Airsheds and Watersheds III:

A Shared Resources Workshop

The Significance of Ammonia

To Coastal and Estuarine Areas

November 15-16, 2000

The BayCenter at Ruddertowne

Dewey Beach, Delaware

Sponsored by the Chesapeake Bay Program, EPA Great Waters Program,

NOAA Air Resources Laboratory, and the

Mid-Atlantic Regional Air Management Association
This report was prepared by:

Maggie Kerchner, NOAA Air Resources Laboratory,

Rebecca Halloran, Chesapeake Research Consortium,

Julie Thomas, EPA Chesapeake Bay Program, and

Bruce Hicks, NOAA Air Resources Laboratory

Assistance with the report, including meeting notes, was provided by Battelle, Inc.

Many thanks go to the workshop planning committee for their

assistance in developing the meeting agenda -

John Chlada, Perdue, Inc.

Bill Cure, North Carolina DENR, Air Quality Division

Rich Gannon, North Carolina DENR, Water Quality Division

David Johnson, Virginia Department of Environmental Quality

Tim Maupin, Rocco, Inc.

Jim Southerland, North Carolina DENR, Air Quality Division

Andy Weber, USDA, CSREES

Susan Wierman, Mid-Atlantic Regional Air Management Association

George Wolff, Chesapeake Bay Commission, and Wolff & Associates

Additional thanks go to the workshop moderators and facilitators:

Jim Skillen, The Fertilizer Institute Holly Greening, Tampa Bay Estuary Prog.

Wayne Robarge, North Carolina State Univ. Bob Campbell, National Park Service

Ann Swanson, Chesapeake Bay Commission Carin Bisland, EPA Chesapeake Bay Prog.

Debora Martin, EPA Office of Water Ruth Chemerys, EPA Office of Water

Diana Esher, EPA Chesapeake Bay Prog. Jim Southerland, North Carolina DENR

Workshop logistics and coordination with the BayCenter at Ruddertowne were handled by:

Alice Lutrey, Mid-Atlantic Regional Air Management Association.

Kathryn Glasgow, Mid-Atlantic Regional Air Management Association

Cover Photograph “Sunrise Over Rehobeth Bay” taken by:

Jack R. Goins

Delaware DNREC, Parks & Recreation

152 South State Street

Dover, DE 19901

Copies of this report are available from the NOAA Chesapeake Bay Office, 410 Severn

Avenue, Suite 107, Annapolis, MD 21403; EPA Chesapeake Bay Office, 410 Severn

Avenue - Suite 109, Annapolis, MD 21403, or NOAA, ARL 1315 East West Highway, Silver

Spring, MD 20910. The report is available electronically at

http://www.chesapeakebay.net/ammoniaworkshop.htm.
i

EXECUTIVE SUMMARY

Emissions of ammonia, the airborne transport of ammonia and its fate were the focus of discussion at the

third “Shared Resources” Airsheds and Watersheds workshop, held November 15-16, 2000 in Dewey Beach,

Delaware. Two previous workshops addressed the regional impacts of atmospheric nitrogen deposition, but

largely from the standpoint of nitrogen oxide (NOx) emissions– less attention was given to ammonia emissions.

Scientific studies now indicate that ammonia emissions may result in a significant and growing form of nitrogen

input to terrestrial and aquatic ecosystems.

Airborne nitrogen compounds in wet and dry deposition, along with nitrogen from fertilizers, sewage, and

industrial discharges, are a source of nutrients to receiving waters via surface water runoff, ground water flow

and direct inputs. Current estimates are that atmospheric nitrogen deposition can contribute from 10 to over

40% of the “new” nitrogen enrichment of coastal and estuarine waters. Since ammonia is often a preferred form

of nitrogen for biological activity, its increasing availability could cause fundamental changes in aquatic algae

communities. Additionally, air quality experts recognize that ammonia plays an important role in the formation

of fine particulate matter, which can affect human health and degrade visibility. The need for managing ammonia

emissions is demonstrated in the Netherlands where the environmental impacts are clearly visible.

According to available assessments, the dominant source of ammonia emissions in the United States is

agriculture, primarily livestock operations and commercial fertilizer applications. Other sources include industrial

and combustion processes and biological activity in soils. Depending on the source, or spatial concentration of

sources, the amount of ammonia released into the air can be substantial. Unlike NOx, ammonia is largely

unregulated, and partially as a consequence existing ammonia emissions inventories are comparatively poor. In

most cases, estimates of ammonia emissions for the various sources have been conducted in different ways,

often for different purposes, and usually as an after-thought.

Ammonia and ammonium are undoubtedly critical contributors to US agricultural production. It should be

remembered that world food production depends on supplementing plant nutrients obtained from the soil with

fertilizers such as ammonia. Currently, there are no feasible alternatives to mineral fertilizers in modern agriculture

given the demands of feeding the world population. Without the use of nitrogen and other fertilizers, the

agricultural sector would potentially be forced to increase the amount of land used for farming, forcing further

invasion of natural ecosystems.

The objectives of this workshop were to generate an awareness of ammonia’s role in impacting our air, land,

and water environments and to lay the foundation for understanding the primary emission sources, the magnitude

of these emissions, and the atmospheric transport and fate of ammonia on a regional and local scale. The twoday workshop was not designed to consider the importance of ammonia in agriculture and industry. Instead, the

workshop was specifically designed to give participants from diverse backgrounds a chance to share information

and ideas about ammonia and its potential impacts on the environment.

Five primary conclusions were reached by the workshop participants:

• Ammonia can affect human health and the environment, and more study is needed to establish cause and

effect relationships.

• Airborne ammonia can travel short or long distances from its source before depositing to the Earth’s surface.

Better emissions data are needed for all of the sources in order to improve ammonia emissions inventories,

and deposition data must be collected in emission “hotspots” in order to enhance and refine computer

models.
ii

3-Dimensional Schematic developed by Battelle, Inc.

• Ammonia is released into the air from many sources. While the dominant source in the United States and

several coastal regions is agriculture, better data must be collected across the agricultural production process

to identify how much and when ammonia is released.

• Because of its importance to human health and the environment, it is necessary to manage ammonia emissions.

Through education, incentives, and new technologies, non-regulatory actions can be implemented now to

reduce or eliminate ammonia releases.

• There was broad agreement on the importance of ammonia and the need for sensitivity to both economic

and environmental issues related to it.

While workshop participants represented a broad range of interests including, agriculture, government,

universities, industry, and environmental groups, not all invited stakeholder groups were present. Additional

meetings are planned to provide educational opportunities and to improve communication, particularly with the

agricultural community.
iii

CONTENTS

Introduction .................................................................................. 1

Effects of Ammonia ..................................................................... 3

Transport and Deposition of Ammonia ........................................ 7

Ammonia Sources and Emissions ............................................... 15

Managing Ammonia Emissions .................................................. 26

Conclusions & Future Directions ................................................ 32

Appendices:

A. Bibliography .................................................. A1-5

B. Abbreviations/Terms ...................................... B1-3

C. Workshop Agenda ........................................ C1-3

D. List of Participants ....................................... D1-7
1

Over the past century, human activities to produce

food and energy have significantly increased the

amount of nitrogen released into the environment.

Interestingly, this increased nitrogen can have positive

and negative impacts on terrestrial and aquatic

ecosystems. One of the most serious negative impacts

is the over-enrichment of U.S. estuarine and coastal

waters (e.g., eutrophication). Too much nitrogen (as

well as other nutrients) can lead to the over-production

of algae [including potentially harmful (toxic, food

web-altering) bloom species]. These blooms can block

sunlight needed for submerged aquatic vegetation to

grow. When the algae die they sink to the bottom and

decay, potentially using up most of the available oxygen

(hypoxia) or all of it (anoxia).

While the most notable human activities that

contribute excessive amounts of nitrogen to coastal

waters are wastewater treatment discharges, failing

septic systems, and over-application of nutrients

(including both fertilizers and manure spread as a

nutrient source), there has been increased recognition

that nitrogen emissions into the atmosphere can be an

important source that negatively impacts coastal waters

– particularly at a regional scale. However, the extent

of this impact is uncertain. This is because there are

many factors that influence the dynamics of nitrogen

emissions and deposition, including the chemical form

of nitrogen emitted, the location of emission sources,

the transformation of nitrogen in the atmosphere, the

cycling of nitrogen within the watershed, the surface

and sub-surface transport of nitrogen from the

watershed, and the cycling of nitrogen in coastal waters.

In the mid 1990s, the Chesapeake Bay Program

began a series of Shared Resources workshops. The

intention of the Shared Resources Initiative was to

address ecological issues shared across geographic and

political boundaries (migratory birds, migratory fish,

the coastal ocean, airsheds, and watersheds). In 1995,

the first Airsheds & Watersheds workshop was held at

the Airlie House in Warrenton, Virginia (the Airlie

Workshop). The main goal of that workshop was to

raise awareness of the need for air and water scientists

and managers to collaboratively address the issue of

atmospheric nitrogen deposition. In 1997, a second

Airsheds & Watersheds workshop was held in Raleigh,

North Carolina (the Raleigh Workshop) to build upon

the momentum generated by the first gathering. Both

workshops focused largely on the role of nitrogen

oxides (NOx)— far less attention was given to

ammonia. There are reasons why the previous

workshops did not focus their attention on ammonia

emissions. Nitrates, from NOx emissions, tend to make

up the majority of the nitrogen in wet and dry

deposition. In addition, unlike NOx, emissions of

ammonia are mostly unregulated. As far as the federal

Clean Air Act is concerned, ammonia is not one of the

six criteria air pollutants nor is it a primary acid rain

pollutant. Ammonia is considered a regulated substance

under the Prevention of Accidental Releases in the

Federal Clean Air Act. This is because at high

concentrations ammonia is known to cause, or has the

potential to cause, serious adverse effects to humans

and the environment. In addition, regulations adopted

by the Occupational Safety and Health Administration

cover the handling, storage of, and exposure to

ammonia in the workplace. Because ambient air

concentrations must be extremely high to be considered

a human health concern, less emphasis has been placed

on collecting data about routine ammonia emissions,

sources, and deposition.

In recent years, however, scientific studies

conducted in Delaware Bay, Chesapeake Bay,

Albermarle-Pamlico Sounds, and Tampa Bay, have

indicated that ammonia emissions may represent a

significant and growing source of nitrogen impacting

terrestrial and aquatic ecosystems. Air quality experts

also have begun to recognize that ammonia plays an

important role in the formation of fine particulate matter

and regional haze. This heightened focus on ammonia

is timely, because the Nation’s coastal populations of

humans and animals have been growing rapidly over

the last several decades, leading to increases in

ammonia emissions and deposition in coastal areas.

As a result of the increased focus on ammonia, its

significance to coastal and estuarine areas became the

focus of the third Airsheds & Watersheds workshop.

The report that follows is a product of this third

workshop held November 15-16, 2000 in Dewey Beach,

Delaware (the Dewey Beach Workshop). The workshop

was sponsored by the Chesapeake Bay Program, EPA

Great Waters Program, the NOAA Air Resources

Laboratory, and the Mid-Atlantic Regional Air

Management Association. The objectives were to

generate an awareness of the impacts of ammonia

emissions to our air, land, and water environments and

to lay the foundation for understanding the primary

INTRODUCTION
2

emission sources, the magnitude of these emissions,

and the atmospheric transport and fate of the nitrogen

on a regional and local scale.

The material presented in this report draws from

the workshop presentations and deliberations. Topics

covered are the effects of ammonia; atmospheric

transport and deposition; ammonia sources and

emissions; and managing ammonia emissions. The

information captured in the discussion sessions are

incorporated into the conclusions and future directions

section. Workshop participants represented a broad

range of interests including, agriculture, government,

universities, industry, and environmental groups. The

Workshop’s agenda and a list of participants are

provided in the appendices. This report, in its entirety,

as well as posters presented during the workshop and

related illustrations may be viewed at: http://

www.chesapeakebay.net/ammoniaworkshop.htm.
3

Ammonia (NH3) is a gas that is readily released

into the air from a variety of biological sources (e.g.,

human and animal wastes, soils, and commercial

fertilizers), as well as from a variety of industrial and

combustion processes. Depending on the source or the

spatial concentration of sources, the amount of

ammonia released into the air can be substantial.

While ammonia has many beneficial uses in society,

environmental managers should be aware that

ammonia emissions can affect the quality of our

environment. The consequences of emissions into the

air were the focus of this workshop.

Effects on Air Quality

Cliff Davidson is Professor of Civil and Environmental

Engineering, and of Engineering and Public Policy at

Carnegie Mellon University. He is also the Director of the

Environmental Institute at CMU. Dr. Davidson has authored

several books and many journal papers dealing with air

quality issues. He has just completed a term as President of

the American Association for Aerosol Research. Dr.

Davidson addressed the effects of ammonia on air quality.

EFFECTS OF AMMONIA EMISSIONS

In recent years it has become apparent that ammonia

plays a key role in the formation of fine particulate

matter (particles less than 2.5 :m in diameter or PM2.5).

Once ammonia is in the air, it can react quickly with

oxidized sulfur and nitrogen (e.g., SO4, HNO3) and form

fine particles, primarily of ammonium sulfate and

ammonium nitrate. According to the EPA, ammonium

compounds are a major component of fine particulate

matter in the Eastern U.S. About half is ammonium

sulfate; much of the PM2.5 is particles of diameter 0.5 –

1.0 :m. Air quality and health experts believe that a

significant fraction of the PM2.5 can be inhaled by

humans and deposited in the bronchioles and alveolar

sacs in the respiratory system, possibly leading to

adverse health effects (Figure 1). This is consistent

with results of epidemiological studies that suggest

mortality rates correlate with fine sulfate particles,

which are typically 0.1 to 0.5 :m diameter.

Other effects include visibility degradation (Figures

2 & 3). Studies have shown that visibility is most

affected by particles with diameters between 0.4 and

0.7 :m, – the wavelength range of visible light.

Airborne ammonium sulfate particles fall mainly in this

Three Compartments of the

Human Respiratory System (Ray, 1995)

size range. While people often associate poor visibility

with urban areas, such as Los Angeles, California, it

also is a serious problem in the Appalachian Mountain

ranges and in coastal regions. Poor visibility over a

large area is referred to as regional haze, because it is

so pervasive and caused by many air pollution sources

dispersed over large areas (rather than by a single

source).

Figure 1 as Presented by Cliff Davidson

Figures 2& 3 Effects of Regional Haze at Newark, NJ

Clear Day Above; Hazy Day Below

http://www.hazecam.net/newark.html
4

Effects on Terrestrial Landscapes

On a global scale, about 60% of the nitrogen

(oxidized and reduced) produced through human

activities (food and energy production), is released into

the air; over half of this nitrogen is ammonia. When

airborne nitrogen (e.g, nitrate and ammonium) deposits

onto terrestrial ecosystems, a substantial portion

remains within the local ecosystem due to retention of

the nitrogen by the soil or by plant uptake. What is not

kept in the terrestrial system is either discharged to

groundwater, streams and rivers, or released back to

the atmosphere. The proportion of nitrogen derived

from wet or dry deposition that is transported to local

waterways from the land depends on the nature of the

landscape in question, especially soil type and

vegetation. Scientists believe that on the average less

than 25% of the atmospheric nitrogen deposited to

terrestrial ecosystems is transported to coastal estuaries.

The acidification begins in the atmosphere where

ammonia (NH3) reacts with a H+ ion, producing

ammonium (NH4

+

). When ammonium deposits (or is

applied) to the soil, it is generally oxidized relatively

rapidly by soil bacteria to form nitric acid. Nitric acid

dissociates readily in the soil solution releasing H+ ions.

In addition, when the ammonium is directly taken up

by a plant, the surrounding soil can become more acid

due to the release of H+ from the plant to balance the

positive charge of the ammonium removed from the

soil solution. Under normal conditions, the internal

chemical reactions within the soil maintain a balance

between acid-producing processes and acid consuming

processes, resulting in little change in soil acidity. With

continued, substantial inputs of ammonium, the original

internal balance within the soil can no longer be

maintained resulting in soil acidification; and the

potential loss of nutrient base cations like calcium and

Figure 4 as Presented by Jim Galloway

Jim Galloway is Professor and Chair of the Dept. of

Environmental Sciences at the University of Virginia. His

research is in the area of biogeochemistry and includes

works on the natural and anthropogenic controls on

chemical cycles at the watershed, regional and global

scales. Dr. Galloway is internationally recognized for his

work on acid deposition effects on soils, waters and forests

and watershed biogeochemistry. Dr. Galloway discussed

the effects of ammonia on terrestrial ecosystems.

The cycling of nitrogen in the soil is complex but

important in understanding the effects of ammonia on

terrestrial ecosystems(Figure 4). Nitrogen occurs as a

nutrient in the soil and is vital for plant growth. The

addition of nitrogen from ammonia/um deposition can

increase plant productivity during the growing season.

However, at the wrong time of year (the winter months),

nitrogen inputs can decrease a plant’s resistance to frost.

This is because there is little microbial activity taking

place. Enhanced ammonium deposition also can cause

the acidification of soils.

magnesium, and an increase in the bioavailability of

potentially toxic cations like aluminum. This induced

change in soil acidity will most likely alter forest

productivity and also bring about a change in plant

community structure with a possible decrease in soil

biodiversity.

In addition to plant fertilization and soil

acidification, there are other effects of ammonium

deposition including nitrogen saturation. All terrestrial

(and aquatic) ecosystems cycle nitrogen through

The Terrestrial N Cycle

Nitrate

NO3

-

Ammon.

NH4

+

Plants

Litter/ Litter/

Soil

Leaching

Atm. Deposition Denitrification

Nitrification

Uptake

Litter

Net Min. Net Min.

