Version 1.0 Listen up. Environmental noise is one of the most prevalent pollutants in the world today, with potential negative impacts on your health. The NoiseWatch mobile app uses a built in microphone on your hand held device to determine the level of sounds it detects, and displays this in decibels (dB). It has been designed solely for citizens to measure noise levels wherever they are. You may choose to send your reading, as a rated level, to be displayed on the NoiseWatch web app at the Eye on Earth website for creating and sharing environmental information.