DONATE
DONATE

Agricultural PM2.5 Pollution

 

  1. 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)]
  2. 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. https://doi.org/10.1016/j.jenvman.2022.116285  [“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.”] 
  3. 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) air pollution exposure is the largest environmental health risk factor in the United States.”]   

PM stands for particulate matter and the 2.5 means 2.5 microns or less in diameter (much less than the width of a human hair). Because PM2.5  gets deep into the airways and bloodstream, exposure can damage a person’s lungs and heart.[1]

Particulate matter has been designated by the EPA as one of six criteria air pollutants for which the agency has set National Ambient Air Quality Standards.[2]

PM2.5 is also referred to as “fine particulate matter,” in contrast to PM10, a coarser form of particulate matter that tends to be somewhat less damaging, with more localized effects and shorter life spans.[3]

 

  1. U.S. EPA (June 20, 2024) Particulate Matter (PM) Basics https://www.epa.gov/pm-pollution/particulate-matter-pm-basics#PM
  2. U.S. EPA (2024) Criteria Air Pollutants. https://www.epa.gov/criteria-air-pollutants
  3. U.S. EPA (2020) Policy Assessment for the Review of the National Ambient Air Quality Standards for Particulate Matter, EPA-452/R-20-002, pp. 2-3. [“Atmospheric lifetimes are generally longest for PM2.5, which often remains in the atmosphere for days to weeks before being removed by wet or dry deposition.” PM10 (particles larger than PM2.5 but smaller than 10 microns) are “generally removed from the atmosphere within hours, through wet or dry deposition.”]

1. Reactive nitrogen is created via the Haber-Bosch process, mostly for use in chemical fertilizers.[1] Reactive nitrogen is also created by nitrogen-fixing crops (primarily soybeans and alfalfa/hay) that take inert nitrogen from the air and turn it into a usable form of nitrogen.[2]

2. Excess nitrogen applied to crops as fertilizer or manure volatizes into ammonia. Fixed nitrogen is left in the soil and in plant residue yet can also volatize into ammonia.

3. Excess nitrogen in animal feed is excreted as manure, some of which quickly volatizes into ammonia.[3]

4. Ammonia reacts with aerosols and other compounds to create PM2.5.[4]

5. PM2.5 can be made up of a wide range of pollutants including heavy metals, volatile organic compounds, and biological materials including bacteria and viruses.[5,6]

 

  1. 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. 3. [“one of the world’s most important discoveries – how to extract N2 from the atmosphere and convert it to ammonia (NH3).”]
  2. Davidson, E. A., et al., (2011). Excess nitrogen in the US environment: trends, risks, and solutions. Issues in ecology, (15), p.3. [“Soybean production has been increasing, which increases biological nitrogen fixation in croplands.”]
  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. https://doi.org/10.1016/j.scitotenv.2017.12.064  [“The main pollutant from agricultural activity is ammonia (NH3), mainly from animal husbandry and its associated manure processing, and to a lesser extent from fertilizer use.”]
  4. 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. 5. [“Gaseous NH3 reacts with aerosols containing sulphuric and nitric acids to create particulates such as ammonium nitrate (NH4NO3), ammonium sulphate ((NH4)2SO4), and ammonium chloride (NH4CL).”]
  5. Thangavel, P., et al., (2022). Recent insights into particulate matter (PM2.5)-mediated toxicity in humans: an overview. International journal of environmental research and public health, 19(12), 7511, pp. 3-4. [“The major components in PM2.5 are black carbon, polycyclic aromatic hydrocarbons, aryl hydrocarbons, volatile organic hydrocarbons, heavy metals organic compounds, minerals, inorganic ions, and biological materials, which collectively make up at least 79–85% of the total mass.”]
  6. McEachran, A. D., et al., (2015). Antibiotics, bacteria, and antibiotic resistance genes: aerial transport from cattle feed yards via particulate matter. Environmental Health Perspectives, 123(4), 337–337. https://doi.org/10.1289/ehp.1408555  

PM2.5 can carry hundreds of miles to upwards of a thousand miles.[1-3] It generally stays in the atmosphere for “days to weeks before being removed by wet or dry deposition.”[4]

 

  1. 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…”]
  2. Emert, A. D., et al., (2024). USEPA CALPUFF validation and dispersion modeling of beef cattle feedlot PM10 and PM2.5 emissions factors. Atmospheric Environment (1994), 316, 120189, p. 2. [“capable of atmospheric transport exceeding hundreds of kilometers…”]
  3. 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…”]
  4. U.S. EPA (January 2020) Policy Assessment for the Review of the National Ambient Air Quality Standards for Particulate Matter. EPA-452/R-20-002, pp. 2-3. [“Atmospheric lifetimes are generally longest for PM2.5, which often remains in the atmosphere for days to weeks before being removed by wet or dry deposition.”]

