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Animal Ag Ammonia and Human Health

1. Ammonia is considered by the EPA to be a “severely hazardous substance,” with direct health risks at the local level, major regional health risks due to the contributions to PM2.5, and wide-ranging risks to planetary and human health due to its central role in nutrient pollution.

2. About two-thirds of all ammonia comes from factory farms. About half comes from concentrated manure and about 20% from fertilizers on feed crops.

3. Ammonia from factory farms is released in astonishingly large volumes that far exceed the EPA’s standards, often at 10 to 50 times the limits that require notifications from any other industry.

4. Despite an awareness of the major health impacts, EPA regulations have been derailed for more than 20 years, buffeted by the complexity as well as the criticisms from industry and the USDA.

5. Ammonia’s role in nutrient pollution creates direct human health threats including nitrates in drinking water and potentially poisonous algae blooms.

6. Long-term, ammonia’s role in nutrient pollution adds to the environmental degradation that threatens a safe operating space for humanity, due to biodiversity loss, forest decline, eutrophication of surface waters, and the spread of invasive species.

There is a lack of societal awareness of the air quality issues of food systems in general.[1] Animal ag emissions are particularly obscured:

The number and complexity of factory farm gases and compounds defy analysis.[2,3]

Animal ag emissions, especially ammonia, are in a constant state of chemical transition.[4]

Current research is limited, especially in comparison to other major sources of air pollution.[5,6]

Pollution in air is fast moving and highly reactive, making attribution challenging.[7,8]

Air emissions from animal ag are almost completely unregulated.[9] This allows emissions to continue unabated without reporting and with limited monitoring.[10]

Factory farm ammonia emissions can be at levels 10 to 50 times or more the EPA’s “reportable quantities.”[11,12] Both the USDA and the industry have pushed back hard on regulation proposals, recognizing that any constraints would be a threat to the viability of the factory farming system.[13]

The impacts from fertilizers on feed crops (the nation’s largest crops) are not generally recognized as attributable to animal ag.

  1. Balasubramanian, S., et al., (2021). The food we eat, the air we breathe: a review of the fine particulate matter-induced air quality health impacts of the global food system. Environmental Research Letters, 16(10), 103004, p. 20. [“The global food system is essential for the health and wellbeing of society, but is also a major cause of environmental damage. Some impacts, such as on climate change, have been the subject of intense recent inquiry, but others, such as on air quality, are not as well understood.”]
  2. Schiffman, S. S., et al., (2001). Quantification of odors and odorants from swine operations in North Carolina. Agricultural and Forest Meteorology, 108(3), 213-240, p. 220. [“A total of 331 different VOCs and fixed gases were found at swine facilities in North Carolina.” Of all documented compounds, more than 150 were determined to be “irritants.”]
  3. U.S. EPA Office of Inspector General (2017) Eleven Years After Agreement, EPA Has Not Developed Reliable Emission Estimation Methods to Determine Whether Animal Feeding Operations Comply With Clean Air Act and Other Statutes, p. 3. [“AFOs can have many and varied sources of air emissions… Each of these emission sources can emit a variety of air pollutants, and emission rates can fluctuate depending on climate and geographical conditions… Further, characterizing AFO air emissions requires expertise in multiple scientific disciplines, including animal nutrition, AFO practices and atmospheric chemistry.”] 
  4. U.S. EPA (2011) Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences, and Management Options, A Report of the EPA Science Advisory Board, p. 4. [“Unlike other element-based pollution problems, the N cascade links the negative impacts, where one N-containing molecule can in sequence contribute to all the environmental issues mentioned above.”]
  5. Congressional Research Service (2016) Air Quality Issues and Animal Agriculture: A Primer, RL32948, p. 1. [“Resolving those questions is hindered by a lack of adequate, accurate, scientifically credible data on air emissions from AFOs, data that are needed to gauge possible adverse impacts and subsequent implementation of control measures.”]
  6. Lavaine, E., et al., (2020). Health, air pollution, and animal agriculture. Review of Agricultural, Food and Environmental Studies, 101, 517-528. [Few economic analyses exist regarding air pollution from agriculture compared to energy or transport (see, Figure 3)]
  7. Krupa, S. V. (2003). Effects of atmospheric ammonia (NH3) on terrestrial vegetation: a review. Environmental pollution, 124(2), 179-221, p. 181. [Ammonia life span of several hours to perhaps 1 to 4 days and a reach of ~.5 to 3 miles]
  8. Aneja, V. P., et al., (2008). Ammonia assessment from agriculture: US status and needs. Journal of Environmental Quality, 37(2), 515-520. [“ammonium aerosols might travel as far as 2500 km…”] 
  9. The National Agricultural Law Center (2025). Federal Court Upholds Reporting Exemption for Livestock Emissions. [“Following the court’s ruling (on August 7, 2025), operators of CAFOs and other livestock facilities will continue to be exempt from both CERCLA and EPCRA notification requirements for air emissions from animal waste.”] For further info, see, Lack of Air Regulations.
  10. Burns, A. M., et al., (2023). Data Gap: Air Quality Networks Miss Air Pollution from Concentrated Animal Feeding Operations. Environmental Science & Technology, 57(49), 20718–20725, p. 20722. [“For example, in national and regional assessments, the EPA documents improving surface air quality. However, those assessments have an implicit bias that largely excludes agricultural locations, even for predominantly rural areas.”]
  11. U.S. EPA (2023) Emergency Release Notification Requirements for Animal Waste Air Emissions under the Emergency Planning and Community Right-to-Know Act (EPCRA) – Technical Background Document, Table 2-6, pp. 12-13. [“If the Reportable Quantity were raised to 500 lbs, the preliminary estimated regulated universe would decrease from 37,891 to approximately 14,825 farms.” At 1,000 pounds (10 times the reportable quantity) more than 5,000 factory farms could be regulated, and at 5,000 pounds more than 850 could be regulated.]
  12. See, Ammonia Emissions by Animal Type and Farm Size https://docs.google.com/spreadsheets/d/1kJ0hu4JYcDz3liG2iHc56zhAiMg5mxvopynve3YdxDg/edit?gid=0#gid=0google
  13. See, Lack of Animal Ag Air Regulations [question: How has the USDA fought against ammonia regulations?]

