When coal plants decrease pollution or shut down, people have fewer asthma attacks

When coal plants decrease pollution or shut down, people have fewer asthma attacks

Inhaler use, ER visits and hospitalizations all decreased after a change in regulations

Asthma attacks decreased significantly among residents near coal-fired power plants after the plants shut down or upgraded their emission controls, according to a new study.


Coal-fired power plants emit air pollution that includes mercury, sulfur dioxide, nitrogen oxides, and particulate matter. Living near coal-fired power plants is linked to higher rates of respiratory and cardiovascular disease, and cancer, and premature death.

According to a study published this week in the journal Nature Energy, when those plants shut down or upgrade their emissions controls, rescue inhaler use, emergency room visits and hospitalizations for asthma all decrease among nearby residents. The study is the first to show decreased inhaler use following a reduction in pollution from coal plants, and builds on previous evidence that living near these facilities leads to increased asthma exacerbations.

The study was conducted between 2012 and 2017 in Kentucky, which ranks among the top U.S. states for air pollution from power generation. Researchers focused on Jefferson County, where one coal-fired power plant shut down and three others upgraded emission controls around the same time, and found that inhaler use, ER visits, and hospitalizations all fell—in some zip codes by up to 55 percent—following the reduction in emissions.

"We saw about three fewer emergency department visits and hospitalizations per quarter per zip code," Joan Casey, assistant professor at the Columbia University Mailman School of Public Health and lead author on the study, told EHN. "That translates into about 400 prevented asthma-related hospital visits per year across the county."

While many studies have looked at health impacts associated with living near coal-fired power plants, this is the first to use digital sensors to track rescue inhaler use among the same group of people before and after a drastic reduction in emissions. They did this by attaching sensors to rescue inhalers distributed among Louisville residents with asthma and chronic obstructive pulmonary disease, commonly referred to as COPD, starting in 2012. The sensors tracked the date, time, and location of each inhaler puff.

The researchers had data for 207 participants before and after the installation of "scrubbers," or emission reduction equipment, at the three coal-fired power plants in 2016. Comparing people to themselves before and after the pollution reduction allowed them to control for factors like socioeconomics, underlying conditions, indoor air quality, age, etc., which is harder to do with hospital data, Casey said.

In the months following scrubber installation, Casey and her colleagues saw an average reduction of inhaler use of about 17 percent, with continued declining use after that.

"A lot of studies have shown that populations living near coal-fired power plants have higher rates of respiratory hospitalizations," Casey said, "but it's been difficult to attribute those directly to coal-fired power plants because poor communities of color tend to be located closer to these facilities in the U.S., and they have a higher burden of diseases like asthma and COPD."

Because of the "natural experiment" created by the drastic change in emissions and the addition of the inhaler data, Casey believes their research more definitively links asthma attacks and resulting hospital visits to unchecked emissions from coal-fired power plants.

"All of that information together convinced us that what we were seeing was probably real," she said.

Rolling back regulations

Coal-fired power plants have been decommissioned at increasing rates each year as the cost of other power sources, like natural gas and renewables, become cheaper.

As of December 2018 (the most current data available), there were 336 predominantly coal-fired power plants still in operation in the U.S., according to the U.S. Energy Information Administration.

It's likely that similar improvements in asthma outcomes occurred in communities across the U.S. during the same time period of the study, thanks to a sweeping change in pollution regulations.

In 2014, coal-fired power plants accounted for 63 percent of sulfur dioxide emissions in the nation. The 2012 federal Mercury and Air Toxics (MATS) rule required all coal-fired plants to install scrubbers that reduce toxics like mercury and sulfur dioxide in emissions by 2015 (or 2016 if they got a special extension). During 2015, plants that had recently installed this equipment reduced their sulfur dioxide emissions by 49 percent.

"I think our findings are exciting," Casey said, "because we're seeing that the cost to install these scrubbers can be made back quickly just through prevented healthcare visits. We're only looking at asthma here, but we know there are other related health outcomes as well, so the benefits are likely far greater than what we're estimating."

