Smoke from the wildfires across California, Oregon, and Washington has sent scores of people to hospitals suffering from asthma, irritated lungs and eyes, and other respiratory problems.

While wildlife smoke is a serious public health hazard, chronic air pollution from other sources poses an even larger threat. It’s estimated to kill 100 thousand to 200 thousand Americans annually, more than car accidents and homicides combined. This is to say nothing of the suffering endured by people living with pollution-related conditions such as lung cancer, respiratory issues, and cardiovascular disease.

Although air pollution typically summons images of diesel trucks and coal power plants, agriculture is shockingly responsible for about half of US air pollution (specifically human-caused fine particulate matter) and one-fifth of the deaths it causes. Efforts to cut air pollution from farming would not only improve American health and save lives, but also could result in food system improvements needed to reduce greenhouse gas emissions.

The primary source of agricultural air pollution is not farm machinery, as one might assume, but rather ammonia generated by livestock and fertilizers. The ammonia reacts with pollutants from vehicles, power plants, and other sources to form fine particulate matter, affecting not just rural farmland, but also blowing into populous cities further away.

Livestock manure generates the lion’s share of ammonia from agriculture as well as a variety of other harmful pollutants — which is why meat, dairy, and other livestock production together make up one of the top five sources of air pollution deaths, with an impact larger than the exhaust from trucking. And it’s a source of environmental injustice. In North Carolina, for instance, noxious odors and a variety of harmful air pollutants from pig manure disproportionately harm Black communities. Farmworkers, the majority of whom are Hispanic, and farming communities also face high exposure to pesticides.

Farmers can be a key part of the solution. Livestock producers can store manure in deep covered pits rather than in liquid lagoons, for example, and tweak the makeup of animal feeds. Crop farmers can use modern “precision” farming equipment to apply only as much fertilizer as needed, use fertilizers that cut both ammonia and greenhouse gas emissions, and plant more diverse crop rotations.

Clearly, tackling food’s air pollution footprint is imperative for public health, but it also has climate co-benefits — many farm practices that reduce air pollution also reduce greenhouse gas emissions.

Reducing farming’s carbon footprint is important — agriculture contributes about 10% of US greenhouse gas emissions. Increasingly, the media, politicians, and the public recognize this, focusing on climate change as agriculture’s most immediate environmental impact. This summer, for instance, Democrats adopted a party platform that aims “to make the U.S. agriculture sector the first in the world to achieve net-zero emissions.”

Yet focusing on the air pollution benefits of food system improvements could motivate broader and quicker bipartisan policy change than the current focus on climate change, which remains a stubbornly polarizing issue. Why?

For one, substantially improving air quality doesn’t require international cooperation. In contrast, the US can’t avert climate change on its own. With the US accounting for about 15% of global greenhouse gas emissions per year, bringing down emissions from other countries is key to slowing the planet’s warming.

Second, the benefits of cutting air pollution appear quickly, much sooner than the climate benefits of many food system changes.

Third, the potential benefits of cutting agriculture’s air pollution are enormous. Air pollution from corn, meat, and other agricultural production causes about seven times more harm to people than farming’s greenhouse gas emissions when calculated using standard economic figures. Similarly, several studies have found that the air quality benefits from sustainable farming practices greatly outweigh the climate benefits.

While cutting ammonia and greenhouse gas emissions often go hand-in-hand, accounting for the large, near-term air quality benefits of food system improvements should spur faster and larger change than a more narrow focus on climate.

Finally, climate change is simply a far more politically polarized issue, and public support for action is highly susceptible to shifts in national politics. At the federal level, Congress has been debating climate change and climate policy for nearly 30 years with relatively little success. In contrast, pollution with short-term visible impacts spurred much of the first modern environmental legislation in the US, most notably the Clean Water and Air Acts.

It’s often said that addressing climate change is a moral imperative. So too is reducing the unnecessary suffering and deaths created by air pollution. Supporting farmers to adopt new technologies and practices is a key solution to both.

Food’s Overlooked Air Pollution Footprint

Oct 6, 2020

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