Whether noise will harm your hearing depends on a combination of factors such as volume, exposure time, frequency and individual susceptibility. A single episode of very loud noise can do damage, but so can not-so-loud noise that extends over a long time.
Decibel readings offer the most convenient way of measuring noise exposure. For context: Ordinary conversation between two people is approximately 60 decibels. At the other end of the spectrum, the pain threshold — where damage can be done quickly and where you’d be inclined to cover your ears — generally starts at around 120 decibels, researchers say.
If you’re interested in monitoring how much noise you’re being exposed to, there are some free or inexpensive noise-measuring apps available both for iPhones (among them Decibel Ultra, NoiSee, dB Meter, SPLnFFT Noise Meter and Noise Hunter ) and Android phones (including Sound Meter, Noise Meter and deciBel).
— Joyce Cohen