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Frequently Asked Questions


Site Selection | The Study
Air Emissions & Study Projections | Planning

Site Selection

Who provided oversight of site selection for the NAEMS?

The Agricultural Air Research Council (AARC), US Environmental Protection Agency (EPA), and representatives of the National Chicken Council, National Milk Producers Federation, National Pork Board, and the United Egg Producers.

On what basis did you select the sites?

We considered the following factors:

a) Participation in the Air Compliance Agreement (required)

b) How representative the site is toward other livestock operations

c) Proximity to a University with required expertise

d) Conduciveness to obtaining good data

e) Producer collaboration and cooperativeness

Do the study sites provide a good representative sample of the whole U.S. livestock industry?

The farms were carefully selected based on the criteria of representativeness within the constraints of the site selection criteria listed above.

How many AFOs will serve as study locations?

The answer is twenty (20). Barn emissions will be monitored continuously at 14 of these farms: five (5) dairies, five (5) pork production sites, three (3) egg layer operations, and one broiler ranch. Emissions from outdoor manure storages or lagoons and a dairy corral will be monitored for 20 days each season at nine farms, with four sites on-location with barn monitoring.
Another study conducted at two broiler facilities in Kentucky qualified as an ACA study site. That brings the total numbers of farms to 22.

Where are the AFOs sampling sites located?

There are two swine barn monitoring sites in North Carolina, and one each in Iowa, Indiana, and Oklahoma. The dairy barn monitoring sites are located in California, Indiana, New York, Washington, and Wisconsin. The layer house monitoring sites are in Indiana, North Carolina, and California. The broiler house monitoring site is in California.
The study sites for outdoor manure storages or lagoons include one swine site each in Iowa and Indiana, and two each in North Carolina and Oklahoma. The dairy corral is located in Texas and the dairy lagoon monitoring sites are in Indiana, Texas, Washington, and Wisconsin.


The Study Itself

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Will you be studying particular Best Management Practices (BMPs) in the course of this project (or any other studies going on simultaneously)? Do you expect the results to point to particular BMPs, or is your goal simply to quantify emissions from various conventional AFO procedures?

The stated objective of the project is to quantify the emissions and answer the question: "How much?" However, the study will also provide a lot of insight into the characteristics of the emissions and will answer the questions: "Where? and "When"? For example, we will learn about the effect of animal behavior on emissions because we will monitor both their activity and their emissions in real time. We will learn about the effect of manure characteristics like pH and moisture content, and environmental parameters like temperature and wind on emission rates.

What is the status of the monitoring project?

We are currently setting up the sites across the country. Updates will be posted on www.agairquality.com. Official NAEMS data collection will start this summer.

How extensive is the description of the NAEMS?

Nearly 2,000 pages of planning documents have been compiled to the EPA, with data collection anticipated to begin in April 2000

Is there anything novel about how you will be gathering or analyzing your data?

We are following about eighty (80) standard operating procedures (SOP) that were painstakingly written for this study. These SOPs cover the range from established methods to new and novel methods. One novel method is the use of ultrasonic technology to measure the airflow through naturally ventilated barns. Another novel method involves the use of vibration sensors to monitor fan operation.

What types of air emissions will be monitored as part of the study?

Per requirements of the Compliance Agreement, pollutants likely to be emitted from animal housing and manure storage facilities at animal production farms will be monitored. We will measure the emissions of three size classes of particulate matter (TSP = total suspended particulate, PM10 = particles smaller than 10 microns diameter, and PM2.5 = particles less than 2.5 microns diameter), which are all regulated by the Clean Air Act. We will also measure ammonia and hydrogen sulfide emissions, as Community right-to-know regulations (CERCLA, EPCRA) requires that the release of these two compounds be reported if either is emitted at a rate of more than 100 lb/day for any 24 hour period. Finally, we will measure the emissions of total volatile organic compounds (VOC) which is also regulated by the Clean Air Act.

How are the air emissions being collected for the farms?

Rates of these emissions will be calculated based on concentrations of these regulated pollutants and the airflow rates through the barns or wind flows across lagoons, manure storages and corrals. Emission rates will be calculated every minute so that averages over any longer intervals (hourly, daily, monthly) can also be determined.

Are the farms constantly being monitored or just periodically? Will they all be monitored throughout the whole study?

The barns and two lagoons will be monitored continuously for the two years. The dairy corral and the other lagoons and storages will be monitored for eight, 20-day periods during the two-year study.

When might enough information be gathered to provide some preliminary results?

After the first quarter, but data must be gathered but the data will be validated and submitted directly to the EPA. The data will not be released to the public until all the data is validated and approved by the EPA, or 18 months following final submittal of the data.

What will the EPA do with the data?

The EPA will use the data to help them estimate the emissions from individual livestock operations using standardized methods and compare them with government regulatory thresholds. The data will also help EPA to construct an Agriculture Strategy, which will outline steps for reducing farm air pollution.

What equipment will be used to study the livestock emissions?

Continuous emissions monitoring equipment and optical sensing monitors will be used during NAEMS. This equipment includes photoacoustic infrared spectroscopy, pulsed fluorescence, gas chromatography mass spectrometry, ion chromatography, and the use of tapered element oscillating microbalances.

