Outdoor Ambient Sound Pressure Levels

Outdoor ambient sound pressure levels (dBA) in rural and urban business and industrial environments with or without limited traffic.

In residential areas most noise comes from transportation, construction, industrial, and human and animal sources. Road traffic noise is the major source of noise.

The noise can be highly variable. It is common that Day-Night sound levels - L_dn - in different areas may vary a range of 50 dB. The outdoor level - L_dn - in a wilderness areas may occur as low as 30-40 dBA compared to 85-90 dBA in a urban areas. Most urban dwellers lives in areas of L_dn more than 48 dBA.

The table below indicates common outdoor sound pressure levels in rural and urban environments at the different octave bands.

Outdoor Sound Pressure *(dB)*
Conditions		Octave Band Center Frequency (Hz)
Conditions		63	125	250	500	1000	2000	4000	8000
Night-time
	Rural, no nearby traffic of concern	42	37	32	27	22	18	14	12
	Suburban, no nearby traffic of concern	47	42	37	32	27	23	19	17
	Urban, no nearby traffic of concern	52	47	42	37	32	28	24	22
	Business or commercial area	57	52	47	42	37	33	29	27
Daytime
	Business or commercial area	62	57	52	47	42	38	34	32
	Industrial or manufacturing area	67	62	57	52	47	43	39	37
	Within 300 ft (91 m) of continuous heavy traffic	72	67	62	57	52	48	44	42