The Figure below shows decibel levels of several different sounds. As decibel levels get higher, sound waves have greater intensity and sounds are louder. For every 10-decibel increase in the intensity of sound, loudness is 10 times greater. Therefore, a 30-decibel “quiet” room is 10 times louder than a 20-decibel whisper, and a 40-decibel light rainfall is 100 times louder than the whisper. High-decibel sounds are dangerous. They can damage the ears and cause loss of hearing.
James is attending a concert. When he first walks in the concert hall there aren't that many people there and it is relatively quiet. As the room fills up it starts to get a bit louder. And when the concert starts its so loud that it is almost painful for him as he is sitting near the speakers.

Given the concert is now over and everyone is leaving, will the decibel levels increase or decrease?