^rf*
I?--
Atmosphere
in Motion
Results from the
National Deposition
Monitoring Networks
2005 Atlas
United States
Environmental Protection
Agency
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Contents
What is the Atlas?
'; The Earth's Atmosphere
Status &Trends in Temperature
Precipitation
What is Atmospheric Deposition?
•' ' Long-term Monitoring Partnerships
;, Regional Monitoring Results
Sulfur Deposition - Focus on Surface Waters
Nitrogen Deposition - Focus on the Coast
;, Ozone Exposure - Focus on Forest Health
;' > Methods of Mapping Status & Trends
'• /, CASTNET Status & Trends in
Regional Air Quality Concentrations
'• /' NADP/NTN Status & Trends in Wet Deposition
"j -;• CASTNET & NADP/NTN Status & Trends
in Total Deposition
•-C' CASTNET & NADP/NTN Monitoring Locations
•-,' '/ Glossary
Online Data, Information and Resources
-,'.'.,- References
This document is published annually.
Public inquiries and copies may be obtained from:
Clean Air Markets Division
Office of Air and Radiation
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW(6204J)
Washington, D.C. 20460
EPA430-R-05-007
www.epa.gov/airmarkets
October 2 005
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What is
he At as?
Tracking Environmental Change
Welcome to the inaugural edition of the annual
atlas, Atmosphere in Motion: Results from the
National Deposition Monitoring Networks. The
maps and data displays presented here show
changes in air quality and atmospheric deposi-
tion over time and space as air quality manage-
ment evolved from 1990 to the present under
the Clean Air Act.
The purpose of the atlas is to track the
environmental results of efforts to
control emissions of sulfur and
nitrogen under the Acid
Rain Program and other
programs designed to
reduce emissions
over broad, re-
gional scales and
to present this
information
in an easily understood format: maps. Future
versions of the atlas will include information
on various ecological responses to changes in
deposition, updates on mercury deposition,
and revised status and trend information as new
monitoring data become available.
as
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2
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The Importance of
Long-term Monitoring
National, long-term environmental monitoring
networks are important tools for understanding
how changes in emissions affect environmental
quality over time and space. These networks are
integral components of the "chain of account-
ability" used to characterize the relationships
between emission sources and environ-
mental effects. Originally devel-
oped for understanding acidi-
fication in the Northeast,
the networks have since
expanded to provide
invaluable infor-
mation relevant
to a variety
of environ-
mental
effects—
such as eutrophication, nitrogen saturation,
ozone bio-injuries, and mercury contamina-
tion—over a range of scales. The networks offer
more than two decades of data based on con-
sistent, standard field and lab procedures and
quality-assured practices.
Since changes in the atmosphere can hap-
pen very slowly, and trends are often obscured
by the wide variability of measurements and
regional climate, many years of continuous
and consistent data are necessary to discern
trends. Long-term monitoring networks are thus
especially important for characterizing deposi-
tion levels and identifying relationships among
emissions, atmospheric loadings, and effects on
human health and ecosystems. The Clean Air
Status and Trends Network (CASTNET) and the
National Atmospheric Deposition Program/Na-
tional Trends Network (NADP/NTN) are two
routine, long-term networks that EPA and its
partners use to track geographic patterns and
temporal trends in regional air quality and at-
mospheric deposition in response to changes in
emissions of sulfur dioxide (SO2) and nitrogen
oxides (NOX). These networks provide a vital
performance measure that is useful in assess-
ing and reporting the effectiveness of current
regulatory programs to improve air quality and
reduce atmospheric inputs to ecosystems. They
also provide the data needed to inform develop-
ment of new policy initiatives.
3
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The Earth's
Atmosphere
The atmosphere is an envelope of several dif-
ferent layers surrounding the Earth, each with
variable temperature and pressure. The lowest
layer of the atmosphere, called the troposphere, is
where weather happens. The troposphere starts at
the Earth's surface and extends 5-9 miles (8-14.5
km) high. Chemical cycles in the troposphere,
along with pollutants of human and natural ori-
gin, can cause changes to the quality of this layer
and to the stratosphere, the atmosphere's second
layer. Changes to these layers can occur over
local, regional, and global scales. The movement
of air within the troposphere is complex. Ground-
level air may move one way and air above it may
move in the opposite direction due to differences
in air pressure and variable local winds. As a
result, air pollution will travel in different
directions depending on its height in
the troposphere.