Factory farms are exempt from federal air quality regulations.[1] Although the EPA is required by the Clean Air Act to determine which stationary sources “cause or contribute significantly to air pollution that may reasonably be anticipated to endanger public health or welfare,” the agency has not added AFOs or CAFOs to the list of sources for which pollution limits must be set.[2] Nor has the EPA established limits (National Ambient Air Quality Standards or “NAAQS”) for the maximum allowable concentrations of factory farm emissions.[3]

Two additional environmental laws, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the Emergency Planning and Community Right-to-Know Act (EPCRA), require reporting of releases of hazardous substances that meet or exceed reportable quantities within a 24-hour period. However, in 2018, Congress passed the FARM Act exempting “air emissions from animal waste (including decomposing animal waste) at a farm” from CERCLA release notification requirements and the EPA has interpreted that to mean they are also exempt from EPCRA requirements.[4]

  1. The National Agricultural Law Center (2025). Federal Court Upholds Reporting Exemption for Livestock Emissions. [“Following the court’s ruling (on August 7, 2025), operators of CAFOs and other livestock facilities will continue to be exempt from both CERCLA and EPCRA notification requirements for air emissions from animal waste.”] For further info, see, Lack of Air Regulations
  2. Clean Air Act 42 U.S.C. 7411(b)(1)(A)
  3. Taft Law Bulletin (2014). Clean Air Act Does Not Require EPA to Regulate Emissions From Animal Feeding Operations. https://www.taftlaw.com/news-events/law-bulletins/clean-air-act-does-not-require-epa-to-regulate-emissions-from-animal-feeding-operations
  4. U.S. EPA (2026) Agriculture and Air Quality – Reporting Requirement for Air Releases from Animal Waste. https://www.epa.gov/agriculture/agriculture-and-air-quality#reportingrequirements [“However, due to legislative changes in the “Fair Agricultural Reporting Method Act” or “FARM Act” in March 2018, “air emissions from animal waste at a farm, such as ammonia and hydrogen sulfide” are exempt from reporting under CERCLA. These types of releases also do not need to be reported under EPCRA.”] 

