In a groundbreaking study published in Communications Earth & Environment, researchers from the University of Michigan have unveiled a comprehensive map pinpointing the locations and spatial footprints of over 15,000 cattle and hog feeding operations across the United States. This unprecedented dataset sheds light on the environmental and social dimensions of these vast agricultural enterprises, which collectively rear the majority of the nation’s livestock. The study not only quantifies their widespread presence but also links these massive facilities to detrimental air quality effects and the disproportionate impact on vulnerable communities.
Livestock production in the U.S. is overwhelmingly concentrated in specialized feeding operations, often termed Animal Feeding Operations (AFOs), where animals are confined and fed intensively for extended periods. These operations raise approximately 70% of the country’s cattle and a staggering 98% of its hogs, underscoring their critical role in the agricultural economy. Despite their prevalence, detailed data on their precise locations and environmental impacts have historically been fragmented and inconsistent, limiting scientific scrutiny and policy responses.
The University of Michigan team, led by environmental scientist Sanaz Chamanara, undertook an painstaking data reconciliation process that combined government records, satellite imagery, and community science contributions to build the most thorough national inventory to date. Initial official datasets listed around 10,000 AFO sites, but ground-truthing via high-resolution imagery revealed many inconsistencies, prompting a comprehensive reevaluation. This work culminated in a robust geospatial dataset covering more than 15,000 verified AFOs across the continental United States.
This spatially explicit inventory revealed a highly uneven distribution of feeding operations: about one-quarter of all sites are clustered in just 30 counties, out of the more than 3,000 U.S. counties. This geographic concentration highlights a critical focus for regulatory efforts and environmental monitoring. The study further mapped the actual land area occupied by these operations, finding that collectively AFOs cover a surface roughly equivalent to 500,000 football fields nationwide. Notably, cattle feeding operations account for nearly 80% of this expansive footprint.
The environmental implications of this spatial pattern are stark. The research team evaluated concentrations of fine particulate matter (PM2.5), a pollutant known to penetrate deep into human lungs and contribute to cardiovascular and respiratory diseases. Using extensive air quality data, they demonstrated that PM2.5 levels were on average 28% higher near cattle feeding operations and 11% higher near hog operations compared with demographically similar counties absent these facilities. These findings highlight the substantial air quality burden posed by intensive livestock agriculture.
Particulate matter emanating from AFOs originates largely from the accumulation and disturbance of animal manure, which releases dust and noxious compounds. While the distinctive smell is the most immediately recognizable nuisance, these emissions also elevate the concentration of harmful airborne dust and microbial agents that can exacerbate asthma, bronchitis, and other chronic conditions. In this context, PM2.5 serves as a critical proxy for broader air pollution impacts tied to concentrated animal feeding.
The study’s detailed sociological analysis adds an important dimension to these environmental findings. Census data reveal that counties with large AFO concentrations tend to have disproportionate shares of socially marginalized communities, including populations with lower health insurance coverage, reduced educational attainment, and higher proportions of Latino residents. This pattern of environmental injustice signals that the adverse health consequences of livestock pollution are not evenly distributed but disproportionately affect vulnerable groups.
Lead author Sanaz Chamanara emphasized the significance of producing an open-access dataset, one that transcends the limitations of prior patchy government data. The project, which dovetailed with her doctoral work at the University of Michigan’s School for Environment and Sustainability (SEAS), leveraged satellite imagery inspection of every continental U.S. county to ensure accuracy. This data-rich approach promises to empower public health officials, environmental justice advocates, and researchers with a more precise tool to develop targeted interventions.
Senior author Joshua Newell elaborated on the policy implications of the geographic clustering of AFOs. By focusing regulatory scrutiny and public health initiatives on the 30 counties where operations are most concentrated, policymakers can more efficiently allocate resources to reduce pollution exposure and improve community health outcomes. This spatial precision contrasts with previous approaches that lacked clear targets, enhancing the potential for impactful environmental governance and community engagement.
The research also confronts a stark paradox embedded within the nation’s food production system: the meat that Americans consume depends on environmentally costly, spatially concentrated infrastructures that externalize air pollution risks onto local populations. Assistant professor Benjamin Goldstein commented on the toxicity of fine particulate matter, describing it as a persistent airborne hazard with no safe threshold for exposure, capable of inflicting lasting damage on the respiratory system.
Dr. Dimitris Gounaridis, a co-author and assistant research scientist at SEAS, noted that while the dataset may not represent every single AFO in the U.S., its scale and rigor provide a reliable foundation for drawing meaningful conclusions. The dataset fills a longstanding data gap in environmental research related to industrial-scale animal agriculture and demonstrates the power of combining multi-source data with spatial technologies.
Importantly, the study transcends prior localized investigations by offering a nationwide perspective, which is critical given the significant scale of these operations and their widespread environmental and health implications. It signals a call to action for integrating environmental justice into agricultural policy and for further refining air quality standards that account for the intense particulate burden borne by communities living near these colossal operations.
This comprehensive work, funded and conducted within one of the world’s most data-rich societies, underscores the paradox that such critical information has only now been systematically compiled and analyzed. The release of this dataset illuminates a pressing need for renewed attention to the intersection of agricultural intensification, environmental pollution, and community wellbeing. With these insights, stakeholders can advance toward more equitable and sustainable food systems that safeguard both public health and the environment.
Subject of Research: Environmental and social impacts of concentrated animal feeding operations in the United States
Article Title: Animal feeding operations are associated with heightened concentrations of fine particulate matter and affect vulnerable communities in the United States
News Publication Date: 12-Aug-2025
Web References: https://doi.org/10.1038/s43247-025-02520-w
References: S. Chamanara et al., Communications Earth & Environment (2025)
Image Credits: S. Chamanara et al., Communications Earth & Environment, 2025 DOI: 10.1038/s43247-025-02520-w
Keywords: Animal Feeding Operations, AFOs, PM2.5, air pollution, environmental justice, livestock agriculture, particulate matter, vulnerable communities, environmental health, satellite imagery, spatial mapping
