|
Items in cart [1] |
Questions? Call 888-624-8373 |
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 29
AIR POLLUTANT DISTRIBUTION AND TRENDS
Rudolf B. Husar
Center for Air Pollution Impact and Trend Analysis (CAPITA),
Washington University, Box 1124,
St. Louis, MO 63130
ABSTRACT
Forest health is influenced by the soil, physical
climate, and its chemical climate. Historically, among the
environmental factors, the role of chemical climate has
received the least attention. This paper constitutes an
annotated chemical atlas of the atmosphere over North America
and to a lesser extent Europe. It covers the emissions for
sulfur and nitrogen oxides, wet deposition of sulfate,
nitrate, and ammonia, airborne concentrations of ozone and
sulfate, and the spatial temporal pattern of atmospheric
haziness.
INTRODUCTION
Forest growth is determined by the environmental conditions that include soil and
soil and physical climate
several centuries. Much
chemical
specific
physical and chemical climate of the atmosphere. The role of
has been dealt with extensively in the literature for the past
less is known about the long-term effect of atmospheric chemicals, i.e.,
climate of the forests. Recognizing the severe uncertainties as to what
atmospheric chemicals may be responsible for potential forest damage, it seems
beneficial to assemble an annotated atlas of atmospheric chemicals that may be relevant
to forests. An examination of such a chemical-climatic atlas and trends in conjunction
with physical climate and observed forest change may reveal the chemical that could be
significant to the damage.
MAN-MADE SOX AND NOX EMISSION PATTERN AND TRENDS
The North American emission densities for SO and NOX for 1977-78 are displayed
in Fig. 1. The contour lines have units of grams of sulfur or nitrogen per square meter
per year. Currently, the sulfur emissions in the subcontinent are estimated to range
between 1 1 and 15 million tons/year (22-30 million tons SO2/year). It is evident that
the highest sulfur emission density occurs over the Ohio River region. The highest NO
emission density is over the states north of the Ohio and east of the Mississippi rivers.
There are substantial differences in the emission trends of smaller regions
within eastern North America. Comparisons of the sulfur emissions north and south of
Ohio River are given in Fig. 2, expressed as emission per unit area (g S/m2/yr). The
emissions north of the Ohio River have increased about 25% since the 1 920s. In contrast,
the emissions south of the Ohio River show a threefold increase since the 1 930s.
Currently, the sulfur emissions density is comparable for the regions north and south
of the Ohio River.
29
OCR for page 30
30
SULFUR EM I SS I ON F I ELD
'it ~ 977-78
~0
1-~
`1~:
', . _ . . ,
~ ~ G. /M~ ~ ~ . ~ ~
J NRH 0. 59
J.73
ENa
EUS
SURE U. 57
3.39
NOX-N EM I SS I ON F I ELD
'a ~ 1 977-78
1~
OOO —7.e
El,.~-~.e
3.0-6.0.
>6.0
19 ~
j ~
~~:
END
EUS 2.27
SURE 3.05
O0.25-0.s0
~0,50-1 .50
~3 1 ~ 50-3 00
-
~ >3.00
US
-
Fig. la' lb. Emission densities, g/m2/yr for the year 1977-78 of man-made
SOx and NOx over North America (Husar and Holloway, 1983).
OCR for page 31
31
5 - .
3 —
>`
C.
,.)
e.
a
o
~ 2 —
-
-
1
Izr
or
>~
o it, ,
l8BO 1900
~ 1~_
l92O 1~0
North
Bomb
1960 1~0 ~000
Fig. 2. Sulfur emission density, g/m2/yr for regions north and south of the
Ohio River (Husar, 1985~.
12 ~
~ ~ _
10 -
9 —
L
8-
Z 7 -
C B -
~ 5 -
-
~ ~ _
3 -
2 —
O ~
1
i
l:)
_~ ~~
1 ~-
1 880 1 900
........................ ,
1 920 1 940
of OMo Riv.
1 960 1 980 2000
Fig. 3. NOx emission trend for regions north and south of the Ohio River
(Husar, 1985~.