In volume, importance, and damage, ammonia (NH3) created from excess nitrogen is the central air pollutant of animal ag.[1-4] Of all ammonia emissions in the U.S., about 70% originate from animal ag.[5]

On factory farms, high levels of ammonia can be damaging to farmed animals,  workers and local communities.[6-8] Ammonia is also a primary precursor gas contributing to the creation of PM2.5, the largest cause of human health-related damage from air pollution.[9,10] Escaped nitrogen in any form, including ammonia, continues to react with other compounds on a long journey of environmental and health damages, moving from one ecosystem to another. This is known as the nitrogen cascade.[11]

  1. U.S. EPA (2024) 2020 NEI Supporting Data and Summaries – Data Queries for Sector Summaries. [Total nitrous oxide from all agriculture at ~1.1 million tons versus ~5.5 million tons ammonia (~70% from animal ag).]
  2. Rotz, C. A., et al., (2014). Ammonia emission model for whole farm evaluation of dairy production systems. Journal of environmental quality, 43(4), 1143-1158, p. 1143. [“Emissions (from animal agriculture) include greenhouse gases, volatile organic compounds, and specific toxic compounds, of which ammonia (NH3) is the most important.”]
  3. Giannadaki, D., et al., (2018). Estimating health and economic benefits of reductions in air pollution from agriculture. The Science of the Total Environment, 622–623, 1304–1316, p. 1305. [“The main pollutant from agricultural activity is ammonia (NH3)…”]
  4. Hill, J., et al., (2019). Air-quality-related health damages of maize. Nature Sustainability, 2(5), 397-403. [Report estimates the PM2.5 pollution costs of corn production (the primary animal feed) at about 8 times the GHG gas damages of corn production, including from nitrous oxide.]
  5. U.S. EPA (2024) 2020 NEI Supporting Data and Summaries – Data Queries for Sector Summaries. [Query: National/Ammonia NH3/Livestock Waste (49.2%), fertilizer application (33.5%), agricultural field burning (2.7%) of total (5,482,484 tons).] Of the 36.2% due to crop production, we estimate at least half is from feed crops. For calculations of anthropogenic emissions, excluding wildfires, see Animal Agriculture Share of Anthropogenic Ammonia Emissions https://docs.google.com/spreadsheets/d/1naMuMuWYGUU9cvN8FoXni9TkfM65s85DGajbWqSP7xw/edit?gid=0#gid=0
  6. Naseem, S., & King, A. J. (2018). Ammonia production in poultry houses can affect health of humans, birds, and the environment—techniques for its reduction during poultry production. Environmental Science and Pollution Research International, 25(16), 15269–15293, p. 15271.   
  7. Schultz, A. A., et al., (2019). Residential proximity to concentrated animal feeding operations and allergic and respiratory disease. Environment international, 130, 104911. p. 5. [“Associations between residential proximity within 3 miles of a CAFO and increased prevalence of allergies, asthma, and decreased lung function were observed.”]
  8. U.S. EPA (2024) Development of Emissions Estimating Methodologies for Animal Feeding Operations, Volume 1: Overview Report, p. 1-1. [“Ammonia also is a source of odor from AFOs, but to a lesser degree because NH3 rapidly disperses in the air.”]
  9. Wyer, K. E., et al., (2022). Ammonia emissions from agriculture and their contribution to fine particulate matter: A review of implications for human health. Journal of Environmental Management, 323, 116285–116285, p. 1. [“There is currently a chain that exists between NH3 emissions, the formation of PM2.5, and the subsequent impacts that this PM2.5 has on human health.” (See, pp. 5-6 for details regarding those transformations)] 
  10. Tessum, C. W., et al., (2019). Inequity in consumption of goods and services adds to racial–ethnic disparities in air pollution exposure. PNAS, 116(13), 6001–6006, p. 6001. [“Fine particulate matter (PM2.5) exposure is a major health risk factor in the United States, responsible for 63% of deaths from environmental causes and 3% of deaths from all causes.”]
  11. Galloway, J. N., et al., (2003). The nitrogen cascade. Bioscience, 53(4), 341-356, Abstract. [“The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade.”]

