A few weeks ago, the President asked Environmental Protection Agency (EPA) Administrator Lisa Jackson to withdraw the agency’s draft for more stringent Ozone National Ambient Air Quality Standards (NAAQS). Although Jackson begrudgingly complied, the EPA is still moving to an ozone standard more stringent than the current one.

The current ozone standard of 84 parts per billion (the concentration of ozone in the air over an 8-hour period—a drop of gasoline in a tanker truck is one ppb) prevailed while the EPA tried to implement even stricter rules, but since President Obama scrapped those plans, the EPA is moving to enforce the 75 ppb that was adopted in 2008.

The costs for states and areas to comply with a tightened ozone standard are substantial, and it will increase the number of areas in nonattainment—areas in which ozone standards are higher than the regulated amount. These federal mandates can discourage companies from expanding or force them to implement costly emission-reduction technologies. The Wall Street Journal reports:

There are 52 areas where air quality fails to meet the 2008 standard, the EPA said in a memo to state officials. Among them are Baltimore, San Diego, Dallas-Fort Worth and parts of Los Angeles. Ms. Jackson said the EPA would enforce the standard in a “common-sense way” to minimize the burden on state and local governments. The Bush-era standard, while more lenient than the 60 to 70 parts-per-billion level considered by the Obama administration, would still harm the economy, according to business groups. Howard Feldman, director of regulatory and scientific affairs at the American Petroleum Institute, said 75 parts per billion would be costly to implement and damaging to job creation. “The tighter the standards get, they become a much larger hurdle to meet,” Mr. Feldman said.

The massive costs of tightening the standard have outweighed the negligible environmental benefits in the past, and enforcing the 75 ppb will have diminishing marginal returns—possibly to the vanishing point. Even the EPA acknowledged lowering the ozone standard to 70 ppb would only lower asthma and respiratory diseases a few tenths of a percent. Enforcing a standard of 75 ppb would have a similar marginal benefit.

It’s important to note that the causality between a more stringent ozone standard and better health effects is unclear, to say the least. The American Enterprise Institute’s Joel Schwartz and the National Center for Policy Analysis’ Sterling Burnett write:

The most serious charge against ozone is that it kills thousands of people prematurely each year. But, like most other claims of harm from low-level air pollution, this one rests on indirect evidence from so-called “observational” epidemiology studies–studies in which researchers look for correlations between air pollution and risk of death in large groups of people. Evidence shows that observational studies give spurious results, often “finding” effects that aren’t really there, and producing results that reflect researchers’ expectations, rather than reality.

Both animal and human laboratory studies demonstrate that real-world ozone exposures aren’t deadly. For instance: Animals exposed by researchers to 10 times the ozone levels found in the most polluted American cities did not die. In laboratory studies, college student volunteers who breathed controlled concentrations of ozone 50 percent greater than the current standard while vigorously exercising for six hours registered only small, short-term changes in lung function.

What is clear and well established, however, is that improved economic well-being means that people are healthier and live longer. A tighter ozone rule will slow economic growth and reduce economic well-being.

The current ozone standard set by EPA is already more stringent than it needs to be and provides more than enough protection for citizens’ health. President Obama made the right decision when he asked Jackson to withdraw the agency’s draft for even stricter ozone standards. If the President wants to provide regulatory certainty and not increase businesses’ costs, he should tell the EPA to keep the ozone standard where it is.

te that real-world ozone exposures aren’t deadly. For instance: Animals exposed by researchers to 10 times the ozone levels found in the most polluted American cities did not die. In laboratory studies, college student volunteers who breathed controlled concentrations of ozone 50 percent greater than the current standard while vigorously exercising for six hours registered only small, short-term changes in lung function.