Unless thay moved them and didn't put links to where, it looks like images have been removed from the EPA website. More government efficiency. I was able to find one link at an apperantly new address.
https://www.airnow.gov/?city=Minneapolis&state=MN&country=USAJim
Edit: Poking around i am able to find some interactive maps, but it looks like the the 'airnowtech.org' system of doing things is gone. All the old region codes have files that are 'no map available.'
Someone smarter than me is going to have to figure out what they are doing and provide updated files.
