The regulation of coal-fired power plants neglects a crucial pollutant

According to researchers at Rice University, cleaning or replacing coal-fired power plants with no sulfur control measures could help Texans breathe cleaner, healthier air.

A study led by environmental engineer Daniel Cohan analyzed models that measure the effects of emissions from 13 coal-fired power plants in Texas. In addition to their findings on the modeling systems themselves, they found that residents located downwind of coal-fired power plants would be much better off if the state focused on reducing sulfur dioxide-generating emissions of particles, in addition to those that cause ozone.

"Texas has more unhealthy coal plants than anywhere else in the country and causes a lot of damage related to air pollution and health effects," Cohan said. "What I found telling in this study, is that most of the health damage comes from particles, but the pollution in Texas is mainly focused on smog ozone. 39 is a real dichotomy where the standard we violate is that of the ground-level ozone, but particles are the main cause of damage. "

The study is published in the journal of the Air & Waste Management Association.

Three of the state's coal-fired plants closed in 2018, but the effects of the other 13 are represented in the data collected from 2012 to 2017 and used by Cohan and his co-authors, Brian Strasert, a former graduate of Rice, currently at GSI Environmental Houston, and undergraduate student. Su Chen Teh.

The researchers wrote that while coal is becoming increasingly expensive and that natural gas and renewable energy such as wind and solar are increasing, companies seem more likely to shut down power plants based solely on economic.

They also point out that the state has missed the opportunity to accelerate the benefits flowing from the implementation of the regional haze plan of the Obama era. This would have reduced emissions of sulfur dioxide, contributing to airborne particles – invisible particles less than 2.5 microns in diameter – in eight of the most emitting plants. Instead, in 2017, the Environmental Protection Agency replaced the plan with a cap-and-trade program.

"That does not mean the plants will get worse," Cohan said. "It simply means factories that should have been forced to clean or close now have a flawless map."

The researchers noted that, according to EPA statistics, Texas power plants emitted more than twice as much sulfur dioxide as Missouri, ranked second. The problem, said Cohan, is that even when particle levels meet current standards, they still represent a health risk, especially for those who are directly downwind of the plants.

"We know that the higher the particle levels, the higher the number of deaths, both on a short-term correlation – when particle levels are high one day, mortality rates are higher during next few days – and also during long-term studies, "he said. "When epidemiologists study subjects over 10 or 20 years, they find that life expectancy is better in places where particle levels are very low compared to places where levels are high.

"Particles are the deadliest of all air pollutants, and they do not just cause death in the way you might think," Cohan said. "This is not only due to respiratory diseases, but also to an increase in the number of heart attacks and strokes. These particles are small enough to pass into the alveoli and enter the bloodstream.

"It was really striking for me," he said. "Because Texas meets the particulate standard, it has not given priority to cleaning up sulfur, far from nitrogen pollution." We allow plants to emit levels of unauthorized pollution since the 1970s. " re is still operational, since the state and the EPA have failed since 2009 to finalize a regional plan of fog. "

Cohan said the EPA was still receiving feedback on his plan for Texas.

The paper also showed that simple and recent atmospheric models that help researchers quickly calculate the health effects of pollution compare favorably to a more complex, advanced model. "This suggests that we can adopt easier approaches to more quickly estimate the impacts of these plants," Cohan said.

Over time, he said, coal-fired plants seem likely to close, either because air pollution standards will be applied in general, or because renewable energies such as the wind and solar make them unprofitable.

"The key message of our document," said Cohan, "is that this delay has very real costs for us in Texas."

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More information:
Brian Strasert et al. The potential closures of coal-fired power plants in Texas have health and health benefits, Journal of the Air & Waste Management Association (2018). DOI: 10.1080 / 10962247.2018.1537984