The total amount of nitrogen mobilized by humans through

energy and food production is about 150 Tg N/yr. This is

greater than the natural terrestrial rate.

 -Dr. James Galloway, University of VA
5

various chemical forms because it is a vital nutrient

necessary to support life. Nitrogen saturation occurs

when inputs of nitrogen essentially overwhelm the

internal nitrogen-cycling processes of an ecosystem.

In a sense, the ecosystem begins to leak nitrogen

because excess amounts occur at certain critical points

in the nitrogen cycle. This excess nitrogen can be lost

via transformation into gaseous nitrogen species, or by

leaching of the soil solution below the active rooting

zone of the soil where it can enter the groundwater,

with eventual discharge to surface water bodies. The

presence of excess nitrogen in groundwater and surface

waters can lead to algal blooms in receiving waters,

and/or can also promote acidification of surface waters.

Excessive amounts of nitrogen (usually nitrates) in

groundwater leaving forest soils are often associated

with cations like H+ or aluminum, both of which can

be detrimental to aquatic life. The changes in a

terrestrial ecosystem approaching nitrogen saturation

are often subtle, being reflected in gradual changes in

plant community structure, and the release of nitrogen

either in the gas phase or in groundwater and surfaces

waters draining the ecosystem.

In summary, enhanced ammonium deposition onto

a terrestrial ecosystem can, in sequence: increase soil

acidity and either increase or decrease forest

productivity. Once it has left the terrestrial ecosystem,

the nitrogen (which is largely in the form of nitrate)

can in sequence: decrease stream/lake biodiversity,

decrease the quality of drinking water, increase coastal

eutrophication, and alter coastal biodiversity. These

sequential effects are referred to as the nitrogen cascade.

The ultimate fate of nitrogen from the air to the soils

with eventual nitrogen saturation, particularly of upland

forest systems, depends on many factors including how

much nitrogen is depositing, how long the deposition

has been occurring, how it is being accumulated, and

most importantly the land use history. Older, mature

forest will be less likely to utilize enhanced amounts

of nitrogen deposition, and will be more likely to

undergo nitrogen saturation. Younger forests (<60 or

70 years old) that are rapidly aggrading and

incorporating nitrogen into the forest biomass could

take decades before becoming susceptible to nitrogen

saturation.

Effects on Coastal and Estuarine Waters

As previously discussed, some of the airborne

nitrogen that is not utilized by the terrestrial ecosystem

can make its way into receiving waters (called indirect

load). Airborne nitrogen deposition also can by-pass

the terrestrial landscape by directly falling onto the

water surface (called direct load). Regardless of

whether the airborne nitrogen is indirectly or directly

loaded into the water, too much of it can have (or

contribute to) a number of ecological effects, including

the acceleration of a natural process called

eutrophication. Eutrophication is the process by which

a water body becomes enriched with organic material

(e.g., algae). This organic material can be stimulated

to harmful levels by large inputs of nutrients, such as

nitrogen and phosphorus. The growth rate of this

organic material can be increased if the nitrogen

deposited is in the form of ammonia/ammonium.

In coastal and estuarine waters, nitrogen is the

nutrient most often controlling primary production, and

too much of it can lead to an over-production of algae,

including harmful, toxic, food web-altering, algal

blooms (e.g., red and brown tides). The algal blooms

also can block sunlight needed for important habitat,

such as submerged aquatic vegetation and corals. When

the algae die, they sink to the bottom and are

decomposed by bacteria. During this process, most of

the water’s oxygen (hypoxia) or all of the water’s

oxygen (anoxia) needed for aquatic life can be depleted.

These problems can cause a decline in fisheries and

recreational activities, which ultimately cost coastal

regions millions of dollars in lost tourism and fisheries

revenues.

Hans Paerl is Kenan Professor of Marine and

Environmental Sciences, at the University of North

Carolina-Chapel Hill, Institute of Marine Sciences. His

research includes nutrient cycling and production dynamics

of aquatic ecosystems, environmental controls of algal

production, and assessing the causes and consequences of

eutrophication. Dr. Paerl’s recent studies have identified

the importance and ecological impacts of atmospheric

nitrogen deposition in estuarine and coastal environments.

His work plays a central role in coastal water quality and

fisheries issues facing the nation. Dr. Paerl addressed the

effects of ammonia on coastal and estuarine aquatic

ecosystems.
6

Figure 5 Seasonal Comparison of Wet Deposition as Presented by Hans Paerl

It has been estimated that atmospheric nitrogen

deposition can contribute from 10% to over 40% of

the “new” nitrogen enrichment of coastal and estuarine

waters. Along the Coastal Atlantic Ocean, there is

greater nitrogen stimulation of primary production

occurring in the near shore region than farther out in

the Gulf Stream. Studies conducted in North Carolina,

for example, show that both ammonium and nitrate

have strong stimulating effects. It appears that the

presence of iron and a complexing agent for metal ions

called EDTA play an additionally important role for

nitrate stimulation. This is not the case for ammonium.

In studies where algae are treated with similar amounts

of ammonium and nitrate, there is greater production

from the ammonium. In essence, it is a preferred

“flavor” of nitrogen for many types of algae. This is

because, unlike nitrate, ammonium is in a ready-touse form of nitrogen for most biological activity. It

does not need to be biochemically converted or reduced,

a process which requires energy. As a result, the

winter spring summer fall

season

0

1

2

3

4

5

6

7

8

9

 average weekly wet NH

4

+

deposition (mg NH

4

+-N/m

2/week)

B

A

A

B B

increasing availability of ammonium could cause a

fundamental change in the algae community.

The different chemical forms and amounts of

nitrogen depositing from the air appear to influence

the type and amount of algae present in the system.

Growth rates of those algae able to use the nitrogen the

fastest will be enhanced, enabling them to most

effectively compete with other types of algae. For

example, ammonium deposited directly onto the surface

waters in the summer could trigger a bloom of “bad”

algae. There is a difference between bad algae and just

too much algae. For example, “bad” algae can produce

toxins, are inedible, or can trigger low oxygen

conditions. Monitoring data collected in North Carolina

indicate that the highest average ammonium deposition

in rain occurs during the spring and summer (Figure 5)

– the primary growing seasons for plants (including

algae). Presently, diurnal (day/night) effects and

differential growth of organisms on a seasonal basis

have yet to be fully addressed.
7

Once nitrogen compounds are released into the air,

there are many physical and chemical factors that

influence their transport and deposition. First, there is

need to consider “reactive” nitrogen compounds in two

distinct groups – Reduced, which is dominated by

ammonia gas, and Oxidized which is dominated by

nitric acid gas and particulate nitrate. Oxidized nitrogen

compounds tend to reside in the air longer than reduced

nitrogen. Both can react with each other and with

other air pollutants, particularly sulfates, and form fine

particulate matter, and both are highly soluble in water.

Some of the factors that determine whether these

airborne gases and particles travel a short or long

distance from their source before depositing include

the source type and height of emission (e.g., industrial

smokestack, automobile exhaust pipe, animal housing

unit), and weather conditions (e.g., wind, temperature,

humidity). The presence of sulfates and nitric acid

gases in the air, for example, is an important modifying

factor for ammonia because they will take up ammonia

gas to form particles, which can then reside in the

atmosphere for several days. Generally, smaller

particles will travel farther than larger ones, although

very tiny particles with high diffusiveness may deposit

quickly onto the Earth’s surface. Small particles also

can coagulate to form larger particles.

Once nitrogen (reduced or oxidized) is released into

the air, it can deposit to the Earth’s surface in the form

of a particle, as a gas, or in precipitation (typically

rainfall). The forms of nitrogen that are a concern to

coastal watersheds, when the nitrogen deposits, are

particulate nitrate (pNO3

-

), nitric acid gas (HNO3) and

nitrate in precipitation, which all originate from NOx

emissions; particulate ammonium (NH4

+

), ammonia gas

(NH3), and ammonium in precipitation, which all

originate from ammonia emissions; and dissolved

organic nitrogen (DON). Although the sources of DON

are not well identified, it is believed at the moment to

be a small fraction of the total nitrogen deposition.

Therefore, this section focuses primarily on reduced

and oxidized nitrogen.

TRANSPORT AND DEPOSITION OF AMMONIA

Fo re s ts

U rba n 

A re as

Ag ric ulture

A tm osp he ric T ra nspo rt

o f G a se s a n d P a rtic le s

B ay/Es tua ry

M obile

E missions

D e position

D e position

E missions

Indus trial/

Po we r P la nts

Stre a ms 

&

R ive rs

E missions D e position

Loadings

Eutro phica tio n

D e ple te d 

Oxygen Algal

B looms

Sediment

G roundwate r

Fo re s ts

U rba n 

A re as

Ag ric ulture

A tm osp he ric T ra nspo rt

o f G a se s a n d P a rtic le s

B ay/Es tua ry

M obile

E missions

D e position

D e position

E missions

Indus trial/

Po we r P la nts

Stre a ms 

&

R ive rs

E missions D e position

Loadings

Fo re s ts

U rba n 

A re as

Ag ric ulture

A tm osp he ric T ra nspo rt

o f G a se s a n d P a rtic le s

B ay/Es tua ry

M obile

E missions

D e position

D e position

E missions

Indus trial/

Po we r P la nts

Stre a ms 

&

R ive rs

E missions D e position

Loadings

Eutro phica tio n

D e ple te d 

Oxygen Algal

B looms

Sediment

G roundwate r

Bruce Hicks is the Director of the Air Resources

Laboratory (ARL) of NOAA’s Office of Oceanic and

Atmospheric Research. His research focuses have been

on issues such as the exchange of materials (e.g., ammonia)

between the atmosphere and the land and water surfaces.

Robin Dennis is a NOAA, ARL scientist who serves as

Senior Program Manager with the Atmospheric Modeling

Division at EPA’s National Exposure Research Laboratory.

Dr. Dennis was involved in setting the vision and

conceptual development for EPA’s Models-3 and in the

conceptual development of EPA’s new Multi-media

Integrated Modeling System. He is currently performing

diagnostic evaluations of regional models for ozone,

particulate matter, acidic and nutrient deposition,

particularly linking air and water for coastal and estuarine

assessments.

Bruce Hicks and Robin Dennis jointly presented

information on the atmospheric transport and deposition

of ammonia/ammonium.
8

Figure 6 Overlapping Oxidized Nitrogen Airsheds

as Presented by Robin Dennis

For the East Coast, it is believed that about 66% of

the nitrogen emitted into the air is from NOx emissions

and 34% is from ammonia emissions. However, in

Eastern North Carolina 57% of the nitrogen emitted

into the air is from NOx emissions and 43% is from

ammonia emissions. This larger fraction of ammonia

emissions in Eastern North Carolina is evident in the

National Atmospheric Deposition Program (NADP: site

NC35 in Sampson County) data, where, on the average,

52% of the nitrogen in wet deposition is nitrate (from

nitrogen oxide emissions); 48% is ammonium (from

ammonia emissions). These data are indicative of the

large number of confined animal operations in that

portion of the state, and they demonstrate that both

forms of nitrogen are important.

In recent years, the EPA’s Regional Acid Deposition Model (RADM) has been used to estimate the area

where nitrogen emission sources have the greatest potential in depositing nitrogen (wet and dry) to a watershed. The area encompassing these sources is referred

to as the “principal airshed.” The airshed is not as firmly

defined as the watershed; there are not clear boundaries to the flow of chemicals in the atmosphere as there

are for the flow of surface and ground waters in watersheds. The absolute influence that an emission source

has on deposition to an area continuously diminishes

with distance. In other words, the airshed represents

the area that encompasses emissions that would contribute most to the deposition across a watershed should

all emission sources be equal.

RADM was first used in the mid 1990s to develop

the NOx airshed for the Chesapeake Bay watershed.

Since that time, NOx airsheds have been delineated

for other east and gulf coast water bodies, including

Delaware Bay, Pamlico Sound, and Narragansett Bay

(Figure 6). More recently, RADM was used to describe

the ammonia/ammonium airshed for the Chesapeake

Bay and Pamlico Sound (Figure 7). The Chesapeake

Bay’s ammonia airshed is about 688,000 km2 in size.

This is four times larger than the Bay’s watershed;

slightly smaller than the NOx airshed – which is

1,081,600 km2 in size (Figure 8). The ammonia airshed

for the Pamlico Sound is roughly 406,400 km2

 in size

or 15 times larger than the watershed drainage area.

It is important to understand the concept of airsheds

because the relationships between emissions and

deposition, and subsequently atmospheric loadings into

a water body, are not equal. For example, if 100 kg of

nitrogen were released into the air from a source, it

will not all be deposited at once nor in one area. The

annual deposition will be distributed over space and

will be unevenly distributed in time. Just as emissions

and deposition are not in a 1 : 1 ratio, neither are

deposition and loadings to a water body. The terrestrial

landscape will retain much of the deposited nitrogen.

For example, the current belief is that approximately

10% of the deposited nitrogen to a typical forest

ecosystem will be transported into receiving waters.

Spatial Variability of Deposition

Once in the air, nitrogen can travel short or long

distances before being removed by precipitation (rain

or snow), called wet deposition, or by the gravitational

settling of particles (not associated with precipitation)

and turbulent exchange of small particles and gases,

called dry deposition. Wet deposition is highly variable

with time and space on an event basis (e.g., some areas

can receive large inputs while neighboring areas receive

little to no input), but this variability is largely random.

However, yearly averaging of wet deposition data from
9

Figure 8 Chesapeake Bay Nitrogen Airsheds

as Discussed by Robin Dennis

one location will yield a total deposition amount that is

much the same as that computed for a neighboring

location, except in extremely complex topography (e.g.,

mountains). Thus, from this yearly averaging, spatial

patterns of accumulated wet deposition appear to be

relatively smooth ( Figure 9).

The factors that determine wet deposition are the

amount of airborne material (e.g., nitrogen) to be

scavenged by clouds (termed “washout”) and the

efficiency of the precipitation scavenging process below

the clouds (termed “rainout”). The efficiency of the

scavenging process varies with location and season.

The amount of material in wet deposition also depends

on the solubility of the chemical. Nitric acid and

ammonia are comparable in solubility, so there is little

difference in the removal efficiency by wet deposition

for oxidized and reduced nitrogen.

This is not the case for dry deposition – the net

consequence of gravitational settling, turbulent

exchange, and surface absorption. Dry deposition is

controlled by meteorological factors (e.g., wind and

temperature), as well as by the nature of the underlying

surface, and occurs largely to landscapes where the

efficiency of transfer is the greatest. For example, dry

deposition to a forest is likely to be far more efficient

than dry deposition to grassland in the same general

area. Thus, the spatial variability of dry deposition is

not random but is more organized according to the

characteristics of the underlying topography and

vegetation.

Diurnal Considerations

During the night, the land surface cools and

becomes colder than the air. The air stratifies — it

forms layers that tend to slide over each other, although

all moving according to the prevailing wind. Trace

gases that are injected into the lowest air layers will

tend to be trapped there. If the nitrogen is emitted by a

source located in a valley, then it is possible that it will

Figure 7 Overlapping Reduced Nitrogen Airsheds

as Presented by Robin Dennis
10

Figure 9 Ammonium ion Deposition across USA, 1999

Figure 10 National Atmospheric Deposition Program (NRSP-3)/

National Trends Network Sites
11

be trapped there, until the sun rises and convection sets

in, unless the wind is strong enough to overcome the

stratification. Shortly after sunrise, the land surface

becomes warmer than the air and convection starts –

“hot air rises.” Turbulent mixing is enhanced in

daytime, by this convection. Trace gases injected into

the lower atmosphere during the daytime will then be

mixed vertically, as high as the convection reaches –

the top of the so-called mixed layer.

Because of this daytime mixing, ambient air

concentration levels experienced by people are reduced,

relative to nighttime situations. During the transition

periods (from night to day and from day to night),

conditions are often highly variable. Convection during

daytime and the lack of it at night are controlling

considerations. It is sometimes postulated that

convection will be augmented because ammonia is

lighter than air. However, this fact is not very important

because ammonia is present in concentrations too small

(even when it is close to the emission source) to modify

the buoyancy characteristics of the air in which it is

mixed. Regardless of its initial concentration, further

dilution will occur more rapidly in daytime than at

night.

As discussed earlier, gaseous ammonia can react

quickly with oxidized sulfur and nitrogen in the air and

form fine particles of ammonium compounds. This

conversion to particulate ammonium occurs at a rate

that depends on the presence of these other pollutants,

temperature, and the presence of water. In daytime,

this conversion can be quite rapid – a time constant of

a few hours. At night, this conversion is much slower.

Thus, much of the ammonia emitted into the air at night

will survive as a gas until the early daylight hours (less

dry deposition occurs at night), but most likely will be

converted to particulate ammonium (sulfate or nitrate)

during the daytime.

Evaluating Wet and Dry Deposition

When collecting and analyzing deposition data, it

is necessary to consider wet and dry deposition

separately. In order to measure wet deposition, a

relatively simple apparatus can be used, involving

samplers that open only when it rains or snows. At

present, there is one national monitoring network

operating in the U.S.— the National Atmospheric

Deposition Program/National Trends Network (NADP/

NTN) (Figure 10). NADP/NTN uses a weekly

sampling protocol with the goal to assess time trends

and spatial patterns of wet deposition. However,

NADP/NTN’s operating procedures impose some

limitations when assessing ammonium deposition to

sensitive coastal areas. For instance, NADP/NTN site

locations have historically been rural by design in order

to assess the relationship between regional pollution

and changes in regional deposition patterns.

Consequently, NADP/NTN site requirements have

historically ruled out operation in areas affected by local

emissions sources (e.g., urbanized areas) and coastal

sea salt.

