Smog Level Down in Eastern U.S. Cities - WebMD

Lung-threatening smog levels dropped 7% last year in the Eastern U.S., a new government report shows.

The Environmental Protection Agency (EPA) said Thursday that levels of smog, also known as ground-level ozone, continued a six-year declining trend since 2000. Overall, smog pollution in the Eastern U.S. has dropped 60% since the beginning of the decade, the report concludes....