Perhaps a stupid question:
Can’t they put some kind of fine screening on the front of the engines?
A screen would have to be like silk and that would not allow sufficient airflow to keep the engines running.
No. That would restrict airflow to the engines and the screen would have to be extremely fine to capture the dust particles not to mention it would be sucked into the engine itself under high power. Even if it were possible though it wouldn’t be economically feasible. Volcanic eruptions have never impacted air travel to this extent. Usually airlines can just route around the ash cloud. This is a once in a century type deal.