Today, the U.S. Environmental Protection Agency (EPA) proposed a revision to the national air quality standard for ozone, a.k.a. smog. EPA is proposing to tighten the primary standard to a level somewhere between 0.060 and 0.070 ppm (parts per million), down from the current standard of 0.075 ppm set in 2008. Under the Clean Air Act, EPA must set the primary standard at a level protective of public health.

EPA is also proposing a separate secondary standard tailored to the environment. “This seasonal standard is designed to protect plants and trees from damage occurring from repeated ozone exposure, which can reduce tree growth, damage leaves, and increase susceptibility to disease,” according to EPA.

EPA’s decision to revise the ozone standard is being hailed by environmentalists and clean air advocates. "This EPA decision will determine the quality of the air we breathe in America for the next decade, and probably beyond, said Frank O’Donnell, president of Clean Air Watch. “If EPA follows through, it will mean significantly cleaner air and better health protection.”

The ozone decision comes on the heels of last week’s announcement that EPA intends to require more air pollution monitors to detect levels of airborne lead. Currently, EPA requires monitors to be placed near sources that emit at least 1 ton of lead per year. On Dec. 30, EPA proposed lowering the placement threshold to 0.5 tons.

Both the ozone and lead standards were most recently updated in 2008 and in both cases, EPA tightened the standards from pre-2008 levels. But the regulations could have been even better if not for the White House.

In the case of the ozone standard, EPA had wanted to set a secondary standard that would have provided extra protection for sensitive plantlife during certain times of the year. But just hours before EPA needed to finalize the rule (to meet a court deadline) the White House Office of Information and Regulatory Affairs (OIRA) objected and asked EPA to set the secondary standard identical to the primary. EPA refused, and President Bush himself was brought in to arbitrate. Bush sided with OIRA.

The White House was not the only party in the wrong. On the larger issue of the primary standard, then-EPA Administrator Stephen Johnson settled on the current 0.075 ppm standard, even though his scientific advisors had recommended a standard between 0.060 and 0.070 ppm (advice current administrator Lisa Jackson and the Obama White House are content to listen to, based on today's announcement). Lowering the primary standard to 0.070 ppm could prevent hundreds of additional premature deaths and heart attacks annually, and prevent tens of thousands of missed school days for children (particularly asthma sufferers), according to EPA estimates.

In the case of the lead standard, EPA had always intended to set the monitor placement threshold at 0.5 tons. But at the last minute, OIRA pressured EPA to double the threshold – a move that would reduce the number of monitors by up to 140 nationwide, making it more difficult for regulators to track airborne lead concentrations and crack down on polluters. (Check out OMB Watch's analysis of the controversy here.)

The proposed lead rule is open for public comment until Feb. 16. The proposed ozone rule will be open for comment for 60 days after it is published in the Federal Register.