Air pollution is strongly influenced by tempera-
ture and precipitation. Temperature, along with
sunlight, plays an important role in the chemi-
cal reactions that occur in the atmosphere to
form ground-level ozone and other pollutants.
Precipitation is important in determining the
magnitude, rate, and location at which atmo-
spheric pollutants are deposited on the Earth's
surface.
Layers of the Atmosphere
Source: EPA
4
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Status & Trends
in Temperature
Temperature plays an important role in atmo-
spheric chemical reactions forming ground-
level ozone. Temperature also affects the
transformation rates of SO2 to sulfate and
NOX to nitric acid.
According to the National Oceanic and At-
mospheric Administration's (NOAA) Climatic
Data Center, 2004 was the 24th warmest year
on record in the contiguous United States, with
a nationally averaged annual temperature of
53.5°F (11.9°C). This is 0.7° F (0.4° C) above the
1895-2003 mean. Three states—Washington,
Oregon, and Idaho—were much warmer than
their mean annual temperature. Thirty-three
states were above average, and 11 states were
near average. Only Maine averaged below the
long-term mean. Spring temperatures across the
United States were above average in all states
except Florida, which was near normal for the
season. Fall was warm across much of the mid-
section of the country, but the West remained
January-December 2004 State Ranks: Temperature
1 = Coldest
110 = Warmest
Record Coldest
Much Below Normal
Below Normal
Near Normal
Above Normal
Much Above Normal
Record Warmest
Source: National Climatic Data Center/NESDIS/NOAA
5
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near average. Winter began relatively warm
for states from the Upper Midwest to the
East Coast.
According to NOAA scientists, the last five
five-year periods (2000-2004, 1 999-2003,
1998-2002, 1997-2001, 1996-2000), were
the warmest five-year periods in the last 110
years of national records. The sixth warmest
five-year period was in the 1930s (1930-34),
when the western United States was suffering
from an extended drought coupled with anoma-
lous warmth. The warmest year on record for
the United States was 1998, where the record
warmth was concentrated in the Northeast.
National (Contiguous U.S.) Temperature 1895-2004
56.0
55.0
Yearly Values
Filtered Values
Long-Term Mean
- 13.0
12.0
- 11.0
o
£
CD
cf
- 10.0
49.0
1900
1920
1940 1960
Year
1980
2000
Source: National Climatic Data Center/NESDIS/NOAA
6
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Precipitation
Precipitation affects the delivery of airborne pol-
lutants to an ecosystem. Wet deposition (rain,
snow) of acids, toxics, and other pollutants can
be the primary pathway of exposure for ecosys-
tems in areas that receive significant quantities
of precipitation.
In 2004, the West experienced persistent mod-
erate dryness, while the South and East were
wetter than average. Thirty-four states were
wetter than average from January-December,
including 10 states that were considerably
above average. Texas had its third wettest year
on record, and portions of the Mid-Atlantic,
the Tennessee Valley, and the Ohio Valley also
experienced near-record precipitation. Four
states—Maine, Washington, Montana, and
Wyoming—were drier than average. Nationally,
2004 ranked as the sixth-wettest year on record.
January-December 2004 State Ranks: Precipitation
1 = Driest
110 = Wettest
Source: National Climatic Data Center/NESDIS/NOAA
Record Driest
Much Below Normal
Below Normal
Near Normal
Above Normal
Much Above Normal
Record Wettest
7
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mmi^m
The landfall of multiple tropical storms and
hurricanes in 2004 contributed to the moisture
in the South and East, while less-than-aver-
age rain- and snowfall were measured
in parts of the West and the far North-
east. The limited rain in the West,
especially during spring months,
exacerbated drought conditions
that have been persistent for up
to five years in some loca-
tions. Short-term drought
relief came to the West,
especially the Southwest
during the fall, with
above-average rain fol-
lowed by early snow.
However, persistent
drought conditions
remain across much
of the western United
States.
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What is
Atmospheric Deposition?
Atmospheric Deposition Processes
Atmospheric deposition is the process whereby
airborne particles and gases are removed from
the atmosphere and deposited on the Earth's
surface.