The EPA has ruled that any release of ammonia above 100 pounds in a 24-hour period is a “reportable quantity,” requiring immediate notification to both federal authorities and the local community.[1-3] Factory farms are exempt from all reporting requirements.[4,5]

  1. U.S. EPA (2026) Emergency Planning and Community Right-to-Know Act (EPCRA), Determining the amount released for Ammonia and Ammonium Hydroxide for Release Notification Requirements under CERCLA section 103 and EPCRA section 304. [“Ammonia (CAS number 7664-41-7) is an Extremely Hazardous Substance (EHS), listed at 40 CFR Part 355 Appendix A and Appendix B with a reportable quantity (RQ) of 100 lbs. Both ammonia and ammonium hydroxide (CAS number 1336-21-6) are listed as Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) hazardous substances at 40 CFR 302.4. Under CERCLA, ammonia is listed with an RQ of 100 lbs and ammonium hydroxide is listed with an RQ of 1,000 lbs.”]
  2. CFR Title 40 § 302.4, 302.4 Hazardous substances and reportable quantities.
  3. U.S. EPA (2026) Emergency Planning and Community Right-to-Know Act (EPCRA) – Reportable Release Time Period. [“Over what time period must a Reportable Quantity (RQ) of a hazardous substance be released for that release to be reportable? EPA has stated that the period during which the person in charge must measure whether an RQ or more has been released is 24 hours. Reporting must occur immediately upon knowledge of the release.”]
  4. U.S. EPA (2021) Emission Estimation Methods for Animal Feeding Operations. Office of Air and Radiation, Office of Air Quality Planning and Standards, pp. 3-1 – 3-6. [A brief history from the EPA covering some aspects of their stalled and eventually doomed efforts to monitor and regulate ammonia emissions from factory farms. “In the years since the Air Compliance Agreement (in 2005) … EPA has finalized rulemakings to provide a reporting exemption for air emissions from animal waste at farms from both CERCLA and EPCRA.”]
  5. Note that releases from non-exempt industries (i.e., other than factory farms) that are continuous or stable in quantity and rate have more limited reporting requirements. See: EPA (2026) Emergency Planning and Community Right-to-Know Act (EPCRA) – CERCLA and EPCRA Continuous Release Reporting. [“The release reporting regulations of CERCLA and EPCRA provide reduced reporting options for “continuous releases” of CERCLA hazardous substances and EPCRA Extremely Hazardous Substances (EHSs). This relief applies to facilities with releases of CERCLA hazardous substances and EPCRA EHSs that are “continuous” and “stable in quantity and rate.”]

Depending on animal type, a typical factory farm generates between 100 and 2,000 pounds of ammonia per day.[1] Daily emissions of 2,000 pounds would be 20 times the EPA’s “reportable quantity” for which any other industrial facility would be required to alert both federal authorities and the local community.[2]

Large factory farms can generate more than 5,000 pounds of ammonia per day, or more than 50 times the reportable quantity.[3,4]

  1. See Ammonia Emissions by Animal Type and Farm Size  https://docs.google.com/spreadsheets/d/1kJ0hu4JYcDz3liG2iHc56zhAiMg5mxvopynve3YdxDg/edit?gid=0#gid=0 [A “typical” factory farm is defined as the approximate size (in animal numbers) for which about half of production is above that size and half below.]
  2. See previous question.
  3. Note: A large factory farm is defined here as among those that generate the top 5-10% of total production. There are wide variations in ammonia emissions of individual factory farms depending on species, number of confined animals, manure management systems, diets, and climate factors. See: U.S. EPA (2024) Development of Emissions Estimating Methodologies for Animal Feeding Operations, Volume 1, Overview Report Draft p. 2-1. [“The volatilization of NH3 from any AFO operation can be highly variable depending on total NH3 concentration, temperature, pH, and storage time.”]
  4. For further support of these figures, see: EPA (2023) Emergency Release Notification Requirements for Animal Waste Air Emissions under the Emergency Planning and Community Right-to-Know Act (EPCRA) – Technical Background Document, Table 2-6, pp. 12-13. [“If the Reportable Quantity were raised to 500 lbs, the preliminary estimated regulated universe would decrease from 37,891 to approximately 14,825 farms.” At 1,000 pounds (10 times the reportable quantity) more than 5,000 factory farms could be regulated, and at 5,000 pounds (50 times the EPA’s level for all other industries) about 860 could be regulated.]

Initially, ammonia pollutes at the factory farm and local community level. Then, it pollutes on a regional level after creating PM2.5. Since nitrogen is highly reactive, it continues to form various compounds, circulating between air, water and soil.

