Farmers
are exposed to many sources of noise, often continuing for
long periods of time at levels that are potentially damaging
to hearing. A number of studies have suggested that farmers
have higher than expected rates of hearing loss. The farm
population suffers an increased risk of hearing loss, largely
due to occupational noise exposure (Broste, et al., 1989).
This exposure to high frequency noise levels can start at
a young age, and the negative results may be compounded when
the person's exposure accumulates over time.
- Damage
to the ear due to noise exposure is cumulative and irreversible.
It is similar to a tooth cavity - once it is there it
never goes away - it only gets bigger.
-
Loud noises affect hearing by damaging tiny "hair
cells" located in the cochlea of the inner ear. Repeated
exposure to loud noises causes the "hair cells"
to lose some of their resilience. When this occurs the
"hair cells" no longer function properly.
-
Sound energy is measured in decibels (dB). The decibel
scale is not linear. An increase of six decibels equals
a doubling of noise produced. This means that a noise
level of 96 decibels is twice as harmful as a noise level
of 90 decibels (Maine Department of Labor, 1998).
-
Actual ear pain occurs above 140 decibels. Noises at 90
decibels and above are considered to put individuals at
risk of hearing loss. Items that are at levels at 60 decibels
and above are at the level of annoyance threshold. Exposure
to high noise levels may cause fatigue, elevated blood
pressure, tension and nervousness, and hearing loss. Hearing
damage can begin at sound levels as low as 85 to 90 decibels,
and many farm machines are louder. Refer to the sound
levels thermometer.
-
Hearing is an essential part of your ability to communicate
with others. With a hearing loss you have difficulty understanding
your surroundings. Examples might include:
-
not being able to hear the auctioneer at the sale barn
-
not being able to negotiate with the seed dealer on
the phone
-
not being able to communicate with your customers
-
not being able to hear your child or spouse say, "I
Love You"
-
Protection: Hearing loss can be prevented by a
combination of increasing the distance between the person
and the noise source, decreasing the exposure time to
the noise source, and using personal protective equipment.
-
Wearing protective earmuffs or earplugs when around noise
levels of 90 decibels or higher is recommended. Earmuffs
that keep ears warm in the winter should not be confused
with those that protect the ears from high noise levels.
- In
selecting hearing protection look for the Noise Reduction
Ratings (NRR) label on the device. The NRR number is an
estimate of the protection provided. Be sure the rating
is high enough to reduce sound pressure to acceptable
levels. Example: A device marked "NRR 26" is
intended to reduce a 100 decibel noise to (100 - 26) =
74 decibels under ideal conditions. In actual use, it
may provide only about 50 percent of that protection,
or 13 decibel, resulting in (100 - 13) = 87 decibel sound
level (Deere & Company Service Publications, 1994).
- Earplugs
are available to help protect damage from high noise levels.
Rubber or plastic earplugs fit into the ear canal and
are effective noise suppressors. A snug fit is important,
so have them custom-fit for comfort and protection. Cotton
plugs do not block high frequency sounds.
-
Protective earmuffs cover the sound-conducting bones around
the ears as well as the ears themselves. They are comfortable,
and they keep ears warm. Using earplugs and earmuffs together
will not protect your ears much better than using just
one type of protection (you cannot add the two).
- Remember
that protecting your hearing should include protection
from all noisy sources, not just farm sources. Construction
and wood working machinery produces high frequency and
high decibel levels. So do motors. If you notice that
others can hear things when you cannot, you need to have
your hearing tested.
- A
good rule to use is the "two arm rule." If you
need to raise your voice to be heard when you are two
arm lengths from the other person, the noise level is
probably high enough that you need to protect your hearing.
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This curriculum guide was supported by Grant Number 1 R01/CCR414307
from NIOSH. Its contents are solely the responsibility of
the authors and do not necessarily represent the official
views of NIOSH. Special thanks to Dr. Ted Scharf.
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.
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