Dust / Smoke

[NedLynch]

Yup same here as well as clouds.
The sad thing about clouds is, it's a realism setting, they actually influence the aircraft negatively when you fly through them performance wise, make your instruments go nuts if you don't have or turn on your pitot heater and of course the pilot with reduced visibility. So it's really desireable to have them on if you want realism.
But on the upside the clouds as well as the whole graphics engine are still not final, as Luthier stated in the future plans, with a reworked graphics engine we should experience a 50% performance increase.