Air Emissions From Animal Feeding Operations (AFOs)
Lingying Zhao
  
The U.S. Environmental Protection Agency (EPA) announced an Air Quality Compliance Agreement with Animal Feeding Operations (the Agreement) in January. The Agreement has stirred up many questions and concerns in the livestock and poultry industry. The Agreement signup period ended in July for poultry and swine producers, and in mid-August for dairies.

What's next?
According to the Agreement, the EPA is initiating a national air emissions monitoring study (NAEMS). The NAEMS is to establish the baseline air emission data associated with AFOs. The baseline air emission data and other existing scientific air emission data will be used to establish Emissions-Estimating Methodologies which will be used in assessing air emission compliance of AFOs with the federal air quality laws.

As an AFO, you may be intuitively curious about:

• What are the air emissions from AFOs?

• What is regulated by the EPA?

• How will the EPA collect the air emission data?

• Where can I get help to clear my questions?

This article is in an effort to address these questions.

Air emissions from animal feeding operations
The major air emissions associated with AFOs are gases (ammonia, hydrogen sulfide, carbon dioxide, and methane), particulate matter, Volatile Organic Compounds (VOCs), and odor.

Ammonia (NH₃) is released during manure storage and decomposition. It is generated because inefficient conversion of nitrogen in the feed to animal products resulted in N excretion in the urine of pigs and cattle and in the uric acid of poultry.

Hydrogen sulfide (H₂S) is a colorless gas, heavier than air, highly soluble in water. It is generated from anaerobic fermentation of manure. Methane (CH₄) is a natural gas, odorless, and produced by microbial degradation of organic matters under anaerobic conditions.

The primary source of (CH₄) in livestock operations is ruminant animals. In additions, (CH₄) emissions also occur during anaerobic microbial decomposition of manure. Carbon dioxide (CO₂) is a part of natural air, odorless, and mainly caused by animal breathing and manure decomposition.

Particulate matter (PM) in and around animal facilities is the airborne particulate emission from AFOs. Feed is usually the main component of the PM, but it also includes manure solids, dander, feathers, and hair. PM particles are carriers of odor, toxic gases, endotoxins, and pathogens.

Volatile Organic Compounds (VOCs) are chemicals that easily vaporize at room temperature. VOCs include fatty acids, nitrogen heterocycles, sulfides, amines, alcohols, hydrocarbons and many more. Some VOCs stink and some don't.

Anaerobic decomposition and transformation of livestock and poultry waste by microorganisms generates odorous compounds. Metabolic processes in the gastrointestinal tract of livestock also generate some of the odorous compounds. Unpleasant smells are not caused by a single chemical but rather are the result of several gases and odorous VOCs.

What air emissions will be monitored?
The EPA will measure ammonia, hydrogen sulfide, carbon dioxide, particulate matter (including total suspended particulates (TSP), particulates that are equal to smaller than 10 micron (PM₁₀₎,  and particles that are equal to and smaller than 2.5 micron (PM_2.5)], and volatile organic compounds from animal housing facilities (barns, covered feedlots, etc.) and manure storage structures (lagoons, covered manure pits, etc.) of representative swine, layer, broiler, turkey, and dairy AFOs. 

Interestingly, methane and odor will not be monitored. They are not listed in the federal air quality laws.

How will they be monitored?
Air emissions will be measured with equipment and methods that would sound complicated even if you're a chemistry major. A mobile air emission lab equipped with gas analyzers and particulate matter samplers and monitors will be used for the study. Ammonia will be measured using chemiluminescence or photo acoustic infrared gas analyzers. Hydrogen sulfide will be measured with a pulsed fluorescence analyzer. Carbon dioxide will be measured using a photoacoustic infrared analyzer. TSP will be measured using iso-kinetic multipoint particulate samplers. PM2.5  will be measured gravimetrically using a federal reference method. PM10 will be measured in real time using tapered element oscillating microbalance technologies. VOCs will be sampled using Silcosteel Canisters and all-glass impingers and evaluated using gas chromtography-mass Spectrometry (GC-MS).

Air quality mobile lab at Farm Science Review
At the Farm Science Review, I will attempt to translate this into common English. On Tuesday, September 20, Dr. Al Heber (director of the EPA study) and I will show you how these air emissions are measured using an OSU air quality mobile lab. I will also share preliminary results from typical Ohio dairy, swine and layer facilities. We will present our program twice, morning and afternoon. We hope to answer many of your questions and concerns about the EPA air quality study.

Air quality program on September 20 at Farm Science Review

9:30 am            What's next after signing the EPA's AFO Consent Agreement--NAEMS study update (Dr. Al Heber, Professor of Purdue University, Director of the NAEMS).

10:00 am           How will the EPA study determine air emissions from animal facilities? (Dr. Heber) 

10:45 am           Preliminary data on air quality and emissions of Ohio poultry, dairy, and swine facilities (Dr. Zhao)

11:30 am           Midday break

1:30 to 3:30 pm  The same program will be repeated

   

Lingying Zhao, assistant professor, and Extension agricultural engineeer, can be reached at zhao.119@osu.edu

 

This column is provided by the OSU Department of Food, Agricultural, and Biological Engineering.