I can drive mine for about 4-5 days in good weather before the dust/pollen etc starts to get annoying. It's not worse than any other black car...
I always avoid any sprinklers or water in the roads. I also quick detail after I clean it to get the water run off from the side mirrors and trunk. Other than that, keep it waxed up so it takes longer for dust to stick.
E92 M3 | Jet Black | All OEM Everything
E30 M3 | Alpine White | Mostly OEM