In recent years the NADP has become open to the

establishment of coastal sites, as more estuary programs

have expressed need for atmospheric nitrogen

deposition data. Another limitation is that weekly data

are of limited use in coupling with meteorological

models and process-oriented studies. The weekly

sampling also hinders the determination of ammonium

deposition because nitrogen compounds are chemically

unstable, and some of the ammonium, being a preferred

form of nitrogen for biological activity, may not survive

in the collected sample.

To improve upon NADP methods, the Atmospheric

Integrated Research Monitoring Network (AIRMoN,

Figure 11), a sub-network of NADP managed by the

National Oceanic and Atmospheric Administration

(NOAA), uses a daily sampling protocol, with a special

focus on urban and coastal regimes. At this stage,

however, there are few wet deposition stations in areas

where data are required for studies of nitrogen

deposition to coastal environments. Yet, it is in such

areas that effects of ammonia emissions are likely to

be the greatest due to increasing human and animal

populations.

Conversely, there is no simple method for

measuring dry deposition. Artificial collection surfaces

(plates, buckets, etc.) do not yield the same answers as

are relevant for natural surfaces, because the properties

controlling dry deposition rates are usually surfacespecific. This is especially the case for dry deposition

of trace gases onto vegetation, where the leaf structure,

function, and surface area are controlling factors. In

general, scientists agree that there are some good

methods for measuring dry deposition, mostly based

on micrometeorological principles. Unfortunately,

these are too complex to be used routinely, except in

unusual circumstances where highly qualified technical

assistance is available.
12

Figure 12 Clean Air Status and Trends Network (CASTNet) sites

http:www.epa.gov/castnet/maps/

Figure 11 NOAA’s Atmospheric Integrated Research Monitoring (AIRMoN) Sites

(solid circles are active sites,open circles are inactive sites)
13

A more widely used technique for estimating dry

deposition rates is the inferential method. This method

combines estimates of the average deposition velocity

(based on a number of observed quantities) with

measurements of weekly average air concentrations of

the chemical species under consideration. Some of

the chemicals being measured exist as gases, others as

particles. However, great care must be taken to ensure

the integrity of the collected chemical samples. There

are two national networks applying the inferential

method— EPA’s Clean Air Status and Trends Network

(CASTNet, Figure 12) and the NOAA’s AIRMoN-dry.

The latter is a research network aimed at further

developing the methods that can be used routinely in

CASTNet and similar operations. Neither of these

networks measure ammonia in ambient air or in

deposition. They only measure ammonium. Currently,

there are only a few dry deposition stations located near

coastal areas. The primary reason for this is that the

presence of sea salt in the air is known to confound the

measurement technique (a multi-filter system) that is

used. Consequently, intensive studies are sorely needed

to accelerate the development of the technologies to

address this issue.

Nitrogen in Wet vs. Dry Deposition

As previously mentioned, nitric acid and ammonia

are comparable in solubility, so there is little

differentiation of the nitrogen (e.g., nitrate and

ammonium) in terms of the rate of deposition of rain

water. However, there are differences with nitrogen in

dry deposition. Using computer models and available

deposition data, scientists have found that along the

East Coast dry deposition of nitrate is mostly in the

gaseous form (nitric acid), rather than in the particulate

form. On the other hand, dry deposition of ammonia

is mostly in the particulate form (e.g., ammonium

sulfate), rather than the gaseous form (except close to

the ammonia emission sources). In short, dry

deposition is dominated by nitric acid gas and

particulate ammonium. However, what is known about

dry ammonia deposition will likely change as improved

measurements and modeling of localized ammonia

emissions in “hotspots” (e.g., confined animal

operations) are established.
14

Density Map of 1998 Ammonia Emissions by County

EPA’s National Air Pollutant Emissions Trends, 1900-1998

1998 National Ammonia Emissions by Principle Source Category

EPA’s National Air Pollutant Emissions Trends, 1900-1998
15

While it is important to understand how ammonia

is transported through the air, and when and where it

deposits onto the Earth’s surface, it is also important to

understand where ammonia emissions originate.

Ammonia is released into the air from biological sources,

whereby it volatilizes from animal wastes and soils;

industrial sources, whereby it is released during the

making of ammonia-based products and other products

or during the use of ammonia-based products; and

combustion sources, whereby it is released in association

with combustion processes. Important questions

associated with each of these are How much ammonia

is released from these sources? When and where is

ammonia released? and, How will emissions change over

time?

A management tool often used to help understand

pollutant emissions is an inventory. An emissions

inventory is a comprehensive listing, by source, of air

pollutant emissions. An inventory represents a specific

geographic area, for a specific time period. A source

can be categorized as a point source, an area source, a

mobile source (on or off-road), or a biogenic source.

Emissions inventories are used for several purposes,

including air quality modeling and analysis, control

strategy development, screening sources, and to estimate

the effectiveness of regulatory controls.

Since ammonia is not one of the six criteria air

pollutants, nor a primary acid rain pollutant, the quality

of existing ammonia emissions inventories is not as good.

In most cases, estimates of ammonia emissions have

been conducted in different ways for different sources,

often for different purposes, and usually as an afterthought. Although, efforts are underway to improve

emissions inventories for ammonia.

Background

The initial development of an ammonia emissions

inventory began around 1985 for the purposes of the

National Acid Precipitation and Assessment Program

(NAPAP). At that time, NAPAP was interested in

ammonia’s role in acid precipitation. While the methods

used to develop the inventory are considered sound, the

data for establishing emission factors and activity levels

were crude. In the early 1990s, the EPA became

interested in improving this inventory because of

concerns with aerosols and the formation of fine

particulate matter (PM2.5

)

EPA prepared an ammonia emissions inventory for

the National Particulate Matter Study by artificially

“growing” the 1985 NAPAP inventory to 1990, using

Bureau of Economic Activity data. To estimate

emissions for a given year, economic estimates are often

used instead of real data, even when data exist. This is

primarily because current inventories are not flexible

enough to incorporate new data as they become available.

However, a research group at Carnegie Mellon

University has constructed a software application that

generates an ammonia emission inventory for the U.S.

based on user-defined input, whereby emission factors

and activity levels can be easily modified. This structure

makes it easy to perform sensitivity analyses and to

AMMONIA SOURCES AND EMISSIONS

Source Category Descriptions

Point Sources: individual large stationary sources

that emit hazardous air pollutants or pollutants

above a given emission threshold.

Area Sources: represents numerous smaller

facilities or activities that emit small amounts of a

given pollutant.

Mobile Sources: portable on-road vehicles that are

certified for highway use; portable non-road

vehicles or equipment that are not certified for

highway use.

Biogenic Sources: living organisms that produce

air pollutants.

Bill Battye is founder of EC/R Incorporated and currently

serves as one of EC/R’s managing partners. He was a

co-author of the infamous “Battye” report and has

worked for over 20 years in the fields of air pollution

control and modeling. He has extensive experience in

preparing emissions inputs for regional models, in

assessing regional haze and PM formation. Mr. Battye

presented the most recent information on the known

substantial sources of ammonia emissions and the

uncertainties associated with emission estimates.
16

update the inventory when new data become available.

This inventory is now available using updated activity

levels and high resolution spatial and temporal

information. The inventory can be found at http://

www.envinst.cmu.edu/nh3/. Figure 13 is a summary of

the categories of the inventory with total amounts of

emissions in each category.

The primary data source for ammonia emissions

estimates has been the 1994 report from EC/R

Incorporated – Development and Selection of Ammonia

Emission Factors by R. Battye, et.al. (herein referred to

as the 1994 Battye Report). Although over the last

several years some of the details of this report have been

questioned, it still remains a useful source. A related

report recently has been written by W. Battye (EC/R,

Inc.) and V. Aneja (North Carolina State University)—

Evaluation & Improvement of Ammonia Emissions

Inventories. The Evaluation Report was prepared for

modeling particulate matter for the Coordinating

Research Council in Atlanta, Georgia.

The 1994 Battye Report was prepared for EPA’s

Office of Research and Development as a compilation

of the literature published after 1985 on ammonia

sources and emission factors. The report presents a

review of the research obtained at that time, provides a

basis for understanding the uncertainties with emission

factors, and identifies data gaps for future emission

factor development. The report demonstrated that there

is considerable variability and uncertainty in ammonia

emissions estimates. For example, emission factors

developed by the European community (who are well

advanced on this issue) are used for certain U.S. sources.

This is because there has been little to no data collected

in the U.S. At this time, it is not clear whether the use

of European emission factors for U.S. sources is

appropriate. Uncertainties also exist because, in many

cases, short-term measurement studies were used to

derive emission factors. A case in point is soils and

vegetation, which may be a major source of ammonia,

but only short-term measurement studies were used to

develop the inventory. To improve the inventory, longterm measurements are needed because soils and

Figure 13 Source Categories in the Carnegie Mellon Ammonia Emissions Inventory

Provided by Cliff Davidson
17

vegetation can be a source of ammonia (in areas where

there is no other source and ambient air ammonia

concentrations are low), as well as a sink of ammonia

(in areas where there are other sources and ambient air

concentrations are high).

Another data source used is the National Emissions

Trends (NET) Inventory, which is prepared annually by

the EPA and is based on periodic updates of inventories

submitted by the States. After 1996, this inventory has

been known as the National Emissions Inventory (NEI).

The EPA uses the inventory for analyses of trends in

emissions. The NET is a repository of data on emissions

for priority air pollutants for modeling regional transport.

Ammonia was added as an after-thought because it was

needed for modeling the formation of particulate matter.

EPA has generated new ammonia emissions data for the

NET by using methodologies recommended in the 1994

Battye Report.

Table 1 shows the percentage of ammonia emissions

for farm animals, fertilizer, and mobile sources on a

national basis (using the NET inventory), a regional basis

(using the NET inventory), and a state basis (using the

Battye and Aneja analysis).

Table 1

Comparative NH3 emissions (Bill Battye, EC/R)

Farm Animals Fertilizer Mobile

 National (NET) 75% 12% ~5%

 Chesapeake Bay Region 58% 13% 18%

 (NET)

 North Carolina 85% 6% 6.4%

 (Battye & Aneja)

The 1996 NET Inventory shows that the major

source of ammonia emissions is agriculture, primarily

from livestock (Figure 14). This is consistent with all

of the other data sources used thus far. However,

depending on the area of interest, the percentage

contribution from sources can vary. For example,

ammonia emissions in the state of North Carolina are

dominated by livestock, estimated at about 11 kg/hectare.

In Charlotte, North Carolina, however, where there are

not many livestock operations, motor vehicles appear

to be the dominant source of ammonia emissions,

estimated at about 7 kg/hectare. When taking all

emissions from the city of Charlotte and comparing them

to emissions in the State, the city’s emissions are about

equal to the State’s livestock emissions (Figure 15).

Furthermore, depending on the source, there may be

seasonal variations in ammonia emissions (e.g.,

agricultural emissions are greatest during the Spring and

Summer).

Inventory Uncertainties

As stated earlier, the 1994 Battye Report

demonstrated that there is considerable variability and

uncertainty in ammonia emissions estimates. However,

because of air quality concerns, efforts are now

underway at both the state and federal levels to improve

ammonia emissions estimates.

The uncertainties associated with ammonia

inventories lie both in the lack of quality data to establish

emission factors and in inadequate information about

activity levels for each source and for categories within

each source. For example, under the livestock source,

there are different emissions (and therefore different

emission factors) associated with each type of animal

(e.g., cattle, hogs, and poultry) and with the class of

animal under each type (e.g., beef cows, milk cows,

fattening pigs, breeding sows, broilers, laying hens).

Emission factors also vary depending on whether the

animal is housed in a barn or grazes in the field.

An emission factor is a representative value that

attempts to relate the quantity of a pollutant released

Emissions Inventories & Emissions Factors

Emission inventories and emission factors are fundamental tools

for air quality management. An emission inventory is a

comprehensive listing, by source, of air pollutant emissions. An

inventory represents a specific geographic area, for a specific

time period. An emission factor is a representative value that

attempts to relate the quantity of a pollutant released to the air

with an activity associated with the release of that pollutant.

Emission factors are usually expressed as the weight of pollutant

divided by a unit weight, volume, distance, or duration of the

activity emitting the pollutant (e. g., kilograms of ammonia

emitted per megagram of nitrogen in the fertilizer). Such factors

facilitate estimation of emissions from various sources of air

pollution. In most cases, these factors are simply averages of all

available data of acceptable quality, and are generally assumed

to be representative of long-term averages for all facilities in the

source category (i. e., a population average).

The above text was developed using information from the EPA

web site: http://www.epa.gov/oar/oaqps/efactors.html which

used information from the introduction to the Fifth Edition of

the Compilation Of Air Pollutant Emission Factors (AP-42).
18

Figure 14 as presented by Bill Battye

Figure 15 as presented by Bill Battye
19

 LIST OF AMMONIA SOURCES

>Agriculture

-livestock

-commercial fertilizers

>Industry

>Refrigeration

>Electric Utilities

>Motor Vehicles

>Biomass Burning

>Non-Agricultural Soils

>Publically-Owned Treatment Works

>Human Breath/Perspiration

The farm community does not see ammonia

loss as an environmental problem. The current priority

regarding airborne emissions from animal production

systems in the U.S. is odor.

-Dr. Larry Jacobson, University of MN

into the air with an activity associated with the release

of that pollutant. In the present context, an emission

factor would be represented as kg NH3

/animal/year.

Emission factors are simply averages of all available

data of acceptable quality. These data can come from

various sources, including research studies and

measurement programs, which can differ greatly from

one another. Too often there are not enough quality

data available to develop a valid emission factor.

From the extensive list of ammonia source categories

(see sidebar), five sources were selected for discussion

during the workshop: agricultural emissions, since they

dominate all other sources; motor vehicle emissions,

since emissions of ammonia may increase in the near

future as a result of improvements to motor vehicles

and fuels, and growth in vehicle miles traveled; electric

utility emissions, since this also may be a growing source

of ammonia due to NOx controls; and refrigeration,

since ammonia is extensively and increasingly being used

as a refrigerant in large commercial and industrial

systems.

Agricultural Emissions

The factors that affect how much ammonia is

released from animal agriculture include the form and

Larry Jacobson is a Professor and Extension Engineer and

Livestock Housing Specialist in the Department of

Biosystems and Agricultural Engineering at the University

of Minnesota. His research and extension emphasis areas

are in indoor and outdoor air quality for both animal and

human health concerns, environmentally safe manure

management systems, and economical facilities for

livestock and poultry in Minnesota. Dr. Jacobson presented

information on ammonia loss from livestock production

systems, including housing, manure handling and storage.

Jack Meisinger is a Research Soil Scientist with the U.S.

Dept. of Agriculture and a Adjunct Assoc. Prof. at the

Univ. of Maryland College Park. He has studied many

aspects of the agricultural nitrogen cycle including use of

soil nitrate tests to estimate N sufficiency, methods to

estimate N2

 fixation, use of cover crops to protect water

quality, effects of no-tillage on the soil N cycle, and the

use of N15 in agricultural research. Dr. Meisinger’s most

recent research is related to nutrient utilization in animal

agriculture. He is currently involved in large

interdisciplinary dairy manure and poultry litter projects

studying methods to conserve N and P in manure and

methods to manage ammonia losses from manures. Dr.

Meisinger presented information on ammonia loss from

land-applied manure and commercial fertilizers.

Photo obtained from http://www.beltie.org/photo.html

amount of nitrogen in the waste (which will vary

depending on the animal type, age, size, and animal feed),
20

and the handling of the waste. The handling of the waste

depends on the amount of time the waste is in the animal

house, in storage, or in the field; the methods used to

collect and store the waste; and the methods used to

treat and use the waste. The amount of ammonia

released from the building varies depending on the type

and size of animals, the animal’s diet, the building

ventilation (climate), and the housing system. The

amount of ammonia released from the storage unit will

vary depending on the type of storage used (e.g., open

or closed tank, pile), the form of waste being stored

(liquid or dry litter), and weather conditions. Table 2

demonstrates the most recent published emission factors

for livestock across a variety of data sources.

The factors that affect how much ammonia

volatilizes into the air from the waste following land

application include the nitrogen content in the waste;

the form of the waste (liquid or dry litter); the chemical

form of nitrogen; the timing of the application relative

to crop demand; the method of application; the nitrogen

demand of the crop/vegetation; soil properties (e.g.,

moisture, alkalinity,and calcium), and weather conditions

(e.g., temperature). In the United States, over 90% of

the animal waste is distributed on crop land. In the past,

much of this waste was surface broadcast and not

incorporated into the soil. Today, a majority of the landapplied waste is either directly injected (usually liquid

form) or tilled into the soil almost immediately after

spreading. This reduces the amount of animal waste

exposed to the air, thereby reducing the amount of

ammonia that can volatilize. Conservation tillage, which

is used to reduce soil erosion, does not cause increased

ammonia volatilization since it is possible to develop

methods to get solid manure into soils with limited

disturbance. This method has been shown to be effective

in preventing ammonia loss to the atmosphere. In short,

the application method and tillage practices used by the

farmer dictates the amount of ammonia volatilized.

However, there is little documentation on what methods

are used, when they are used, and whether the manure is

spread on crop land or other types of land. In some

situations, such as with North Carolina swine farms, a

certified nutrient management plan is needed for

Table 2

a Schmidt and Winegar (1996)

b McCulloch et al (1998), summer only for finishing pigs

c Aneja (2000)

d Harper (2000)
21

spreading the animal manure, thereby providing some

documentation.

Many of the same factors that affect the release of

ammonia from land-applied animal waste also apply to

urea-containing fertilizers and anhydrous ammonia.

Currently, to estimate ammonia emissions from

commercial fertilizers only county-level total sales data

are used. This is not an accurate method for estimating

ammonia emissions since emissions will depend on the

type of fertilizer, the application method, and the local

soil properties. Furthermore, where the fertilizer is sold

may not be the same as the county where it is applied.

