The louder the noise, the greater the noise level. You can listen to noises that are 70 decibels or lower for as long as you wish. Sounds at 85 dBA can cause hearing loss if listened to for more than 8 hours. At 100 dBA, you should stop listening to them after 4 minutes. Decibels are measured with an electronic device called a decibel meter. The sound of a lawn mower, for example, is around 75 dBA. A jackhammer is about 90 dBA. The higher the number, the louder the noise. Even sounds at low levels can be heard by sensitive ears. For example, the whirring of a fan is about 45 dBA; the ticking of a clock is about 35 dBA. Sounds range in intensity from very soft voices (about 60 dBA) to very loud noises (about 110 dBA). Most noises you hear every day are between these two values, such as when someone opens a door or takes out the trash. Loud noises are those that exceed 120 dBA for longer than 3 minutes; they can cause damage to your ears. Examples include car accidents, explosions, and power tools. Your risk of hearing loss increases with the length of time you expose your ears to high-intensity sounds.