BOAC
PLease read what I said. Yes you can see see particles liquid or solid in the air.
You know that.
If they are so dispersed to a very low level NO you wont see them.
That is the very arguement which opened up our airspace. At what level of density does ash cause a hazard.
That has been raised and may be raised again or lowered as more data comes in from normal operational aircraft.
Pace