Wet deposition is defined as the portion of
atmospheric deposition contained in precipita-
tion. Dry deposition is the fraction deposited in
dry weather through such processes as settling,
impaction, and adsorption. The factors that
influence dry deposition include whether the
substance is in gaseous or particulate form, the
solubility of the species in water, the amount of
precipitation in the region, and the terrain and
type of surface cover.
Acidic compounds in the atmosphere can lead to
acid deposition. Acidic wet deposition is called
The Formation of Acid Deposition
so
Dry deposition
Source: EPA
9
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acid precipitation or, more commonly, acid rain.
Acidity in precipitation is measured by collect-
ing samples of rain and measuring its pH, which
is lower when acidic compounds are present.
"Clean" or unpolluted rain has a slightly acidic
pH of 5.6, because carbon dioxide and water
in the air react together to form carbonic acid,
a weak acid. Throughout much of the eastern
United States, pH in rain is less than 4.5.
Acid deposition occurs when SO2, NOX, and
ammonia (NH3) in the atmosphere react to form
sulfuric acid (H2SO4), nitric acid (HNO3), and
ammonium (NH4). These pollutants originate
from natural sources (such as forest fires and
volcanoes) as well as anthropogenic ones (such
as the burning of fossil fuels in power plants
and motor vehicles, and agricultural practices).
They are transported from the atmosphere and
deposited to the Earth's surface in particles,
gases, rain, snow, clouds, and fog. Once these
compounds enter an ecosystem, they can
acidify soil and surface waters, leading to
"t\. a cascade of adverse ecological ef-
^££11 fects. Low pH in lakes and streams
*3^W^s harms fish and other aquatic
™ organisms, alters forest soils,
degrades the growing con-
ditions for some tree spe-
cies, and affects other
vegetation.
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Long-term
Monitoring Partnerships
The Clean Air Status and Trends Network
(CASTNET) and the National Atmospheric
Deposition Program/National Trends Network
(NADP/NTN) are complementary long-term
monitoring networks that provide the informa-
tion necessary to track temporal and spatial
trends in regional air quality and atmospheric
deposition.
CASTNET provides atmospheric data on the
dry deposition component of total acid deposi-
tion, ground-level ozone, and other forms of
atmospheric pollution. Established in 1987,
CASTNET now consists of over 80 sites across
the United States. EPAs Office of Air and Radia-
tion operates most of the monitoring stations;
the National Park Service funds and operates
National Deposition Monitoring Networks
Source: EPA
11
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approximately 30 stations in cooperation with
EPA. Many CASTNET sites are approaching
a continuous 20-year data record, reflecting
EPA's commitment to long-term environmen-
tal monitoring.
NADP/NTN is a nationwide, long-term net-
work monitoring the chemistry of precipita-
tion. The network is a cooperative effort in-
volving many groups, including the State
Agricultural Experiment Stations, U.S. Geologi-
cal Survey, U.S. Department of Agriculture,
EPA, NPS, NOAA, and other governmental and
private entities. The NADP/NTN has grown
from 22 stations at the end of 1 978 to more
than 250 sites spanning the continental United
States, Alaska, Puerto Rico, and the Virgin
Islands.
The monitoring sites of both CASTNET and
NADP/NTN are located to represent ma-
jor physiographic, agricultural, aquatic, and
forested areas within each cooperating state,
region, or ecoregion.
Wherever possible, monitoring sites are
co-located with other monitoring and
research programs to optimize existing
monitoring resources and help scientists
capture a wider variety of data from a given
location. They also are located using criteria to
minimize impacts from local emission sources,
typically in areas where urban influences are
minimal. In effect, these networks provide
regionally representative data. Each network
offers a rigorous quality assurance program,
including consistent, standardized and trans-
parent field and lab procedures that as-
sure the comparability of data
across network sites.
12
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CASTNET & NADP/NTN
Measurements
Scientists and policy analysts use data from
CASTNET and NADP/NTN to monitor long-
term trends in atmospheric pollutant concen-
trations and precipitation chemistry. They also
use the data to study environmental effects,
particularly those caused by regional
sources of emissions for which
long-range transport
plays an important
role.
Each CASTNET dry deposition station mea-
sures weekly average atmospheric concentra-
tions of sulfate (SO4), nitrate (NO3), NH4/ SO2/
and nitric acid (HNO3); hourly concentrations
of ambient ozone levels; and meteorological
conditions required for calculating dry deposi-
tion rates. Dry deposition rates are calculated
inferentially using atmospheric concentrations,
meteorological data, and information on land
use, vegetation, and surface conditions.
