It’s become an annual spring ritual, but the American Lung Association’s “State of the Air” report — essentially a report card on the country’s air — contains some valuable lessons.

First is that we have seen progress in dealing with widespread air pollutants such as ozone, or smog, and fine particle soot. States with the most aggressive cleanup approaches, such as California, have seen the most improvement.

But second, and equally important, we still have a major public health problem from air pollution. This is important since virtually all public attention regarding smokestacks and tailpipes concerns global warming. The ALA found that about two in five Americans live in areas afflicted by dirty air. (That number will increase under the new EPA ozone standard.)

Third, progress appears to have stalled in many places. This is a pretty obvious manifestation of seven years of Bush administration negligence and deal-cutting for industry. The poster child is Pittsburgh, which earned the dubious honor of being the dirtiest city in American for short-term exposure to deadly particle soot.

And finally, we need stronger protections to accelerate further progress. Congress may need to step in and compel additional cleanup of old coal-burning power plants. And the EPA should consider requiring the 13 million existing diesel engines to use modern pollution controls.