Environmental noise is the summary of noise pollution from outside, caused by transport, industrial and recreational activities.
Noise is frequently described as 'unwanted sound', and, within this context, environmental noise is generally present in some form in all areas of human activity. The effects in humans of exposure to environmental noise may vary from emotional to physiological and psychological.

Noise at low levels is not necessarily harmful; environmental noise can also convey a sense of liveliness in an area, and is not then always considered 'unwanted'. However, the adverse effects of noise exposure (i.e. noise pollution) could include: interference with speech or other 'desired' sounds, annoyance, sleep disturbance, anxiety, hearing damage and stress-related cardiovascular health problems.

As a result, environmental noise is studied, regulated and monitored by many governments and institutions, as well as forming the basis or branch for a number of different occupations.

Monitoring for compliance with the noise emission conditions of an IPC Licence should be primarily based upon International Standard ISO 1996: Acoustics Description and Measurement of Environmental Noise – or a method approved by the Agency. In certain instances, some of the assessment procedures and methodologies outlined in BS 4142 and BS 5228 (Appendix III) may be utilised as part of the overall strategy.