One billion teenagers and young adults around the world are in the face of losing their hearing by listening to loud music. This is according to the World Health Organization. Few things can make people happy and full of energy like good music. Many people believe louder is better if you are listening to rock and roll. But if you really listen to the music loudly, even really good music, it can hurt your hearing badly. If a person takes a subway to go from one place to the other for half an hour in the morning and a half an hour in the evening, and every day has to _ on his audio device because there is so much of noise of the train and everything around, and is listening to for one hour every day, his hearing is going to be hurt seriously in a few years, in a couple of years time, for sure. There can be many kinds of unsafe levels of sound. It depends on how loud the sound is and how long you listen to it. Unsafe can mean noise levels of 85 decibels for eight hours a day or 100 decibels for just 15 minutes. There are simple ways to protect people from unsafe sound levels. Young people who wear earplugs during concerts can enjoy music at 90 decibels as much as they can at 110 decibels. But earplugs may not look very cool. The fact that earplugs may look un-cool may be true today, but if there is nothing wrong with your hearing in the future may be true and wearing earplugs may actually be cool. Another common suggestion is to turn down the volume on your personal audio devices. The World Health Organization also advises young people to limit their use of such devices to less than one hour a day. Besides, the World Health Organization reminds people to use technology, such as smart audio devices keep listening levels safe. The levels of sound is safe or not depends on   _  .
what kind of music is and where you listen to it how loud the sound is and how long you listen to it how clear the sound is and how often you listen to it how much the audio device is and how long you keep it