However, in the absence of more refined fertilizer

application data and improved fertilizer emission factors,

this is the only method available.

While ammonia emissions can be estimated using a

simple mass balance approach (a comparison between

what goes into a system versus what comes out), nothing

will be learned about when and how ammonia is released

across the agricultural production process. In order to

prepare an ammonia emissions inventory for livestock,

for example, the number of animals first must be

determined. Then, an appropriate emission factor must

be identified for each animal type, each waste handling

system, and each land application method. Once

emission factors are completed, county level emissions

must be computed. These emissions are then apportioned

to smaller geographic areas. Finally, seasonal, daily,

and hourly allocation factors are applied.

Ammonia released from urea containing fertilizers used by homeowners also will contribute to the total ammonia

emissions. Urea based fertilizers on home turf can be especially vulnerable to ammonia loss because they are not

incorporated into the soil, homeowners are more likely to over-fertilize, and most homeowners apply fertilizer

during the warm months of the year when losses will be largest. However, compared to the acreage of farms, the

home turf use should be a much smaller source. Analyses of commercial fertilizer sales data show the non-farm

use is small, although it is likely under-reported.

The nitrogen flow diagram for a typical dairy farm

(Figure 16) offers a good opportunity for an

overview of nitrogen and ammonia cycling in a

livestock operation. Figure 16 summarizes the data

of Bussink & Onemma (1998), which illustrate

several important points: 1) the dairy can be viewed

as a biological protein factory which converts about

21% of nitrogen input into milk and meat (upper

right); 2) the major ammonia escape points are

housing and manure storage, grazing, and land

application of manure; and 3) the total estimated

ammonia loss is 19% of the nitrogen input (middle

right), which is comparable to the nitrogen removed

in milk and meat. Figure 16 also illustrates that

managing ammonia emissions will require a wholefarm approach with careful attention to:

management of building and manure storage

facilities, grazing management, and management of

land application of manures.

Dairy farms can be viewed as a biological protein factory,

with about 20-30 percent of the nitrogen

converted to product and 70-80 percent to waste.

-Dr. Jack Meisinger, USDA

Dairy Cattle

421

Crops

531

Silage

97

Grazing

178

Shed + St.

137

Grass

218

NO3 +N2 +SON 

216 (41% crops)

Conc.

106

Fert N

230

Dep.

45

Milk +Beef

88 (21%)

NH3 - 19

NH3 - 14

NH3 - 43

NH3 - 2

NH3 - 1

Bussink & Oenema, 19989

Annual N Flows on a Dutch Dairy Farm, kg N / ha

Tot. NH3

79 (19%)

Figure 16

N Flow Diagram as presented

by Jack Meisinger
22

Motor Vehicle Emissions

Ammonia is emitted by motor vehicles under certain

conditions. The potential for ammonia to be emitted

exists with vehicles equipped with three-way catalysts,

operating under certain fuel-rich or fuel-lean conditions,

and when the catalyst is operating in some kind of failure

mode. The main purpose of the three-way catalyst is to

reduce emissions of unburned hydrocarbons, carbon

monoxide and NOx. A fuel-rich condition means that

in the air to fuel ratio, there is more fuel than there is

oxygen in the mix. When conditions are fuel-rich, there

will be excess volatile organic compounds

(hydrocarbons) and a small amount of NOx generated

after the combustion process.

in very low concentrations of both VOCs and NOX.

Therefore, high ammonia emissions from these vehicles

are believed to be unlikely. However, ammonia can be

produced if the catalyst is operating in hyper-efficient

mode (it should be good, but not too good) or is faulty.

The most plausible scenarios for generating

ammonia are when the vehicle’s engine is not calibrated

correctly or when equipment fails, causing the engine to

operate slightly fuel-rich or slightly lean. Other

conditions include short-term transients (increases or

decreases in fuel or air) in normally operating vehicles

due to sudden changes in fuel flow (accelerations),

coupled with an imperfectly operating catalyst. In reality,

transients are too brief to constitute as a major emission

source and most equipment failures preclude

simultaneous high VOC and NOX emissions. Thus, high

ammonia emissions are thought to be associated with a

relatively small fraction of vehicles. However, cold starts

and quick acceleration will create some NH3

 emissions

from most vehicles. It is believed that roughly10% of

the vehicles emit 90% of the ammonia.

In spite of the

uncertainties associated

with the ammonia

emissions from

vehicles, there are a

large number of

vehicles operating in the

United States. This,

coupled with increased

vehicle-miles-traveled,

makes it possible that

motor vehicles are a

significant, although

probably not dominant,

source of ammonia

emissions. An

additional uncertainty is

that three-way catalysts are present on a large and

increasing portion of the motor vehicle fleet, yet it is

unknown how much ammonia is produced from them.

Just because NOx emissions are found to be reduced

by the catalyst does not mean that the nitrogen was

converted to an inert form (N2

). Some portion may have

been converted to ammonia. Measurements of ammonia

are not typically included in studies of vehicle emissions.

Those tests that are conducted are based on new or

artificially-aged catalysts, and the applicability of those

results to the entire motor vehicle fleet is uncertain, at

best.

Dr. Michael Rodgers is the Director of the Air Quality

Laboratory, a Principal Research Scientist in the Schools

of Civil and Environmental Engineering and Earth and

Atmospheric Sciences, and an Adjunct Professor in the

School of Public Policy at the Georgia Institute of

Technology. He also serves as chief scientist for atmospheric

chemical and meteorological measurements of the Southern

Oxidants Study. In the transportation area, Dr. Rodgers

directs a number of projects that are quantifying emissions

from motor vehicles, under sponsorship of the U.S. EPA,

the state of Georgia, and other agencies. His primary

research interests include regional and global atmospheric

chemistry, air quality related public policy, atmospheric

emissions modeling, and satellite remote sensing. Dr.

Rodgers presented information on the emission of ammonia

from motor vehicles.

Conversely, if more oxygen is present during the

combustion process (a fuel-lean condition), there will

be more NOX generated and a small amount of VOCs

left. The requirements for ammonia to be produced are

that there must be a fair amount of nitrogen (usually

NOx), a fair amount of hydrogen (usually from the

VOCs, but can be from the water vapor), and a reduction

catalyst present simultaneously. Newer cars are designed

and built to achieve pure stoichiometry in the combustion

process, with the exact mixture of fuel and air to result

http://www.howstuffworks.com/catalytic-converter.htm
23

Consideration should be given to upcoming

improvements to motor vehicles and fuels in how the

changes may affect ammonia emissions. These

improvements include: new catalyst design, high

efficiency materials for low emission vehicles, new types

of fuels, and new emissions regulations. Another

consideration is that existing catalysts will continue to

age. All of these changes could cause a shift in the

contribution of ammonia emissions from motor vehicles

over the next several years.

Electric Utility Emissions

Ammonia is released from electricity generating

facilities, primarily during the use of ammonia as a

reducing agent in Selective Catalytic Reduction (SCR)

and Selective Non-Catalytic Reduction (SNCR) systems.

Some ammonia also may be released as a by-product of

incomplete combustion. The amount of ammonia

released from incomplete combustion depends on the

type of fuel (e.g., coal, oil, natural gas) used by the power

plant.

SCR and SNCR are two important technologies

used by the electric utility sector to reduce NOx

emissions (see sidebar) at fossil-fuel burning power

plants. Both technologies use ammonia to reduce NOx

to elemental nitrogen (N2

) and water. When these

technologies are used, some of the ammonia remains

after the NOx has been converted. This excess ammonia

gets emitted into the flue gas, termed “ammonia slip.”

The ammonia slip then can react with other flue gas

constituents, such as sulfate, to form compounds that

can coat the preheater surfaces or adhere to fly ash.

The ammonia slip also may enter the smokestack and

be released into the atmosphere. In both technologies,

using more ammonia can produce greater NOx

Tom Feeley is the Environmental and Water Resources

Product Manager for the U.S. Department of Energy’s

National Energy Technology Laboratory (DOE/NETL). He

is responsible for strategic planning, policy, budgeting,

program development, and outreach related to DOE/

NETL’s fossil energy environmental research programs.

Mr. Feeley has over 20 years experience in managing the

research and development of flue-gas-cleanup, carbonsequestration, coal-preparation, and coal-conversion

technology for coal-based power systems, with particular

focus on fine particulates, mercury, ozone, and air-water

interface issues. Mr. Feeley presented information on the

loss of ammonia from the electric utility sector.

NOx Emissions &

Ground-Level Ozone

Nitrogen oxides (NOx) are a precursor to the formation

of ground-level ozone (O3), a major component of

urban smog. The formation and accumulation of O3

involves complex non-linear processes. Therefore,

the following is a simplified description:

Nitric oxide (NO) is produced during combustion. The

NO is converted to nitrogen dioxide (NO2) by reacting

with either inorganic or organic radicals formed from

oxidized VOCs (volatile organic compounds) or by

reacting with O3. In the presence of sunlight, the

NO2 then forms O3 and NO. When NO2 is formed

without reacting with O3, the ground-level O3

accumulates.

An abundance of ground-level O3

 can result in

detrimental effects on human health, agricultural

crops, forests, and other plants.

NOx SIP Call

22 States and the District of Columbia are required

to revise their State Implementation Plan (SIP)

measures under EPA’s NOx SIP Call to ensure that

emissions reductions are achieved to mitigate the

regional transport of O3 across State boundaries in

the eastern half of the U.S. Reducing the formation

and regional transport of O3 is necessary to help

certain States attain the human health standards for

ground-level O3.

A portion of the electric-utility industry, in the states

affected by the NOx SIP Call will be required to install

SCR, and to a lesser extent, SNCR, technology to

reduce their NOx emissions during the ozone season–

May through September.

reductions, but at a cost of producing more ammonia

slip.

SCR involves the injection of ammonia into the flue

gas downstream of the furnace as it passes over a catalyst

bed, usually vanadium pentoxide/titanium oxide. This

results in a greater than 80% NOX emission reduction.

In the SNCR system, urea (an ammonia derivative) is

directly injected into the furnace; no catalyst is used.

SNCR typically results in a 25-40% NOXemission

reduction.

Recently, the U.S. Department of Energy (DOE)

prepared an analysis to estimate the amount of ammonia
24

that could be released to the atmosphere as a result of

increasing installation of SCR and SNCR technologies.

The increased installations are in response to the NOx

SIP call (see sidebar). As a part of this analysis, DOE

established a relative, rather than an absolute, estimate

of future ammonia emissions from fossil fuel-fired

boilers. In their approach, DOE created a matrix (with

limited field data) of possible internal ammonia slip vs.

the percent of slip that could be emitted into the stack

(Table 3).

DOE then applied the matrix to the anticipated

installation of SCR/SNCR technologies under three

possible scenarios: a best-case scenario, a mid-case

scenario, and a worst-case scenario to estimate annual

emissions of ammonia (Tables 4,5,6). In the best case

scenario of 2 ppmv (parts per million by volume)

ammonia slip, if 1% of the slip made it into the stack,

the resulting ammonia emission into the air would be

about 33 tons/year. Under the worst case scenario of

10 ppmv, if 25% of the slip made it into the stack, the

resulting ammonia emission into the air would be about

4,174 tons/year. Based on this preliminary analysis,

DOE concluded that the potential NH3 emissions from

fossil-fuel-fired boilers equipped with SCR/SNCR in

the NOx SIP Call region could range from 33 to 4,174

tons/year. Although, even under the worst-case scenario,

future ammonia emissions from utility boilers would be

dwarfed by emissions from other sources, such as

livestock.

It is important to note that DOE made several

important assumptions in carrying out the analysis.

First, they assumed that there is actually ammonia

escaping up the stack in a well-performing SCR or

SNCR system. Secondly, they assumed that the amount

of ammonia released from the stack was independent of

the coal sulfur content. Both of these assumptions would

result in potentially higher NH3 emissions.

Coal-fired Electric Power Plant (Courtesy of NREL)

Ammonia Slip Matrix

Internal

NH3 Slip,

ppmv

% Internal NH3 Slip to Stack

2 1 10 25

5 1 10 25

10 1 10 25

Best Case Results -

2 ppmv NH3 Slip

% Slip to Stack NH3 emitted from stack,

 tons/year

1 33

10 334

25 835

Mid-Case Results -

5 ppmv NH3 Slip

% Slip to Stack NH3 emitted from stack,

 tons/year

1 84

10 835

25 2087

Worst Case Results -

10 ppmv NH3 Slip

% Slip to Stack NH3 emitted from stack,

 tons/year

1 167

10 1670

25 4174

Table 3 Table 4

Table 6 Table 5
25

expands into a gas, thereby absorbing heat; when

compressed back into a liquid the heat is released. A

good refrigeration fluid should have a low enough boiling

point (35oF – 60oF) to cycle at ambient temperatures.

Since this is a closed loop system, there should be no

releases. However, these systems are not perfect and

there are fugitive emissions, accidental spills, and

leakages that can occur. The key issues and concerns

surrounding the loss of ammonia from refrigeration

systems are employee exposure, off-site vapor clouds,

contamination of surface water, fish kills, vegetation

Vendors of SCR and SNCR technologies and the

electric utility industry are striving to minimize ammonia

slip from the standpoint of equipment performance

guarantees, balance-of-plant issues, and potential

environmental impacts. Vendors and utilities agree that

actual field data will need to be collected before a

definitive answer can be given to the question of how

much ammonia is emitted from fossil-fueled power

plants. Currently, limited data exists on the performance

of these technologies, particularly on plants using highsulfur and low-rank coals. Data also will need to be

collected on the ultimate fate of the ammonia slip—

that is, the distribution of the ammonia between the fly

ash, the atmosphere, and that which deposits on air

preheater.

Large Refrigeration Systems

Ammonia is used extensively as a refrigerant in large

commercial and industrial systems, as a replacement

for banned chloroflourocarbons (CFCs), and for the

phasing-out of hydrochloroflourocarbons (HCFCs) and

hydroflourocarbons (HFCs). Ammonia has been a

favorable replacement because it is a natural compound

with a short lifetime in the air. CFCs, on the other hand,

are man-made and have a lifetime of 40-100 years in

the atmosphere.

A commercial refrigeration unit is similar to a home

air conditioning system, but about 1000 times larger.

The system works by removing heat from one place (the

cooler) and exhausting it in another (generally outside

air). The premise of refrigeration is simple: a liquid

damage, loss of cooling capabilities, and product

contamination. At ambient air concentrations of 25 parts

per million, ammonia can be detected by its odor–

although it is not harmful to humans at that level.

Refrigeration systems use about 12 kg of ammonia

per ton of cooling. For an average-size system, there

could be 22,000 kg of ammonia stored at a plant for

use. A well-operating plant may lose about 5% (~

1,200 pounds) of ammonia per year. A moderatelyoperated plant may lose between 5% and 20%, and a

poorly-operated plant may lose 100% (or ~22,000 kg)

of ammonia per year.

At this time, there are no good sources of data on

the total usage of ammonia as a refrigerant or on releases

of ammonia from refrigerant processes. Therefore, there

are large uncertainties with ammonia emissions

estimates from this source. The1994 Battye Report

estimates that ammonia emissions from refrigeration are

probably high ~250 million kg per year. Other data

sources estimate emissions at approximately 25 million

kg per year, but these numbers are questionable as well.

The EPA estimates, also with high uncertainties, that

ammonia emissions are about 90 million kg per year.

Another source of information that can be used is

ammonia purchases. Refrigeration plants purchase

annually between 2,200 and 22,000 kg per year.

Compared to other sources, potential ammonia losses

from the refrigeration industry are not large.

Industrial Refrigeration Unit

DOE estimates that the electric utility industry will be

installing SCR on 495 boilers with a total capacity of 175.5

Gigawatts of energy, and SNCR on 208 boilers with a total

capacity of 12.8 Gigawatts of energy through the year 2007.

Thus, it is predicted that ammonia emissions will increase

as a result of increased use of SCR and SNCR. How much

it will increase is unknown at this time.

Kent Anderson is President of the International Institute

of Ammonia Refrigeration (IIAR), a foundation whose

membership includes contractors, manufacturer’s

representatives, end users, engineers, wholesalers and

manufacturers of ammonia refrigeration products. IIAR

is the only organization dedicated specifically to the use

of ammonia as a refrigerant. Through its membership,

IIAR promotes the safe and efficient use of ammonia by

the refrigeration industry. Mr. Anderson presented

information on the loss of ammonia from large

commercial and industrial refrigeration systems.
26

This next section highlights two different

experiences of governments that have taken action to

address the issue of ammonia emissions. The first

describes the environmental situation in the Netherlands

and the actions that have been taken by the Netherlands’

government to manage agricultural ammonia. The

second describes the environmental problems occurring

in the coastal region of North Carolina and the actions

currently being pursued by the State to reduce nutrient

pollution from large-scale swine operations, including

ammonia emissions. The final part of this section raises

the idea of using environmental assessments as the link

between science and policy development.

Lessons Learned from the Netherlands

Biologically available nitrogen is an important

environmental threat in the Netherlands. Today, there

are approximately 16 million people, 15 million pigs,

100 million chickens, and five million cows, all in an

area approximately 16,000 square miles in size, and

all generating nitrogen through their waste products.

The Netherlands (Figure 17 below) is slightly less than

twice the size of New Jersey.

Two centuries ago, there was equilibrium between

nutrients in the soil and the crops grown. As the human

population grew and farmland became scarce, people

began to convert natural, wilderness areas into

farmland; this land was poorer in nitrogen. At that time,

animals were used primarily for their manure to fertilize

crops, not as much for food. As the demand for crop

foods increased, more nutrients were required and this

drove the need to produce and use commercial

fertilizers.

