, and massive increases in frequency result in very real impact, though the measurement efficiency seem lacking.

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