Each NADP/NTN site measures sulfate,
nitrate, hydrogen ion (a measure of acid-
ity), ammonium, chloride, and base cations
(calcium, magnesium, and potassium). To
ensure comparability of results, laboratory
analyses for all samples are conducted by
the NADP's Central Analytical Lab at the Il-
linois State Water Survey. A relatively new
sub-network of the NADP, the Mercury De-
position Network, measures total mercury in
precipitation at over 80 sites nationwide.
For more information on NADP, visit http://
nadp.sws.uiuc.edu/, and for CASTNET visit
http://www.epa.gov/castnet.
13
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Co-located Instrumentation at a CASTNET Monitoring
Station Grand Canyon National Park (GRC474),
Coconino County, Arizona
Source: CASTNET
14
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Regional
Monitoring Results
Ambient Concentrations, Wet
Concentrations, and Wet Deposition
One measure of the effectiveness of emission
control programs is whether sustained reduc-
tions in atmospheric deposition are occurring
across broad areas of the country. Long-term
monitoring data from CASTNET and NADP/
NTN show the geographic patterns and tempo-
ral trends in regional air quality and atmospher-
ic deposition. In the table below, three-year
mean annual concentrations and deposition of
sulfur and nitrogen compounds are compared
from 1989 through 1991 and 2002 through
2004. From 1989 through 1991, the highest
levels of wet sulfate deposition in the East were
Regional Changes in Air Quality and Acid Deposition, 1989-2004
Measurement
Wet sulfate deposition kg/ha
Wet sulfate concentration mg/L
Ambient sulfur dioxide
concentration
Ambient sulfate concentration
Wet inorganic k -
nitrogen deposition &
Wet nitrate concentration
Ambient nitrate concentration ng/m3
Total ambient nitrate
concentration
Region
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Mid-Atlantic
Midwest
Northeast
Southeast
Average*
1989-1991 2002-2004
20
16
14
15
1.6
1.5
1.2
1.0
7.9
5.7
3.1
3.2
13
10
6.8
5.2
6.4
5.6
3.9
5.4
5.9
6.0
5.3
4.3
3.5
4.0
2.0
2.2
5.5
5.7
4.5
4.3
1.1
1.3
1.0
0.7
0.9
1.8
0.5
0.7
2.9
3.5
1.8
2.0
* Measurement data are reported as two significant digits.
** Percent change is estimated from raw measurement data, not rounded; some of the
measurement data used to calculate percentages may be at or below detection limits.
Source: CASTNET and NADP/NTN
Percent
Change**
-24
-32
-36
-19
-37
-46
-54
-39
-27
-33
-33
-26
-8
-4
-16
0
27
14
Air Quality and Acid Deposition Regions
15
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observed in parts of the Northeast, in the Mid-
Atlantic near western Pennsylvania, and along
the Ohio River Valley (see map on page 35).
Since 1991, wet sulfate deposition has decreased
significantly, with average levels in the eastern
U.S. decreasing 36 percent in the Northeast, 24
percent in the Mid-Atlantic, and 32 percent in the
Midwest. Like wet sulfate deposition, monitoring
data from CASTNET show that ambient sulfur
dioxide and ambient sulfate concentrations
decreased throughout the eastern United
States over the past decade, by an average
of 30-40 percent. The more than 50 per-
cent reduction in sulfur dioxide concen-
trations in the Northeast is particularly
noteworthy over this time period.
- In contrast to the reduction of sulfur
levels, reductions in the nitrogen
deposition recorded since the early
1990's have been less dramatic.
Inorganic nitrogen deposition
decreased modestly in the Mid-
Atlantic and Northeast (averaging
8-1 6 percent), but remained virtu-
ally unchanged in other regions.
Total ambient nitrate concentrations
(nitric acid + particulate nitrate), an
indicator of NOX emissions changes,
also decreased modestly, particularly
in the Mid-Atlantic (by an average of
15 percent), and in the Midwest (by an
average of 13 percent). Other regions
have not shown much change.
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Sulfur Deposition
Focus on Surface Waters
Impacts to Acid-Sensitive
Surface Waters
The acidification of surface waters results from
direct deposition of acidic compounds from the
atmosphere as well as from indirect pathways.
