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A new study finds that environmental damage caused by corn production results in 4,300 premature deaths annually in the United States, representing a monetized cost of $39 billion.

The paper, published in Nature Sustainability, presents how researchers have estimated for the first time the health damages caused by corn production using detailed information on pollution emissions, pollution transport by wind, and human exposure to increased air pollution levels. Corn is a key agricultural crop used for animal feed, ethanol biofuel, and human consumption.

Production-weighted national average human mortality per million tonnes of maize produced, by pollutant and supply chain stage. a, Absolute mortality. The average annual mortality per million tonnes of maize is 13.4. b, Relative mortality. NG, natural gas. Hill et al.

The study also shows how the damage to human health of producing a bushel of corn differs from region to region and how, in some areas, the health damages of corn production are greater than its market price.

The deaths caused per bushel in western corn belt states such as Minnesota, Iowa, and Nebraska tend to be lower than in eastern corn belt states such as Illinois, Indiana, and Ohio.

—lead researcher Jason Hill, associate professor at the University of Minnesota (UMN) College of Food, Agricultural and Natural Resource Sciences

The researchers used county-level data on agricultural practices and productivity to develop a spatially explicit life-cycle-emissions inventory for corn. The data show that reduced air quality resulting from corn production is associated with the premature deaths annually in the United States, with estimated damages in monetary terms of $39 billion. This uses a value from the US EPA of $9 million for each death avoided.

Increased concentrations of fine particulate matter (PM_2.5) are driven by emissions of ammonia—a PM_2.5 precursor—That result from nitrogen fertilizer use. Average health damages from reduced air quality are $3.07 per bushel (56.5 lbs) of corn, which is 62% of the $4.95 per bushel average corn market price of the last decade. This paper also estimates life-cycle greenhouse gas emissions of corn production, finding total climate change damages of $4.9 billion, or $0.38 per bushel of corn.

It’s important for farmers to have this information so that they can implement practices that reduce the environmental impact of the crops they grow. Farmers can greatly improve the environmental profile of their corn by using precision agriculture tools and switching to fertilizers that have lower ammonia emissions.

—Jason Hill

In addition to changing the fertilizer type and application method, the study’s results suggest potential benefits from strategic interventions in corn production, including improved nitrogen use efficiency, switching to crops requiring less fertilizer, and changing the location where corn is grown.

Aware that changes in practices can take time and planning, Hill suggests farmers could be offered incentives to switch to crops that demand less applied nitrogen while still offering market and nutritional benefits.

Research was funded by the United States Department of Agriculture, the US Environmental Protection Agency, the US Department of Energy, and the Wellcome Trust.

Resources

Jason Hill, Andrew Goodkind, Christopher Tessum, Sumil Thakrar, David Tilman, Stephen Polasky, Timothy Smith, Natalie Hunt, Kimberley Mullins, Michael Clark & Julian Marshall (2019) “Air-quality-related health damages of maize” Nature Sustainability doi: 10.1038/s41893-019-0261-y