WHAT IS A DECIBEL?
A decibel (dB) is a unit of measurement for sound. A-weighted decibels, abbreviated dBA, are an expression of the relative loudness of sounds in air as perceived by our ears.
SAFE & UNSAFE DECIBELS
The National Institute of Occupational Safety (NIOSH) states that for a 115 decibel (dB) sound, the exposure limit is just 28 seconds.
Exposure to noise louder than the Environmental Protection Agency (EPA) safe noise level of 70 dB over 24 hours will damage hearing.
An abundance decibel-reading apps for smartphones make it easy to learn how much noise is in the world around us. Most apps use the smartphone’s microphone to give a reading of the decibel level.
As with a professional-grade meter, most phone apps can also show how the noise fluctuates over time, in real time, and provide numerical reference points that users can compare to their own sound levels. Some apps even let you geo-tag the decibel level to a specific location, like your favorite restaurant or your workplace.
HHF used Decibel Meter Pro to record the noise levels of hundreds of New York City subways. The samples show the average noise levels on all subway platforms and on all subway rides (inside subway trains) is between 72.5 and 76.5 dB and between 74.1 and 75.8 dB, respectively. With maximum readings actually as high as 119 dB on platforms and 120 dB on rides—based on actual recorded data within the sample—the subway system is an auditory minefield.