The impact of acidic compounds on ecosys-
tems depends on the chemical properties of the
system: some bodies of waters are better able
than others to neutralize acidic inputs, a char-
acteristic known as acid neutralizing capacity
(ANC). However, even some surface waters
with high ANC are unable to buffer episodic
spikes in acidic inputs caused by runoff from
melting snow or heavy downpours. The regions
highlighted below are sensitive to acid deposi-
tion and contain many lakes and streams with
low ANC and high levels of acidity. Despite
substantial emissions reductions over the last 20
years, high levels of sulfur and nitrogen deposi-
tion still enter acid-sensitive lakes and streams,
leading to high levels of acidity.
Wet Sulfate Deposition, 2002-2004
Source: EPA: OAR/OAP/CAMD
17
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Nitrogen Deposition
Focus on the Coast
Impacts to Coastal Ecosystems
Much of the nitrogen entering coastal and
estuarine ecosystems along the eastern United
States originates from atmospheric sources. The
over-enrichment of these aquatic systems by
nutrients such as nitrogen can lead to eutrophi-
cation. Eutrophication is a process whereby a
body of water becomes "over-fertilized" with
nutrients that stimulate excessive plant growth
(e.g., algae and weeds). This enhanced plant
growth, often called an algal bloom, reduces
dissolved oxygen in the water when dead plant
material decomposes, causing other organisms
to die. According to NOAAs National Estuarine
Eutrophication Assessment, 44 estuaries (repre-
senting 65 percent of the estuary surface area
assessed) showed symptoms of being highly
eutrophic. Most of these estuaries are located in
the Mid-Atlantic and Gulf of Mexico regions.
Wet Nitrate Deposition, 2002-2004
Source: EPA: OAR/OAP/CAMD
18
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Ozone Concentrations
Focus on Forest Health
Ozone Formation and Effects
Ground level ozone is an air pollutant in the low-
er atmosphere, formed from reactions of volatile
organic compounds (VOCs) and nitrogen oxides
in the presence of sunlight. Emissions from auto-
mobile engines and industrial processes produce
most of the compounds that result in ozone. It is
a major component of urban smog. The airborne
transport of ozone to remote forested areas has
led to increasing concern about how this pollutant
influences the health of forests. Possible impacts
of ozone on trees and other forest plants include
reduced growth, reduced seed production, and
increased susceptibility to insects and disease.
Long-term ozone stress may lead to changes in
forest species composition and biodiversity.
Ozone injury to Yellow Poplar
(Liriodendron tulipirfera L)
How do scientists measure ozone
exposure and injury to plants?
One common measure of plants' exposure
to ozone is the seasonal sum of hourly ozone
concentrations at or above 0.06 parts per million
(ppm), known as SUM06. SUM06 is measured
in parts per million-hours (ppm-hrs). The SUM06
exposure maps presented here were generated
using the CASTNET ambient ozone dataset (un-
adjusted for meteorology), for the ozone season
June 1 to August 31, 8 am-8 pm.
The USDA Forest Service administers a long-
term, nationwide ozone biomonitoring program
to address public and scientific concerns about
ozone impacts on forest health. The Ozone
Biomonitoring network tracks the magnitude
and severity of visible ozone injury on ozone-
sensitive bioinidicator plant species over time.
Through long-term monitoring, the Forest Ser-
vice evaluates the status, changes, and trends in
forest condition, and assesses the relationships
between air quality and forest ecosystem health.
For more information on ozone biomonitoring,
visit http://www.fiaozone.net/.
In assessing the relationship between visible
ozone injury and ambient ozone exposure, the
Forest Service has found that ozone injury oc-
curs in both low-ozone (SUM06 < 5 ppm-hrs)
and high-ozone areas (SUM06 >25 ppm-hrs),
although the amount and severity of injury is
greatest in high-ozone areas.
Source: Courtesy of USDA Ozone Biomonitoring Program.
