Well..DUH!
https://www.investors.com/politics/editorials/ethanol-environment-damage/
The devastating report — based on, yes, actual "science" — shows that the forced addition of ethanol to the nation's gasoline is making our air dirtier.
The irony, of course, is that ethanol's entire rationale is that it would make our air cleaner.
Why do we keep doing this? The farm-based ethanol lobby not only wants current standards of up to 10% of our fuel made up of ethanol (the "E10" standard), but would like to see it rise to 15% (E15). And, unfortunately, President Trump seems open to the idea.
https://www.investors.com/politics/editorials/ethanol-environment-damage/