OCR for page 32
32
The overwhelming fraction of NOX emissions arises from the combustion of fossil
fuels (coal, oil, and gas). Fuel consumption data constitute the most important input
for the estimation of NOX emissions. However, the estimation of the current and
historical emission trends is more difficult than for sulfur compounds. Since most of
the nitrogen oxides are formed by the fixation of air nitrogen at high temperatures
rather than oxidation of fuel nitrogen. Thus, NO emission depends primarily on the
combustion process and to a lesser degree on the duel properties. The fuel combustion
processes in internal combustion engines and boilers have changed since the turn of the
century. It is thus likely that the NO emission per fuel consumption has also changed
historically. Hence, the following ~Ox emission trends have substantially higher
uncertainty than those for sulfur oxides.
The NOX emissions since 1940 (Fig. 3) have been estimated to have increased by
threefold by the 1 970s. The sharp rise in the 1 960s is attributed to the rise of the
emissions from industrial and electric utility sources. Evidently, the NOX increase was
more pronouncer! north of the Ohio River compared to the south.
WET DEPOSITION DATA FOR SULFATE, NITRATE, AND AMMONIA
Motivated by increasing concern about "acid rain," at least five major
precipitation chemistry networks have operated over North America since 1978. In
Europe, most of the monitoring is conducted in the framework of the Economic Community
of Europe (ECE), Co-operative Programme for Monitoring and Evaluation of the Long Range
Transport (EMEP) network.
Sulfate
The yearly average sulfur deposition and the precipitation- weighted
concentration fields arising from the five network data sets for the time period
1977-1980 are given in Fig. 4. Some of the sulfur in precipitation is due to sea salt and
its contribution may be estimated either from Na or C1 data. Taking the sea salt sulfate
to be 0.047 x C1, the marine sulfate deposition over the continent was calculated to be
only about 6% of the sulfur wet deposition over North America. For the sites more than
100 km from the coastline the marine sulfur deposition was insignificant. In the
following discussion S refers to the excess beyond the sea salt sulfur.
For the North American continent (NAM), excluding Mexico, the average sulfur wet
deposition is 0.34 g S/m2/yr. The area considered is 18 x 1012 m2 and the total wet S
deposition is thus 6.2 Tg S/yr. The highest sulfate deposition rate and concentration
in precipitation occurs in the region surrounding the eastern Great Lakes. The sulfate
wet deposition there exceeds 1 g S/m2/yr. For the region east of the Mississippi River
and south of the James Bay (defining here eastern North America ENA area 5.8 x 1012 ma)
the sulfate wet deposition is about 0.63 g S/m2/yr. The lowest sulfate deposition rate
of about 0.1 g/m2/yr is measured in northwestern Canada and southwestern U.S. Both of
these regions have less than 0.5 m/yr of rainfall.
The weighted average sulfate concentration in precipitation (Fig. 4) ranges
between 15 ,ueq/1 in remote U.S. and Canadian regions to about 70 peq/1 in the vicinity
of the Great Lakes. Hence, while the average deposition - rate varies tenfold over the
continent, the average precipitation sulfate concentration increases only fivefold
from remote regions to industrial hot spots.
There are few areas of North America for which it can be safely assumed that the
sulfate deposition values represent the "natural background." Considering the wind
pattern and the anthropogenic S emission fields over the continent, a possible area
uninfluenced by man may be northwestern Canada, inland from the Pacific Coast. The
OCR for page 33
b
SOq-S DEPOSITION
~~ J~N77-OEC80
nor ~ Ad;
f4:>
J:> .. :. :
A:::: : ::: ::. ~ ~
- A; G/M2. YR
/ ENR 0.6S
EUS 0, 73 ~ -
\ ~ SURE 0.82
33
5
On -5
~ONCENTRRT I ON
'A ~ JRN77-OEC80
K~1~2
........ .... ,, , _%
~~, ~
22' `~9''22 -I
Elos-oso ~ ~ ~25-50
> 1 . 00 ~ / END 41.26
EU5 46.73
SURE S2. AS
GO. 10-0.25
\ ~ NOR ZB. B~
Fig. 4. Maps of sulfate wet deposition rate, (g/m2/yr) and precipitation-
weighted average concentration (peq/yr) over North America (Husar and
Holloway, 1983~.
