It’s great to have some real estimates on this, and wow: Economists: Every $1 of Electricity from Coal Does $2 in Damage to U.S.

Plus, the original source article even indicates this is a very conservative estimate because it doesn’t include costs related to climate change.  I imagine it’d be a lot harder to tie the climate impact of emissions in the US directly back to problems the US, since climate change is a more global effect.  Detecting health problems due to local pollution is easier.