PM2.5 is the largest cause of human death due to environmental factors, estimated to cause more than 60% of all premature human deaths from environmental causes.[1,2]

PM2.5 from anthropogenic sources is estimated to be responsible for approximately 100,000 premature deaths per year.[3,4] This is more than deaths from firearms and motor vehicle crashes combined.

Globally, of all causes, PM2.5 is considered the largest or 2nd largest individual contributor to disease and premature death.[5,6]

 

  1. Tessum, C. W., et al., (2019). Inequity in consumption of goods and services adds to racial–ethnic disparities in air pollution exposure. Proceedings of the National Academy of Sciences – 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.”]
  2. 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. https://doi.org/10.1021/acs.estlett.0c00424  [“Exposure to air pollution remains the greatest environmental health risk factor in the United States…”] 
  3. Tessum, C. W., et al. (2019), p. 6001. [“Of these, 102,000 are caused by US anthropogenic emissions,” in 2015.]
  4. 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. [“107K deaths]
  5. Brauer, M., et al., (2024). Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021. The Lancet, 403(10440), 2162-2203, p. 2162 and Figure 2. [“Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021.”]
  6. Health Effects Institute (2024) State of Global Air 2024. Special Report. Boston, MA. [Air pollution trailing only high blood pressure, with 8.1 million total deaths in 2021 (p. 3). Of total air pollution deaths, 7.8 million due to PM2.5 (p.14)]  

One report estimates that PM2.5 is responsible for more than 90% of U.S. air pollution-related health damages, based on an analysis of a 2011 EPA report.[1]

This figure would be in line with a major global finding, attributing more than 95% of air pollution deaths to PM2.5.[2]

 

  1. Tschofen, P., et al., (2019). Fine particulate matter damages and value added in the US economy. Proceedings of the National Academy of Sciences, 116(40), 19857–19862, p. 19857. [“Among these are fine particulate matter, or PM2.5, which the Environmental Protection Agency (EPA) estimates is responsible for over 90% of air pollution-related health damages.”] This statement refers to U.S. EPA (2011) The Benefits and Costs of the Clean Air Act from 1990 to 2020, Final Report – Rev. A.  
  2. Health Effects Institute (2024) State of Global Air 2024. Special Report. Boston, MA, p. 14. [Air pollution premature deaths at 8.1 million in 2021. Of total air pollution deaths, 7.8 million due to PM2.5, ~96%]

Researchers estimate ~15,000 premature deaths per year are due to PM2.5 from U.S. agriculture.[1-4]

Of these, the great majority are attributable to animal agriculture.[5]

 

  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. [Estimates deaths due to agriculture at 19,000 including 3,100 from food prep and processing (Figure 1)]      
  2. Domingo, N. G., et al., (2021). Air quality–related health damages of food. PNAS, 118(20), e2013637118, p. 1. [17,900 deaths due to agriculture, with more than 95% from PM2.5]
  3. 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 [“Agriculture (15,000 premature deaths): crop and livestock production.” (Supplementary Information, p. 2)]
  4. Lelieveld, J., et al., (2015). The contribution of outdoor air pollution sources to premature mortality on a global scale. Nature, 525(7569), 367-371. [Estimates 29% of 55,000 deaths in 2010 or approximately 16,000 deaths (Table 2). Includes agriculture-related deaths due to ozone which are less than 10% (Table 1)]
  5. Domingo, N. G., et al., (2021), p. 1. [17,900 deaths due to agriculture, with more than 95% from PM2.5. Of these, about 12,700 (~70%) “attributable to animal-based foods, both directly from animal production and indirectly from growing animal feed.”]                 

