| At what
level will hearing damage occur?
Generally, 120 dBA is
recognized as the threshold of pain
and considered a dangerous noise
level. Noise levels less than 120
dBA can damage hearing if the
listener is exposed to the noise for
an extended time period. Noise
levels less than 90 dBA are
generally not recognized as noise
levels that can cause hearing
damage. Typically, traffic noise
levels in areas of frequent human
use do not approach these noise
levels. A 90 dBA traffic noise level
would occur if a person stood 10 to
20 feet from a roadway carrying
approximately 1,000 trucks per hour.
It is unlikely that residents would
be exposed to this level of noise,
and therefore it is unlikely
residents experience hearing damage
due to traffic noise.
How loud is 67 dBA?
A sound level of 67 dBA
is associated with normal speech at
3 feet. Some common sound levels are
shown in the following
chart.
What is Leq?
Leq is the equivalent
steady-state sound level which in a
specific period of time contains the
same acoustic energy as a
time-varying sound level during the
same period. The Leq is used to
describe the period as an overall
noise level. The graph below
represents the time-varying data for
a 50-second monitoring period. For
this period, the approximate Leq is
72 dBA.
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