Do Coal Plants Really Kill People?

Why Romney was right.

Foggy day in London, December 1952.

London smog, December 1952.

Photo by N T Stobbs.

During the presidential campaign, any whiff of anti-coal sentiment was considered an election-year liability. In 2003, Gov. Romney went after a coal plant in Massachusetts for spewing air pollution and announced: “I will not create jobs or hold jobs that kill people. And that plant, that plant kills people.” President Obama tried to stick it to him with that quote in an ad in coal-friendly Ohio. Romney, in turn, tried to bash Obama with remarks that Joe Biden made in 2007 about coal as a potential killer.

But while politicians have been busy obscuring their views on coal, public health researchers have been accumulating ever clearer data. Emissions from coal-fired power plants and other coal-burning sources have been linked to neurological and developmental deficits in children, a worsening of asthma, and cardiovascular disease and other health woes. Coal-burning is bad, bad, bad for your health—and looking ahead, the best we can hope for is that it will get marginally better.

Coal was partly responsible for two spectacular deadly smogs in the mid-20th century. In October, 1948, the small industrial town of Donora, Pa., was choked by “an acrid, yellowish gray blanket.” As former residents recalled: “I’d accidentally step off the curb and turn my ankle because I couldn’t see my feet.” The Halloween parade just looked like “shadows moving through the gloom.” In a few days, 20 people died and about 6,000 more fell ill. Similarly, in December, 1952, London was smothered in a smog so dense that “parents were advised not to risk letting their children get lost on the way to school, unless it was literally round the corner,” a resident recalled to the BBC. More than 4,000 deaths were attributed to the smog, mainly due to respiratory and cardiovascular complications. Both smogs helped catalyze clean air legislation, including the Clean Air Acts of 1963 and 1970, which expanded the government’s role in controlling pollution and helped to reduce coal emissions. These were some of the first, crucially important environmental laws on the books.

Today, acute pollution crises are rare in the developed world, but coal-burning still exerts an insidious effect on health. The worst impact is on children. Burning coal releases mercury, nitrogen oxides, sulfur oxides, and fine particulate matter, among other nasty emissions. Mercury from power plants settles in water, where bacteria transform it to an organic form called methylmercury. It contaminates fish and bioaccumulates through the food chain, so larger predators are especially contaminated. That’s bad news for lovers of swordfish and spicy tuna, especially for women who plan to have children. During pregnancy, methylmercury crosses the placenta and gets into the developing brains of fetuses. Research shows that this exposure can cause neurological and developmental deficits down the road. One pivotal study, conducted in the Faroe Islands, looked at methylmercury levels in mothers’ hair samples and babies’ umbilical-cord blood at birth. Seven years later, the children who had had higher levels tended to show deficits related to language, attention, and memory on a battery of neuropsychological tests. Other large studies of methylmercury exposure during gestation, conducted in New Zealand and the Seychelles, have come to similarly worrisome conclusions. Coal is not kind to children’s brains.

What about children’s lungs? Nitrogen oxides, which are emitted from smokestacks, are known to irritate the respiratory tract. They also react with other pollutants to produce ozone, which is a key component of smog. And hazy, smoggy, ozone-filled air is just terrible for kids with asthma. In one key study, researchers looked at emergency visits by low-income children in Atlanta during the summer of 1990. They correlated the dates of these visits, which were for asthma or reactive airway disease, with data on local ozone levels. Following the six highest ozone days, the average number of emergency visits spiked 37 percent compared to other days. Lots of other research confirms that ozone can make asthma worse. (Some evidence links it to the development of asthma, too, though that is not as well-established.) Then there is particulate matter, especially the tiny particles with a diameter of less than 2.5 micrometers, which studies show can trigger asthma attacks. Children are especially vulnerable because they tend to breathe through their mouths, which means less filtering of pollutants by nose hair; they tend to hang out more outside, where levels of these pollutants are usually higher; and they run around a lot, which means they take in more nasty stuff and inhale it deep into their lungs.

But it isn’t just children who are vulnerable. In adults, higher levels of small particulates are associated with an increase in heart attacks, exacerbations of congestive heart failure, and the triggering of cardiac arrhythmias. An excellent rundown of the research appears in Alan Lockwood’s The Silent Epidemic: Coal and the Hidden Threat to Health. Lockwood cites, for example, a finding from the Women’s Health Initiative looking at more than 60,000 older women. That work found that each increase of 10 micrograms in the concentration of very fine particles per meter cubed of air upped women’s chances of a “cardiovascular event” by 24 percent. And it increased the chances of death from such an event by 76 percent. Lockwood’s book paints a similarly bleak picture of air pollution and lung cancer.

The good news is that the body can rebound when the air is cleaner. One of the most striking studies of the public health effects of air pollution came during the Beijing Olympics in 2008. As a condition for hosting the games, the Chinese government promised to clean up the air, which it did by imposing strict controls on traffic and high-polluting factories and power plants, including those fired by coal. Junfeng Zhang of the University of Southern California and his colleagues took advantage of this natural experiment to study whether a brief drop in the levels of many pollutants—including particulate matter, nitrogen oxides, sulfur oxides, and others—would have a measurable impact on healthy, young volunteers. For work published in the Journal of the American Medical Association in May, they drew blood from 125 volunteers and measured the levels of several biochemical markers before, during, and after the games. They found that when air pollution levels dropped, key markers of inflammation and clotting showed small but significant decreases. These changes have been linked previously to a lowered risk of heart attacks and strokes. In other words, even healthy people can get a little healthier with a lessening of life’s aerial assault.

The air has gotten much better in the United States as a result of the Clean Air Act and its amendments. The acid rain program in particular has substantially reduced levels of nitrogen oxides and sulfur oxides. But coal-fired power plants still spew these pollutants, which blow across state lines and contribute to health woes far away. Northeastern states, for instance, are forced to breathe emissions from coal plants in the Midwest. Various kinds of smokestack filtration can help. There are baghouse filters, which work “like the filter in your vacuum cleaner that traps particles,” according to Lockwood. There are also electrostatic filters, which put an electrical charge on particles, causing them to move toward an electrode in the filter. And injecting limestone in flue gases to form gypsum reduces sulfur emissions.

The EPA’s Cross-State Air Pollution Rule would have pushed more power plants to implement technologies like these to control their emissions. But the rule was struck down this summer by the United States Court of Appeals for the District of Columbia. Now the agency must try to revise its regulations so they can withstand court challenges. Going forward, more filtration may be the best we can hope for (and even that will continue to be a fight), though really, from a health perspective, the only good future for coal would be less of it.