New Mexico dairy CAFOs drives hundreds of millions in health costs, study finds

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Air pollution from large, concentrated New Mexico dairy farms causes an estimated $217 million annually in health costs, with most of the toll coming from ammonia emissions that form dangerous particulate matter, according to a new study.  

The pre-print study from the Journal of Agricultural and Resource Economics is the first to estimate the state’s dairy industry air pollution toll, and finds that the health costs of raising dairy cows in concentrated animal feeding operations (CAFOs) offsets approximately 15% of the industry’s revenue. The researchers also used the New Mexico data to calculate the US total from such CAFO dairy pollution, pegging it at $33 billion annually.

New Mexico is a top-10 dairy producing state and has one of the largest herd sizes and concentration of dairy cows in the country. The state defines dairy CAFOs as those farms with more than 700 mature dairy cows (large CAFOs) or between 200 and 699 mature dairy cows (medium CAFOs) that confine the animals for 45 or more days per year.  

The New Mexico State University Dairy Extension program estimates the state’s dairy industry brings more than $2 billion annually to the state and creates more than 6,800 jobs. However, the number of New Mexico dairy farms decreased from 46,000 to 26,000 — a 44% decrease — over the last decade. 

This consolidation means the vast majority of the dairy cows are in CAFOs, which are major emitters of ammonia that can irritate people’s eyes and respiratory systems and also react with other airborne pollutants to form particulate matter pollution (PM2.5). PM2.5 particles are tiny air pollutants 30 times smaller than the width of a human hair,  and inhalation of them has been linked to asthma, heart and lung problems and preterm births. Ammonia contributes to 30% of US PM2.5 pollution, according to estimates. 

An estimated 80% of atmospheric ammonia, which is a nitrogen-based gas, comes from agriculture via fertilizer and animal manure. In 2023, researchers examined CAFO prevalence and ammonia air pollution across the US and found the levels were highest in counties that had a high density of livestock.

In the new study, researchers estimated the emissions from 337,000 dairy cows from 132 dairy CAFOs in New Mexico. They then calculated the health costs — finding that each year dairy emissions are responsible for an estimated 20 premature deaths and $217.66 million in health costs. 

Suraj Ghimire, lead author of the new paper and a researcher and assistant teaching professor at New Mexico Institute of Mining and Technology’s department of computer science, said location seems a bigger factor in a farm’s environmental toll than herd size. 

“Farms situated near metro areas impose average damages of $1,086 per cow annually, which is more than double the $544 per cow damage originating from rural farms,” he said. “Downwind communities are bearing the brunt of the health costs without receiving any of the compensating dairy revenues.” 

“Downwind communities are bearing the brunt of the health costs.” – Suraj Ghimire, New Mexico Institute of Mining and Technology

The researchers warned that the health cost estimates are likely conservative since “other pollutants from dairy CAFOs, including hydrogen sulfide, volatile organic compounds, bioaerosols, and odor, as well as water quality and ecosystem damage from nutrient runoff are excluded.” 

Neither the Dairy Producers of New Mexico nor Dairy MAX, a regional National Dairy Council affiliate that covers New Mexico, responded to requests to comment on the new study’s findings. On its website the Dairy Producers of New Mexico says it “works closely with environmental advisors and local and regional environmental regulators to formulate environmentally protective, sensible, and efficient operating procedures.” 

The new findings come as dairy was featured heavily in the updated Dietary Guidelines for Americans released in January. The updates included a new food pyramid that featured mostly “protein, dairy & healthy fats” and “vegetables & fruits,” with “whole grains” occupying a smaller portion. The new guidelines differed from previous versions in suggesting full-fat dairy products instead of fat-free or low-fat versions. 

CAFO regulations 

Drew Goretzka, director of communications with the New Mexico Environment Department (NMED), said “the study seems to indicate that ammonia is not on NMED’s radar … this is not the case.” 

“The study seems to indicate that ammonia is not on NMED’s radar … this is not the case.” – Drew Goretzka, New Mexico Environment Department

He said the agency’s Air Quality Bureau models ammonia from facilities that require air quality permitting, and that includes secondary PM2.5 formation. Currently five dairy CAFOs in the state require permits with the Air Quality Bureau (AQB).  

“Permitted or registered facilities with AQB are required to submit ammonia emissions for emissions inventories, and [the Air Quality Bureau] is expanding an air monitoring network around the state — including for PM2.5,” he said. 

The agency “takes the assertions in this new study seriously and will consider this study” as it makes decisions on where to put new air monitoring equipment, he said, adding that none of the current state monitors show PM2.5 levels over the national ambient air quality standards, including those in areas where dairy CAFOs are located.

The researchers acknowledge some limitations of the study — including that the emissions were calculated estimates rather than direct measurements and that weather patterns and atmospheric chemistry can differ between states. 

Ghimire said that the study points to “several necessary shifts in agricultural policy,” including stricter regulations in places where more people live, and considering potential air quality impacts when granting CAFO permits.

Featured image credit: Brian Bienkowski/TNL