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.)