After World War II, however, food became scarce,

and urgent efforts were taken by the Netherlands’s

government to produce more food. Livestock then

became viewed as an important food source. Animals

were imported into the country, fed, and then processed

into meat products. Only about 20-30% of the nutrients

fed to livestock are converted into meat; the rest ends

up in animal waste. While much of the meat products

is exported, the animal waste stays in the Netherlands.

These intensive livestock operations, which are the

dominant source of ammonia, are located adjacent to

the remaining valuable, natural wilderness areas in the

Netherlands. The four main areas for ammonia

emissions from animal waste in the Netherlands are

the animal housing units, unconfined animals in the

field, storage facilities, and land-application.

Studies show that wet deposition of ammonia has

increased by a factor of five over the last 100 years.

The deposition data reflect the ammonia emissions data.

The annual average atmospheric concentration of

ammonia is 5 Fg/m3

, with hot spots of 20-25 Fg/m3.

The deposition rate is about 30 kg NH3

/hectare, with a

maximum deposition rate to forests and natural areas

of approximately 90 kg NH3/hectare. This is much

higher than for most of the U.S.

The effects of this much ammonia include direct

harm to plants (e.g., leaf burning) and threats to human

health. The indirect effects include eutrophication, algal

blooms, pests and diseases in the forests. But, the most

important indirect effect observed in the Netherlands

has been a decrease in biodiversity. The Netherlands’s

government believes that in order to protect

biodiversity, a 90% reduction in ammonia emissions is

needed. To protect forest growth and groundwater, a

70% reduction is needed. However, these reduction

goals are unrealistic.

MANAGING AMMONIA

Dr. Jan Willem Erisman is Program Manager for

Environmental Research, Head of the Department of

Integrated Assessment, Energy Research Center of the

Netherlands, ECN. He has been involved with a variety

of environmental issues, including air quality, acid rain,

and eutrophication. Dr. Erisman presented the actions

that had been taken in the Netherlands to control

ammonia emissions.

Figure 17 Map of The Netherlands
27

In the late 1980’s, the government established

abatement measures focused on covering storage

facilities, using slurry injection, and building low

emission housing systems. Not long ago, there was

great interest in converting the nitrogen in the manure

to nitrogen gas (N2)

 . However, this process was found

to be expensive and problematic. Today, the

Netherlands considers this to be a good option for

reducing ammonia emissions and for combating nitrate

pollution of ground water and surface water. Other

abatement measures for decreasing ammonia emissions

include keeping livestock in barns at night, allowing

ammonia trading with 25% reductions and requiring

farmers to have mineral accounting. The government’s

requirements intend to optimize the use and generation

of nitrogen on the farm. If the farmer exceeds certain

limits, he will be fined. Estimates of the abatement

measures showed that at least two of them would lead

to major ammonia emissions reductions. The first and

most important measure is the injection of the manure

into the land. This should have reduced emissions by

50% between 1990 and 1997. Several other types of

land application were tested in the laboratory showing

that up to 90% emission reduction was feasible. The

second abatement measure is the use of low emission

housing systems, such as flushing systems where the

manure is stored under the building or in tunnel dryers

where the manure is dried. These should have reduced

emissions from the housing units somewhere between

50 and 80%.

From the application of all of these abatement

measures, the Netherlands expected a reduction in

ammonia emissions to be about 37% between 1990 and

1997. When results of the measures were studied, it

was found that the reduction achieved was only about

18% (Figure 18). This gave rise to the idea that there

was an “ammonia gap.” Possible reasons for this gap

include a) the manure was not concentrated over small

regions but was transported across the country

providing a larger emissions area; b) more animal

manure was being land-applied during the warm Spring

and Summer months because Winter applications were

stopped; c) practical application is different from

laboratory studies; d) the regulations had not been

fulfilled; e) there might be long-term ammonia

emissions, not just over some short periods of time; f)

sulfur emissions had been reduced in Europe, thereby

decreasing the sink for ammonia. Perhaps the most

important reason is that basically there is too much

nitrogen in the system. It will come out eventually, as

nitrate to ground water and as ammonia, or N2

O gas to

the air.

Today, regulations in the European Union and the

Netherlands are mainly for limiting nitrates, “the Nitrate

Directive,” not for limiting ammonia. A new directive

is expected to be implemented which will include a

national ammonia emission ceiling with limited targets

for the different European countries. In the near future,

there will be regulations for low emission housing

systems. There also will be an intensification in

managing the manure by incorporating it into the soil.

Moreover, there will be emission free zones of 250 or

500 meters around nature areas, where animal

production will be limited.

Other new abatement measures include

optimization of the nitrogen cycle for concentrated

animal operations which have land and those which do

not have land. Also, there are new control technologies

that convert ammonia and other gases into less reactive

forms. There are new studies of agro-business parks

that concentrate production and storage. These are

closed energy and water systems where the production

of animal meat is combined with other nutrient

production.

It is important to look not only at whether ammonia

emissions have been reduced from individual sources,

but also whether reactive forms of nitrogen are removed

from the system. The question remains, does the effect

Figure 18 as Presented by Jan Willem Erisman
28

Actions Currently Being Pursued by the State of

North Carolina

In recent years, North Carolina has explored several

options to reduce the amount of nitrogen lost from

hog operations, including an integrated nitrogen

approach and best management practices. During the

ten-year period, from the late 1980s to late 1990s, there

was a significant expansion of the swine industry from

about 2 million hogs to nearly 10 million. Like the

Netherlands, the State of North Carolina has a greater

number of animals than humans. In addition to this

rapid growth, the number of small independent farms

in the state has decreased while individual operations

have become much more concentrated. Most of the

these large-scale operations are clustered together in

six counties in the central coastal plain (Figure 19),

of ammonia emissions abatement lower the total

nitrogen in the system? An integrated nitrogen

approach is clearly needed. In order to limit the amount

of reactive nitrogen in a region, there first must be a

determination of the maximum amount of nitrogen

produced or imported into a region. This determination

would be based on critical limits for all nitrogen-related

effects. Once that is determined, there are three options

that can be used: 1) the amount of nitrogen that is

imported must be decreased; 2) reactive nitrogen must

be converted into N2

, and 3) nitrogen must be exported

to poorer nitrogen regions.

where the land is flat and the ground water table is

high. Around the mid- 1990s, concerns were raised

over nutrient loadings to the sensitive Pamlico Sound

and Neuse River basins. These basins are home to the

greatest concentration of swine operations in the state.

Following a series of environmental problems,

including algal blooms and fish kills in the lower rivers

and sounds, the North Carolina State Legislature began

looking into the causes. While nutrient sources come

from several areas, agriculture is believed to be the

primary concern in these basins because of nutrient runoff from farm fields, failing waste lagoons, and overfertilization. There also is concern over the contribution

of atmospheric nitrogen deposition. Estimates indicate

that up to approximately two-thirds of the nitrogen in

the swine excretions is emitted to the air in accordance

with the design of a lagoon and sprayfield system.

Studies estimate that swine facilities produce

approximately 20% of North Carolina’s total

atmospheric nitrogen compounds, which can react with

other constituents in the air and subsequently deposit

to soils, vegetation, and water bodies.

In response to the problems in the coastal waters,

the North Carolina State Legislature mandated a 30%

reduction in nitrogen loading to the Neuse River from

1990 levels. They also mandated funding for research

and modeling atmospheric nitrogen impacts in the

Neuse Estuary, and they placed a moratorium on new

swine operations. In 1995, the state implemented

stricter standards for point source discharges and nonpoint source discharges, including 50-foot buffer

requirements on designated water bodies.

In 1998, then Governor Jim Hunt initiated a plan

for lagoon conversion. The plan included a 10-year

phase-out of open lagoons used in swine operations.

The goal was to convert all hog lagoons and sprayfields

to new technologies within seven years. This plan

provided a framework to begin implementation of

environmentally superior animal manure management

technologies and to improve existing animal manure

management systems, through monitoring, technical

assistance and compliance inspections.

In 2000, then Attorney General Mike Easley (now

Governor) entered into an agreement with two of the

largest integrators in the swine industry. The

agreements between the North Carolina Office of the

Attorney General and Smithfield Foods, Inc. and

Premium Standard Farms, Inc. represent a commitment

Ms. Robin Smith is currently the Assistant Secretary

for Environmental Protection with the North Carolina

Department of Environmental and Natural Resources.

Ms. Smith supervises all of the Department’s

environmental divisions, including air quality and

water quality. Ms. Smith presented a summary of

North Carolina’s efforts to reduce ammonia emissions

from hog operations.

Basically, there is too much nitrogen in the system.

It will come out eventually as nitrate to ground water

or as ammonia or N2

O gas to air. An integrated approach

focused on the decrease of reactive nitrogen

is needed.

 -Dr. Jan Willem Erisman, Netherlands Energy

Research Foundation
29

by the companies and the state to develop

environmentally superior technologies for swine

operations. In this agreement, Smithfield, Inc. will

provide $15 million for research on waste management

and economic feasibility of new control technologies

for lagoons owned by Smithfield. The new technologies

will be evaluated based on several criteria, including

the control of ammonia emissions. They also agreed

to survey their farms to identify those with

environmental problems, such as those located in the

100-year flood plains and develop a plan to address

those issues.

Today, in addition to the work under the Smithfield

and Premium Standard Agreements, North Carolina is

working to reduce the excess nitrogen loss from the

lagoon/sprayfield system. To date, the Department of

Environment and Natural Resources (DENR) has

discussed the development of a “Nitrogen Efficiency

Rule” to adopt an integrated nitrogen approach to

control for loss of nitrogen from the swine facilities,

including loss through ammonia emissions. The rule

was initiated directly by the Environmental

Management Commission, a 17-member Commission

appointed by the Governor, the Senate Pro Tempore

and the Speaker of the House. The Commission is

responsible for adopting rules for the protection,

preservation and enhancement of the State’s air and

water resources. It also oversees and adopts rules

initiated by several divisions of the DENR, including

the Division of Air Quality. The ultimate deposition

of ammonia in nutrient sensitive waters was the impetus

behind the development of the Nitrogen Efficiency

Rule.

The basic concept behind mass balance is very

simple, that what goes in must equal what comes out

(i.e. no mass is lost or destroyed). For hog production

in North Carolina, the nitrogen comes onto the farm as

grain and comes out as pork, crops, sludge, and lost

nitrogen. Due to the difficulty of measuring ammonia

emissions, the concept envisioned measuring the

nitrogen utilized by the pork, crops, sludge, and N2

.

Therefore, the mass balance approach would allow lost

nitrogen to be accounted for without difficult

measurements, and provide a mechanism for those

losses to be controlled. Lost nitrogen includes

atmospheric loss of ammonia and N2 as well as land

applied nitrogen, which leaches into the groundwater

or leaves the site as runoff. Of course, no agricultural

system can hope to function without some loss of

nitrogen, so the goal of the rule would be to limit the

nitrogen loss to an acceptable level. What is acceptable

was to be determined by reference to other water quality

goals and concerns in the region.

Figure 19 North Carolina Swine Map
30

Nitrogen lost to the atmosphere from hog waste

has been estimated to equal about 66% of the total

nitrogen in the waste, or approximately 50% of the

nitrogen imported as grain for feed. The nitrogen lost

to the atmosphere is thought to be lost largely as

ammonia but some research suggests N2 loss could also

be important. Loss of nitrogen as N2

 is acceptable, as

it is benign. Studies are still unclear as to the ratio of

ammonia to N2 emitted from swine operations.

Through consideration of the “Nutrient Efficiency

Rule,” the department has struggled with the

identification of values for nitrogen used by the pork,

as N2, and other variables that must be accounted for in

order to ensure a comprehensive mass balance

approach. Due to the uncertainties at this time and

until additional information is available, the DENR has

begun to explore other options for reducing nitrogen

loss, including the development of best management

practices aimed at managing nitrogen on the farm.

Environmental Assessments as the Link Between

Science and Policy Development

Important lessons about the role and use of

environmental assessments as the link between science

and policy development can be derived from two

research programs: the Center for Integrated Study of

the Human Dimensions of Global Change (HDGC) and

the Global Environmental Assessment project (GEA).

These two research programs address environmental

issues in very different ways, both of which may be

beneficial to the current study of ammonia in coastal

and estuarine areas.

In the HDGC (http://hdgc.epp.cmu.edu/), the social

and natural sciences are applied to study problems

related to global environmental change, and the focus

is on how people understand the world and make

decisions, while not ignoring physical phenomena.

Then, those decisions and phenomena are modeled to

determine potential consequences. A key feature of

this approach is the use of Integrated Assessment

Models (IAMs), which contains simplified models of

complex systems, often specifying parameters as

probability distributions (i.e., they are usually stochastic

models). It is usually not appropriate to start

investigations of a problem with IAMs, since useful

examples always rest on detailed (and often

disciplinary) research on specific subsystems and

phenomena (e.g., the atmospheric transport and fate of

ammonia). However, the traditional disciplinary

academic approach to addressing problems is often not

well suited to developing useful policy advice, since it

can be overly narrow, typically treating either physical

systems or social systems, but not both. For example,

consider the question of whether climate change is

important in determining the spread of malaria. Simple

physical models have suggested this is the case, but

integrated assessments have shown that public health

measures dominate the incidence of malaria no matter

what climate change occurs. An integrated assessment

of this type is only feasible in areas where considerable

disciplinary research has already been conducted, so

that reduced form equations can be specified and

uncertainties quantified. Thus, IAMs can be used to

combine various disciplinary approaches coherently,

prioritize research, and address policy questions.

One of the largest and most complex IAMs is the

Integrated Climate Assessment Model (ICAM), which

has been developed by the Center for Integrated Study

of the HDGC. Given the importance and substantial

complexity of ammonia (or reactive nitrogen) in the

economy and in the environment, the impressive

existing research basis on the topic, and the significant

uncertainties remaining, a stochastic IAM could be very

useful in understanding policy issues and opportunities.

The Global Environmental Assessment Project

(http://environment.harvard.edu/gea) has an entirely

different focus. Rather than attempting to develop or

apply better assessment tools in specific policy areas,

the project seeks to promote better understanding of

the actual relationships among the sciences, assessment,

policy and management in societies’ efforts to grapple

Dr. Alex Farrell is a research faculty member with

the Department of Engineering and Public Policy,

Center for the Integrated Study of the Human

Dimensions of Global Change, at Carnegie Mellon

University. His research is mainly in the area of

environmental economics and policy, particularly

air pollution. For the last several years, Dr. Farrell

has been part of a research project based at Harvard

University that has been exploring the interface

between science and public policy. He is currently

editing a book on that topic, called The Design of

Environmental Assessment: Global and Regional

Cases. Dr. Farrell presented examples of how

environmental assessments are used as the link

between science and policy development.
31

with global environmental change. The project is a

multi-year, interdisciplinary effort based at Harvard

University. It draws on the faculty and students from

the natural sciences and social sciences, as well as

practitioners and professional scholars from around the

world. Over the last five years, GEA researchers have

conducted case studies on issues such as climate change,

acidification, genetically modified organisms, and

photochemical smog.

Although these case studies each looked at

assessments of very different environmental issues, that

were conducted by different people using different

information, and aimed at different outcomes, it became

clear that there were general lessons that could be

learned about how to design an environmental

assessment. One of the most important lessons is that

although an environmental assessment usually entails

the creation of discrete products (e.g., models, forecasts,

reports), they are best thought of as social processes in

which the interests of the people conducting the

assessment are important, as well as the institutional

framework of rules, norms, and expectations

surrounding the assessment. The other key findings of

the GEA project relate to understanding what an

effective environmental assessment is, and why some

assessments are effective while others are not.

Effectiveness can be defined by different

participants in a variety of ways (which are sometimes

contradictory). For example, did the assessment allow

for the formulation and evaluation of new policy

options? Did it improve scientific knowledge? Did it

help win further research funding in the area being

assessed? Did it prevent (or delay) action? Did it

establish environmental policy or change the

negotiating positions of policy-makers? Did it enhance

the prestige of particular researchers or institutions?

Three central factors strongly affect the

effectiveness of an environmental assessment: saliency,

credibility, and legitimacy. Often, these can be in

conflict with one another and require balance. Saliency

can be defined by whether the assessment addressed

an issue that is of interest and relevant to actions that

users (i.e., decision makers) can actually take, and

whether the assessment process can adapt to changes.

Credibility can be defined if the authoritative technical

community (or communities) finds the assessment

acceptable. Legitimacy can be defined as the belief by

the users that the process respects the rules and norms

of relevant institutions, and the users feel their values

and interests have been acknowledged and considered.

The GEA research shows quite clearly that effective

environmental assessments always have reasonably

high levels of salience, credibility, and legitimacy.

The insights of the GEA project may be very useful

for those charged with, or simply interested in, future

assessments of ammonia policy. A key insight from

both of these research projects is that the framing of an

issue is crucial to how it will be perceived, what sorts

of questions it will touch on, and which organizations

will be interested. It will be important to frame the

ammonia issue correctly. It may be more useful to think

about ammonia within the context of “reactive”

nitrogen. It also may by useful to determine whether a

single-endpoint view, such as nitrogen-caused

eutrophication, should be pursued or whether it is more

useful to adopt a multi-pollutant/multi-receptor view.

The ammonia issue is clearly rising in salience,

and it would be worthwhile to have discussions on

whether the issue is managing nitrogen or managing

the activities that affect nitrogen. That is, should an

assessment of the “ammonia issue” consider the

possibility of reducing agricultural production as a

policy option or not? It may be necessary to consider

conducting an Integrated Assessment Modeling for

Reduced Nitrogen. When doing so, the focus should

be on the process, as well as the content, and it should

provide incentives for participation.
32

I. Ammonia can effect human health and the

environment.