Data from the 2020 EPA’s National Emissions Inventory [NEI] assesses that agriculture (including agricultural field burning) is responsible for about 85-90% of total U.S. ammonia emissions.[1] This is in line with an older U.S. analysis as well as with global estimates.[2,3]

 

  1. 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. Total ag ammonia (4,675,035) / total ammonia (5,482,484 tons) = 85.3%. EPA includes 321,482 tons of ammonia from unprescribed wildfires in total ammonia; not including this in total ammonia (thereby considering only anthropogenic) makes ag contribution ~91%.]
  2. 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, Table 2. [3,218 MMT anthropogenic /3,587 = 89.7% for 2005]
  3. Nair, A. A., & Yu, F. (2020). Quantification of Atmospheric Ammonia Concentrations: A Review of Its Measurement and Modeling. Atmosphere, 11(10), 1092, p. 9. [“Approximately 60% of total NH3 emissions are from anthropogenic sources, of which 80–90% are from agricultural activity (fertilizers and livestock wastes) [18,192,195,203].”]

Broadly estimated, ~20-30% of U.S. anthropogenic PM2.5 pollution comes from agriculture, with most of that share from ammonia transformed into PM2.5.[1-6]

 

  1. Lelieveld, J., et al., (2015). The contribution of outdoor air pollution sources to premature mortality on a global scale. Nature, 525(7569), 367-371, Table 2. [Estimates 29% from agriculture in U.S. in 2010.]
  2. Bauer, S. E., et al., (2016). Significant atmospheric aerosol pollution caused by world food cultivation. Geophysical Research Letters, 43(10), 5394–5400. [“Agriculture is responsible for about half of the total anthropogenic pollution in both the eastern and western United States.” at p. 5396. Ammonia specifically about 30%. (Figure 1)]
  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, 116285–116285, p. 1. [“NH3 emissions from agriculture are responsible for 30% of all PM2.5 in the US…” (reference to Bauer (2016) for this figure)]
  4. 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, 8777. [“The single largest contribution to total anthropogenic damages (in Fig. 3) is ground-level release of NH3 from agriculture (i.e., application and storage of manure; fertilizer use), contributing 12% of total impacts.”]
  5. 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. [Deaths due to agricultural emissions are ~15% of total: (8,400 + 6,600) / 100,000)]
  6. Tschofen, P., et al., (2019). Fine particulate matter damages and value added in the US economy. PNAS, 116(40), 19857–19862. [Gross external damages from agriculture appear to be about 25-30% of total GED, with ammonia contributing about a two-thirds share.]     

Ammonia emissions and their effects may be underestimated for several reasons.

Despite its wide-ranging impacts, ammonia is not regulated as a criteria air pollutant by the EPA’s National Ambient Air Quality Standards (NAAQS).[1] 

The EPA monitors air quality from data acquired from thousands of monitoring sites.[2] However, there is no system in place to monitor ammonia emissions at factory farms – the largest NH3 emitters. Starting with a 2005 agreement between the animal ag industry and the EPA to engage in a monitoring study, the long journey towards regulation continues after almost 2 decades.[3,4]

Additionally, because air pollution policy in the U.S. is focused on large point sources (such as industrial plants), mobile emissions, and highly populated areas, surface monitoring sites are sparsely located in rural agricultural areas. “Approximately one-third of all EPA air quality sites are located in rural settings, and ~10% are in agricultural locations.”[5] 

“It is commonly acknowledged that the major uncertainties [of environmental impacts of excess nitrogen] are related to reduced nitrogen compounds, and in particular NH3.”[6]

 

  1. U.S. EPA (2024) Criteria Air Pollutants. https://www.epa.gov/criteria-air-pollutants [The 6 criteria air pollutants are ozone, particulate matter, carbon monoxide, lead, sulfur dioxide and nitrogen dioxide.]
  2. U.S. EPA (2024) Air Quality System (AQS), AQS Primer, 3.2 Geography. https://www.epa.gov/aqs [as of 2020]
  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, No. 17-P-0396.
  4. Madison McVan (April 20, 2023) 18 years and counting: EPA still has no method for measuring CAFO air pollution, Investigate Midwest. https://investigatemidwest.org/2023/04/20/18-years-and-counting-epa-still-has-no-method-for-measuring-cafo-air-pollution/
  5. 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. 20721.
  6. Van Damme, M., et al., (2014). Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations. Atmospheric Chemistry and Physics, 14(6), 2905–2922, p. 2906.

Air Quality