Local – Most air-borne ammonia is short lived and will be deposited in a day or two within 2 or 3 miles of its source.[1,2] Yet at the factory farm level, ammonia causes respiratory and other diseases for workers and nearby residents.[3,4] It is also a component of factory farm odors, which have significant impacts on quality-of-life issues for local homeowners.[5]

Regional – In a second stage, some portion of ammonia reacts with aerosols to create PM2.5 which can create damage locally and drift hundreds or even a thousand miles or more from the source.[6-8] Human respiratory and cardiovascular diseases are well documented, with more than 10,000 U.S. deaths per year attributed to ammonia’s role in PM2.5.[9]

National – There is a third stage of ammonia pollution, much less predictable and harder to study. Escaped nitrogen in any form, including ammonia, continues to react with other compounds on a long journey of environmental and health damages, moving from one ecosystem to another. This is known as the nitrogen cascade.[11] The eventual impacts include: biodiversity loss, forest decline, eutrophication of surface waters, hypoxia of coastal waters, harmful algal blooms, and the spread of invasive species.[12]

A portion of the ammonia that escapes into the environment yearly is advected beyond the U.S “to other nations or to the global atmospheric or ocean commons.”[13]

  1. Krupa, S. V. (2003). Effects of atmospheric ammonia (NH3) on terrestrial vegetation: a review. Environmental pollution, 124(2), 179-221, p. 181. [Ammonia lifespan of several hours to perhaps 1 to 4 days and a reach of ~.5 to 3 or 4 miles. PM2.5 assumed lifespan of about a week.]
  2. Note: each of these stages of ammonia pollution are covered in more detail in the following questions.
  3. Naseem, S., & King, A. J. (2018). Ammonia production in poultry houses can affect health of humans, birds, and the environment—techniques for its reduction during poultry production. Environmental Science and Pollution Research International, 25(16), 15269–15293, p. 15271. 
  4. Schultz, A. A., et al., (2019). Residential proximity to concentrated animal feeding operations and allergic and respiratory disease. Environment international, 130, 104911, p. 5. [“Associations between residential proximity within 3 miles of a CAFO and increased prevalence of allergies, asthma, and decreased lung function were observed.”]
  5. U.S. EPA (2024) Development of Emissions Estimating Methodologies for Animal Feeding Operations, Volume 1: Overview Report, p. 1-1. [“Ammonia also is a source of odor from AFOs, but to a lesser degree because NH3 rapidly disperses in the air.”]
  6. Goodkind, A. L., et al., (2019). Fine-scale damage estimates of particulate matter air pollution reveal opportunities for location-specific mitigation of emissions. PNAS, 116(18), 8775-8780, Abstract. [“We find that 33% of damages occur within 8 km of emission sources, but 25% occur more than 256 km away…”]
  7. Chamanara, S., et al., (2025). Geography of animal feeding operations and their contribution to fine particulate matter pollution in vulnerable communities in the United States. Communications Earth & Environment, 6(1), 620, Abstract. [“… we find that AFOs raise local PM2.5 levels by 28% near cattle operations and 11% near hog farms, even after accounting for urban and industrial confounders.”]
  8. Aneja, V. P., et al., (2008). Ammonia assessment from agriculture: US status and needs. Journal of Environmental Quality, 37(2), 515-520. [With a lifespan of about 1 to 15 days, “ammonium aerosols might travel as far as 2500 km…”]    
  9. See, Animal Ag PM2.5 and Human Health for further info.
  10. Behera, S. N., et al., (2013). Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies. Environmental Science and Pollution Research, 20, 8092-8131, pp. 8121–8124, p. 8108. [“After particulate formation and with the advantage of atmospheric lifetimes of the order of 1–15 days, NH4 salts have the tendency to be transported and deposited at larger distances from emission sources, contributing to soil acidification, forest decline and eutrophication of waterways.”] 
  11. Galloway, J. N., et al., (2003). The nitrogen cascade. Bioscience, 53(4), 341-356, Abstract. [“The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade.”]
  12.  U.S. EPA (2011) Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences, and Management Options, A Report of the EPA Science Advisory Board, p. 4. [“Unlike other element-based pollution problems, the N cascade links the negative impacts, where one N-containing molecule can in sequence contribute to all the environmental issues mentioned above.” See also, Table ES-1 and pp. 41-42]
  13.  U.S. EPA (2011) Reactive Nitrogen in the United States, p. ES-6. [Of total NH3 emissions, “about 1 Tg N/yr (of a total of 3.1 Tg N) is advected out of the U.S. via the atmosphere.”]   