• Through the production of food and energy, humans

mobilize twice as much nitrogen as nature

produces.

• As a gas, ammonia contributes to air quality

problems after it converts to particle form. Particles

(dominated by ammonium sulfates in the East) can

effect human health and degrade visibility.

• Ammonia/um that deposits to the land can serve

as a fertilizer, or it can acidify soils or lead to

nitrogen saturation in certain sensitive terrestrial

systems. Nitrogen that does not get used by the

terrestrial landscape will eventually make its way

into downstream ecosystems where waters can

become acidified or over-fertilized. The ultimate

fate of nitrogen, from the air to the soils to the

point it leaves the terrestrial landscape, depends

on many factors including how much nitrogen is

depositing from the air, how long deposition has

been occurring, and the land use history.

• Ammonia/um deposition also can cause (or

contribute to) water quality problems, including

the over-stimulation of algae growth. Scientists

estimate that nitrogen deposition can contribute

from 10 to over 40% of the “new” nitrogen

enrichment of coastal and estuarine waters.

• For many algae species, ammonia/um is a preferred

“flavor” of nitrogen. As a result, the increasing

availability of ammonia/um could cause a

fundamental change in the algae community.

• The decrease in biodiversity in the Netherlands is

believed to be associated with the high

concentrations of ammonia emissions and

deposition.

Future Directions:

• More studies are needed on the role of ammonia in

the formation of particulate matter, and the effects

of ammonia-based particles on human health.

• Further study is needed on the terrestrial and aquatic

biological responses to ammonia/um deposition, in

order to establish cause and effect relationships.

• Studies are needed to identify the relative

magnitude of ammonia verses total nitrogen

deposition.

• Further study is needed to better understand at what

point nitrogen saturation of soils occurs, the regions

where it occurs and to what types of forest systems.

II. Airborne ammonia compounds can travel short or

long distances from their source before depositing in

wet or dry forms to the land or water.

• Models used to describe ammonia airsheds indicate

that reduced nitrogen does not just deposit locally

but may travel long distances through the air before

depositing. This means that some of the ammonium

depositing to coastal watersheds comes from

sources well beyond a jurisdiction’s boundary line.

However, models (including the airshed model) are

only as good as the information put into them.

There is little deposition data for emission

“hotspots;” even less information on dry deposition,

and no information on how much, and in what

forms, airborne nitrogen is entering coastal

estuaries via offshore waters.

• NADP data show that ammonium in wet deposition

CONCLUSIONS AND FUTURE DIRECTIONS

Ammonia is a significant source of nitrogen

to coastal waters and watersheds.

 -Bill Matuszeski, EPA

Chesapeake Bay Program

The conclusions presented in this section are derived primarily from the platform presentations, the question

and answer sessions that followed, and the wrap-up session. Future directions (for which there is no order

intended) are derived from the platform presentations, the breakout sessions, and the wrap-up session and represent

either the collective thinking of the group, or the opinion of one or more of the participants.
33

is increasing in certain parts of the country. In some

regions, ammonium deposition is almost as high

as nitrate deposition. These data appear to be

indicative of the high concentrations of emissions,

and they demonstrate that both forms of nitrogen

are important.

Future Directions:

• More focused, repeatable studies are needed to

better understand seasonal and diurnal cycles for

emissions, ambient air concentrations and

deposition of ammonia, sulfates, and nitrates; the

interactions between gas and particle phases; and

the influences of coastal sea salt for model

development, improvement, and evaluation.

• The density of deposition monitoring stations (wet

and dry) must be improved to capture the spatial

variability of ammonia emissions and deposition,

particularly in areas where there are the greatest

concentrations of emissions (e.g., hotspots and

coastal).

• Intensive studies are needed to accelerate the

development of the technologies that can better

quantify dry deposition, in particular better

techniques are needed to measure ammonia gas.

• Fixed, monitoring stations, placed in the near-shore

coastal shelf (e.g., on an oil drilling platform), are

needed to assess the contribution of airborne

nitrogen deposition to the coastal ocean.

III. Ammonia is released into the air from many sources.

• The dominant source of ammonia emissions in the

U.S. is agriculture (livestock wastes and

commercial fertilizers). Depending on the area,

however, the percentage contribution from sources

can vary.

• Ammonia emissions vary greatly across source

categories and within a source category.

• The quality of current ammonia emissions

inventories is poor for a variety of reasons.

• For many U.S. sources, emission factors were

derived from European studies (again, little to no

data has been collected in the U.S.) and from shortterm measurement studies.

• The types of animals; the animal waste handling

system; the fertilizer application times and methods

can each dictate how much ammonia is released

into the air.

• Certain techniques, such as covering the animal

waste, using bio-filters, and incorporating the waste

into the soil, can reduce the amount of ammonia

released into the air.

• Ammonia is emitted by motor vehicles under

certain conditions, generally when the catalyst is

operating in some kind of failure mode.

• The millions of vehicles in the U.S. and increasing

vehicle miles traveled make it likely that motor

vehicles are a significant source of ammonia in

urban/suburban areas, although they are probably

not a dominant source of ammonia emissions

nationwide.

• It appears that roughly 10% of the vehicles emit

90% of the ammonia attributable to traffic.

• Upcoming improvements to motor vehicles, as well

as aging catalysts, may cause ammonia emissions

to increase and change the relative contribution of

ammonia from motor vehicles.

• SCR and SNCR technologies, used by the electric

utility industry, can significantly reduce NOx

emissions.

• At this time, there is limited data on how much

ammonia slip is generated by SCR and SNCR

technologies, particularly on power generating

plants using high-sulfur and low-rank coals.

• Ammonia emissions are expected to increase (by

an undetermined amount) as a result of increased

use of SCR and SNCR technologies.

• There are no good sources of data on the total usage

of ammonia as a refrigerant or on releases of

ammonia from refrigerant processes. Since

ammonia is increasingly being used as a refrigerant,

economically the trend is to decrease its release.
34

Future Directions:

• Ammonia emissions inventories need to be

improved and structured in an easily modified

format to allow for the incorporation of new data

as they are received. More specifically,

-Emission factors across and within source

categories should be improved/updated.

-Better quantification of emissions generated

by agriculture from the various production

processes is needed to identify how much and

when ammonia is released.

-Studies on motor vehicles should be

conducted in real-world settings to document

and formulate their ammonia contribution.

-More studies should be conducted on SCR and

SNCR technologies to quantify their current

and future ammonia releases.

-Long-term measurements should be made to

improve estimates of ammonia exchange

between the air and soils and vegetation since

these can serve as either a source or a sink.

-Data should be collected to describe seasonal

and diurnal variations in emissions.

-Standardized methods should be used for

quantifying ammonia emissions.

• Farm-level fertilizer use (both manure and

commercial) and method, place, and timing of

application should be documented and made

available for updating the inventories.

• Better data (small scale resolution) are needed on

land use/land cover.

• Considerations should be given to how future

changes with a source category (whether its animal

agriculture, motor vehicles, NOx control

technologies, or refrigeration) will affect changes

in ammonia emissions.

• Ammonia emissions should be considered in the

design or testing of new technologies.

IV. Ammonia needs to be managed.

• Experience in the Netherlands demonstrates that

nitrogen emissions pose a serious threat to the

environment, particularly through reduction in

biodiversity.

• Wet deposition of ammonia has increased in the

Netherlands by a factor of five over the last 100

years.

• Various agricultural abatement measures used by

the Netherlands did not result in the expected

emissions reductions, giving rise to the idea that

there is an “ammonia gap”.

• The most likely reason for the gap is that there is

too much nitrogen in the system.

• The Netherlands is about 10 years ahead of the U.S.

in quantifying ammonia emissions, monitoring

deposition, and developing and implementing

controls.

• Water quality problems in coastal North Carolina

are believed to be associated with the high

concentrations of animal operations.

With ammonia, we have an opportunity

 to do it right.

-Patricio Silva, Natural Resources

Defense Council

We are ultimately talking about regulation,

but not the kind that would be related to the extensive

 and convoluted process of the CAA or the TMDL process

under the CWA. What is needed is something

at the state level and not prohibitively intrusive on the

farmer.

 -Bill Matuszeski, EPA

Chesapeake Bay Program
35

• Studies estimate that hog facilities in North

Carolina produce approximately 20% of the state’s

total atmospheric nitrogen compounds.

• North Carolina is in the early stages of drafting air

rules for ammonia.

• Managing ammonia should involve both regulatory

and voluntary approaches.

• Integrated environmental assessments can be used

to link science and policy.

Future Directions:

• A nitrogen mass balance should be conducted for

farm operations.

• Provide incentives and education for farmers to

optimize management of nitrogen on the farm.

• Ensure the continued economic well-being of

agricultural communities by adopting alternative

nutrient management practices that address air and

water quality concerns and are economically

feasible.

• Certain techniques, such as covering the animal

waste, using bio-filters, and incorporating the waste

into the soil, should be used to reduce the amount

of ammonia released into the air.

• Reduce the amount of nitrogen that is imported (via

feed) to nutrient sensitive areas.

• Establish an ammonia emission standard.

• Encourage the development and use of technologies

that convert ammonia to N2

 or reduce the release

of ammonia compounds (e.g., enclosed anaerobic

digesters, or waste-to-energy).

• Export the animal waste to areas that are poorer in

nitrogen.

• Watch the North Carolina rule making process to

see if it could serve as a model for a national

approach.

• Consider establishing a nitrogen cap or emission

trading program on a national, regional, local basis.

There is a need to educate farmers on the nature of

the ammonia problem and the methods that can be

used to reduce losses.

-Dr. Jack Meisinger, USDA

Non-regulatory actions can be implemented

 faster through education and innovation.

We need to look for pollution prevention opportunities,

for these can be implemented tomorrow.

-David Johnson, VA Dept of Env. Quality

There is, and will be, a need to develop ammonia

 control technologies for agricultural sources in the near future.

 -Dr. Larry Jacobson,University of MN

• Provide education and improve communication,

particularly with the agricultural community, on

ammonia releases as both an economic issue and a

pollution issue.

• Involve all parts of animal agriculture in the process

to develop strategies to minimize nitrogen

emissions and deposition.

• Encourage development of motor vehicle catalysts

that don’t emit ammonia.

• Consider conducting Integrated Assessment

Modeling for Reduced Nitrogen.

• Correctly frame the ammonia issue.

• Integrate all non-point source pollution issues into

the TMDL and NPDES processes.

• Encourage air quality management policies to

consider terrestrial and aquatic ecosystem impacts

of nitrogen deposition.
36

This Airsheds & Watersheds workshop gave participants from diverse backgrounds a chance to share

information and ideas about ammonia and its impacts to the environment. There was broad agreement on the

importance of ammonia and the need for sensitivity to both economic and environmental issues related to

ammonia. This workshop raised awareness, provided a context to begin discussing future directions, and pointed

the way toward developing better tools to understand and manage this multi-disciplinary issue. The organizers

encourage all interested parties to continue to develop and share information and to pursue ways to reduce

ammonia emissions.

I think we all agree we are dealing with an extremely complex problem,

and it will take a concerted effort on the part of all of us

 working together to develop strategies to minimize nitrogen deposition.

-Doug Marvil, Perdue, Inc.
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Langford, AO & FC Fesenfeld. 1992. Natural vegetation

as a source or sink for atmospheric ammonia: a case study.

Science 255: 581-583.

Meisinger, J. J. and W. E. Jokela. 2000. Ammonia

volatilization from dairy and poultry manure. pp. 334-

354. In Managing nutrients and pathogens from animal

agriculture. Proc. Conf. March 28-30, 2000 Camp Hill

PA. Nat. Resource Agr. Eng. Serv. NRAES-130, Ithaca,

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Monteny, G.J. en Erisman, J.W. (1998) Ammonia

emission from dairy cow houses: a review of measurement

techniques, influencing factors and possibilities for

reduction. Neth. Journ. of Agric. Sci., 46, 225-247.

Morgan, M. G. and H. Dowlatabadi (1996). “Learning

From Integrated Assessment of Climate Change.”

Climatic Change 34: 337-368.

Paerl, H. W. 1985. Enhancement of marine primary

production by nitrogen-enriched acid rain. Nature

316:747-749.

Paerl, H. W. 1993. The emerging role of atmospheric

nitrogen deposition in coastal eutrophication: A

biogeochemical and trophic perspective. Canadian

Journal of Fisheries and Aquatic Sciences 50:2254-2269.

Paerl, H. W. and M. L. Fogel. 1994. Isotopic

characterization of atmospheric nitrogen inputs as sources

of enhanced primary production in coastal Atlantic Ocean

waters. Marine Biology 119:635-645.

Paerl, H. W. 1995. Coastal eutrophication in relation to

atmospheric nitrogen deposition: Current perspectives.

Ophelia 41:237-259.

Paerl, H. W., C. Aguilar and M. L. Fogel. 1997.

Atmospheric nitrogen deposition in estuarine and coastal

waters: Biogeochemical and water quality impacts. pp.

415-430, in J. Baker [ed.], Atmospheric Deposition

Impacts in Coastal Waters. SETAC Press, Pensacola, FL.

Paerl, H. W. 1997. Coastal eutrophication and harmful

algal blooms: Importance of atmospheric deposition and

groundwater as “new” nitrogen and other nutrient sources.

Limnology and Oceanography 42:1154-1165.

Paerl, H. W. and D. R. Whitall. 1999. Anthropogenicallyderived atmospheric nitrogen deposition, marine

eutrophication and harmful algal bloom expansion: Is

there a link? Ambio 28:307-311.

Paerl, H. W., Walter R. Boynton, Robin L. Dennis, Charles

T. Driscoll, Holly S. Greening, James N. Kremer, Nancy

N. Rabalais, Sybil P. Seitzinger. 2001. Atmospheric

Deposition of Nitrogen in Coastal Waters:

Biogeochemical and Ecological Implications. In: Nitrogen

Loading in Coastal Water Bodies: An Atmospheric

Perspective, Coastal and Estuarine Studies, Pages 11-52.

Valigura, R.A et al Editors. American Geophysical Union.

Paerl, H. W., R. L. Dennis, and D. R. Whitall. 2001.

Atmospheric deposition of nitrogen: Implications for

nutrient over-enrichment of coastal waters. Estuaries (In

press).

Peierls, B. L. And H. W. Paerl. 1997. The bioavailability

of atmospheric organic nitrogen deposition to coastal

phytoplankton. Limnology and Oceanography 42:1819-

1823.

Parson, E. A. (1997). “Informing global environmental

policy-making: A plea for new methods of assessment

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2: 267-279.

Robarge, WP and W Cure. 1999. Using throughfall

measurements to measure nitrogen deposition in the

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NC, pp. 361-364.

Robarge, WP, R McCulloch and W Cure. 1999.

Atmospheric concentrations of ammonia and

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A-4
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Hill, P.W., Fowler, D., Schjoerring, J.K., Mattson, M.E.,

Nielsen, K.H., Husted, S., Erisman, J.W., Otjes, R.,

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M., Genermont, S., Neftel, A., Blatter, A., Herrmann, B.,

Jones, S.K., Horvath, L., Fuhrer, E.C., Mantzanas, K.,

Koukoura, Z., Gallagher, M., Williams, P., Flynn, M. and

Riedo, M. (2001) Biosphere-atmosphere interactions of

ammonia with grasslands: Experimental strategy and

results from a new European initiative. Plant and

Soil,228,131-145.

Sutton, M. A., U. Dragosits, Y.S. Tang, and D. Fowler

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in the UK. Atmospheric Environment 34: 855-869.

Valigura, R.A., R. B. Alexander, M. S. Castro, T.P. Meyers,

H. W. Paerl. P. E. Stacey, and R. E. Turner (eds). 2000.

Nitrogen Loading in Coastal Water Bodies: An

Atmospheric Perspective. Coastal and Estuarine Studies

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van der Hoek, K.W., Erisman, J.W., Smeulders, S.M.,

Wisniewski, J.R. en Wisniewski, J. (Eds.) (1998)

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issue of Environmental Pollution).

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Estuarine, Coastal and Shelf Science 49:1-20.

Weber, A. J. and R. L. Kellogg. Assessing Loadings of

Nitrogen and Phosphorus From Agriculture in The

Chesapeake Bay Watershed. Presented at the Integrated

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Chevy Chase, MD.

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spatiotemporal variability of atmospheric nitrogen

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Wyers, G.P. and Erisman, J.W. (1998) Ammonia exchange

over coniferous forest. Atmospheric Environment 32,441-

452.

A-5
Appendix B- Commonly-Used Abbreviations & Terms

A.D.N. Atmospheric Deposition Nitrogen

AFO Animal Feeding Operation

AIRMoN Atmospheric Integrated Research Monitoring Program

ARS Agricultural Research Service

BACT Best Available Control Technology

BMP Best Management Practice

CAA Clean Air Act (1970)

CAAA Clean Air Act Amendments (1990)

CAFO Confined Animal Feeding Operation

CASTNet Clean Air Status and Trends Network

CBP Chesapeake Bay Program

CWA Clean Water Act (1972)

DO Dissolved Oxygen

DOE Department of

EPA Environmental Protection Agency

g gram

GIS Geographic Information System

ha hectare

HNO3 Nitric Acid

kg kilogram

LNB Low NOx Burners

MACT Maximum Achievable Control Technology

N2 Unreactive Molecular Nitrogen

NAAQS National Ambient Air Quality Standard

NADP/NTN National Atmospheric Deposition Program/National Trends Network

NAPAP National Acid Precipitation Assessment Program

NEP National Estuary Program

NERRS National Estuarine Research Reserves System

NH3 Ammonia (gas)

NH4

+ Ammonium (aerosol)

NHX ammonia+ammonium

NH4-NO3 Ammonium nitrate

NH4-SO4 Ammonium sulfate

N-org. Organic nitrogen

NO Nitric oxide

NO2 Nitrogen dioxide

NO3

- Aerosol nitrate

NOX Oxides of nitrogen (NO + NO2)

NOAA National Oceanic and Atmospheric Administration

NPDES National Pollution Discharge Elimination System

O3 Ozone

OTAG Ozone Transport Assessment Group

OTC Ozone Transport Commission

OTR Ozone Transport Region

PM Particulate Matter

POTW Publically Owned Treatment Works

RADM Regional Acid Deposition Model

RELMAP Regional Lagrangian Model of Air Pollution

REMSAD Regulatory Modeling System for Aerosols and Deposition

SCR Selective Catalytic Reduction

SIP State Implementation Plan

SNCR Selective Non-Catalytic Reduction

SO2 Sulphur dioxide

B-1
SO4

2- Sulfate

TMDL Total Maximum Daily Loads

TRI Toxics Release Inventory

USDA United States Department of Agriculture

VOCs Volatile Organic Compounds

Acid neutralizing capacity (ANC): A measure of the ability for water or soil to neutralize

added acids. This is done by the reaction of hydrogen ions with inorganic or organic bases

such as bicarbonate (HCO3-) or organic ions.

