Studies

FAA Noise Metrics

For decades the FAA has been using a seriously flawed and outdated manner of measuring noise impacts on a community with a metric called DNL 65dB (annual day/night average of noise decibels). DNL levels are based on averages rather than single noise occurrences. Of course, people hear and are disturbed by single noise occurrences, not averages of noise.

The decibel scale is logarithmic and, like the Richter Scale, not linear. An increase from 10 dB to 20 dB equals a 10-fold increase in perceived loudness.

The EPA recommends a maximum of 55 DNL to protect human health and welfare. But the FAA contends that 65 DNL, 10 times more, is the measurement below which impacts are deemed insignificant. In fact, the FAA noise recommendations are far higher than those recommended by the World Health Organization (50 DNL maximum to prevent serious annoyance), the Federal Energy Regulatory Commission (55 DNL maximum limit for noise in residential areas), and even the World Bank (55 DNL noise limit for any new development). Use of FAA noise regulation as a method of determining impacts on communities surrounding the Olympia Airport supposes that it is acceptable to subject communities near the airport with noise levels that the EPA, World Health Organization, Federal Energy Regulatory Commission and World Bank have determined are unacceptable and unhealthy to human beings.

A 2020 letter to the FAA from twenty five members of Congress (including Washington’s Adam Smith) states:

…When the FAA Reauthorization Act of 2018 was passed into law, Congress sought to address community airplane noise concerns by utilizing the scientific and research arms of the FAA to substantively evaluate alternative noise metrics with an eventual eye to having those metrics inform FAA decision-making. There is widespread consensus that the DNL metric remains an inadequate measure because it averages noise over a 24-hour period, thereby understating the impact of individual noise incidences. Thus, the congressional intent underpinning Sections 188 and 173 was to address the inadequacy of the DNL metric and nudge the FAA towards a more comprehensive measure. The report fails to understand that intent. Instead, we have received a delayed and highly insufficient report that does not address community impacts of noise….

Letter to FAA from twenty-five members of Congress, September 23,2020

The FAA has not replaced the 65 DNL noise metric with one that more accurately depicts the actual effect of noise on those living in airport communities. Thus, unless the FAA addresses this concern soon, the Olympia Airport Master Plan Update currently being prepared will continue to use an outdated and inaccurate means of measuring the effect of aircraft noise on our community.

Adverse Impacts of Unfettered Aviation

There are growing concerns globally about the many significant adverse impacts associated with unfettered growth of the aviation industry, including concerns about impacts of aircraft emissions on public health and on climate. A concern often undermined, ignored, minimized by airport planners and aircraft owners is that of noise impacts.

In 1978 former U.S. Surgeon General William Stewart stated “Calling noise a nuisance is like calling smog an inconvenience.” Many studies have since found that noise pollution increases risks for heart problems, high blood pressure, stroke and much more.

A recent publication in the Oxford Academic discussed a study which concluded:

 “Aircraft noise exposure induces pro-inflammatory transcriptional changes in the vasculature and primes cardiovascular inflammation … Aircraft noise exposure prior to MI worsens cardiac and vascular function… Patients with incident MI have higher C-reactive protein levels at baseline and show worse left ventricular fraction when they had a history of aircraft noise exposure and annoyance.”

Https://academic.oup.com/cardiovascres/article/119/6/1416/7005408

A recent (April 7, 2024) publication of the Journal of the American College of Cardiology discussed a UK study which concluded:

“Aircraft noise exposure was associated with adverse cardiac remodeling and asymmetric septal hypertrophy. BMI and hypertension are potentially on the causal pathway. Given the ongoing expansion of the aviation industry, findings call for urgent consideration by policy makers.” (Emphasis added.)

 https://www.jacc.org/doi/10.1016/S0735-1097%2824%2906603-8