Both factory farm workers and nearby homeowners are impacted by high levels of ammonia from factory farms.

Workers – It is widely understood that chronic and acute exposure to high levels of ammonia emissions create respiratory health problems in humans.[1] Ammonia exposure on factory farms has been identified as a significant health concern among workers.[2] Ammonia levels on factory farms often exceed the levels at which respiratory irritation is to be expected.[3,4] According to the EPA, “Chronic exposure to airborne ammonia can increase the risk of respiratory irritation, cough, wheezing, tightness in the chest, and impaired lung function in humans.”[5]

Homeowner Disease – Many reports document connections between factory farm gases and respiratory diseases for nearby residents, especially children.[6-9] However, while ammonia is a central air emission and often assumed to play a significant part, it is difficult to assign attribution to any specific gas.

Homeowner Quality-of-life – Odors from factory farms negatively impact health and quality of life.[10,11] Ammonia is a central component of odors, though it is difficult to parse effects from individual gases.[12] Odors from factory farms can also have negative economic, social, and psychological effects, often exacerbated for people of color and those with fewer assets.[13]

  1. Berner, T., et al., (2016). Toxicological Review of Ammonia Noncancer Inhalation, CASRN 7664-41-7, U.S. EPA, p. 1-33. [“Thus, the weight of evidence of observed respiratory effects observed across multiple human and animal studies identifies respiratory system effects as a hazard from ammonia exposure.”]
  2. Naseem, S., & King, A. J. (2018). Ammonia production in poultry houses can affect health of humans, birds, and the environment—techniques for its reduction during poultry production. Environmental Science and Pollution Research, 25(16), 15269-15293, p. 15271. [“Respiratory symptoms during and after work in poultry houses has increased in recent years. All studies showed acute and chronic effects on poultry workers’ health.”]
  3. U.S. Dept of Health and Human Services (2004). Toxicological Profile for Ammonia, Public Health Service Agency for Toxic Substances and Disease Registry, p. 26. [“Ammonia is an upper respiratory irritant in humans. Exposures to levels exceeding 30 ppm result in immediate irritation to the nose and throat.”]
  4. Bist, R. B., et al., (2023). Ammonia emissions, impacts, and mitigation strategies for poultry production: A critical review. Journal of Environmental Management, 328, 116919, See p. 4, Table 4. [Midwest egg-laying operations including high-rise and cage-free housing tend to have high levels. Levels in all CAFOs tend to be higher in winter because operators conserve heat by reducing ventilation.]  
  5. Berner, T., et al., (2016), p. 1-33.
  6. Schultz, A. A., et al. (2019). Residential proximity to concentrated animal feeding operations and allergic and respiratory disease. Environment International, 130, 104911–104911, p. 1. [“Associations between residential proximity within 3 miles of a CAFO and increased prevalence of allergies, asthma, and decreased lung function were observed.”]
  7. Loftus, C., et al., (2020). Estimated time-varying exposures to air emissions from animal feeding operations and childhood asthma. International journal of hygiene and environmental health, 223(1), 187-198, p. 10. [“In general, our findings of increased respiratory morbidity associated with AFO air exposures were in line with findings from our previous, smaller study of lung function and monitored ammonia (Loftus et al., 2015a), as well as those of other recent studies of pediatric asthma in communities impacted by AFO-related pollution (Merchant et al., 2015; Mirabelli et al., 2006; Pavilonis et al., 2013; Radon et al., 2007; Rasmussen et al., 2017).”]
  8. Rasmussen, S. G., et al., (2017). Proximity to industrial food animal production and asthma exacerbations in Pennsylvania, 2005–2012. International journal of environmental research and public health, 14(4), 362, Abstract & p. 7. [“This study contributes to growing evidence that industrialize food animal production (IFAP) may impact health, in this case clinically-documented asthma exacerbations. … We found 11% and 29% increased odds of OCS orders and asthma hospitalizations, respectively, among asthma patients living within 3 miles of IFAP, compared to living farther away.”]
  9. Simões, M., et al., (2022). Residential proximity to livestock animals and mortality from respiratory diseases in The Netherlands: A prospective census-based cohort study. Environment international, 161, 107140, p. 6. [“We found higher risk of mortality due to all three respiratory endpoints in people living near farms raising pigs, observing Hazard Ratios above unity consistently across all buffer sizes and a tendency for increasing risks in people living in proximity to higher as compared to lower animal counts.”]
  10. Wing, S., et al., (2008). Air pollution and odor in communities near industrial swine operations. Environmental health perspectives, 116(10), 1362, p. 1366. [“One-third of participants reported ceasing or changing their activities due to malodor…”]
  11. Guadalupe-Fernandez, V., et al., (2021). Industrial odour pollution and human health: a systematic review and meta-analysis. Environmental Health, 20(1), 108, p. 17. [“Animal Feeding Operations and waste were the most common industrial sources. … Meta-analysis results showed that residential odour exposure was associated to an increased risk of headache and cough/phlegm, and to a borderline risk of nausea and vomiting.”]
  12. Blanes-Vidal, V., et al., (2012). Residential exposure to outdoor air pollution from livestock operations and perceived annoyance among citizens. Environment international, 40, 44-50, Abstract. [“The results suggest that atmospheric NH3 levels measured at local air quality stations or estimated at the residences from emission-dispersion models could be used as indicators of odor annoyance in non-urban residential communities.”]
  13. Nicole, W. (2013). CAFOs and environmental justice: the case of North Carolina. Environmental health perspectives, 121(6), a182, p. a183. [“The odor plume, which often pervades nearby communities, contains respiratory and eye irritants including hydrogen sulfide and ammonia. A growing body of research suggests these emissions may contribute not only to mucosal irritation and respiratory ailments in nearby residents but also decreased quality of life, mental stress and elevated blood pressure.”]