so-7s
ins
OCR for page 34
34
measured sulfur wet deposition rate in that region is 0.1 g S/m2/yr, compared to the
North American average of 0.34 g S/m2/yr. In estimating the natural global sulfur cycle
from rain chemistry data, Granat et al. (1976) have chosen 0.15 g S/m2/yr as the
representative background deposition over nondesert land areas. Considering the severe
uncertainties of the deposition estimates, 0.07 g S/m2/yr would also seem reasonable as
a North American average background. Scaled to the nondesert land area of the world
(120 x 1012 m2), the global S wet deposition from the above "background" sources would
be 9-18 Tg S/yr, which is below the estimate of 18 Tg S/yr by Granat et al. (1976~. An
increasing data base of precipitation sulfur values obtained in the southern
hemisphere, e.g., Stallard and Edmond (1981), from the Amazon region, and data from the
polar ice caps dictates that continental average background deposition outside the 0.07
to 0.15 g S/m2/yr range is unlikely. A documentation of this statement is best available
in Granat et al. (1976), but will require continuous reevaluation as the global data base
expands.
The lower (0.07 g S/m2/yr; 1.3 Tg/yr) and the upper bound (0.15 g S/m2/yr; 2.5
Tg/yr) of the estimated "natural background" sulfur deposition constitutes 20 to 40% of
the measured total sulfur deposition (0.34 g S/m2/yr; 6.2 Tg/yr) over North America.
For eastern North America the average excess sulfur deposition rate is about 0.63 g
S/m2/yr (3.7 Tg/yr) and the "background" (0.5-1.0 Tg S/yr) deposition would account for
12-25% of the total ENA wet deposition. This is a substantial upward revision of
previous estimates of "natural contribution" for North America (Galloway and Whelpdale
1980~.
It is also instructive to compare the measured wet deposition pattern and rates
to the emission field of man-made sulfur over North America (Fig. 1~. The average
emission density over eastern North America is 1.9 g S/m2/yr while the average wet
deposition over the same region is 0.63 g S/m2/yr, i.e., about 30% of the known man-made
emissions. If we further assume that the natural sources contribute on the average 0.07
g/m2/yr, the measured wet deposition of sulfur amounts to only 25-30% of the man-made
sulfur. The remaining 70-75% of the man-made sulfur is then either dry deposited as S02
or S04, or exported to the Atlantic by the prevailing winds.
The sulfate concentration in precipitation over Europe (Fig. 5) shows the highest
yearly average values over eastern Europe (GDR, Poland, Hungary, Romania). In those
areas it exceeds 100 peq/1 which is more than double the highest concentrations over
eastern North America.
Nitrate
The average deposition and concentration pattern of nitrate over NAM is given in
Fig. 6. The average NAM wet deposition rate is 0.13 g N/m2/yr corresponding to 2.4 Tg/yr.
The highest deposition rates (0.4g N/m2/yr) are observed in the area surrounding the
eastern Great Lakes. The average over ENA is 0.23 g Nlm2/yr. Using again the deposition
data for remote western Canada (0.03-0.06 g N/m /yr), approximately an order of
magnitude increase may be observed from remote to high emission regions. Similarly as
for the sulfate, the nitrate concentration in rain has only a fivefold increase from
remote (3-6 /leq/l) to industrialized regions (25 peq/1~.
If we take the "background" nitrate wet deposition rate to range between 0.03-0.06
g N/m2/yr over the entire continent, the "background" wet removal will contribute
0.5-1.0 Tg N/yr. As for sulfate wet deposition, the "background" nitrate deposition
would account for 20-40% of the measured nitrate deposition in precipitation. Over
eastern North America, the corresponding background contribution would be 10-25% of the
total measured wet deposition. Taking 0.03-0.06 g N/m2/yr as representative over the
nondesert land areas ( 1.2 x 1014 m2) of the world, the global nitrate wet deposition
would range between 3 and 7 Tg N/yr. This is an order of magnitude less than the total
OCR for page 35
35
S04 in PRECIPITATION
El''EP Network nuerage
I,
i ~_~
NOS in PRECIPITATION
El'1EP Network Overage
K:N
_s
_
100 ~ ~
Fig. 5. Sulfate and nitrate concentration, (,ueq/l) in Europe (EMEP network
average).
OCR for page 36
36
(dry and wet removed, natural and man-made) nitrate deposition (32-83 Tg N/yr) estimated
by Soderland and Svennson (1976~. Using the average measured NAM nitrate wet deposition
of 0.13 g N/m2/yr and applying it to the global nondesert land area, yields 16 Tg N/yr
which is still a factor of two to five less than the nitrate deposition (dry and wet)
estimated by Soderland and Svennson (1976~.
