To add a bit to this, though, it’s worth taking a closer look at why environmentalists and clean-air advocates are so furious right now. Groups that have been lobbying for the long-delayed ozone update say they were essentially betrayed by the Obama administration, which, back in 2009, had fended off a lawsuit over Bush-era ozone rules by promising to issue tougher new standards. That, obviously, isn’t going to happen now. What’s more, critics note, the White House’s stated reasons for yanking the rules make no sense at all. Do they have a point?

First, some context. Under the Clean Air Act, the EPA is required to conduct a review of national standards on industrial smog every five years. Ground-level ozone is formed when emissions from power plants, vehicles and factories reacts with sunlight. The resulting pollution can, as the EPA explains, “trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma.”

The last time new ozone standards were set was back in 1997 — at 84 parts per billion. In 2006, the EPA reviewed the science on ozone and health, which had advanced considerably over the years: It wasn’t until the 2000s, for instance, that researchers realized ground-level ozone might actually be killing people, not just causing respiratory problems. Realizing that the old standards were woefully out of date, EPA scientists recommended a new level of 60 to 70 parts per billion. The Bush administration, however, decided to go with a less-stringent level of 75 parts per billion in its final rules, issued in 2008.

Groups such as the American Lung Association quickly filed a lawsuit to stop the Bush rules, which they claimed were too weak and would lead to thousands of unnecessary deaths and cases of respiratory disease. After Obama got elected, however, the new EPA said it basically agreed with the critics and would issue stronger rules by August 2010. At that point, the ALA agreed to hold off on its lawsuit. “We said, that sounds reasonable to us,” says Paul Billings, the ALA’s vice-president for policy and advocacy. “We basically trusted their intentions.”

But August 2010 rolled around. Still no rules. The EPA asked for a further extension. Then October. Then December. Still nothing. Then the EPA said it wanted to go back and look at the science again, just to double-check. Sure enough, EPA’s scientific review board said that a standard of 60 to 70 parts per billion was the most cost-effective way to protect public health. And EPA administrator Lisa Jackson announced that the final rules would be in line with the science.

Industry groups, obviously, weren’t pleased with this. They noted that complying with a stricter standard could cost them anywhere from $19 billion to $90 billion per year by 2020. (The EPA did, however, note that a tougher standard would yield benefits of $13 billion to $100 billion, and that the benefits would outweigh the costs.) Republican House Majority Leader Eric Cantor dubbed the ozone proposal “possibly the most harmful of all the currently anticipated Obama administration regulations.”

So now, today, the White House announced that it’s not going to have any new rules. On a call with reporters, White House officials argued that it doesn’t make sense to put out new rules in 2011 when there’s going to be another scheduled review of the ozone science in 2013.

But critics say that this reasoning is flawed. For one, notes Amy Royden-Bloom of the National Association of Clean Air Agencies, if the EPA did issue a new ozone standard this year, then it could always just postpone its next scientific review until 2016, in line with the law. Second, notes Frank O’Donnell of Clean Air Watch, there’s no reason to think that a brand-new ozone standard will actually be issued by 2013. That’s just when the scientific review is due. Crafting new rules will take longer than that, given the inevitable delays and lawsuits. “I’d say three years, minimum,” says O’Donnell. (When I asked White House officials about this, they said they weren’t sure how long it would take.) And third, says Paul Billings of the ALA, it’s not clear that the science on ozone and human health will change dramatically between now and 2013 — if anything, the case for regulating ozone is likely to get stronger.

So what happens now? Right now, most states are still operating under the old 1997 standards. The EPA had earlier directed states not to follow the (somewhat stricter) 2008 Bush standards, because it was working on even tighter rules. But now those tighter rules aren’t happening. As Bill Becker of the National Association of Clean Ar Agencies told me, the EPA now has the option of directing states to follow the Bush-era rules, but that seems unlikely, given the White House’s preference to wait until the 2013 review. Which means states would keep operating under the old 1997 standards, which are more lax than even what the Bush administration had proposed. “We would have stricter protections right now if we had just followed the Bush-era rules back in 2008,” says Becker.

And it’s unclear whether the ozone rules will get updated anytime soon. Becker notes that with each delay, the political debate over ratcheting up the standard becomes fiercer and fiercer, because the costs of compliance of any new rule will go up. And if a new president hostile to environmental regulation comes into office — Rick Perry, say — then the EPA may never get around to issuing new ozone rules.

Not surprisingly, business groups are pleased with this prospect. “This is an enormous victory for America’s job creators,” the Chamber of Commerce announced today. The White House, meanwhile, is trying to deflect criticism by pointing out all the other new EPA regulations they’ve been moving forward with. But this move looks like it could leave a lasting rift between the White House and its environmental base.