How often will the emissions data be reported to the EPA?

The Purdue University team is responsible for submitting quarterly progress and data reports to the EPA. The EPA may obtain data more frequently, if requested.


Air Emissions and Study Projections

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How do emissions from agricultural operations differ from emissions from other industries?

Livestock air emissions are emitted relatively low to the ground and have multiple points of emissions as compared with a single or multiple tall stacks at an industrial plant. Livestock air emissions are also typically more variable, both diurnally and seasonally. Agricultural emissions decrease significantly in the winter due to lower barn airflow and colder temperatures of outdoor waste facilities that suppress biological activity. The effect of weather on air emissions is coupled with the effect of manure accumulation, animal age and growth cycles, moisture content in manure storages, and animal weight and feed consumption.

Will ambient emissions monitoring be done to determine background levels in addition to the emissions monitoring at the site?

Background concentrations of ventilation air entering the barns, and of air immediately upwind of lagoons, basins and corrals will be measured. Downwind concentrations in the vicinity of neighbors will not be measured.

What changes do you anticipate most livestock farms may need to make to be in compliance?

Preliminary data from other studies indicates that many farms exceed the CERCLA reportable quantity thresholds because more than 100 lb of ammonia are released in any 24-hour period from the facility. There is potential that some of the very largest operations exceed 100 lb/day release of hydrogen sulfide. After the study is completed, the EPA will use the NAEMS data coupled with existing data to determine what sizes and types of farms emit reportable quantities.
Changes to production operations would be required by the EPA under the Clean Air Act if VOC and PM emissions exceed thresholds. The farms that exceed these thresholds will need to obtain a permit and reduce their emissions below the threshold. The changes that are needed will depend on the required emission reduction. EPA needs the NAEMS data to make those determinations.

What might it cost producers to operate under the air emissions thresholds?

The cost to report ammonia and hydrogen sulfide releases to the EPA are insignificant. The costs to reduce PM and VOC emissions cannot be determined until we know the abatement requirement. If ammonia becomes a regulated pollutant, then the costs to control its emissions will be significant.

Do you think it is going to be possible to establish emissions thresholds for animal operations?

The EPA will establish the emission threshold based on the NAEMS data. For this reason, they will oversee the study and make sure the data quality is sufficient to give them confidence in their conclusions about the emission estimating methodologies that they develop after the study is complete.

Will emissions thresholds for agricultural operations differ according to geographical locations/different parts of the county?

EPA will most likely consider any geographical effects that are evident in the data when they develop the emissions estimating methodologies.

What would you say the main "take-home message" about the research would be for livestock producers on this topic?

The U.S. EPA is going to wait for the scientific air emission data to be collected before proceeding to enforce current regulations on their farm. In the meantime:


Prepare for potential abatement and/or reporting of emissions


Take advantage of the study infrastructure to add more scientific measurements


at the study sites.

What is the ultimate goal of this project?

The overall goal of the study is to improve air quality.

Why is this important for livestock producers?

This landmark air emissions study will be conducted using some of the best measurement technology and scientific instruments available and will benefit from years of preparation and planning. After two years, the data will be in EPA's hands so they can develop the emissions measurement methodologies, or scientific models that predict emissions from farms of various types.


Project Planning

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Is Purdue University heading up the study for all the species?

Yes. Purdue University is the Independent Monitoring Contractor and Purdue Professor Albert Heber is the Science Advisor.

How did Purdue University get involved with the process and what is your role?

In November, 2004 Dr. Albert Heber was invited to attend a 2.5-day NAEMS protocol development meeting in Washington, D.C. with other scientists from around the country. This meeting was organized by the USDA and the USEPA. A few weeks later, he was asked to lead the study with his team from Purdue University's Agricultural Air Quality Laboratory (PAAQL).

What is the total budget of the study?

The allocated funds for the NAEMS, including contingency funds, are $6M from pork, $5M from dairy, $2.8M from eggs, and $1M from broilers for a total of $14.8M.

When will the study begin?

The ordering of equipment began in December, 2006 and collecting data shall start in summer, 2007.

Did you do anything in particular to help make the study as "watertight" as possible?

We have spent a great deal of time planning the study and obtaining feedback from the USEPA and other scientists regarding the study protocol before we began. The planning document is nearly 2,000 pages long!

How did the USEPA-approved two-year air emissions monitoring study of animal feeding operations come about?

The USEPA offered animal feeding operations in the swine, dairy, broiler chicken, and egg industries a one-time opportunity to participate in a legal agreement the provides protection against potential past federal air law violations. As part of the agreement, an extensive nationwide study was planned to generate data for determining emissions from major types of farms in geographic areas where they are located.

Are USEPA researchers involved?

Several researchers and scientists from the USEPA-OAQPS have overseen the protocol development and will provide quality oversight during execution of the project.

What do study participants have to do to take part in the study?

The participants need to collaborate with the researchers as we conduct the study. They will need to provide production information such as feed and water consumption, mortalities, and production of meat, eggs, or milk, depending on the type of farm. They also need to keep careful records of barn cleaning, maintenance, and inventory.

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