An emission map (Fig. lb) for man-made NOX over eastern North America shows that
the highest emission density is in excess of 3 g N/m2/yr in the Great Lakes region and it
roughly coincides with the location of the highest deposition density (Fig. 6~. The
comparison with the deposition data also reveals that wet deposition accounts for only
20% of the known man-made NOX emissions over eastern North America. The remaining 80%
is thus either dry deposited or exported from the continent.
The nitrate concentration in precipitation over Europe (Fig. 5) shows the highest
values over western Europe including northern Italy and France. In those areas it
exceeds 80 peq/1 which is more than double the highest nitrate concentrations over
eastern North America.
Ammonia
The yearly average ammonium ion deposition field is shown in Fig. 7. The North
American average deposition is 0.11 g N/m2/yr (2.0 Tg N/yr) and for eastern North America
0.16 g N/m2/yr ( 1.0 Tg N/yr). The highest deposition rates, ranging 0.25-0.50 g N/m2/yr,
occur from the Great Lakes to the Rocky Mountains, an area generally known as the corn
belt region. West from the Rockies and in northern Canada the deposition rate is below
0.1 g N/m2/yr. Conspicuously, the industrialized northeastern part of the U.S. does not
show high ammonia deposition values. Here again, it is useful to compare the measured
NAM ammonium wet deposition rates (2 Tg N/yr), scaled to the globe (13 Tg N/yr), to the
global dry and wet ammonium/ammonia deposition rates (91-186 Tg N/yr), estimated by
Soderland and Svennson (1976~.
Possible sources of ammonia. Unlike SOX and NOX, an emission inventory of man-made
or "known" ammonia sources over North America currently does not exist. As an aid to
interpret the measured ammonia wet deposition field, we have constructed a tentative
inventory for the U.S. The emission factors for domestic animals were taken from Bottger
et al. ( 1978~. For nitrogen fertilizer it was assumed that 10% N is volatilized to the
atmosphere. Minor contributions from known industrial sources were also included. The
resulting ammonia emission density map is shown in Fig. 8. The total U.S. ammonia
emission from the above "known" sources is estimated at 3.4 Tg N/yr with the highest
emission density in the corn belt region exceeding 1 g N/m2/yr.
There is a rough coincidence of the area of high measured deposition rate and
estimated emission density, both extending through the corn belt region. The estimated
U.S. ammonia emission rate from "known" U.S. sources is 3.4 Tg N/yr, which is comparable
to the wet deposition integral of 2 Tg N/m2/yr for NAM. However, considering the severe
uncertainties of the "known" source estimates, little significance is attached to the
emission values beyond suggesting that the inventory is within the right order of
magnitude.
The ammonia concentration in precipitation over Europe (Fig. 9) shows the highest
yearly average values over central and eastern Europe stretching from Great Britain
through Poland and Romania. In many areas the concentration exceeds 100 peq/1 which is
more than three times the highest concentrations over eastern North America.
In spite of the uncertainties associated with the spatial-temporal coverage,
sampling, and analytical procedures, and the interpretation of the wet deposition data,
it is most gratifying that such continental-scale data bases currently exists for North
OCR for page 37
37
NO3 -N DEPOS I T I ON
>~ JON77-DEC80
~ :~0R~
,~
1 1 - c ~
.\ , ~
U ..N a,
~ . . . . . . . . . . . . . +.
~ ~ ~ G. / M , T ~
~ ~NRM J-13 - ~ 30. 25—0.50
/ END O.22 ~ ~ >0.50
EN 0.27
. SURE 0; 30
~ ~'~'~?\ ~
NO3 -N CONCENTRRT I ON
,,~ JON 7 7 -OK C so
............ __
'if - <
/ END l7.l.
EU5 20.16
SURE 22. 24
uEO/L
0 5-10
E} 10-25
25-50
>50
Fig. 6. Maps of nitrate wet deposition rate (g/m2/yr) and precipitation-
weighted average concentration (peq/l) (Husar and Holloway, 1983~.
OCR for page 38
38
NH~ -N DEPOS I T I ON
If.
Oo.os-o. 10
Elo. 10-0.2s
~0.2s-o.so
(~ ~ ENa o le ~ · >O.50
~ ~ SU" 0.21
NH~ -N CONCENTRRT I ON
\\ ~ ~ ~ -
·~] 4-~- :~
<~ V-~ uEO/L
51 ~ ~ ~ o s-~o -
25-50
£ - 12 ~ ~ ~ ,50
SV" 16-0.
