I am not savvi abough about the science, and can't really comment on the chemistry and biology behind the relationship between carbon fuel emissions and human health, but I do have a sense of a dead horse being flogged.
Battery and Fuel Cell vehicles deliver zero-exhaust-emissions. I think you'll have a hard time selling the idea that having some exhaust emissions is somehow better than having no exhaust emissions... as far as the health of people breathing the air near and around these cars is concerned, anyway.