Prolonged exposure to loud sounds and any exposure to extremely loud sounds contribute to hearing loss. Sound is measured in decibels (dB). The higher the decibels of a sound, the more damaging it is to a person's hearing. Many sounds rank high in terms of decibels but do not produce pain. Though they produce no pain, that does not mean they are not causing hearing damage.
No Risk (40 dB and below)
Noises in this range pose no hearing risk. Normal breathing rates at 10 dB. Rustling leaves, which are considered to just be audible, rate at 20 dB. The average whisper registers 30 dB, while a humming refrigerator produces 40 dB of sound.
Minimal Risk (41 dB to 84 dB)
Most of the sounds in this decibel range pose no threat to hearing, though constant exposure to some can result in very minimal damage. A quiet office produces approximately 50 to 60 dB of sound, whereas conversation at a normal level ranges between 50 and 65 decibels. Sounds ranging between 70 and 79 decibels include hair dryers, vacuums, dishwashers and washing machines. City traffic, garbage disposals and moving diesel trucks generate sounds ranging from 80 to 84 dB. At this range, minimal hearing loss is possible with prolonged exposure.
Moderate Risk (85 dB to 100 dB)
Hearing damage begins at 85 dB but requires prolonged exposure. Televisions and recreational vehicles produce 70 to 90 dB, while lawnmowers and blenders create 85 to 90 dB and subways produce 88 dB of sound. At these levels, eight hours of exposure can produce hearing loss. Unprotected exposure to sounds between 90 dB and 100 dB can result in hearing damage if exposed for greater than 15 minutes. Newspaper presses produce 97 dB of sound and tractors on a farm produce 98 dB. Garbage trucks and cement mixers rate at 100 dB.
High Risk (101 dB to 120 dB)
Any sound over 100 dB is considered high risk for causing hearing damage, and exposure should be limited to less than one minute. A jet flying at 1,000 feet produces 103 dB of sound. A snowmobile creates 105 dB when in use. Power tools, such as jackhammers and chainsaws, generate 110 dB. Stereos over 100 watts create decibel levels ranging from 110 to 125. Symphony orchestras produce 110 dB of sound. Nearby thunder can create decibel levels up to 120.
Extreme Risk (121 dB and above)
Sound causes pain beginning at 125 dB. Oxygen torches rate just below the threshold of pain, at 121 dB, but aeroplanes produce sounds above 125 dB. Take-off generates 130 dB, while the constant hum of a working jet engine produces 140 dB. Shotguns create 130 dB of sound when fired. Rock concerts produce a range of decibel levels from 110 to 140. All rock concerts pose a risk to hearing, but some actually induce pain from the high decibel levels.