The health effects of noise are divisible into two – auditory and non-auditory.
The first are about impairment of hearing and occur almost exclusively in industrial settings. Environmental noise levels do not produce these effects.
Non-auditory effects include, most commonly, annoyance (if such an effect can truly be called a ‘health’ effect), sleep disturbance, interruption of speech and social interaction, disturbance of concentration (and hence of learning and long-term memory), and hormonal and cardiovascular effects, though it is not clear to what extent these effects are actually harmful.
While it is often suggested, there is no real evidence that noise per se induces mental illness, though there is some to suggest that noise-sensitive people are more prone to mental illness and that the effects of noise may be more pronounced in mentally ill people.
For more information on how noise can affect health, visit the WHO Noise and Health website.