Photo by: John Skelly (USFS)
19
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Methods of Mapping
Status & Trends
Regional Air Quality and Total
Atmospheric Deposition
The status and trend maps on the follow-
ing pages show the geographic variability in
ambient air concentrations of SO2/ SO4/ NO3/
HNO3/ NH4/ and ozone from CASTNET mea-
surements; wet nitrogen and sulfate deposition
from NADP/NTN measurements; and total sul-
fur and nitrogen deposition (wet and dry) from
co-located CASTNET and NADP/NTN moni-
toring stations. The status maps depict mea-
surements for 2004. The trend maps cover two
three-year averaging periods: 1 989-1991 and
2002-2004. The measurement units are ^ig/m3
for ambient air concentrations and kg/ha for
wet and total deposition (the amount of pollut-
ant deposited over an area).
Ambient air concentration is the principal
measure of air quality. It is the monitored
amount of pollutant in the air reported in
micrograms per cubic meter (\ig/m3) or parts
per million (ppm).
Atmospheric deposition is the amount of
air pollution hitting the Earth's surface
reported in kilograms per hectare (kg/
ha). Wet concentration, presented
in milligrams per liter (mg/L), is
the amount of pollutant in a
standard volume.
Ambient Air Concentrations
The CASTNET ambient concentration maps
were generated in Arclnfo CIS software using an
inverse distance weighting (IDW) interpolation
technique. Using IDW, the surface is most influ-
enced by the nearest point values and less so by
more distant points. In developing the trend map
surfaces, the point concentration values for each
year in the three-year period were gridded to a
10 km2 surface. CASTNET sites within 400 km
of each grid point were used in the computation.
The three annual grids from the three-year period
were averaged to derive the mean concentration
of the three-year period. Only sites meeting com-
pleteness criteria for at least two of the three years
of the averaging period were included.
See the CASTNET website for
information on com-
pleteness crite-
ria. Color
20
-------
contours represent the classes of concentration
values indicated in the legend. The color is
ramped from green to red, representing the range
of concentration values from low to high.
Only grid points within 400 km for all three years
were included in the averages; grid points for
which no estimate is made are represented by
white. These are areas for which no data exist due
to gaps in CASTNET monitoring coverage (i.e.,
low site density, particularly in early years as the
network was growing).
Wet Deposition
Similar to CASTNET concentration maps, the
NADP/NTN wet deposition maps were gener-
ated in Arclnfo using an IDW
interpolation technique.
In developing the
trend map
surfaces, the point deposition values for each
year in the three-year period were gridded to a
10 km2 surface. NADP/NTN sites within 400 km
of each grid point were used in the computation.
The three annual grids from the three-year period
were averaged to derive the mean concentration
of the three-year period. See the NADP website
for information about NTN completeness criteria.
Total Deposition
(Wet and Dry Sulfur and Nitrogen)
The total deposition maps created in Arclnfo
show scaled pie charts of sulfur (S) and nitro-
gen (N) deposition at co-located CASTNET and
NADP/NTN monitoring stations. Each pie chart
consists of total S or N deposition at a single
point location. The wet deposition component
is derived from a wet concentration grid us-
ing the IDW technique mentioned above. The
interpolated value on the wet concentration
surface at a co-located CASTNET site is then
multiplied by measured precipitation at that
site. The dry deposition component is from
CASTNET, derived from an inferential model.
Only sites meeting completeness criteria for at
least two of the three years of the averaging
period were included. Note that total N
"^^^* deposition maps are labeled as "total"
although ammonia (NH3), a major
component of total nitrogen, is not
measured by any networks. Meth-
ods for routine measurement of
NH3 in a network mode are
needed.
21
-------
CASTNET Status & Trends in
Rural Air Quality Concentrations
Gaseous Sulfur Dioxide (SOZ
2004
Source: CASTNET
22
-------
1989-1991
2002-2004
T
23
-------
CASTNET Status & Trends in
Rural Air Quality Concentrations
Participate Sulfate (SO
4
2-'
2004
Source: CASTNET
24
-------
1989-1991
2002-2004
'
25
-------
CASTNET Status & Trends in
Rural Air Quality Concentrations
Participate Nitrate (N03
2004
Source: CASTNET
26
-------
1989-1991
2002-2004
27
-------
CASTNET Status & Trends in
Rural Air Quality Concentrations
Gaseous Nitric Acid (HN03
2004
Source: CASTNET
28
-------
1989-1991
2002-2004
29
-------
CASTNET Status & Trends in
Rural Air Quality Concentrations
Particulate Ammonium (NH4H
2004
3.0
>35
Source: CASTNET
30
-------
1989-1991
2002-2004
'
31
-------
SUM06 Ozone (03) Exposure
June 1-August 31
2004
SUM06
Jun-Aug
(ppm-hrs)
0
Source: CASTNET
32
-------
1989-1991
•-.
