By December 2, 2015 Read More →

Houston and Dallas can’t meet new EPA air-quality standards

Clean Air Act puts EPA in a bind

By Daniel Cohan, Rice University


Daniel Cohan argues the EPA standards make sense if health thresholds are all that is considered, but it ignores the reality of what states actually can achieve. Dallas News photo.

When the U.S. Environmental Protection Agency (EPA) issued its new tighter standard for ozone smog in October, predictable lines of debate emerged. Opponents claimed reducing ozone would be too costly and not yield measurable benefits. Environmental groups argued 70 parts per billion (ppb) was not tight enough to protect public health, after external advisors and internal staffrecommended a 60 to 70 ppb range.

Both sides are wrong. I’ve studied the issue as a scientist, and in my view, ozone smog harms health even at levels below the previous 75 ppb standard. While there is an achievable path to reduce the worst of these health hazards, it is also true that the EPA’s new 70 ppb standard will prove impossible to attain by 2025 in several regions — including Dallas-Fort Worth and Houston.

The EPA acknowledges that parts of California will need extra time to reach the 70 ppb standard. However, EPA claims all other states can achieve 70 ppb by 2025 or sooner. After reading the EPA’s own analysis, I don’t believe attainment that soon is possible.

Some improvements are bound to happen, no matter what a state does: Let’s call those “on-the-way” emission control measures. Those include more stringent Tier 3 fuel and vehicle emission standards, and power plant emission reductions expected under the Clean Power Plan and other policies.

The EPA projects these “on-the-way” measures will not be sufficient to bring the Los Angeles-South Coast and the San Joaquin Valley into attainment. EPA thus plans to give those regions support and longer attainment timelines.

Outside OF California, the EPA isn’t giving other regions extra time or help. And admittedly, many places won’t need it. The EPA uses the best available methods for photochemical modeling and analysis to project that most regions currently exceeding 70 ppb will attain the standard by 2025 based solely on “on-the-way” measures — in other words, without making any extra effort. In Texas, those regions include San Antonio, El Paso, Killen-Temple-Fort Hood, Tyler, Longview, and Granbury.

The problem comes, though, in more polluted areas — the regions that can’t rely on “on-the-way” measures to bring them into 70 ppb attainment by 2025. The EPA claims it is possible for all regions outside of California to hit that standard by adding new controls.

On this point, I must dissent. I’ll illustrate the impossibility of attainment by 2025 specifically for the Houston-Galveston-Brazoria and Dallas-Fort Worthnon-attainment regions.

EPA’s analysis estimates reductions of 123,000 tons of NOx per year would be needed in eastern Texas to bring Houston and Dallas-Fort Worth into attainment by 2025. Houston’s attainment would require an additional 20,000 tons of hydrocarbon reductions.

But these tonnages of emission reductions are unfathomably large for eastern Texas to achieve in ten years. Where could these cuts of 123,000 tons of NOx and 20,000 tons of VOC possibly come from?

They can’t come entirely from industry. Houston industrial sources are already capped at around 3,000 tons. Total NOx emissions from all major facilities throughout Texas (not just eastern Texas) were only 121,000 tons in 2014.

So what about Texas’ other great source of pollution: vehicles?

There’s simply not much that a city or state can do about them. Fleet turnover is already considered in “on-the-way” controls. And opportunities for states to control vehicle emissions beyond fleet turnover are limited.

Admittedly, my past research on ozone and particulate matter has shown state implementation plans do succeed in achieving air quality standards. The pattern fits the environmental management adages that regulation breeds innovation, and that what gets measured gets done.

The history of air quality management has shown repeated instances of industry decrying the cost of new standards, only to meet them more affordably than expected. For example, from 1980 to 2014, air pollutant emissions fell 63 percent, even as the economy more than doubled.

Tightening a 75 ppb standard by just 5 ppb doesn’t seem so stringent, as emissions of precursors continue to plunge. But the chemistry of ozone formation causes ozone to be insensitive to controls. In other words, it takes a much larger percentage reductions in emissions of precursor gases, NOx and hydrocarbons, to achieve a given percentage reduction in ozone. One recent study found several U.S. cities would need NOx reductions of more than 70 percent to attain 70 ppb ozone.

What makes ozone so unresponsive to emission controls? A substantial amount of ozone comes from sources that cannot be controlled: biogenic hydrocarbons and NOx, lightning, international emissions, stratospheric ozone intrusions, and so forth.

What will happen when a mandatory ozone limit collides with emissions that can’t be cut enough? That problem will arise long before 2025. Cities like Houston and Dallas do not violate the new limit by a huge margin (their “design values” are each 80 ppb now), and thus are likely to be classified as “moderate” nonattainment regions. Such regions typically are given six years to meet an ozone standard. However, if 2025 is unattainable, so is a six-year deadline.

What next? Regulatory conflict and litigation will likely proliferate as non-attainment continues. Furthermore, the health and agricultural benefits projected to result from 70 ppb ozone will be forestalled (though, as I’ll argue in my next article, those benefits are likely to be small).

This quagmire ahead arises in part from outdated provisions of the Clean Air Act. Since the Act requires EPA to consider only health in setting air quality standards, valid concerns such as feasibility and cost receive insufficient attention. That has been advantageous at times — witness the many rules attained far more affordably than industry has forewarned.

But this time, affordability isn’t the main concern. It’s whether it’s possible to attain the standards at all.

In my analysis, there’s simply not enough opportunity for the areas to control their smog. Houston and Dallas can’t possibly hit their targets by 2025.

There is a better way to control air pollution in the U.S. Over a decade ago, the National Research Council outlined a better path to air quality management. They recommended more integrated approaches, looking at groups of related pollutants instead of individual ones, and with more emphasis on measurable outcomes than the process by which we reach them. I myself have suggested paths toward more integrated air quality management that consider both health benefits and control costs.

The Clean Air Act, though, puts the EPA in a bind. The law requires the agency to create its standards based on health, not feasibility or affordability. And so we get the 70 ppb standard. It makes sense if health threshholds are all that is considered, but it ignores the reality of what states actually can achieve.

There is a better way. But with Congress gridlocked on an update to the Clean Air Act, I expect many more years of non-attainment and litigation.

Daniel Cohan is an associate professor in the Department of Civil and Environmental Engineering at Rice University. His research specializes in the development of photochemical models and their application to air quality management; uncertainty analysis; energy policy; and health impact studies.

This article originally appeared in the Houston Chronicle on December 2, 2015.

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