Exposure to sound levels in excess of 85 decibels for more than eight hours is potentially unhealthy. Eighty-five decibels is roughly equivalent to the noise of heavy truck traffic on a busy road.
Above 85 decibels, hearing damage is related to sound pressure (measured in decibels) and to time of exposure. The major cause of hearing loss is occupational exposure to noise, although other sources (particularly recreational noise) are also culprits. Studies suggest that children seem to be more vulnerable than adults to noise induced hearing impairment. Children in noisy environments are also found to have more difficulty reading and learning, and experience a diminished quality of life.
Children, the elderly, and those with underlying depression may be particularly vulnerable to noise pollution because they may lack adequate coping mechanisms.
Noise pollution impairs task performance at work and in school, increases errors, and decreases motivation. Focusing, problem solving, and memory are most strongly affected by noise.
Although noise pollution is not believed to be a cause of mental illness, it is assumed to accelerate and intensify the development of latent mental disorders, anxiety, stress, nervousness, nausea, headache, emotional instability, argumentativeness, sexual impotence, changes in mood, increase in social conflicts, neurosis and psychosis. Population studies have suggested associations between noise and well-being, the use of psychoactive drugs and sleeping pills, and increased mental-hospital admission rates.
Noise levels above 80 decibels are associated with both an increase in aggressive behavior and a decrease in behavior helpful to others. News agencies regularly report violent behavior arising out of disputes over noise, often ending in injury or death. The effects of noise may help explain some of the dehumanization seen in the modern, congested, and noisy urban environment.
Noise pollution effects the environment very differently than regular fossil fuel pollution, but it can still have very negative effects. For this reason, many states and counties have developed noise control laws that designate exactly how much noise a vehicle can legally emit, or how loud a band can play in an outdoor restaurant. The problem with noise control laws, however, is they can be very difficult to enforce.