Fig. 7. Maps of ammonia wet deposition rate, (g/m2/yr) and precipitation-
weighted average concentration, (peq/l) (Husar and Holloway, 1983).
NH3 -N EM I SS I ON
,\N
~_
CU, o. ~S
'.\ ~ stmc o. S6
.
Oo. 10-0.25
E~ o. 25-0. so
E3 0. SO- 1. 00
,=', · ' 1 . 00
Fig. 8. Estimated emission density of ammonia emissions for the U.S. (Husar
and Holloway, 1983~.
OCR for page 39
39
HYDROGEN ION in PRECIPITATION
EMEP Network average
.
100
peq
NH4 in PRECIPITATION
EMEP Network peerage
it,
i ~W
Fig. 9. Ammonia and hydrogen ion concentration, (peq/l) in Europe (EMEP
network average).
OCR for page 40
40
America and Europe. Prudent use of such data bases will undoubtedly provide us with a
much improved perspective on both scientific and other aspects of the "acid rain"
problem.
AIRBORNE OZONE CONCENTRATION
It is well established that high airborne ozone concentrations can damage
forests. Regrettably, national climatic maps for ozone are not available. One of the
most difficult problems pertains to the calculation of "representative" concentrations.
The concentration at a given location has a diurnal, synoptic scale (3 to 5 days),
seasonal and long-term trends that result from the interacting NOX, hydrocarbon sources
physical and chemical removal processes, and atmospheric transport. Nevertheless,
attempts have been made to compile the ozone distribution pattern. Vukovich et al.
( 1985) have explored the daytime ozone concentrations for nonurban locations over the
eastern U.S. for August 1978- 1981 as displayed in Fig. 10. The daytime ozone
concentrations exceeding 60 ppb cover the area of the Ohio River valley and the
mid-Atlantic states, New Jersey-North Carolina. It is worth noting, however, that the
concentrations are about 40 ppb in the upper Midwest. Hence, the regional variability
of the summer daytime ozone is only about a factor of two. It is likely that the spatial
gradients in the winter time are more pronounced.
Singh et al. (1978) have proposed a semi-quantitative picture of the seasonal
variation of the ozone in the lower layers of the atmosphere (Fig. 1 1~. The natural
ozone pattern is indicated by the shaded area marked A. Superimposed on this natural
background is a man-induced perturbation marked with B and C. At remote sites the
natural ozone concentration reaches the maximum in the early spring. In areas
influenced by man-made sources, a summer peak may arise. Here's again, we emphasize that
on the average the man-made ozone is a mere perturbation over a substantial natural
background.
VISIBILITY
Atmospheric optical data are much more abundant on a continental scale than
chemical composition data, with the exception of the water vapor content. Hence, if a
reasonably well defined relationship can be established between, for example, the
visual range or turbidity and the fine particle content of the atmosphere, then the
extensive meteorological observations by human observers inherent in the interpretation
of the visibility data obtained by routine meteorological observation networks. These
include the subjectivity of the human observer, the lack of suitable visual targets, and
the numerous natural phenomena that perturb the visual environment (rain, fog, blowing
dust, natural haze, etc.~. The spatial and trend analysis of the visibility data,
therefore, needs to be conducted with utmost caution. The data presented below arise
from the analysis of 147 U.S. and 177 Canadian stations from 1948 to 1980.
human observer, the lack
The quarterly average extinction coefficient (3.9/visual range, km) from noon
observations in the absence of precipitation and fog is shown in Fig. 12. At
midlatitudes (40-60° N) there are three hazy regions: surrounding the Great Lakes, the
Mississippi Delta and southern California including the San Joaquin Valley. A
conspicuously hazy region also exists north of the arctic circle, the cause of which is
unknown and will be ignored here. The lowest mean extinction coefficient (<0.1 ~ /km)
occurs in the U.S. Rocky Mountain Region. The long-term availability of visibility data
also permits the examination of secular trends of continental haze from about 1950 to
1980. The five-year average map for 1950- 1954 shows substantially lower haziness than
the 1976- 1980 period. The important changes in the three decades occurred in the
southeastern U.S. (mostly in the summer months) as well as over the northwestern U.S.
and adjacent southwestern Canada (mostly in the winter months).
