ATLANTA (AP) _ Today marks the start of smog season in metro Atlanta.
The American Lung Association ranks the region the 12th smoggiest metro area in the nation. That's up from Number 25 last year.
Most of metro Atlanta's smog-forming pollution comes from vehicles.
Clean Air Campaign spokesman Brian Carr says many people are unaware that their daily driving is bad for the environment. In his words, "You're trying to undo a mentality of an entire region that's so dependent on cars.''
If this year is like the past two, metro Atlanta can expect orange- or red-alert warnings on about 30 days.