Acidification: refers to the loss of ANC or the lowering of pH.

Adsorb: To take up and hold (a gas, liquid, or dissolved substance) in a thin layer of molecules

on the surface of a solid substance.

Animal Unit: a measure that represents the number of animals of different types in a common

unit based on live weight; 1 animal unit represents 454 kg (1000 pounds) of live animal

weight.

Anions: Negatively charged molecule such as sulfate (SO42-) and nitrate (NO3-). In

combination with hydrogen (H+), these molecules act as strong acids.

Anoxia: Absence of oxygen.

Atmospheric Deposition: process whereby pollutants in the air fall on the land or water.

Pollution deposited in snow, fog, or rain is called wet deposition, while the deposition of

pollutants as dry particles or gases is called dry deposition.

Atmospheric Transport: The movement of pollutants through the air. Pollutants can travel

short or long distances depending on the emission source, chemical make-up, and weather

conditions.

Buffering capacity: The resistance of water or soil to changes in pH.

Cations: Positively charged ions such as magnesium, sodium, potassium, and calcium that

increase pH of water when released to solution through mineral weathering and exchange

reactions.

Critical Loads/Levels: The concentrations of pollutants above which direct adverse effects

on receptors may occur (according to present knowledge).

Critical Thresholds: The point at which a system switches to another state as a result of

changes in that system.

Deposition Gradient: defines the variability in deposition rates from a source.

Deposition Rate: the rate at which deposition occurs.

Discharge: a release of a pollutant into water.

Emission: The flux of material into the air.

Emission Factor: an estimate of a pollutant’s emission from a particular source type at a

particular point in a process.

B-2
Eutrophication: A process whereby excessive amounts of nutrients over-fertilize a body

of water, feeding the growth of algae blooms. When the algae die, they sink to the bottom,

where the dead algae decompose in a process the depletes the water of oxygen. These areas

of “dead water” are no longer able to support fish and other aquatic life.

Flux: The rate of transport of a material across an interface. For example, the flux of

nitrogen moving from soils to groundwater may be expressed as kilograms of nitrogen per

hectare per year.

Hypoxia: A deficiency in the amount of oxygen.

Leaching: Process by which water removes chemical solutes from soil through chemical

reactions and the downward movement of water.

Loading: The total mass of material entering an environmental reservoir (e.g., water body,

atmosphere) in a given time. May be expressed as pounds or kilograms per year.

Nitrogen Fixation: The process in which bacteria convert biologically unusable nitrogen

gas (N2) into biologically usable ammonia (NH3) and nitrates (NO3-).

Nitrogen Saturation: A condition in which a system, such as a forest, contains all the

nitrogen it can hold.

Non-point Source: A diffuse source of pollution that cannot be attributed to a clearly

identifiable, specific physical location or a defined discharge channel.

Point Source: A source of pollution that can be attributed to a specific physical location, as

in a waste water treatment plant effluent pipe or a smokestack.

Reactive Nitrogen: primarily oxides of nitrogen, but includes organic nitrogen.

Reduced Nitrogen: ammonia and ammonium.

Transformation: The chemical alteration of materials, either completely or partially.

Volatilization: re-emission of previously deposited gaseous species into the atmosphere

due to many factors, including chemical reactions, vapor pressure, gas-particle partitioning,

temperature, and wind speed.

B-3
Appendix C - Agenda for Shared Resources Workshop

Airsheds and Watersheds–

The Significance of Ammonia to Coastal and Estuarine Areas

November 15, 2000

8:00 am Workshop Check-In Begins

A continental breakfast will be provided

9:00 am Welcome

Dr. Bruce Richards, Director, Delaware Inland Bays Program

Workshop Moderator:

Susan Wierman, Executive Director, Mid-Atlantic Regional Air

 Management Association

9:30 am Keynotes:

These three keynote presentations are intended to examine, for the workshop

participants, the role and impacts that ammonia emissions and deposition can have

on air, land, and water resources. Presenters will address the strengths and

weaknesses of the knowledge base that supports the understanding of these roles

and impacts.

Dr. Cliff Davidson, Carnegie Mellon University

Ammonia Effects to Air Quality

Dr. James Galloway, University of Virginia

Ammonia/um Deposition Effects to Terrestrial Ecosystems

Dr. Hans Paerl, University of North Carolina, Institute of Marine Science

Ammonia/um Deposition Effects to Aquatic Ecosystems

Plenary– Questions & Answers

10:45 am Refreshment Break

11:00 am Session I – Atmospheric Transport and Deposition

Moderator: Jim Skillen, The Fertilizer Institute

Dr. Robin Dennis, NOAA/EPA, will examine the physical and chemical processes

and the variables that affect and effect the atmospheric transport of ammonia/

ammonium and its subsequent deposition.

Mr. Bruce Hicks, Director NOAA Air Resources Laboratory, will examine the

variables that influence the shape, size and spatial distribution of deposition

gradients, the characteristics of deposition (wet–but mostly dry), and our ability to

quantify the magnitude of nitrogen deposition.

C-1
Plenary– Questions & Answers

12:30 pm Lunch

Lunch will be served buffet style in the large banquet hall on the 1st level of

the Baycenter. Posters will be on display around the lunch area, and poster

presenters will be available to allow for informal discussions.

1:45 pm Session II – Sources and Emissions

Moderator: Dr. Wayne Robarge, North Carolina State University

Mr. William Battye, EC/R will present the most recent information on the

known substantial sources of ammonia emissions, the coefficients used to

estimate emission losses, and the gaps in identifying and estimating the

respective contributions.

2:30 pm Panel Responses

Individual panel members will respond from their own perspective within

the context of the following areas:

Dr. Larry Jacobson, University of Minnesota, will address ammonia loss

from livestock production systems, including housing, manure handling

and storage.

Dr. Jack Meisinger, USDA Agriculture Research Service, will address

ammonia loss from land-applied manure and commercial fertilizers.

Mr. Tom Feeley, U.S. Dept of Energy, will address the issue of ammoniaslip from selective catalytic and non-catalytic reduction technologies which

are used by electric power generating facilities to reduce oxidized nitrogen

emissions.

3:30 pm Refreshment Break

3:40 pm Continuation of Panel...

Dr. Mike Rodgers, Georgia Tech, will address ammonia loss from the

automobile.

Mr. Kent Anderson, International Institute of Ammonia Refrigeration,

will address ammonia loss from commercial and industrial refrigeration

systems.

Plenary– Questions & Answers

5:30 pm Poster Presentations & Reception

Light food and a cash bar will be set up on the 1st level of the Baycenter.

Posters will be on display around the area, and presenters will be available

for discussions.

C-2
November 16, 2000

8:00 am Continental breakfast

8:30 am Summary of Day 1 and Charge to Breakout Groups

9:00 am Breakout Session

Participants will be pre-assigned to one of 7 breakout groups. Each group

will identify important gaps in our understanding, identify priorities, and

identify opportunities for addressing these gaps.

10:30 am Refreshment Break

10:45 am Session III – Managing Ammonia

Moderator: Ann Swanson, Executive Director, Chesapeake Bay

Commission.

Dr. Jan Willem Erisman, Head of the Department of Air Quality and

Technology, Netherlands Energy Research Foundation, will present an

assessment of the actions taken in the Netherlands to manage ammonia

emissions and the lessons learned.

Ms. Robin Smith, Deputy Secretary, North Carolina Dept. of Environment

and Natural Resources, will present the course of action currently being

pursued by the State of North Carolina to control ammonia emissions.

Dr. Alexander Farrell, Dept. of Engineering and Public Policy, Carnegie

Mellon University, will address the role and use of assessments as the link

between science and policy development.

Plenary– Questions & Answers

12:15 pm Working Lunch

Participants will be pre-assigned to one of the round table discussion groups.

Each group will address the following questions:

What management initiatives can or should we take to manage ammonia

losses? What, if any, are the barriers to implementing these initiatives?

1:30 pm Wrap-up

A diverse panel will share their perspectives of the salient points of the

workshop. One or more of the facilitators will conclude with a summary of

the group breakouts and round table discussions.

Panel:

Doug Marvil, Perdue Inc.

Bill Matuszeski, EPA Chesapeake Bay Program

Patricio Silva, Natural Resources Defense Council

David Johnson, Virginia Dept. of Environmental Quality

3:15 pm Adjournment - Susan Wierman

C-3
Bill Achor

Wenger’s Feed Mills

101 W. Harrisburg Avenue

Rheems, PA 17570

Phone: (800) 692-6008

bachor@wengerfeeds.com

John Ackermann

US EPA- Region 4

61 Forsyth Street, SW

Atlanta, Ga 30303

Phone: (404) 562-9063

ackermann.john@epamail.epa.gov

Carroll (Dick) Amerman

US Department of Agriculture

Agricultural Research Service

5601 Sunnyside Avenue

Beltsville, MD 20705

Phone: (301) 504-4634

Fax: (301) 504-6231

cra@ars.usda.gov

Kent Anderson

International Institute of Ammonia

Refrigeration

1110 North Glebe road, Suite 250

Arlington, VA 22201

Phone: (703)312-4200

Fax: (703)312-0065

kent_anderson@iiar.org

Ben Apelberg

Abt Associates

400 Montgomery Lane, Suite 6000

Bethesda, MD 20814

Phone: (301) 913-0528

ben_apelberg@abtassoc.com

Robert Armstrong

International Institute of Ammonia

Refrigeration

1110 North Glebe Road, Suite 6000

Arlington, VA 22201

Phone: (703) 312-4200

Fax: (703) 312-0065

robert_armstrong@iiar.org

Richard Artz

NOAA Air Resources Laboratory

1315 East-West Hwy.

Silver Spring, MD 20910

Phone: (301) 713-0972

richard.artz@noaa.gov

Tim Barrick

State Conservation Commission

2301 North Cameron Street

Harrisburg, PA 17110

Phone: (717) 705-1688

Tbarrick@state.pa.us

William Battye

EC/R Inc.

1128 Weaver Dairy Road, Suite AA1

Chapel Hill, NC 27514

Phone: (919) 933-9501 X228

battye.bill@ecrweb.com

Mark Biddle

Delaware DNREC

Watershed Assessment Section

820 Silver Lake Blvd., Suite 220

Dover, DE 19904

Phone: (302)739-4590

Fax: (302) 739-6140

mbiddle@state.de.us

Carin Bisland

US EPA

Chesapeake Bay Program Office

410 Severn Ave., Suite 109

Annapolis, MD 21403

Phone: (410) 267-5732

Fax (410) 267-5777

bisland.carin@epa.gov

Terry Black

PA Dept. of Env. Protection

Rachel Carson State Office Bldg.

400 Market Street, P.O. Box 8468

Harrisburg, PA 17105

Phone: (717) 787-2030

Fax: (717) 772-2303

tblack@state.pa.us

John Karl Bohlke

US Geological Survey

431 National Center

Reston, VA 20192

Phone: (703) 648-6325

jkbohlke@usgs.gov

Leonard S. Bull

NC State University

Animal & Poultry Waste Mgmt. Ctr

Box 7608

Raleigh, NC 27695

Phone: (919) 515-6836

Fax: (919) 515-1762

leonard_bull@ncsu.edu

Arthur Butt

VA Dept.of Environmental Quality

Chesapeake Bay Program

P. O. Box 10009

Richmond, VA 23240

Phone: (804) 698-4314

ajbutt@deq.state.va.us

Bob Campbell

National Park Service

Chesapeake Bay Program Office

410 Severn Ave., Suite 109

Annapolis, MD 21403

Phone: (410) 267-5747

Fax: (410) 267-5777

campbell.bob@epa.gov

Lynette Cardoch

US EPA

Atmospheric Protection Branch

86 TW Alexander Drive, MD-63

Durham, NC 27711

Phone: (919) 541-0809

Fax: (919) 541-7885

cardoch.lynette@epa.gov

JD Chauhan

North Carolina DENR

Division of Air Quality

1641 Mail Service Center

Raleigh, NC 27699

Phone: (919) 715-2968

jatinderpaul.chauhan@ncmail.net

Appendix D—Workshop Participants

D-1
Ruth Chemerys

US EPA

Office of Water

1200 Pennsylvania Ave., 4503F

Washington, DC 20460

Phone: (202) 260-9038

chemerys.ruth@epa.gov

Kevin Civerolo

New York DEC

50 Wolf Road, Room 198

Albany, NY 12233

Phone: (518) 457-3200

Fax: (518) 485-8410

kevin@air.dec.state.ny.us

James Collier

DC Bureau of Environmental

Quality

51 N Street, NE

Washington, DC 20002

Phone: (202) 535-1660

james.collier@dc.gov

Ellis Cowling

NC State University

College of Forest Resources

1509 Varsity Drive

Raleigh, NC 27606

Phone: (919) 515-7564

Fax: (919) 515-1700

ellis_cowling@ncsu.edu

Lynn Dancy

Chesapeake Bay Foundation

614 N. Front Street, Suite G

Harrisburg, PA 17101

Phone: (717) 234-5550

Fax: (717) 234-9632

ldancy@dbf.org

Cliff Davidson

Carnegie Mellon University

Pittsburgh, PA 15213

Phone: (412) 268-2951

Fax: (412) 218-7813

cliff@cmu.edu

Robin Dennis

US EPA/NOAA

Atmospheric Modeling Division,

MD-80

Research Triangle Park, NC 27711

Phone: (919) 541-2870

Fax: (919) 541-1379

rdennis@hpcc.epa.gov

Al Deramo

Delaware DNREC

Air Quality Management

156 South State Street

Dover, DE 19901

Phone: (302) 739-4791

Fax: (302) 739-3106

aderamo@dnrec.state.de.us

Frank Divita

EH Pechan

5528-B Hempstead Way

Springfield, VA 22151

Phone: (703) 813-6700 X164

frankd@pechan.com

Linda Eichmiller

ASIWPCA

750 First Street, NE , Suite 1010

Washington, DC 20002

Phone: (202)898-0905

l.eichmiller@asiwpac.org

George (Leif) Eriksen

University of Maryland, Coop. Ext.

18330 Keedysville Road

Keedysville, MD 21756

Phone: (301)432-2767 X312

geriksen@wam.umd.edu

Jan Willem Erisman

Dept. of Integrated Assessment

Energy Research Center of the

Netherlands, ECN.

1755 ZG Petten

PO Box 1

Netherlands

erisman@ecn.nl

Diana Esher

US Environmental Protection

Agency

Chesapeake Bay Program Office

1650 Arch Street

Philadelphia, PA 19103-2029

Phone: (215) 814-2706

Fax: (215) 814-2201

esher.diana@epa.gov

Alex Farrell

Carnegie Mellon University

Dept. of Engineering & Public

Policy

Pittsburgh, PA 15213

Phone: (412) 268-3756

Fax: (412) 268-3757

afarrell@andrew.cmu.edu

Tom Feeley

US Dept. of Energy

National Energy Technology Lab.

