Involuntary and Persistent Environmental Noise Influences Health and Hearing in Beirut, Lebanon
Table 1
Physiological and psychological effects of noise pollution.
Effect
Comment
Annoyance
Even relatively low levels of noise can cause annoyance and frustration. A tranquil background can make noise more intrusive. Natural sounds are generally less annoying than unnecessary or controllable sound such as car horns. For instance, intermittent sounds such as a tap dripping on a quiet night can be more disturbing than the sound of falling rain.
Speech interference
Noise can interfere with speech. When the background noise level is 50 dBA, normal conversation can be easily carried with someone up to 1 m away. Any more than that, problems will arise.
Sleep interference
Noise can wake people from sleep and keep them awake. Even if not actually woken, a person’s sleep pattern can be disturbed, resulting in a reduced feeling of well-being the next day. External noise measuring up to 30 dBA in a bedroom is appropriate for sleep.
Decreasedwork performance
Noise pollution can make people nervous. Accordingly, it can prevent people from concentrating on their work. As noise levels increase, ability to concentrate and work efficiently and accurately reduces. Louder noise bursts can be more disruptive. Noise is more likely to reduce the accuracy of the work than reduce the total quantity of work done. Complex tasks are more likely to be impaired.
Hearing loss
Prolonged exposure to noise levels above 85 dBA can damage inner ear cells and lead to hearing loss. At first, hearing loss is usually temporary and recovery takes place over a few days. After further exposure, people may not fully recover and develop deafness. The extent of deafness depends on the degree of exposure and individual susceptibility. Even brief exposure to very high levels of 130 dBA or more can cause instant, irreversible hearing damage. Research has shown that noise is one of the leading causes of hearing loss for millions of people with impaired hearing in the United States.
Physiological changes
Noise can change a man’s physiological state by speeding up pulse and respiratory rates. There is medical evidence that noise can cause heart attacks in individuals with existing cardiac injury and that continued exposure to loud noises could cause such chronic effects as hypertension or ulcers. According to medical studies, there is an increased risk to the cardiovascular system from a sound pressure level of above 65 dBA.