But despite these benefits—and the fact that these pollution controls have already been successfully installed at coal-fired power plants across the country—the current U.S. Environmental Protection Agency administration intends to roll back the MATS rule, undoing the regulations that have kept people in places like Jefferson County, Kentucky, healthier.

The administration also recently announced plans to suspend enforcement of environmental regulations during the coronavirus pandemic.

"It's disappointing to see the EPA suspend enforcement of environmental laws during the COVID-19 pandemic," Casey said, "especially as we're starting to see stark disparities in COVID deaths among the same groups—communities of color and the poor—that face the greatest respiratory harm from pollution, including coal-fired power plants. We should be tightening environmental regulations, not abandoning them during this time."

Banner photo: The Mill Creek Generation Station coal plant in Louisville, Kentucky. (Credit: William Alden/flickr)

tony reames energy department justice
Photo by Sara Cottle on Unsplash

Energy Department is serious about equity

"Equity and justice are central to everything that we do: As the U.S. Department of Energy’s deputy director for energy justice, Dr. Tony Reames helps to put equitable energy policy into action.

Senator Whitehouse & climate change

Senator Whitehouse puts climate change on budget committee’s agenda

For more than a decade, Senator Sheldon Whitehouse gave daily warnings about the mounting threat of climate change. Now he has a powerful new perch.
gas energy emissions climate europe
Photo by Théo Rué on Unsplash

EU approves 2035 ban on sales of gas-powered cars

EU countries have approved an end to the sale of gas-powered cars in 2035, allowing the law to enter into force.

columbia river salmon hatcheries
Photo by Jamie Pilgrim on Unsplash

Federal leaders finally increase money for hatcheries, but tribes say it’s nowhere near enough

The federal government has announced plans to increase funding for the Columbia River Basin’s salmon hatcheries, the often-crumbling facilities that maintain the river’s dwindling salmon populations. But tribes and state agencies say the influx of funds is only a fraction of what is needed.

european court of human rights climate lawsuits
Photo by Saúl Bucio on Unsplash

Climate fights at European court may ripple across the globe

Three climate lawsuits are making their way to a prominent court in France. Its rulings cannot be appealed and may have ripple effects in the United States.
climate kelp farming
Photo by Shane Stagner on Unsplash

Can we counter climate change by dumping carbon in the ocean?

Researchers and start-ups are exploring a variety of ways of locking up carbon in the sea, from seaweed farming to fertilising the oceans with iron – but we know little about the implications.

Brandon Moffatt: Climate Action 2.0 starts with certainty and access to capital green economy leaders

Climate Action 2.0 means acknowledging Canada is now in a competition with other advanced nations that are building their own foundations to attract the top talent of the green economy.

NY finalizes list of ‘disadvantaged communities’ first in line for climate change funds

New York State has finalized the list of so-called “disadvantaged communities” to be targeted for extra funding and cleanup in the state’s ambitious multibillion-dollar climate plan.

From our Newsroom
oil and gas wells pollution

What happens if the largest owner of oil and gas wells in the US goes bankrupt?

Diversified Energy’s liabilities exceed its assets, according to a new report, sparking concerns about whether taxpayers will wind up paying to plug its 70,000 wells.

Paul Ehrlich

Paul Ehrlich: A journey through science and politics

In his new book, the famous scientist reflects on an unparalleled career on our fascinating, ever-changing planet.

oil and gas california environmental justice

Will California’s new oil and gas laws protect people from toxic pollution?

California will soon have the largest oil drilling setbacks in the U.S. Experts say other states can learn from this move.

popular stories 2022

Our 5 most popular reads from 2022

A corpse, woodworking dangers, plastic titans ... revisit the stories that stuck with our readers this past year.

Stay informed: sign up for The Daily Climate newsletter
Top news on climate impacts, solutions, politics, drivers. Delivered to your inbox week days.