The stench of cow feces, urine and ammonia is forcing residents to keep their windows and doors closed in parts of California’s farmland. Some people constantly use air purifiers at home to fight odor and, they say, to fight air-related diseases.
“We have a lot of health problems going on in this community, and most of them are respiratory problems,” Beverly Whitfield said among dairy farmers in Pixley, a small town in Tulare County. She believes her allergies, her grown son’s asthma, and other people’s breathing. the issues are related to pollution from nearby dairies.
Industrial-scale dairy farms are already among the biggest polluters in the San Joaquin Valley, a major US agricultural region with poor air quality. Now residents like Whitfield worry methane solvents, which can turn manure into a biofuel that’s cleaner than traditional fuels like gasoline, could make health problems worse. Biofuel experts say solvents can reduce air pollution.
Home to about 1.7 million cows, California is the nation’s leading dairy producer and a major contributor of methane. Digging and cow dung release the powerful planet-warming gas, which over a shorter period is far more powerful than carbon dioxide.
In recent decades, digesters that convert manure and other organic waste into biogas to create electricity or power vehicles have spread across the country.
The number is expected to increase since waste management practices, such as solvents, became eligible for funding from the Inflation Reduction Act — President Joe Biden’s law to fight climate change.
Most solvents are in dairies that capture methane from cow manure lagoons and turn it into biofuel. Liquid cow manure is usually stored in a covered digester where microbes from the animal’s digestive system produce gas. The gas is then cleaned and compressed into a liquid fuel that can be used as an energy source.
In the past decade, about 120 distilleries have popped up across California, and approximately 100 more are in the pipeline. But a technology hailed as a cost-effective way to help the state meet its methane reduction goals has become controversial.
Environmental justice organizations say mostly low-income Latino communities are facing pollution from nearby digesters, and they want California to stop offering financial incentives for more. Critics also say state policies favor industrial dairies, entrenching unsustainable animal agriculture.
Rebecca Wolf with the environmental group Food and Water Watch said the state is encouraging dairies to continue running large operations that already pollute. “You’re never going to stop polluting” with this system in place, she said.
The dairies argue that the state’s financial program plays an important role. “There has to be a financial incentive there to give up some of your land to operate these systems,” said dairy farmer Brent Wickstrom, whose solvent recently went online.
Supporters point to the technology’s effectiveness in mitigating climate change. AgSTAR, sponsored by the Environmental Protection Agency and the US Department of Agriculture, estimates that manure-based solvents reduced greenhouse gas emissions by more than 10 million metric tons of carbon dioxide equivalent in 2022. This is approximately the annual greenhouse gas emissions from more than 2 million passenger vehicles.
Supporters note that methane biofuels reduce pollution by replacing fossil fuels such as gasoline with cleaner vehicle fuel.
“This technology reduces odors and some local air pollutants,” said Sam Wade, director of public policy for the Renewable Natural Gas Coalition. “At the same time, it reduces greenhouse gas emissions.”
Residents near the dairies complain of flies and strong winds.
“You don’t want the doors open because you’re afraid of all the smells,” said Whitfield, whose family left the doors open when they moved to Pixley in the 1970s. “Everything has changed now with the dairy.”
Some dairies say digester tarps that cover manure reduce odors. “If anything, it should retain some of that smell instead of producing more,” said Wickstrom, the Merced County dairy farmer.
Studies have found that people living near large dairies can experience fatigue, breathing problems, burning eyes and runny noses if the odors are concentrated enough. A 2017 University of Wisconsin study found that solvents can increase ammonia emissions by up to 81%. Ammonia can form fine particles that can enter the lungs and bloodstream. Long-term exposure to the particles has been linked to heart and respiratory problems.
“Having a reduction in greenhouse gas emissions is good, but you also have to think about the impact on human health,” said lead author Michael A. Holly, an associate professor at the Green Bay campus.
California air regulators said the Midwest study doesn’t necessarily apply to that state’s different weather conditions and solvent types. They added that studies are underway to understand the effects of solvents on ammonia emissions.
A recent study funded by the California Air Resources Board found that dairy waste emissions in the San Joaquin Valley contributed little to ozone and fine particulate matter concentrations.
“The air quality impacts are essentially zero, and indeed we can make a decision whether or not to approve solvents based on greenhouse gas emissions,” said Michael Kleeman, the study’s lead researcher and a professor at the University of California, Davis. “There is already so much excess ammonia in agriculturally rich regions that (solvents) will not significantly affect air quality.”
Maria Arevalo, a 74-year-old activist and former farm worker, believes her asthma and sleep apnea are linked to pollution from dairies near her home in Pixley. She sleeps with a machine to help her breathe. Likewise, her 34-year-old son and 11-year-old grandson.
Her neighborhood often smells of ammonia, she said, but many families can’t afford air conditioning and open windows to let in air. “These dairies should not be in the areas where the communities are.”
In her town of about 4,000 inhabitants, there are more cows than people. According to the nonprofit Leadership Council for Justice and Accountability, Pixley’s 26 dairies house approximately 140,000 cows. According to AgSTAR, nine have digesters operating on farms with thousands of animals.
Recently, 15 members of Congress wrote against the USDA’s decision to make certain large-scale agricultural practices, such as roofs and covers for waste management facilities, eligible for federal funding.
“The storage of hundreds of thousands of gallons of liquid manure … pollutes the air and water of surrounding communities,” they said. “This inherently unsustainable system of manure storage has only been further entrenched by … solvents.”
Researchers have found that nearly 40% of methane emissions from human activity come from livestock and agriculture. The EPA estimates that each cow can produce 154 to 264 pounds (about 70 to 120 kilograms) of methane per year.
In California, supporters see solvents as important to helping the state meet climate goals and as a source of renewable natural gas for vehicles.
Biomethane improves the air in cities “because trucks don’t emit any emissions when they run on natural gas,” said Eric McAfee, CEO of renewable fuels and biochemicals company Aemetis.
Joey Airoso, who had a digester on his 2,900-cow farm as of 2018, found that odors were reduced and the nitrogen-rich residue could be used as crop fertilizer. “This is a big deal for the environment because it makes it easier to put in extra nitrogen,” he said.
Colin Murphy, of the Energy, Environment and Economic Policy Institute at UC Davis, said that while solvents have benefits, they don’t solve air pollution “and they don’t make it any more pleasant to live around.”
Some valley residents who have complained of odors and breathing problems say they have been told to move. But many of them have lived in small rural towns long before the dairy came – and relocation isn’t always financially possible.
“Where will you move? You don’t have the money to move,” said Whitfield, a Pixley resident with allergies.