Noise pollution in the United States has increased to such an extent that it affected the people to a great extent. People suffer from increased blood pressure, they are deprived of sleep and even their heart rate has increased. If the volume of the car stereo or an iPod is increased to such a level that   other people are also able to hear it clearly it means that you are assaulting your won ears and over the course of time your ears would also get adjusted to the new level. So to protect your ears from any noise pollution related disorders one has to lower the volume and listen to music.