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Sound is measured in decibels. A decibel (dB) is basically the level of intensity of a sound, also called sound pressure. Silence is 0 dB. A normal conversation is approximately 60 dB—if you’re a participant in the conversation. If you’re 10 metres away from that conversation, the decibel level is far less. So, because decibel level is determined in relation to a human ear, distance from a sound is an important factor in determining the decibel level of that sound.
What’s important to remember is that sounds above 85 dB can cause hearing loss. A lawnmower is about 90 dB for the person who is mowing. A snowmobile is about 100 dB for the person who is snowmobiling. Yet, those persons don’t lose their hearing after mowing or snowmobiling. That’s because the length of exposure is also a factor in how those high-decibel sounds affect hearing. Someone who has a job mowing lawns—and therefore does it every day for months and years—would eventually start to experience hearing loss if he or she didn’t wear ear protection.
The music at a rock concert is in the range of 120 to 140 dB. When a sound is 140 dB or more, it can cause hearing loss in a very short period of time. If you go to a rock concert, wear earplugs, don’t ever sit or stand close to the speakers, and walk out every once in a while, to give your ears a break.
People sometimes say that loud sounds burst your eardrums, and that’s what causes hearing damage. That actually isn’t what happens. High-decibel sounds damage tiny hair cells in your inner ear. These hair cells send signals to your brain so that you can hear voices, music, and other noises. When those hair cells are damaged, they can’t properly send signals to your brain. That’s hearing loss.