In the last 15 years, the proportion of employees exposed to hearing-hazardous noise has increased both in Europe and worldwide.

The construction and industry sectors continue to be among the most affected, so it is necessary to apply rigorous measures to reduce this problem.

Difference between sound and noise

Sound is the auditory sensation produced by the vibration of an object. These vibrations are captured by our ears and transformed into nerve impulses that are sent to our brain.

Noise is the auditory sensation of variable type and intensity but of an unpleasant nature.

Parameters that define noise

Noise is characterized by the following parameters:

• Frequency: It is the number of pressure variations per second. It allows to distinguish the bass sounds (low frequencies), medium or sharp (high frequencies).

This quality is measured in Hertz (HZ), of which the human ear can only perceive sounds (noise) that are in the frequency range between 20 and 20,000Hz. At the same intensity, high-frequency sounds are more damaging to the human ear than low-frequency sounds.

• Intensity: Intensity indicates the amount of energy. This depends on the amplitude of the wave of the sound emitted since, the greater the amplitude of the wave, the greater the intensity of the sound or, what is the same, the greater the “volume”. It is measured in decibels (dB).

• Exposure time: The longer the noise exposure time, the greater the probability that noise exposure will be harmful.

• Nature of the noise: The noise can be continuous or an impact.

Legislation

In Europe, noise has been recognized as a cause of occupational disease since 2003. Directive 2003/10/EC establishes a common policy to fight noise in the workplace, the most frequently reported disease in the European Union.

• From 80dB(A)

– Provision of individual protectors against noise
– Training on the risks posed by noise
– Audiometric exam

• From 85dB(A)

– Implementation of a program of measures to reduce exposure to noise
– Mandatory use of hearing protectors
– Intensified audiometric exam

• From 87dB(A)

– Threshold not to be exceeded (individual noise protectors in place)
– Application of immediate measures to reduce exposure
– Limitation of the duration of exposure of workers

The effects of noise

Except in cases of exposure to extreme intensities, the effects of noise on hearing take time to manifest. However, the consequences of noise are not limited to hearing and affect the body and daily life both directly and indirectly.

• Listening fatigue: Hearing fatigue is a temporary state of partial deafness during which the ear loses some of its sensitivity. Therefore, it is heard less for several hours, even for several days.

• Tinnitus: Tinnitus is a ringing sound that can be heard even when there is no noise around. Tinnitus can be temporary or chronic, affecting one or both ears.

• Hyperacusis: Hyperacusis is a hearing dysfunction in which the affected ear becomes hypersensitive to certain sound frequencies. In such a case, the person is said to hear “too well.”

• Acute sound trauma (ATS): TSA is a hearing problem linked to intense sound shock. It can manifest through all of the effects described above. Military personnel, police officers or musicians frequently suffer from acute sound (or acoustic) trauma.