Noise can be thought of as unwanted sound and can vary greatly in volume. The definition of noise in the RMA includes vibration, which in most cases is associated with high levels of noise. In environmental assessments, it is usually the noise effects that are of most concern. However, specific vibration effects can arise from some types of commercial activities and these may require specialist investigation which is outside the scope of this guidance note.
The effects of environmental noise are usually expressed in terms of:
- speech interference - high levels of noise can make normal speech difficult to hear
- performance - some noises can make concentration difficult and interfere with tasks such as learning, checking fine details (such as any job with a large mathematical component or where the meaning of words is critical) or work where small, precise, movements or intense concentration is required
- mental health (including noise-induced stress-related effects)
- sleep disturbance - in addition to fatigue and mental health effects, disrupted sleep patterns can leave people irritable, change their behaviour, and reduce their ability to work or perform tasks.