Continued exposure to noise above 85 dBA (adjusted decibels) over time will cause hearing loss. The volume (dBA) and the length of exposure to the sound will tell you how harmful the noise is.In general, the louder the noise, the less time required before hearing loss will occur.According to the National Institute for Occupational Safety and Health, the maximum exposure time at 85 dBA is eight hours.he volume (dBA) and the length of exposure to the sound will tell you how harmful the noise is. In general, the louder the noise, the less time required before hearing loss will occur.