How urban hum became the noise limit in ontario


  • Tim Kelsall Hatch, 2800 Speakman Drive, Mississauga, Ont. L5K 2R7


Environmental impact, Job analysis, Laws and legislation, Municipal engineering, Traffic control, Urban planning, Community reaction, Sound level, Traffic noise, Urban hum


Since 1978 MOE has used the equivalent sound level of urban hum, that amalgam of distant traffic and other sounds which forms the background noise in most urban and suburban areas, as the primary limit for assessing the noise impact from industry and other sound sources. This means that the limit to be used at a specific location is based on the sound actually received at that location, rather than an arbitrary number. This has made sense to industry, residents and consultants, who have used this limit for over 25 years. It has also been used in a Federal-Provincial guideline and many practical limits are found to be based indirectly on urban hum. In this paper, the origins of this limit are explored and some of the issues which were examined at that time and later are discussed. How urban hum behaves, how widespread it is and how it is used as a limit are also reviewed.

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How to Cite

Kelsall T. How urban hum became the noise limit in ontario. Canadian Acoustics [Internet]. 2004 Sep. 1 [cited 2024 Jul. 20];32(3):44-5. Available from:



Proceedings of the Acoustics Week in Canada