OCR for page 41
41
~~-
e:
Fig. 10. Mean diurnal maximum ozone concentration isopleths for August 1978-
1981 (Vukovich et al., 1985~.
Ion .
.
too _
80
20
I T I I -I --it
DIRECT 03 TRANSPORT
f ROM URBAN CENTERS
LOCAL OZONE \
SYNTHESIS
~ NO_ I NTRUSIC)N,
~':',',',W'' · ~
YOU JAN '4AR
WAY JUL SEPT NOW
Fig. 11. Idealized ozone variations at remote locations (Singh et al., 1978).
OCR for page 42
to
~ -
-
~ -
1
a,
-
42
Levi ' :11:~
'a
, Cot
c, a
C)
1
C)
0
CL~
V]
.
U.
lo_
~ 0 -
- } 4 00
ED O
° I.4
I
O
~ O
Q ~ ~
Do C
CO
C) ~ ~
Ct-—X
Cot _
~ C~ ~
~ ~ O
Ce
_ C:
en. - o
_ 4 - c:
C:.—0
4_ Cd
~ ~ Q
Ce (1) ·—
Ct ~
~ ~u Q
Ed ct o
Go
OCR for page 43
43
A more detailed trend pattern for eastern U.S. haze is shown in Fig. 13. It is
apparent that in some areas, such as in New England, the haze decreased for the first
quarter of the year. Other regions, such as surrounding the Smoky Mountains, exhibit a
strong increase, particularly during the third quarter (July, August, September). In
the New England and New York area the SOX emissions have declined since the 1 950s
primarily because of the shift from coal to oil. The Smoky Mountain region on the other
hand, experienced a substantial increase of SOX emission nrimarilv rl~,`` tn in~r-~cin~
electric utility coal consumption (see Emission section above).
- _ ~_^ ~e,
Beyond demonstrating that substantial changes have occurred in the optical
environment, the visibility data demonstrate that within the eastern U.S. some
subregions may exhibit a decline, others an increase of haziness. This implies that in
spite of Long range transport" subregions covering several U.S. states will exhibit
trends in fine particle concentration consistent with their own emission trends. In
other words, the long-term haze data base confirms the most revealing conclusion of the
European OECD project, namely that-every source region impacts on itself more than on any
other region.
_
ACKNOWLEDGMENTS
This research was partially supported by the U.S. Environmental Protection Agency
cooperative agreement #CR 810351-02, the National Academy of Sciences, and Washington
University. Special thanks to Dr. Ellis Cowling for his encouragement to pursue and
refine our concepts of Chemical Climatology.
OCR for page 44
44
a
Thu. u''' J~\
b NEW ENGLAND
~~-~ my, 5F-— ~Y~R7iR ~ -me 5 rout OR ~
__, ~ ~~.: _
_~ NEWEST
=~
C EASTERN SUNBELT
44 4E
., ~,'
NO I3SO 1960 i970~ 1 ~ [i5~50 ''to i 'co Alto
',—Am. ~ ~ ~J ,~9II! 'It
2j ~ ~~ .2'~
~ 3 'L
l
19~0 t950 i960—l',o i980 into 1~ -
d SMOKY MOuNtR I NS
' E '32
31-
.2
.1:
::: ~
it,
1
19S'O 1~0 isio it Also
ousa tIR ~
vats , ]
' t
'9q~ Isso 1960 1970 ~ ~ '950 ~i60 '9~0 19~0 '990 19~o ;9SO t980—197
·SE~!=,.CR ~._, ~ _ ,~arIs 11 ~ ouasT ~ \ _
e 2L ~ 2F ~ ~ 2 ~ ~ 2t ~
19~0 t9S0 1950 1970 19~0 1990 1940 1950 1960 1870 1~0 15 -
't ~ 3 ';
19q0 t9SO'` 1960''l~19 - 1~9aO 1990
Fig. 13 Location of 70 eastern U.S. sites where detailed trend analysis was
performed. The trend lines indicate mean and arithmetic standard
deviation among the stations within each region, b.-d. Trends of
extinction coefficient by yearly quarters for New England
southeastern sun belt, and the Smoky Mountain region (Husar et al.,
OCR for page 45
45
REFERENCES
Bottger, A., Ehhalt, D.H., and Gravenhorst, G. 1978. Atmospherische Kreislaufe von
Stickstoffen und Ammoniakum. Berichte der Kernforschunsanlage Julich, 1558.
