Beausoleil
What I should have said was "ash" of course. Silly me. I was going to mention, but didn't, soot from the Kuwait oilfields that were ignited during the gulf war, which along with blowing sand, caused huge amounts of "clag" in the area, but did not stop operations.
However, if you think we are not dealing with "grit" and "silicon" what do you suggest it is that has been deposited on my car this morning?