2002-2004
-
33
-------
NADP Status & Trends in Wet Deposition
Wet Sulfate (S04
2004
Source: NADP/NTN
34
-------
1989-1991
2002-2004
35
-------
NADP Status & Trends in Wet Deposition
Inorganic Nitrogen (N) from
Nitrate and Ammonium
2004
Source: NADP/NTN
36
-------
1989-1991
2002-2004
37
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CASTNET & NADP/NTN
Status & Trends in Total Deposition
Sulfur
t
\1
2004
^PHIH
v v
"
V fc
V
O7 V*
n • - ' «
V 0.7
Source: CASTNET and NADP/NTN
-------
1989-1991
* ti
2002-2004
39
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CASTNET & NADP/NTN
Status & Trends in Total Deposition
Nitrogen
2004
r
V
v
,. e
*
Source: CASTNET and NADP/NTN
40
-------
1989-1991
v
tf
2002-2004
V
V
u
1- j*
V
V
\
41
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CASTNET & NADP/NTN Monitoring Locations
Source: EPA
http://www.epa.gov/castnet/site.html
http://nadp.sws.uiuc.edu/sites/ntnmap.asp?
42
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Glossary
acid neutralizing capacity (ANC)
A measure of the ability of water or soil to neu-
tralize acidic inputs and resist changes in pH.
acid precipitation
Precipitation (rain, snow, clouds, mist, or fog)
having increased acidity due to atmospheric
pollutants.
adsorption
The adhesion of an extremely thin layer of gases,
solids, or liquids to the surface of another solid or
liquid.
Arclnfo
A geographic information system (CIS) software
package for data management, visualization,
modeling, and analysis developed by ESRI.
atmospheric deposition
The process whereby airborne particles and gases
in the atmosphere are deposited on a surface
through precipitation, such as rain or snow, or
through settling, impaction, or adsorption.
deposition
The amount of a substance deposited on a given
area, measured in kilograms per hectare (kg/ha).
dry deposition
Atmospheric deposition that occurs when par-
ticles settle to a surface and attach to it, or when
gases stick to a surface (adsorption) or are ab-
sorbed.
episodic acidification
Temporary spikes in the acidity of a body of water
due to surges in acidic inputs. These surges are
most often associated with seasonal events such
as snowmelt that can release quantities of stored
acidic ions.
estuary
Region of interaction between rivers and near-
shore ocean waters, where tidal action and river
flow mix fresh and saltwater. Such areas include
bays, mouths of rivers, and lagoons.
eutrophication
An increase in the rate of supply of nutrients to a
coastal ecosystem that leads to excessive algae
growth, oxygen depletion, and resulting impacts
on species and ecosystems.
nitrogen saturation
A condition in forested ecosystems in which
nitrogen impacts have led to long-term removal
of nitrogen limitations on biotic activity, accom-
panied by a decrease in the capacity of an eco-
system to retain nitrogen.
PH
A measure of acidity and alkalinity of a solution.
A pH value is a number on a scale from 0 to 14
with lower numbers indicating increasing acid-
ity and higher numbers increasing alkalinity. A
pH value of 7 represents neutrality. Each unit of
change represents a tenfold change in acidity
or alkalinity. Natural waters usually have a pH
between 6.5 and 8.5.
wet deposition
Commonly known as acid rain, although it can
also take trie form of snow, sleet, or hail
43
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On-line Data,
nformation and Resources
Regional Air Quality and
Atmospheric Deposition
Monitoring Networks
Atmospheric Integrated Research and Monitoring Networks
(AIRMON) — http://www.arl.noaa.gov/research/programs/
airmon.html
Canadian Air and Precipitation Monitoring Network (CAPMoN)
— http://www.msc.ec.gc.ca/capmon/index_e.cfm
Clean Air Status and Trends Network (CASTNET)
— http://www.epa.gov/castnet/
Interagency Monitoring of Protected Visual Environment
(IMPROVE) http://vista.cira.colostate.edu/improve/
National Atmospheric Deposition Program/Mercury Deposition
Network (NADP/MDN) — http://nadp.sws.uiuc.edu/mdn/
National Atmospheric Deposition Program/National Trends
Network (NADP/NTN) http://nadp.sws.uiuc.edu/
Ecological Monitoring
and Assessment
Biomonitoring of Environmental Status and Trends Program
(BEST) — http://www.best.usgs.gov/
Clean Air Mapping and Analysis Program (CMAP)
— http://www.epa.gov/airmarkets/cmap/index.html
Climate Monitoring
— http://www.ncdc.noaa.gov/oa/climate/research/monitoring.
