Coming full circle on a campaign promise, the Obama administration will propose tightening the amount of a smog-forming pollutant in the air.

People familiar with the proposal tell the Associated Press that the EPA will recommend lowering the limit for ground-level ozone to 65 to 70 parts per billion, down from a 75 parts per billion standard set in the 2008.

The proposal will be announced Wednesday to meet a court-ordered Dec. 1 deadline. The stricter standard makes good a campaign promise Obama made during his first run for the White House: to reverse President George W. Bush's decision to set a limit weaker than scientists advised.

In 2011, facing re-election, Obama scrapped an EPA plan to tighten the standard after Republicans and industries said it would hamper the economy.