Airport Noise Mitigation

Airport Noise Mitigation

It began with the first manned flight of an aircraft by the Wright brothers in 1903 in the town of Kitty Hawk, North Carolina, forever changing the face of transportation in not only the United States but indeed the world. The invention of the airplane allowed for the traveling of greater distances in a shorter period of time than had previously been allowed with rail travel, or horse drawn carriage as the more popular modes of transportation of the day.

It really wasn't until the late 1940s & 50s that passenger air travel began to take shape in the form we know it today, and since that time the number of air passengers has multiplied exponentially. In recent years alone passenger traffic increased 7.2% between 2003 and 2004, illustrating an increase that wavered only in the immediate aftermath of the terrorists attacks of September 11, 2001 (Bureau of Transportation Statistics, 2005). In order to accommodate the increasing demand for not only passenger air travel but cargo air transport, military traffic, and civilian pleasure craft as well, cities began building airports that required large tracts of land as its major resource. In the initial stages of airport construction and expansion, many communities overlooked the effects of the airport on the surrounding communities in the immediate vicinity of the airport as well as the environmental consequences of construction itself. Many airports were built in or very near the "core' of their cities or just adjacent to residential areas with no forethought given to the future expansion of the city itself, or the cohesion of the neighborhoods already present, thus heralding in one of the first and still persistent grievances from those affected by the airports; noise.

Simply, 'noise' is defined as unwanted sound. Sound is typically measured in what are known as "decibel" units, which reflect intensity, or pressure (Stevenson, p.2). Noise has been shown to affect health by causing both psychological and physiological damage, most notably deafness. Numerous studies conducted since the early 1960s (when the fist studies on its affects were commissioned) now conclude that excess noise can indeed produce permanent hearing loss (Stevenson, p.3). These same studies indicate that prolonged exposure to levels just over 80dB can promote such loss. As the chart below on average decibel levels of common noise sources illustrates, the average decibel level of the noise in question; jet aircraft, produces approximately 150dB, far above the 80dB shown to produce permanent hearing loss (Stevenson, p.3).

Decibel Readings for various Noise sources

Decibel Level Sound Source

175 Jet Rocket Launching

150 Jet Aircraft taking off

130 Machine Gun

125 Diesel engine

120 Threshold of physical pain

117 Jet Aircraft ramp

111 Motorcycle

110 Nightclub

104 Subway train

93 Electric food blender

81 Rush hour traffic

60-70 Normal conversation

40 Average residence

10 Breathing

It should be noted however, that the degree of such hearing loss depends on the noise level itself, the length of exposure to the individual and the hearer's "individual susceptibility". Interestingly enough a 3dB difference is noticeable to the average person, while a reduction of 10dB is perceived by the human ear as a 50% reduction of noise (Thomson, p.1).

Evidence suggests that after an initial adjustment to a particular noise environment, "people become less, rather than more, tolerant of continued exposure to aircraft noise (Stevenson, p. 17). This would seem to contradict with air industry supporters who have tried to paint the noise mitigation issue as a "nuisance", something to adapt to. The U.S. Surgeon General, Dr. William H. Stewart, perhaps but it best when he stated in 1978 that "calling noise a nuisance is like calling smog an inconvenience. Noise must be considered a hazard to the health of people everywhere".

Various psychological effects have also been attributed to excessive noise exposure including what one medical consultant to the Federal Aviation Administration (FAA) has dubbed a "dream deficit"; whereby interruption of sleep and the dreams that result thereof, can result in multiple neuroses and psychoses stemming from such disruption causing chronic fatigue, loss of productivity, and mood swings among others (Stevenson, p.3). The citizen action groups formed of the affected residents near these airports were not willing to have their complaints dismissed as nuisances that required adaptation and coping on their part. They took their issue up with local and federal authorities to curtail the noises, resulting in some of the legislation that will be discussed later, complaining that the noises were not simply bothersome, but were making them "sick" (Bronzaft, p.13).

Perhaps the most notable and quantifiable effect of airport noise can be found in the real estate surrounding the airports. The value of residential homes located near airports is usually far less than similar homes in adjacent neighborhoods, and has shown a much lower rate of appreciation and re-sale value. Homes located near these airports are often sold far below market value due to the constant roar of aircraft over the homes and the potential home buyers desire to live away from such constant disruptions of living. Conversely, many businesses and industries look to locate near the airports due to their dependence on transportation logistics for their goods or because of the ability to locate functions such as landfills near these already "undesirable" tracts of land thereby lessening any civic opposition they may have incurred otherwise (Vittek, p.602).

In what has become a model for other communities faced with this issue, the city of Louisville, KY took an innovative approach to mitigate the effects of airport noise on residential housing when seeking to expand the airport in the mid 1990s. Minor Lane Heights, a community of 552 households located near Louisville International Airport, requested and eventually received state and federal funding that would allow property owners to purchase homes in quieter locales (NY Times,