html
Environmental Monitoring and Assessment Program (EMAP)
— http://www.epa.gov/emap/
Forest Health Monitoring Program (FHM)
http://fhm.fs.fed.us/
Long-term Ecological Research Network (LTER) —http://
lternet.edu/
Ozone Biomonitoring Program —http://www.fiaozone.net/
National Water Quality Assessment Program (NAQWA)
— http://water.usgs.gov/nawqa/
Emissions Databases
Air Markets Emissions Data and Maps
— http://dcjsweb01.customs.epa.gov/gdm/index.cfm
Emissions and Generation Resource Integrated Database (E-
GRID) — http://www.epa.gov/cleanenergy/egrid/index.htm
National Emissions Inventory (NEl)
— http://www.epa.gov/ttn/chief/net/index.html
Mapping, Spatial Data
and Technology Resources
ArcExplorer — http://www.esri.com/software/arcexplorer/
index.html
Arclnfo — http://www.esri.com/software/arcgis/arcinfo/index.
html
Bureau of Indian Affairs Geographic Data Center
— http://www.doi.gov/bureau-indian-affairs.html
Environmental Systems Research Institute (ESRI)
— http://www.esri.com/
Federal Geographic Data Committee (FGDC)
— http://fgdc.er.usgs.gov/
Geography Network — http://www.geographynetwork.com/
Internet Guide to Geographic Information Systems
— http://www.gis.com/
National Atlas of the United States — http://nationalatlas.gov/
National Ocean Service Data Explorer
— http://oceanservice.noaa.gov/dataexplorer/
44
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References
Bricker, S.B., CG. Clement, D.E. Pirhalla, S.P. Or-
lando, and D.R.G. Farrow. 1999. National Estua-
rine Eutrophication Assessment: Effects of Nutri-
ent Enrichment in the Nation's Estuaries. NOAA,
National Ocean Service, Special Projects Office
and National Centers for Coastal Ocean Science.
Silver Spring, MD: 71 pp.
Driscoll, C.T., G.B. Lawrence, A.J. Bulger, T.J.
Butler, C.S. Cronan, C. Egar, K.F. Lambert, G.E.
Likens, J.L. Stoddard, and K.C. Weathers. 2002.
Acid Rain Revisited: Advances in the Scientific
Understanding Since the Passage of the 1970 and
1990 Clean Air Act Amendments. Hubbard Brook
Research Foundation. Science Links Publication
Vol 1, no.1. http://www.hubbardbrook.org/hbrf/
Mathison, R., T. Prichard, E. Jepsen, and G. Smith.
The Relationship Between Visible Ozone Injury
and Ambient Ozone Exposures. USDA Forest
Health Monitoring Ozone Biomonitoring Net-
work. 1996-1999 Northern Region.
NAPAP. 1991. 1990 Integrated Assessment Re-
port. U.S. National Acid Precipitation Assessment
Program, Washington, DC.
National Atmospheric Deposition Program/ Na-
tional Trends Network (NADP/NTN) http://nadp.
sws.uiuc.edu/
National Oceanic Atmospheric Administration
(NOAA). 2005. The Climate of 2004: U.S. Sum-
mary. National Climatic Data Center, Asheville,
NC. http://lwf.ncdc.noaa.gov/oa/climate/re-
search/2004/ann/us-summary.h tml
U.S. Department of Agriculture, U.S. Forest Ser-
vice, Forest Health Monitoring, Ozone Biomoni-
toring Program, http://www.fiaozone.net
U.S. Environmental Protection Agency.
Clean Air Status and Trends Network (CASTNET)
http://www.epa.gov/castnet
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46
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Clean Air Markets Division
Office of Air and Radiation
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW(6204J)
Washington, D.C. 20460
EPA 430-R-05-007
www.epa.gov/airmarkets
October 2 005
:d with Vegetable Oil-Based Inks on Recycled Paper (Minimum !
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