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Harmful Effects of Jet Engine Noise

Worries about the effects of jet engine noise are as old as the Jet Age. An article from a 1952 issue of "Time" magazine observed that people who lived near a military base tended to "blame all sorts of ailments on the screaming jets." Since that time, different factions have voiced concerns about the detrimental effects of living near an airport or flight path or working in close proximity to aircraft. In 1952, when jet engines were considerably louder than they are today, the greatest threats to a military worker's well-being were the "powerful sound fields" created by roaring engines. These fields could knock a man to his knees. Even with the noise reduction that has been achieved in intervening years, prolonged exposure to jet engine noise can impair mental and physical health.

  1. Causes

    • In operation, modern jet engines involve the "violent turbulent mixing of the exhaust gases with the atmosphere," according to a document on noise control from Purdue University College of Engineering. "Turbulence created near the exhaust exit causes a high-frequency noise (small eddies) and, further downstream of the exhaust, turbulence causes low-frequency noise (large eddies)." If the velocity of the exhaust surpasses the speed of sound, a "shock wave" is formed.

    Measuring Decibels

    • The American Speech-Language-Hearing Association lists the decibel levels associated with common activities and machines. Jet engine noise falls into the "painful" category at 140 dB. Compare this to a chain saw -- "extremely loud" at 110 dB -- or a blow dryer -- "very loud" at 80 to 90 dB. A 2004 study from the journal "Medycyna Pracy" concluded that, "even during a single test," aircraft technicians were subjected to noise levels that surpassed recommended limits by a considerable margin.

    Hearing Loss

    • The noise generated by jet engines at close proximity exceeds the ability of the most advanced noise-protection devices to buffer it. Extreme noise moves through the ear canal and can damage the cilia, or hair cells, that line the inner ear. If it is loud enough, "it can dislodge the tiny bones of the middle ear," notes the American Speech-Language-Hearing Association. These changes can cause significant hearing loss.

    Other Effects

    • Among the ill effects linked to jet engine noise -- even among people who live near an airport -- are fatigue, irritability, reduced attention, learning impairment, tinnitus (ringing in the ears), hypertension and insomnia, according to the Center for Hearing and Communication. In addition, sustained exposure to jet noise, even from a distance, can have detrimental effects on wildlife, according to the Noise Pollution Clearinghouse.

    Remedies

    • Over the course of the Jet Age, engines have grown considerably quieter, and further progress is possible. For example, NASA has a program under way to reduce the noise level of commercial aircraft; the Occupational Safety and Health Administration monitors noise levels in work environments, including the commercial airlines and military; and civilian groups are advocating for greater public awareness of the problem. In the meantime, avoid close proximity to jet engines if you can help it. If you must work near an operating jet engine, wear the strongest hearing protection you can find.

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