The enemy around us

Sound results from movements in air particles caused by changes in atmospheric pressure. The sound we hear is characterized by:

• Its frequency in Hertz (Hz) – The human ear can hear frequencies ranging from 20 Hz (the lowest-pitched frequency) to 20,000 Hz (the highest-pitched frequency);
• Its intensity in decibels (dB) – The human ear can hear sounds above 0 dB, but sounds above 120 dB are painful; and
• Its duration.

Noise can be defined as unwanted sound. Comprised of many frequencies, it is often complex, and one person’s noise is music to another person’s ears. However, some sounds—such as an explosion, a backfiring engine, or blaring music…and the list goes on—are considered annoying by everyone.

Scientists use the following objective criteria to determine whether a sound can be classified as noise:

• Its intensity (almost any sound that is too loud is unpleasant);
• Its frequency (high-pitched sounds are generally considered more unpleasant than low-pitched sounds);
• Its duration;
• Its complexity;
• Its abruptness (sudden sounds make us feel uneasy); and
• Its rhythm (rapidly-changing sounds can lead to fatigue).

Doctors agree that different people respond to noise in different ways. A person’s noise tolerance depends on the kind of noise and the person’s personality and lifestyle. Quies has developed a range of products, including both wax and foam earplugs, to give you total peace of mind, for even brief exposures to noise.

Noise, the danger is real

Masking effect
Very low frequencies can mask high frequencies and make them difficult to hear (for example, the difficulty we sometimes have hearing someone speaking in a noisy room). This masking effect makes it almost impossible to hold a conversation in a noisy environment. The immediate consequence of this masking effect is fatigue, which is especially dangerous in an industrial workplace because it causes distraction and difficulty focusing.

Auditory fatigue
Auditory fatigue is a temporary reduction in hearing ability. It typically occurs after prolonged exposure to loud noise (above 60 dB), and especially intense noise (above 90 dB). It makes you feel like you have cotton in your ears, and is often accompanied by a ringing or buzzing in the ear. Auditory fatigue will disappear after resting in a quiet environment.

Auditory trauma
Auditory trauma is irreversible damage to the cochlea. It is caused by exposure to violent noise, either once or repeatedly, and can occur even after a single exposure. Hearing damage caused by frequent, long-term exposure to very loud noise (over 85 dB for 8 hours in a row) cannot be reversed, because it destroys the hair cells in the cochlea. Auditory trauma eventually leads to deafness. It can also lead to tinnitus (ringing, buzzing, or drumming sounds in the ear), which is what often prompts unsuspecting victims to see a doctor.

Eardrum rupture
Eardrums can be ruptured by impulse noise, which is an extremely dangerous burst of acoustic energy. Impulse noise often comes from pure, high-frequency sounds like those of an alarm being tested or a firearm going off. These noises can rupture the tympanic membrane immediately, which causes sharp, intense pain. The resulting deafness can be permanent.