barryh 11-18-10

Dangerous Decibels

By Barry Hulse
Contributing Writer

I sometimes get to school a little early in the morning and when I do I usually make copies, check my schedule and stop by the library to check out the newspaper. I can’t help but notice the large number of students that are preoccupied with their Personal Music Players (PMP’s). I notice them walking down the hallway, sitting at their lockers, and standing in a group of their peers, listening to their music with ear-buds in. The music is often so loud I can recognize some of the songs as I walk by. Knowing that PMP’s can produce sounds ranging from 20 to 120 decibels and that the use of ear-buds channel the sound and can cause increased damage at high decibels, I can’t help but wonder if the trend of listening to PMP’s at high decibels for extended periods of time will cause hearing loss for this generation of music lovers.

A group of researchers, led by audiologist Cory Portnuff, at Colorado University and Children’s Hospital in Boston found in a small study of 30 young IPOD users that teens not only tend to play music louder than adults, but they are often unaware of how loud they’re playing it and the consequences associated with the high volume. A teenager listening to music isn’t anything new, but the amount of time they are listening to music and at the decibels they are listening should be of concern. The concentrated sound produced by the ear-buds directed toward the inner ear can be harmful to the ear at high decibels and cause permanent hearing loss. Portnuff said that over time, the noise can damage the delicate hair cells in the inner ear that transform sound waves to the electrical signals that the brain understands as sound.

The term decibel is derived from Alexander Graham Bell, the famous American inventor whose work was instrumental in developing telephone systems. Originally, the bel represented the amount of signal power loss due to resistance over a standard length of electrical cable. Now, it is defined in terms of the common (base 10) logarithm of a power ratio (output power divided by input power): It was later decided that the bel was too large of a unit to be used directly, and so it became customary to apply the metric prefix deci (meaning 1/10) to it, making it decibels, or dB. Now, the expression “dB” is so common that many people do not realize it is a combination of “deci-” and “-bel,” or that there even is such a unit as the “bel.”

We know that prolonged exposure to sounds of 100 decibels or more can be harmful to the ear and cause permanent hearing loss. Here are some common sounds and their decibel readings: a typical conversation takes place at 65 decibels, a gas lawn mower at 95 and a leaf blower, rock concert, and chainsaw at about 115 decibels, a jack hammer at 125 and a Jet plane at 135 while a shot gun has a decibel reading of 165.

The NIOSH and CDC have developed some permissible exposure times related to decibel readings. For example: 85 dB -no more than 8 hrs, 94 dB- no more than 1hr, 100 dB- no more than 15 minutes and 115 dB -no more than 30 sec.

Some form of ear protection is recommended when operating loud machinery or when working in an environment that has continuously high decibel readings. Ear plugs and ear muffs are available and can reduce the amount of sound reaching the middle ear by as much as 18 to 32 dB depending on the style and type of product used.

OSHA’s daily permissible noise level exposure guidelines are less strict: 90 dB -no more than 8 hrs, 100 dB- no more than 2 hrs and 110 dB -no more than ½ hr.

Rock music has registered it’s highest decibel reading at 150 dB a reading not even posted by OSHA. The eye opener for me was noticing that my riding lawn mower has a decibel reading of about 100 decibels which has a permissible exposure time of 2 hrs and my lawn takes about 3 hrs to complete so I should be wearing ear protection when I am mowing my lawn.

Hearing loss can take place as we get older and if you find yourself having to turn up the volume on the TV more frequently and asking ”what” repeatedly. You may have prebycusis also known as age-related hearing loss.

Medicare does not cover the purchase of hearing aides and therefore a large number of elderly do not purchase them do to their high cost. A hearing aid costs between $1000.00 to $4000.00 dollars which over the life time of the device (3 to 5 yrs) is about $3 dollars a day. Most health insurance policies do not cover the purchase of hearing aids. Knowing this information is helpful for young adults who could prevent hearing loss by lowering the volume on their PMP’s and cutting down the amount of time they listen to their music with headphones.

Keeping the sounds of our lives at moderate levels and using ear protection when sounds are extremely loud for prolonged periods of time is essential for maintaining good hearing.

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Posted 3 years, 8 months ago by Barry Hulse | Email .(JavaScript must be enabled to view this email address) | View Barry Hulse's profile.

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