Many people complains about Coaler Cough. I suggest a filter to prevent insane dmg, might be implemented in few ways:
1. Just another 1R item, Coaler mask, working exactly like miner helmet.
2. Add a fuel bar to Boreworm mask or bandits mask, fuel stands for an hour, and prevent all damage. Refill with filter.
Filter should have a raw wool and water in recipe, maybe cloth if it will be a mask.