Galloway, J.N. and Whelpdale, D.M. 1980. An atmospheric sulfur budget for eastern North
America. Atmospheric Environ. 14, 409. -
Granat, L., Rodhe, H., and Hallberg, R.O. 1976. The global sulfur cycle. In Nitrogen
Phosphorus, and Sulfur-Global Cycles. Svensson, B.H. and Soderlund, R., eds.,
SCOPE, Report 7. Ecol. Bull. (Stockholm) 22, 23.
Husar, R.B. and Patterson, D.E. 1987. Project Summary: Haze Climate of the United
States. U.S. Environmental Protection Agency, EPA/600/SB-86/071.
Husar, R.B., Patterson, D.E., Holloway, J.M., Wilson, Jr., W.E., and Ellerstad, T.G.
1979. Trends of Eastern U.S. Haziness Since 1948. Proceedings of the Fourth
Symposium on Turbulence, Diffusion, and Air Pollution, Jan. 15-1S, 1979.
Husar, R.B. and Holloway, J.M. 1983. Sulfur and nitrogen over North America. In
Ecological Effects of Acid Deposition, National Swedish Environment Protection
Board-Report PM 1636, Stockholm, Sweden.
Husar, R.B. 1985. Manmade SOX and NOX emission and trends of Eastern North America.
Background paper for the National Academy of Sciences Committee on Monitoring
and Assessment of Trends in Acid Deposition.
Singh, H.B., Ludwig, F.L., and Johnson, W.B. 1978. Tropospheric ozone: concentrations
and variations in clean remote atmospheres. Atmospheric Environ., 12, 2185-2196.
Soderland, R., Svensson, B.H. 1976. The global nitrogen cycle. In Sevensson, (B.H. and
Soderland, R., eds., Nitrogen, Phosphorous, and Sulphur - global cycles. SCOPE,
Report 7. Ecol. Bull. (Stockholm) 22:23-73.
Stallard, R.F. and Edmond, J.M. 1981. Geochemistry of the Amazon. 1. Precipitation
chemistry and the marine contribution to the dissolved load at the time of peak
discharge. J. Geophys. Res. 86,9844.
Vukovich, F.M., Fishman ]. and Browell E.V. (1985~. The reservoir of ozone in the
boundary layer of the Eastern United States and its potential impact on the global
tropospheric ozone budget. J. Geophysical Res., 90-03, 5687-5698.
OCR for page 46
46
LIST OF FIGURES
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Fig. 9.
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Emission densities, g/m2/y for the year 1977-78 of manmade SO and NO over
North America (Husar and Holloway, 1983~. x x
Sulfur emission density, g/m2/yr for regions north and south of the Ohio
River (Husar, 1985~.
NO emission trend for regions north and south of the Ohio River (Husar,
1983~.
Maps of sulfate wet deposition rate, (g/m2/yr) and precipitation-weighted
average concentration (,ueq/yr) over North America (Husar and Holloway,
1983~.
Sulfate and nitrate concentration, (,ueq/l) in Europe (EMEP network
average).
Maps of nitrate wet deposition rate, (g/m2/yr) and precipitation-weighted
average concentration, (peq/~) (Husar and Holloway, 1983~.
Maps of ammonia wet deposition rate, (g/m2/yr) and precipitation-weighted
average concentration, (,ueq/l) (Husar and Holloway, 1983~.
Estimated emission density of ammonia emissions for the U.S. (Husar and
Holloway, 1983~.
Ammonia and hydrogen ion concentration, (peq/13 in Europe (EMEP network
average).
Mean diurnal maximum ozone concentration isopleths for August 1978- 1981
(Vukovich et al., 1985~.
Idealized ozone variations at remote locations (Singh et al., 1978~.
The quarterly (Q1 Jan-March, Q2 April-]une, Q3 July-Sept, Q4 Oct-Dec)
average extinction coefficient from noon observations in the absence of
precipitation and fog (Husar and Patterson, 1987~.
Location of 70 eastern U.S. sites where detailed trend analysis was
performed. The trend lines indicate mean and arithmetic standard deviation
among the stations within each region; b.-d. Trends of extinction
coefficient by yearly quarters for New England, southeastern sun belt, and
the Smoky Mountain region (Husar et al., 1979~.
Representative terms from entire chapter:
deposition rate
