Read here. Scientists now know that soot (black carbon) is a huge contributor to global warming, climate change, and Arctic melting, plus causing some 1.5 million+ deaths per year. Why won't the politicians and bureaucrats solve this easily solvable, dirty problem? It would seem they can't figure out how to tax soot in order to generate tax revenues for themselves.
Cleaning up the global soot problem provides any U.S senator with an opportunity to lead and excel. Will any senator do so? Nope. Senators are too pre-occupied with tax revenues from CO2 emissions to make a real humanitarian difference, unfortunately.