P.O. Box 10940

Pittsburgh, PA 15236

Phone: (412) 386-6134

Fax: (412) 386-5917

feeley@netl.doe.gov

James Ferguson

University of Pennsylvania

New Bolten Center

382 West Street Road

Kennett Square, PA 19348

Phone: (610) 444-5800 X2338

Fax: (610) 925-8123

ferguson@caph2.nbc.upenn.edu

Don Fiesta

PA Department of Environmental

Protection

P.O. Box 8465

Harrisburg, PA 17105

Phone: (717)772-5644

fiesta.donald@dep.state.pa.us

James Galloway

Department of Environmental

Sciences

University of Virginia

Clark Hall

Charlottesville, VA 22903

Phone: (804) 924-0561

jng@virginia.edu

Alice Gilliland

EPA NERL/NOAA ARL

Atmospheric Modeling Division

MD-80

Research Triangle Park, NC 27711

Phone: (919) 541-0347

Fax: (919) 541-1379

gilliland.alice@epa.gov

Kathryn Glasgow

Mid-Atlantic Reg. Air Management

Association

711 West 40th Street, Suite 318

Baltimore, MD 21211

Phone: (410) 467-0170

Fax: (410) 467-1737

kglasgow@marama.org

D-2
Doug Goodlander

State Conservation Commission

2301 N. Cameron Street, Room 407

Harrisburg, PA 17110

Phone: (717) 705-3895

dgoodlande@state.pa.us

Holly Greening

Tampa Bay Estuary Program

100 8th Avenue, SE

St. Petersburg, FL 33701

Phone: (727) 893-2765

hgreening@tbep.org

Jerry Griswold

USDA, Natural Resources

Conservation Service

Chesapeake Bay Program Office

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-5754

Fax: (410) 267-5777

griswold.jerry@epa.gov

Christopher Gross

USDA, Natural Resources

Conservation Service

339 Busch’s Frontage Road, Ste. 301

Annapolis, MD 21301

Phone: (410) 757-0861 X321

Fax: (410) 757-0687

cgross@md.nrcs.usda.gov

Rick Haeuber

US EPA

Clean Air Market Division

1200 Pennsylvania Avenue, NW

Ariel Rios Building (6204J)

Washington, DC 20460

Phone: (202) 564-2667

haeuber.richard@epa.gov

Brad Hendrickson

University of North Carolina

Institute of Marine Science

3431 Arendell Street

Morehead City, NC 28557

Phone: (252) 726-6841 X134

Bruce Hicks

NOAA - Air Resources Laboratory

1315 East-West Hwy., Room 3151

Silver Spring, MD 20910

Phone: (301) 713-0684

bruce.hicks@noaa.gov

Patti Holowecky

Battelle

505 King Avenue

Columbus, OH 43201

Phone: (614) 424-7885

Fax: (614) 424-3638

holoweckyp@battelle.org

Larry Jacobson

University of Minnesota

210 BAE Building

1390 Eckles Avenue

St. Paul, MN 55108

Phone: (612) 625-8288

Fax: (612) 624-3005

jacob007@tc.umn.edu

David Jellerson

Cargill Fertilizer, Inc

8813 US Highway 41, South

Riverview, FL 33569

Phone: (813) 671-6297

Fax: (813) 671-6149

david_jellerson@cargill.com

David Johnson

VA Department of Environmental

Quality

629 E. Main Street

Richmond, VA 23219

Phone: (804)698-4020

dajohnson@deq.state.va.us

Darrell Joseph

Battelle

505 King Avenue

Columbus, OH 43201

Phone: (614) 424-3645

Fax: (614) 424-3638

josephd@battelle.org

Preston Keller

Tyson Foods, Inc.

P. O. Box 2020 CPO32

Springdale, AR 72765

Phone: (501) 290-4713

kellerp@tyson.com

Robert L. Kellogg

USDA

Natural Resources Conservation

Service

904 Shady Drive

Vienna, VA 22180

Phone: (202) 690-0341

robert.kellogg@usda.gov

Maggie Kerchner

NOAA, Air Resources Laboratory

Chesapeake Bay Program Office

410 Severn Avenue, Suite 107A

Annapolis, MD 21403

Phone: (410) 267-5670

Fax: (410) 267-5666

margaret.kerchner@noaa.gov

Carol Kinsley

Delmarva Farmer

P. O. Box 2026

Easton, MD 21601

Phone: (410) 822-3965

kinsley@americanfarm.com

Rao Kona

PA Department of Environmental

Protection

400 Market Street

Harrisburg, PA 17105

Phone: (717) 787-3965

rkona@state.pa.us

Craig Kovach

CF Industries, Inc.

P. O. Box 1480

Bartow, FL 33831

Phone: (863) 533-3181

ckovach@cfifl.com

David Krask

DC Bureau of Environmental

Quality

Air Quality Division

51 N Street, NE

Washington, DC 20002

Phone: (202) 535-2263

david.krask@dc.gov

Andrea Kreiner

Delaware DNREC

89 Kings Highway

Dover, DE 19901

Phone: (302) 739-3822

Fax: (302) 739-6242

akreiner@dnrec.state.de.us

Randy Larsen

University of Maryland

Chesapeake Biological Laboratory

P. O. Box 38

1 Williams Street

Solomons, MD 20688

Phone: (410) 326-7204

larsen@cbl.umces.edu

D-3
Louise Lawrence

Maryland Department of Agriculture

50 Harry Truman Pkwy

Annapolis, MD 21401

Phone: (410) 841-5863

lawrenl@mda.state.md.us

Alan Lefcourt

USDA, Agricultural Res. Service

B163F Powder Mill Road

Beltsville, MD 20705

Phone: (301) 504-8451

alefcourt@anri.barc.usda.gov

Lewis Linker

US EPA

Chesapeake Bay Program Office

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-5741

Fax: (410) 267-5777

linker.lewis@epa.gov

Denis Lohman

US EPA- Region 3

Air Protection Division (3AP00)

1650 Arch Street

Philadelphia, PA 19103-2029

Phone: (215) 814-2192

Fax: (215) 814-2124

lohman.denny@epa.gov

Carl Luebben

Shenandoah Valley

Soil & Water Conservation District

1934 Deyerle Avenue, Suite B

Harrisonburg, VA 22801

Phone: (540) 332-2853

Winston Luke

NOAA, Air Resources Laboratory

1315 East-West Highway

Silver Spring, MD 20910

Phone: (301) 713-0971

Fax: (301) 713-0119

winston.luke@noaa.gov

Alice R. Lutrey

Mid-Atlantic Regional Air

Management Association

711 West 40th Street

Suite 318

Baltimore, MD 21211

Phone: (410) 467-0170

Fax: (410) 467-1737

alutrey@marama.org

Russell L. Mader, Jr.

USDA, NRCS

Chesapeake Bay Program Office

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-5752

Fax: (410) 267-5777

mader.russ@epa.gov

Mohammed Majeed

Delaware DNREC

Air Quality Management

156 South State Street

Dover, DE 19901

Phone: (302) 739-4791

Fax: (302) 739-3106

mmajeed@state.de.us

George (Bud) Malone

University of Delaware

Animal & Food Science

Research & Education Center

RD 6, Box 48

Georgetown, DE 19947

Phone: (302) 856-7303

malone@udel.edu

Darrell Ray Marshall

VA Dept. of Conservation &

Recreation

3800 Stillman Parkway

Suite 102

Richmond, VA 23233

Phone: (804)527-4219

dmarshall@dcr.state.va.us

Debora C. Martin

US EPA- Office of Water

MD 4504F

1200 Pennsylvania Avenue, NW

Washington, DC 20460

Phone: (202) 260-2729

martin.debora@epa.gov

Doug Marvil

Perdue Farms, Inc.

P. O. Box 1537

Salisbury, MD 21802

Phone: (410) 860-4185

doug.marvil@perdue.com

Tim Maupin

Rocco, Inc.

1 Kratler Road

Harrisonburg, VA 22802

Phone: (540) 568-1482

tmaupin@rocco.com

Don McCubbin

Abt Associates, Inc.

4800 Montgomery Lane

Suite 600

Bethesda, MD 20814

Phone: (301) 913-0521

donald_mccubbin@abtassoc.com

Sean McGuire

Maryland Department of Natural

Resources

Tawes State Office Building E-2

Annapolis, MD 21401

Phone: (410) 260-8727

smcquire@dnr.state.md.us

Jack Meisinger

USDA, Agricultural Res. Service

Building 007, Room 205

BARC-West

Beltsville, MD 20705

Phone: (301) 504-5276

jmeising@anri.barc.usda.gov

Joseph Morgan

WV Dept. of Env. Protection

Office of Air Quality

7012 MacCorkle Avenue, SE

Charleston, WV 25304

Phone: (304) 926-3742

Fax: (304) 926-3637

joemorgan@mail.dep.state.wv.us

Scott Mower

University of South Florida

8310 Boxwood Drive

Tampa, FL 33615

Phone: (813) 806-9189

smower@earthlink.net

George Murray

North Carolina DENR

Division of Air Quality

1641 Mail Service Center

Raleigh, NC 27699

Phone: (919) 733-1487

Fax: (919) 733-1812

george.murray@ncmail.net

Mark Nilles

USGS

Box 25046

Denver Federal Center

MS 401

Denver, CO 80225

Phone: (303) 236-1878

manilles@usgds.gov

D-4
J. Richard Nottingham

LE S REC

27664 Nanticoke Road

Salisbury, MD 21801

Phone: (410) 742-1178

jn67@umail.umd.edu

Mike O’Connell

National Park Service

Assateague Island N.S.

Berlin, MD 21811

Phone: (410) 641-1443

mike_oconnell@nps.gov

Hans Paerl

Univ. of North Carolina-Chapel Hill

Institute of Marine Sciences

3431 Arendell Street

Morehead City, NC 28557

Phone: (252) 726-6841 X133

hans_paerl@unc.edu

Jim Parsons

Perdue Farm, Inc.

P. O. Box 1537

Salisbury, MD 21802

Phone: (410) 860-4232

jim.parsons@perdue.com

Scott Patey

Tyson Foods

10129 Old Ocean City Blvd.

Berlin, MD 21811

Phone: (410) 641-0900

Fax: (410) 641-1788

pateys@tyson.com

Kenn Pattison

PA Dept. of Env. Protection

P. O. Box 8465

Harrisburg, PA 17105

Phone: (717) 772-7577

kpattison@state.pa.us

Jesus I. Peralta

CF Industries

1401 Eye Street, NW, Suite 340

Washington, DC 20005

jperalta@cfindustries.com

Russ Perkinson

VA Dept. of Conservation & Rec.

203 Governor Street

Suite 206

Richmond, VA 23219

Phone: (804) 371-0061

rperkinson@dcr.state.va.us

Thomas E. Pierce

US EPA/NOAA ARL, MD-80

Research Triangle Park, NC 27711

Phone: (919) 541-1375

pierce.tom@epa.gov

Noreen D. Poor

University of South Florida

College of Public Health

13201 Bruce B. Downs Blvd.

Tampa, FL 33612

Phone: (813) 974-8144

npoor@hsc.usf.edu

Stephen D. Preston

USGS, Chesapeake Bay Prog. Office

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-9875

spreston@epa.gov

Jonathon Priday

Maryland Dept. of Environment

2500 Broening Highway

Baltimore, MD 21224

Phone: (410) 631-6751

Fax: (410) 631-3202

jpriday@mde.state.md.us

Don Pryor

NOAA/National Ocean Service

1305 East-West Highway

Room 9306

Silver Spring, MD 20910

Phone: (301) 713-3020 X119

don.pryor@noaa.gov

Jim Reeves

USDA, Agricultural Res. Service

Building 163-F, BARC - East

Beltsville, MD 20705

Phone: (301) 504-8294

jreeves@lpsi.barc.usda.gov

Bruce Richards

Center for the Island Bays

467 Highway One

Lewes, DE 19958

Phone: (302) 645-7325

brichard@udel.edu

Megan Roadman

Uof Del, College of Marine Studies

700 Pilottown Road

Lewes, DE 19958

Phone: (302)645-4008

mroadman@UDel.Edu

Wayne Robarge

NC State University

Soil Science Department

Box 7619

Raleigh, NC 27695

Phone: (919) 515-1454

wayne_robarge@ncsu.edu

Mike Rodgers

Georgia Tech

723 Research Drive

Hinman Building, Room 312

Atlanta, GA 30332

Phone: (404) 894-5609

Fax: (404) 894-9223

michael.rodgers@ce.gatech.edu

William R. Rohrer, Jr.

DE Nutrient Mgmt.Program

DE Department of Agriculture

2320 S. DuPont Highway

Dover, DE 19901

Phone: (302) 739-4811

nm@dda.state.de.us

Kurt Roos

US EPA

1200 Pennsylvania Avenue, NW

Washington, DC 20001

Phone: (202) 564-9041

roos.kurt@epa.gov

Kristinia Russell

University of Virginia

Dept. of Env. Services, Clark Hall

Charlottesville, VA 22903

Phone: (804) 924-3938

krissy@virginia.edu

Dan Salkovitz

VA Dept. of Environmental Quality

P. O. Box 10009

Richmond, VA 23240

Phone: (804) 698-4404

Fax: (804) 698-4510

ddsalkovit@deq.state.va.us

James Salvaggio

PA Dept. of Environmental

Protection

P. O. Box 8468

Rachel Carson Building, 12th Floor

Harrisburg, PA 17105

Phone: (717) 787-9702

Fax: (717) 772-3415

jsalvaggio@state.pa.us

D-5
Robert Scarborough

DE DNREC

DE Coastal Programs

89 Kings Highway

Dover, DE 19901

Phone: (302) 739-3436

bscarboroug@state.de.us

Charlotte Schomburg

USDA, Agricultural Res. Service

B-007, Room 214, BARC - West

Beltsville, MD 20705

Phone: (301) 504-6524

schombuc@ba.ars.usda.gov

Jackie Schreiber

Chesapeake Research Consortium

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-5726

Fax: (410) 267-5777

schreiber.jackie@epa.gov

Jaclin Schweigart

Chesapeake Research Consortium

645 Contees Wharf Road

Edgewater, MD 21037

Phone: (410) 798-1283

Janea A. Scott

Environmental Defense

257 Park Avenue South

17th Floor

New York, NY 10010

Phone: (212) 616-1267

jscott@environmentaldefense.org

Joseph Scudlark

U of Del, College of Marine Studies

700 Pilottown Road

Lewes, DE 19958

Phone: (302) 645-4300

scudlark@udel.edu

Ronald R. Sharpe

USDA, Agricultural Res. Service

1420 Experiment Station Road

Watkinsville, GA 30677

Phone: (706)769-5631 X227

rsharpe@arches.uga.edu

Gary Shenk

US EPA Chesapeake Bay Program

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-5745

shenk.gary@epa.gov

John Sherwell

MD Dept. of Natural Resources

Tawes State Office Building, B-3

Annapolis, MD 21401

Phone: (410) 260-8667

Fax: (410) 260-8670

jsherwell@dnr.state.md.us

Ron Siefert

University of Maryland

Chesapeake Biological Laboratory

P. O. Box 38

1 Williams Street

Solomons, MD 20688

Phone: (410) 326-7386

siefert@cbl.umces.edu

Patricio Silva

Natural Resources Defense Council

1200 New York Avenue, NW

Suite 400

Washington, DC 20005

Phone: (202) 289-6868

psilva@nrdc.org

Thomas W. Simpson

University of Maryland

College of Agriculture & Natural

Resources

Symons Hall, Room 1209

College Park, MD 20742

Phone: (301) 405-5696

Fax: (301) 405-2963

ts82@umail.umd.edu

Jim Skillen

The Fertilizer Institute

501 2nd Street, NE

Washington, DC 20002

Phone: (202) 675-8250

jskillen@tfi.org

Robin W. Smith

North Carolina DENR

1601 Mail Service Center

Raleigh, NC 27699

Phone: (919) 715-4141

robin.w.smith@ncmail.net

Christopher Smith

Maryland Department of the

Environment

2500 Broening Highway

Baltimore, MD 21224

Phone: (410) 631-3719

Fax: (410) 631-8050

c.smith@mde.state.md.us

James Southerland

North Carolina DENR

Division of Air Quality

1641 Mail Service Center

Raleigh, NC 27699

Phone: (919) 715-7566

james.southerland@ncmail.net

Helen Stewart

MD Dept. of Natural Resources

Tawes State Office Building, E-2

580 Taylor Avenue

Annapolis, MD 21401

Phone: (410) 260-8783

hstewart@dnr.state.md.us

Ann Pesiri Swanson

Chesapeake Bay Commission

60 West Street, Suite 200

Annapolis, MD 21403

Phone: (410) 263-3420

apswanson@qwest.net

Jeff Sweeney

University of Maryland

Chesapeake Bay Program Office

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-9844

Fax: (410) 267-5777

sweeney.jeff@epa.gov

Ram Tangirala

Metro Washington COG

777 North Capital Street, NE

Washington, DC 20002

Phone: (202) 962-3244

rtangirala@mwcog.org

Alan W. Taylor

Chesapeake Research Consortium

7302 Baylor Avenue

College Park, MD 20740

Phone: (301) 441-1819

rolyatnala@hotemail.com

John A. Thomas

Delaware DNREC

Air Quality Management

715 Grantham Lane

New Castle, DE 19720

Phone: (302) 323-4542

Fax: (302) 323-4598

jthomas@state.de.us

D-6
Julie Thomas

US EPA, Chesapeake Bay Program

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-9848

Fax: (410) 267-5777

thomas.julie@epa.gov

Tamera Thompson

VA Dept. of Environmental Quality

629 East Main Street

P. O. Box 10009

Richmond, VA 23240

Phone: (804) 698-4502

Fax: (804) 698-4510

tmthompson@deq.state.va.us

Julie Trask

Chesapeake Research Consortium

Chesapeake Bay Program Office

410 Severn Avenue, Suite 109

Annapolis, MD 21403

Phone: (410) 267-5753

Fax: (410) 267-5777

trask.julie@epa.gov

Naomi Tsurumi

US EPA

OAQPS, MD-13

Research Triangle Park, NC 27711

Phone: (919) 541-2688

tsurumi.naomi@epa.gov

William Ullman

University of Delaware

Graduate College of Marine Studies

700 Pilottown Road

Lewes, DE 19958

Phone: (302) 645-4302

ullman@udel.edu

Randy Waite

US EPA- OAQPS, MD-13

Research Triangle Park, NC 27711

Phone: (919) 541-5447

waite.randy@epa.gov

George Weber

Honeywell, Inc.

905 E. Randolph Road

Hopewell, VA 23860

Phone: (804) 541-5438

george.weber@honeywell.com

Steven Weber

Maryland Farm Bureau, Inc.

8930 Liberty Road

Randallstown, MD 21133

Phone: (410) 661-9085

Melanie Wertz

Chesapeake Bay Foundation

614 North Front Street, Suite G

Harrisburg, PA 17101

Phone: (717) 234-5550

mwertz@cbf.org

David Whitall

Hubbard Brook Research Foundation

Syracuse University

Phone: (315) 443-4121

drwhital@mailbox.syr.edu

Susan Wierman

Mid-Atlantic Regional Air

ManagementAssociation

711 West 40th Street, Suite 318

Baltimore, MD 21211

Phone: (410) 467-0170

Fax: (410) 467-1737

swierman@marama.org

D-7