Word: knudsen
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...Noise Hater Knudsen, former chancellor of the University of California at Los Angeles, is a crusader whose stamp-out-sound vendetta started 38 years ago while he was a graduate student at the University of Chicago, where he earned his doctorate with a thesis on the physics of hearing. With his trusty, ever-present sound-level meter, Knudsen tours the world, makes surprising discoveries. He once measured a noise level of 90 decibels* at a U.C.L.A. faculty tea. In the surf at Santa Monica, he registered a 3-ft. breaker at 80 decibels from a distance...
...Knudsen next turned to traffic, found that, even from 200 ft. away, a truck barreling along Los Angeles' San Diego Freeway pushed the needle up to 91 decibels -which is still twelve decibels lower than an accelerating Lexington Avenue bus in midtown Manhattan. At 92 decibels, New York's Times Square is probably the world's noisiest intersection; London's Oxford Circus registers 87, and Paris' Place de la Madeleine...
Physical Effects. Doctors agree with Physicist Knudsen that noise is a hazard to physical health. The most obvious danger: deafness. "The Good Lord in his mercy provided the majestic elephant and the lowly ass with ear flaps that would at least partially close the ear canal," observes Knudsen. "But man, poor creature, was not so favored...
...humans are ever exposed to such severe noise intensities. But some occupations (e.g., airline pilots, aircraft workers, riveters, boilermakers) require constant exposure to dangerously high sound levels. Such prolonged exposure, says Knudsen, results in a degeneration of the organ of Corti-part of the middle ear's acoustic apparatus-and a decrease in the number of ganglia, or nerve cells, in the ear. The U.S. Air Force's Dr. Henning E. von Gierke warns that continued exposure to 135 decibels of noise for longer than ten seconds once a day, or to 100 decibels for more than eight...
Loud noise also causes a number of unpleasant bodily sensations, such as vibration of the head and eyeballs, loss of vision, loss of equilibrium and heating of the skin. A noise of 160 decibels can kill rats and mice. Explains Knudsen: "The body temperature rises to a lethal level. It's the conversion of sound energy into heat that kills." In humans, at sounds near and above 160 decibels, the stirrup (one of three little bones in the middle ear) may be driven through the small "window" in the well of the inner ear. Possible result: meningitis, from infection...