Specialists propose the following values as acceptable upper limits for the duration of noise exposure: A loudness of 85 dB, which roughly corresponds to the amount of noise inside a car, may be safely maintained for eight hours.
A noise level of 90 decibels, as produced by a standard lawn mower, may easily be tolerated for 2.5 hours. 95 decibels is the decibel level generated by a motorbike, which should not be exposed to for more than 47 minutes. The metro and automobile horns emit 100 decibels, which should not be sustained for more than 15 minutes.