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mercíless noise as the worst enemy of
heaJth."
That tragic day may not be far off.
Until recently, attention on enviren–
mental matters has been directed toward
the increasing plagues of air, water, and
solid pollution, with the health hazards
they pose. Little attention was focused
on the dangers of increasing noise. Now
the ballooning problem of noise is forc–
ing a change.
A high official of the American Medi–
ca! Association, Dr. Gerald B. Dorman,
told a recent symposium on noise pollu–
tion: "We recognize that noise is as
much of an environmental pollutant as
the noxious gases, chemicals and wastes
that befoul our air, water, crops and
soil."
Dr. Vern
O.
Knudsen, chancellor
emeritus of the University of California,
asserts: "Noise, like smog, is a
slow
agmt of death.
If
it continues for the
next 30 years as it has for the past 30,
it could become
lethal."
Just what are the true dimensions of
the noise pollution problem? A few
statistics emphasize the gravity of the
problem.
In the United States, the Federal
Coun=il for Science and Technology
reports: "The overall loudness of
envirc nmental noise is doubling every
ten F ::rs in pace with our social and
industrial progress."
In sorne American communities, the
noise leve! in 1968 was four times what
it was in 1956- and 32 times what it
was back in 1938!
What
IS
Noise?
Just what is noise? What does it
mean to "double" environmental noise?
Webstcr defines noise as "a sound ...
that lacks agreeable musical quality or is
noticeably loud, harsh, or discordant."
Noise
produces sound waves which
are uneven and jagged in appearance, as
viewed through an oscilloscope, whereas
music
sound waves are even and
flowing.
The
intemity
of a noise is measured
in
beis,
a unit named after Alexander
Graham Bell. A
decibel
is one tenth of
a be!. Theoretically, the threshold of
hearing is
zero
decibels, but this is only
accomplished in experimental condi–
tions. What we would call "silence" is
The
PLAIN TRUTH
CITY TRAFFIC
PRINTING PRESS
WITH All
KITCHEN
APPLIANCES
GOING
•
lOUD MUSIC OR SIREN
August September 1970
SOUND LEVELS OF
MODERN LIVING..
1
DEATH lEVEl
(HAS KlllED MICE)
SATURN V ROCKET AT lAUNCH PAD
Ambo•sodor
Co/lege
Pholos
Here a re just a few of the representative sound levels in modero urban
society. At about
80
decibels, annoyance begins; at 90-11 O d ecibels, in a
constant working environment, permanent damage results; at 140 there
is definite pain and temporary loss of hearing; and at 175 decibels, experi–
mental animals hove died.
normally around 25 decibels. Pain
1s
infticted ( depending on the
t¡tldlity
and
pitch
of the sound) at about 120 deci–
bels. Severe pain and temporary Joss of
hearing are inflicted after only
a
few
minutes at 140 decibels or a few sec–
onds at 150 or more decibels.
For the nonscientific reader, it
is
important to note that tbe decibel
scale is
logarithmic,
that is, 60 deci–
bels of sound is
1
O
times more intense
than 50 decibels, 100 times more
intense than 40 decibcls, and 1,000
times more intense than 30 decibels. A
jet taking off at close proximity (140
decibels) is
one bi/lio11
times more
inteose than "normal" background
noise in a suburban neighborhood (50
decibels)!
That sounds impossible - a
billion
times? The key is that
intensity
is not
quite the same as
Joudneu.
The best
example of this is a 5,000-watt radio
station signal versus a 50,000-watt sig–
nal. The signa! ( intensíty) is ten times
- ten decibels - as powerful, but the
volume (loudness) is only about
twice
as powerful.
Measuring Decibels
In July, 1969, tbe United States Gov–
ernment set limits for decibel levels on
the job. Any exposure for more than the
allotted time, they reported, would lead
to
pemllment hearing d·tmage.
Workers in a very noisy factory
job were found to have lost an
avel'flge of 50 decibels
of their hear–
ing rangc by working
15
years at a
100 decibcl noise leve!. This means that
their normal threshold of hearing (20-
25 decibcls) had been changed to about
70 decibels. Normal conversation ( 60
decibels) had to be repeated louder at
70-75 decibels) for the workers to hear.
The government accordingly set 90