In the U.S., PM2.5 is the largest cause of human mortality due to environmental factors, estimated to cause more than 60% of all premature deaths from environmental causes.[1,2] Ammonia is a critical component in PM2.5 creation.[3]

More than 10,000 deaths per year are attributed to air pollution from animal ag, mostly due to ammonia generated from manure and feed crop fertilizers transforming into PM2.5.[4]

  1. Thakrar, S. K., et al., (2020). Reducing Mortality from Air Pollution in the United States by Targeting Specific Emission Sources. Environmental Science & Technology Letters, 7(9), 639–645. [“Exposure to air pollution remains the greatest environmental health risk factor in the United States…”] 
  2. Tessum, C. W., et al., (2019). Inequity in consumption of goods and services adds to racial–ethnic disparities in air pollution exposure. PNAS, 116(13), 6001–6006, p. 6001. [“Fine particulate matter (PM2.5) exposure is a major health risk factor in the United States, responsible for 63% of deaths from environmental causes and 3% of deaths from all causes.”]
  3. Wyer, K. E., et al., (2022). Ammonia emissions from agriculture and their contribution to fine particulate matter: A review of implications for human health. Journal of environmental management, 323, 116285, p. 2. [“…studies have shown that NH3 is the precursor which has the biggest impact on the formation of this pollutant.”]
  4. For references and further information see, Animal Ag PM2.5 & Human Health

Broadly estimated, ~15-20% of the total nitrogen leaked to the environment is ammonia.[1-4] This makes ammonia a major conduit of nutrient pollution.[5]

Escaped nitrogen in any form, including ammonia, continues to react with other compounds on a long journey of environmental and health damages, moving from one ecosystem to another. This is known as the nitrogen cascade.[6] The eventual impacts include: biodiversity loss, forest decline, acidification and eutrophication of surface waters, hypoxia of coastal waters, harmful algal blooms, and the spread of invasive species.[7]

The many direct human health impacts of these various forms of environmental degradation include nitrates in drinking water,[8] the dangers of harmful algae blooms,[9,10] and the loss of recreational opportunities in water bodies or the psychological impacts of changing landscapes.[11]

More broadly, it is understood that environmental health and human health are inextricably linked. Nutrient pollution is one of the 9 planetary boundaries, and the nitrogen component is most definitively in the “high risk zone.” This is currently threatening “a safe operating space for humanity.”[12]

