Noise exposure is measured as an integrated dose, trading level against duration

Evidence

The integrated noise dose is defined as the equivalent level of the sound over a fixed period of time, which is currently 8 hours. In other words, the noise exposure can be greater than the second action level provided that it is for an appropriately shorter time, which results in a noise dose that is less than that which would result from being exposed to noise at the second action level for 8 hours. The measure used is the Leq mentioned earlier, and the maximum dose is 85 dB Leq over 8 hours. This means that one can be exposed to 88 dBA for 4 hours, 91 dBA for 2 hours, and so on. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 686

Categorization

• DEFINE: Defines integrated noise dose and the Leq measure with a concrete trading rule of level against time.
• XREF: Connects to the reader’s parallel interest from soundscape/noise-damage books where dose-response is similarly inverted.