Shouting Into the Void

I don’t think of fog as something that echoes. If an empty room filled with fog, I think shouting would end up swallowed, the sound absorbed and reflected by the fog rather than bouncing off far walls. I don’t actually know, and if I looked for answers on the internet, what would I write about here?

If you know the answer, shout it into the void, and perhaps it will reach me.

Rules:
Normal Sudoku rules apply.
Adjacent digits on solid green lines differ by at least five.
Digits within cages sum to the total in the top left corner of the cage.
Fog: Correct digits reveal the cells surrounding them, up to eight.

Estimated difficulty: 1 out of 5