  1. Houlton, B. Z., et al., (2013). Intentional versus unintentional nitrogen use in the United States: trends, efficiency and implications. Biogeochemistry, 114, 11-23, See Figure 3, p. 18. [Estimate is 13% of total N is lost to the environment via NH3. Of anthropogenic N creation this would be about 16%.]  
  2. Sobota, D. J., et al., (2015). Cost of reactive nitrogen release from human activities to the environment in the United States. Environmental Research Letters, 10(2), 025006, pp. 6-7. [At the national scale, anthropogenic N leakages per year = 4.8 surface freshwater, 4.2 groundwater, 3.0 ammonia, 1.9 coastal zones, 1.4 fossil fuel combustion (p. 6). Calculation: 3.0 Tg N / 15.3 = 19.6%. Ammonia emissions have grown to ~5.5 million tons (~5 Tg N) per the EPA, so the 15-20% figure could be an underestimate.]
  3. Liu, L., et al., (2022). Exploring global changes in agricultural ammonia emissions and their contribution to nitrogen deposition since 1980. PNAS, 119(14), e2121998119. [Notes that 17% of N in fertilizer applications (the largest N input) is lost to NH3 in the U.S. Does not appear to give total NH3 lost from manure, except as kilograms per head (Supporting information Table S-3.)]
  4. Note: National figures on total escaped N are not regularly calculated. According to USDA researchers, “there are no national estimates of total reactive N loss…” [See: Rotz, A., et al., (2021). Environmental assessment of United States dairy farms. Journal of Cleaner Production, 315, 128153]
  5. For more information about nutrient pollution, see, Nitrogen & Air Pollution and Nutrient Pollution of Waterways [Nutrient pollution = an excess of nitrogen and phosphorus in air, water, soil, and land.]
  6. Galloway, J. N., et al., (2003). The nitrogen cascade. Bioscience, 53(4), 341-356, Abstract. [“The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade.”]
  7. U.S. EPA (2011) Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences, and Management Options, A Report of the EPA Science Advisory Board, p. 4. [“Unlike other element-based pollution problems, the N cascade links the negative impacts, where one N-containing molecule can in sequence contribute to all the environmental issues mentioned above.” See also, Table ES-1, pp. 41-42, and Appendix G.]
  8. See, Nitrates in Drinking Water [NH3 emissions can undergo atmospheric deposition whereby nitrogen compounds enter terrestrial and aquatic ecosystems, eventually entering surface and groundwater drinking water sources.]
  9. Office of Inspector General (2021). EPA Needs an Agencywide Strategic Action Plan to Address Harmful Algal Blooms, Report No. 21-E-0264, p. 2. [“HABs can sicken people and kill animals; create oxygen-poor zones in rivers and lakes, making them unsuited for aquatic life; raise treatment costs for drinking water; cause economic hardship for industries that depend on clean water; and negatively impact recreational activities. Human exposure to cyanotoxins can result in dermatitis, respiratory illness, gastrointestinal effects, liver and kidney damage, neurotoxicity, paralysis, and death in rare circumstances.”]
  10. Grattan, L. M., et al., (2016). Harmful algal blooms and public health. Harmful algae, 57, 2-8, p. 2. [“Often due to the activity of HAB related toxins, seafood consumption has become the leading cause of food-borne illness with known etiology.”]
  11. Dodds, W. K., et al., (2009). Eutrophication of US freshwaters: analysis of potential economic damages, Environmental Science & Technology, 43:1, p. 12. [“Lakes and rivers provide drinking water, recreation, and aesthetic benefits, all of which can be negatively influenced by eutrophication.”]
  12. Sutton, M. A. et al., (2021). The nitrogen decade: mobilizing global action on nitrogen to 2030 and beyond. One Earth, 4(1), 10-14, p. 10. [“Many are aware of nitrogen as one of the most transgressed ‘‘planetary boundaries.’’ What is less widely understood is that nitrogen also affects the exceedance of all of the other planetary boundaries. By massively increasing the supply of nitrogen compounds, humans are worsening air and water quality, contributing to climate change and stratospheric ozone depletion, and thereby threatening health, biodiversity, and livelihoods.”]

It is likely that the overriding reason is because efforts to constrain ammonia emissions would present a direct challenge to the factory farm system and its ability to mass produce extremely inexpensive animal-sourced foods.

More specifically, the reasons include: agricultural exceptionalism, the USDA’s pushback on regulations, the complex science of counting emissions, widely varying emissions by location, and antiregulatory zeal.[1]

  1. For more information see, Lack of Air Regulations

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