The human ear is an incredible machine. It detects noises by converting sound waves into nerve impulses which the brain then interprets. These sound waves are produced when air is mechanically disturbed.
The ear measures sound by it’s frequency and intensity. Frequency is the high or low pitch of a particular sound and is measured by the number of complete sound wave cycles each second. Intensity is how loud a particular sound is and is measured in decibels.
Ears effortlessly measure both the frequency and intensity of the sound instinctively. Sound waves enter the ear canal, causing the eardrum to vibrate. These vibrations then pass through three tiny, connected bones in the middle of the ear, which activates fluid in the inner ear into motion.
This moving fluid then bends thousands of delicate hair-like cells that convert the vibrations into nerve impulses, which are then instantly shot into the brain via the auditory nerve. The brain then translates these impulses into the sound we hear.
How Hearing Can Be Damaged
High frequency sound waves and excessively loud noises can cause both temporary and permanent damage to this natural hearing system.
With temporary hearing loss, hearing is normally restored after a period of time after the noise cease.
But with permanent hearing loss — which can occur when the ear is continually exposed to high-frequency or excessive noises — the tiny hair cells within the ear harden and die and the body can’t regenerate them.
Symptoms of permanent hearing loss include the inability to hear high-pitched or soft sounds, trouble understanding other people when they are talking, the inability to hear people speaking over the telephone, and a continual ringing or roaring in the ears known as tinnitus.
Hearing Aids Help But Don’t Heal
While hearing aids can help amplify sounds so that people with permanent hearing loss can hear them better, they don’t restore noise-damaged hearing.
In addition to hearing loss, excessive exposure to loud or high-frequency noises also can contribute to mental and physical anxiety, accidents and even physical illness.
The US Occupational Safety and Health Administration (OSHA) places limits on the amount of noise that workers can legally be exposed to in the workplace. Exposure of an average of 90 decibels over eight hours is prohibited by federal law.
How loud is 90 decibels? The noise of a power mower or an air hammer is about 90 to 100 decibels. Rock concerts, riveters and compacters emit about 100 to 130 decibels of noise. And the sound of a jet taking off or a shotgun being fired is about 140 decibels or more.
Benefits of Earplugs
Earplugs and other hearing protection devices (HPDs) are the best defense against temporary and permanent hearing loss. When worn properly earplugs reduce the amount of decibels the reach your inner ear by providing a barrier to reduce sound levels.
In workplace environments in which high-frequency or loud noises are common, workers may be required to wear earplugs or other HPDs such as ear muffs or canal caps to help prevent temporary and permanent hearing loss. They also can increase productivity and reduce accidents.