Environmental Effects Of Noise Pollution

Noise pollution (or acoustic contamination) is called the excess of sound that disturb normal ambient conditions in a specific area. While noise does not accumulate, moved or maintained over time as other pollutants, can also cause extensive damage to the quality life of people, if is not well controlled.

The term "noise pollution" refers to noise (defined as excessive and annoying sound) caused by human activities (traffic, industry, entertainment, aircraft, etc.), which produces negative effects on hearing, physical health and mind of living beings.

This term is closely related to the noise because this is when the noise is considered a contaminant. Transportation, building construction and public works, industry, etc. are examples of factors that contribute to this pollution.

3.2 INTRODUCTION

For years the noise has become a pollutant factor that affects people, but now is a serious problem with physiological, psychological, economic and social effects. Noise has existed since ancient times, but from the past century the problem of urban noise begins to appear, as a result of the Industrial Revolution, the development of new means of transport and the growth of cities.

Noise has some differences with respect to other pollutants:

3.4.1 Effects produced by noise

The noise appears to be the most innocuous of pollutants since, is perceived by one sense, hearing, and occasionally in the presence of high levels of sound pressure, by touch (vibration perception), whereas the other pollutants are captured by several senses with similar level of discomfort . As if this were not enough, the perception and the damage of these pollutants is usually instantaneous, unlike the noise that the effects are cumulative.

3.4.1.1 Physiological Effects

• Auditory effects

Hypoacousis or hearing loss that occurs from exposure to extremely loud sounds during brief moment (for example 130 dB for a minute) or to loud sounds repeated over several years (e.g. exposure related to employment 90 dB over 5 years). But even, moderate levels like 75 dB permanently for 40 years, cause hearing loss, in susceptible people. It is important noted that hypoacousis caused by noise is irreversible, and primarily affects the sensory cells of the inner ear, which are not

The ear is a transducer, does not distinguish between noise sources. The separation and identification of sound sources occurs in the brain. The human voice produces sound in the range 100 to 10,000 Hz, but practically all nonverbal information is contained in the region of 200-6000 Hz. The frequency band for speech understanding (understanding words and phrases) is contained between 500 and 2500 Hz. It is believed that interference with speech communication during work activities can lead to accidents caused by the inability to hear warning calls or other indications. In offices and schools and homes, interference in the conversation is a significant source of