Physical Properties of noise
The annoyance caused by noise effects is related to some of the physical properties of noise.
- Level and exposure: High noise levels have more negative effects and are more annoying. WHO recommends a maximum continuous noise exposure of 85 dB(A) for 8 hours per day. Hearing damage is negligible below 75 dB(A). For each extra 3 decibels louder, the noise is twice as strong so the exposure time should be halved.
Level and expsure
| Level db (A) | 85 | 88 | 91 | 94 | 97 | 100 | 110 |
| Permissible exposure time | 8h | 4h | 2h | 1h | 30m | 15m | 1m |
- Frequency: The ear is more sensitive to high frequencies than to low frequencies. As a natural result of this, high frequency noise is more disturbing and annoying than low frequency noise.
- Spectrum: Annoyance as a result of noise is greater for pure-tone (or sound having tonal components) than for broad-band noise
- Temporal changes: Annoyance is greater for intermitted noise than continuous noise.
There are more items effecting annoyance such as;
- Annoyance is greater for moving or unlocatable (reverberant) noise than for a fixed location sound,
- Much greater for an intelligence-bearing noise (neighbors radio) than for a non-sense noise
