Any special needs especially air, oil, and fuel filtering. Just remembeering the effects of Mt St Helens.
The problem from Mt. St. Helens would have been rocky ash that was pushed into the atmosphere - ash would physically clog air filters and if ingested in internal combustion engines would score and damage piston walls and valve seats and thus virtually eliminate compression within the engine that is required for the engine to continue to operated.
Smoke would, I suspect, decrease the amount of oxygen in the air and thereby decrease power output by some small percentage - no worse than operating at high altitude in ‘clean’ air.