Over the coming year, President Obama will either repeat or undo one of his greatest insults to the environmental community — and to the nation’s air quality.

On Friday, the EPA reaffirmed its longstanding scientific finding that current rules allow too much ozone (a.k.a. smog) in the air and do not adequately protect human health. EPA staff issued a 600-page policy assessment echoing the findings released in June by its advisory panel of outside scientists: The current standard of 75 parts per billion (ppb) of ozone in the air does not protect the health of children, asthmatics, and the elderly. Instead, they say a safe level would be between 60 and 70 ppb, and the lower it is on that spectrum, the more asthma attacks will be averted and lives saved. A 60 ppb standard would prevent up to 12,000 premature deaths, 21,000 hospitalizations, and the loss of 2.5 million work and school days a year, the EPA says.

The move sets up EPA Administrator Gina McCarthy to potentially propose a stricter smog standard this fall. That, in turn, would usher in a period of intense lobbying on both sides of the issue. When that’s done, Obama will have the final say.