How are noise levels measured?
Noise specialists measure levels by decibels or dBA — a unit of relative loudness. This unit of relative loudness closely approximates the human ear’s response to sound. On this scale, normal breathing registers about 10 dBA, a clothes dryer at 10 feet registers about 50 dBA, and a pickup truck going 50 miles per hour and 50 feet away registers about 70 dBA. Adding 10 decibels doubles the apparent noise level.
