Food production kills 15,900 people in the U.S. each year through air pollution — but thousands of lives could be saved with some relatively simple reforms, researchers found.

"There's a lot of low-hanging fruit for food producers to substantially improve health outcomes," said Nina Domingo, a doctoral candidate in the University of Minnesota's bioproducts and biosystems engineering department and the lead author of a new study, published Monday in Proceedings of the National Academy of Sciences. 

The study found that agricultural producers could save 7,900 people per year through on-farm changes. Livestock waste management and fertilizer practices, in particular, were key areas for improvement; the biggest driver of air pollution, by far, was the production of meat, including raising animals and raising food for those animals. Red meat, currently the source of 13% of Americans' calories, was the worst polluter; animal-based foods in general caused 12,700 deaths annually. 

But, Domingo said, there are "practices that farmers can adopt today to reduce those emissions." She pointed out that something as simple as planting trees near buildings where animals are confined can reduce the amount of ammonia that spreads to nearby communities.

Domingo and her co-authors cross-referenced emissions data from the U.S. Environmental Protection Agency with cropland data from the U.S. Department of Agriculture, linking specific food products, such as beef or almonds, to specific emissions, a breakthrough that could help inform targeted policies and regulations. The researchers connected those precisely located emissions with mortality research from the American Cancer Society measuring the deaths associated with increasing concentrations of pollution in a given area. 

Then, they examined potential solutions, looking at how deadly emissions could be reduced through farm-management changes and dietary shifts. 

Using three reduced-complexity models to evaluate emissions-reducing strategies, the researchers found that human health could be significantly improved if farmers implemented mitigation practices, particularly surrounding meat production and ammonia. There were 12,400 deaths caused by ammonia — 69% of deaths, mostly from livestock waste and fertilizer application.

The authors wrote that many of the techniques they suggested could be expensive, but they would have savings benefits to society 1.3 to 14.7 times higher than the highest estimated implementation costs. And some strategies, including more efficient fertilizer application, could actually save lives while saving farmers money.

Jason Hill, a co-author and a University of Minnesota professor, noted that, currently, "The costs are the external costs that are borne by society. They're borne by the people that live downwind from agriculture, which is all of us, pretty much. The cost is premature mortality."

In contrast to greenhouse gas emissions, air pollution matters most when it's in proximity to people. The current findings have serious implications for all Americans, but particularly for those people living in 308 counties causing 8,400 deaths each year. These counties are mostly in agricultural areas in California, Pennsylvania, North Carolina and the Upper Midwest Corn Belt. Politicians, particularly in the states most affected, have an opportunity to save constituents' lives, Hill said. 

"Regulation and incentives and so forth can come into play: Society can help food producers clean up agriculture," Hill said.

Domingo said the simplicity of some of the interventions — and the modeled effectiveness — stood out to her. "Solutions are available right now," she said.

The paper, "Air quality-related health damages of food," published May 10 in Proceedings of the National Academy of Sciences, was authored by Nina G. G. Domingo, Srinidhi Balasubramanian, Sumil K. Thakrar, Stephen Polasky, David Tilman and  Jason D. Hill, University of Minnesota; Michael A. Clark, University of Oxford; Peter J. Adams, Nicholas Z. Muller, Spyros N. Pandis, Allen L. Robinson and Peter Tschofen, Carnegie Mellon University; Julian D. Marshall, University of Washington; and Christopher W. Tessum, University of Illinois.