Complete burn is not guaranteed to be 100% clean. If you don't filter coal plants you get all the nasty up in the air. If you could burn something at a level y

Complete burn is not guaranteed to be 100% clean. If you don't filter coal plants you get all the nasty up in the air. If you could burn something at a level you don't need exhaust filters, and that even doesn't clean up all the harmful particles, we'd be building coal plants everywhere, rendering PV and renewables (and even nuclear) research unnecessary.