That no matter what scientists and engineers try, when combusting fossil fuel, the exhaust smells like a terrible latrine.
I think that would spur a quick response from everyday citizens as to what they heat their homes with, or how they get around their cities.
In fact, in contrast to not harming people, it actually has the potential for a great boost in economic activity. Giving money/erasing debt for low income/middle income people tends to result in local spending. These people don’t hoard wealth like occurs when you give rich people or corporations tax cuts.