Farm fumes contribute to deadly air pollution

Rising ammonia emissions from farm animal waste and fertilizer are a major contributor to air pollution, causing death and illness around the world, according to FERN’s latest story, published with Ensia.

“In the past 70 years, global emissions of ammonia have more than doubled, from 23 to 60 teragrams per year,” writes Lindsey Konkel, noting that one teragram is 2.2 billion pounds. “Researchers say the increase is due in large part to an increase in ammonia emissions from agriculture.” In the United States and Canada, as much as 75 percent of all ammonia emissions are due to agriculture.

When nitrogen in manure and fertilizer turns into gaseous ammonia, it joins “with air pollutants — mainly nitrogen and sulfuric oxide compounds — from nearby vehicles, power plants, and factories to form PM2.5,” tiny particles that can penetrate deep into the lungs. These particles, Konkel says, “can travel long distances in the atmosphere. That’s how ammonia emissions in one part of the country can impact air quality in a downwind region.”

According to the World Health Organization, air pollution killed 7 million people around the world in 2012, and kills as many as 115,000 people a year in the United States. “When people think about air quality, they think about factories and power plants and transportation. But agriculture is a substantial contributor to reduced air quality, too,” says Jason Hill, associate professor of bioproducts and biosystems engineering at the University of Minnesota.

Ammonia isn’t as tightly regulated as other gaseous pollutants, in part because of the way it is emitted, says James Galloway, a biogeochemist at the University of Virginia. “It’s relatively easy to regulate air pollution point sources by putting a catalytic converter on a car or a reduction device on a smokestack, but the sources of ammonia are heterogeneous and diffuse. ‘With ammonia there’s no direct way of regulating the emissions. You have to become more efficient in growing crops and managing manure,’ Galloway says.”