The Environmental Protection Agency (EPA) this week finalized more stringent standards for automotive emissions and the sulfur level in gasoline. The agency claims that the new rules will prevent 2,000 premature deaths per year (!) and 50,000 cases of respiratory ailments in children.

Don’t believe it. As is commonly the case, the EPA vastly exaggerates the benefits of its regulations and lowballs the costs.

The so-called Tier 3 standards are designed to reduce emissions of volatile organic compounds and nitrogen oxides by 80 percent and particulate matter (PM) by 70 percent. The standard for sulfur in gasoline will drop from 30 parts per million (ppm) to 10 ppm beginning in 2017. (The EPA claims that the reduction in sulfur will improve the performance of emissions control technologies.)

Slashing pollutants by such seemingly large percentages sounds mighty impressive. But those numbers are meaningless without knowing the current volume of emissions. As it is, the previous standards already cut the vast majority of tailpipe emissions (between 77 percent and 90 percent), while sulfur in gasoline was likewise previously slashed by 90 percent. Simply put, there’s not much left to cut, which means little improvement in air quality at great cost.

The EPA pegs the cost of the new standards at $3.4 billion annually (by 2030). However, industry analysts have calculated significantly higher costs. The American Petroleum Institute, for example, says refineries will incur more than $10 billion in costs to reformulate gasoline under the new sulfur standard. The impact on gasoline prices could be as much as an additional 9 cents per gallon—a price spike that would negatively impact low-income households the most.

Far more problematic are the agency’s purported benefits—more than 50 percent of which are credited to reductions in PM. However, researchers have not found a causal link between PM levels and mortality. The agency’s list of uncertainties in the regulatory impact analysis includes “limited scientific literature supporting a direct biological mechanism for observed epidemiological evidence” and “causal agents within the complex mixture of PM have not been identified.”

Regulators also lack reliable monitoring data to determine the actual degree of public exposure to PM. And the agency claims benefits from PM reductions in a variety of other regulations, which essentially amounts to double-counting.

In fact, the benefits cited to justify the regulations are based solely on computer modeling, not epidemiology, making them rife with questionable assumptions. For example, the agency assumes that virtually any exposure to PM, no matter how small or fleeting, poses a health threat of some sort. Treating it that way boosts the agency’s benefit calculation.

The EPA also lacks research results that show a meaningful impact on emissions control of additional sulfur reductions.

Auto manufacturers are supporting the new standards, knowing full well that the costs will ultimately be borne by consumers. They also are pleased to be sharing the regulatory burden with refiners rather than incurring even more stringent regulation on their own. But the nation is already overburdened by unnecessary regulations that sap the economy and family budgets. Americans can no longer afford to sit idly while the EPA and the other swarms of regulators churn out more regulations that lack any justification whatsoever.