v>EPA
United States Office of Environmental Engineering
Environmental Protection and Technology
Agency Washington DC 20460
EPA 600/7 80 126
June 1980
Research and Development
Transport and
Transformation of
Sulfur Oxides
Through the
Tennessee Valley
Region
Interagency
Energy/Environment
R&D Program
Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
systems; and integrated assessments of a wide range of energy-related environ-
mental issues.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/7-80-126
JUNE 1980
TRANSPORT AND TRANSFORMATION
OF SULFUR OXIDES THROUGH THE
TENNESSEE VALLEY REGION
by
Timothy L. Crawford and Lawrence M. Reisinger
Office of Natural Resources
Tennessee Valley Authority
Muscle Shoals, AL 35660
Interagency Agreement No. EPA-IAG-D9-E721
Project No. 81-BDL
Program Element No. 1NE-832
Project Officer
C. W. Hall
U.S. Environmental Protection Agency
401 M Street
Washington, DC 20460
Prepared for
OFFICE OF ENERGY, MINERALS, AND INDUSTRY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, DC 20460
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DISCLAIMER
This report was prepared by the Tennessee Valley Authority and has
been reviewed by the Office of Energy, Minerals, and Industry, U.S.
Environmental Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the views and
policies of the Tennessee Valley Authority or the U.S. Environmental
Protection Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
TVA is an equal opportunity employer, and is committed to ensuring that
the benefits of programs receiving TVA financial assistance are available
to all eligible persons regardless of race, color, national origin, handicap,
or age.
11
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ABSTRACT
This report is directed to scientists interested in the long-range
atmospheric transport and transformation of sulfur compounds.
Statistical and climatological analyses of historical data and the
results of two long-range transport studies are presented. The two long-
range atmospheric transport field studies were conducted over a 300-km
area of the southern United States centered on the Tennessee Valley region.
The first study was conducted during the spring of 1976, and the second
was conducted during the summer of 1977. The field study region contains
seven large coal-fired power plants and one large city.
Results indicate that the predominant flow and mass transport
direction is from the southwest to the northeast. Also, aerometric
measurements obtained by aircraft and ground sampling compared favorably
with results obtained with an analytical transport-transformation model
developed for this study. Results indicate that, during prevailing
southwesterly airflow, large gaseous sulfur influxes are present. These
influxes, which are of the same order of magnitude as the Tennessee Valley
regional emission fluxes, can only partly be explained by upwind
anthropogenic sources. Natural source emissions are hypothesized to
account for about half of this sulfur influx.
This report was submitted by the Tennessee Valley Authority, Office
of Natural Resources, in partial fulfillment of Energy Accomplishment
Plan 81 BDL under terras of Interagency Agreement EPA-IAG-D9-E721 with the
Environmental Protection Agency. Work was completed as of June 1979.
111
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EXECUTIVE SUMMARY
The objective of the Tennessee Regional Atmospheric Transport Study
(TREATS) is to develop an understanding of the characteristics and mecha-
nisms affecting regional pollutant levels and interregional transport of
primary and secondary sulfur pollutants. This report not only addresses
the measurement and modeling of the transport and transformation of sulfur
species, but also looks at climatological variations of aerometric and
meteorological parameters and emission rates as they impact the Tennessee
Valley region. Other pollutant species are dealt with primarily as they
relate to the formation of fine particulate sulfates.* Principal ingre-
dients of this analysis are the results from two long-range transport field
studies conducted during the spring of 1976 and the summer of 1977. These
studies are among the first ever conducted in the United States over
distance scales of hundreds of kilometers.
During these studies, aerometric and meteorological measurements
defined airmass pollution levels and interregional pollutant mass trans-
port as airmasses entered, passed through, and left the Valley. These
unique measurements have led to several significant findings.
In presenting these findings, two important terms, concentration and
flux, are used to describe pollutant levels within airmasses. Concentra-
tion is simply the mass or amount of pollutant per unit volume of air,
typically reported as micrograms per cubic meter (|Jg m~3), whereas flux is
a less frequently used term that describes the rate of pollutant mass
transport through a horizontal or vertical area and is reported in micro-
grams per square meter per second (ug m~2 s"1). As typically expressed
in this report, flux is obtained by multiplying the concentration by the
wind speed. This parameter is important in describing the movement of
pollutants.
Many different sampling and analytical techniques were used to deter-
mine relationships between and among the various parameters measured. One
of the more significant findings from these analyses describes the hori-
zontal and vertical diurnal variations of various pollutants. In particular,
multiple aircraft traverses at various altitudes and at widely separate
locations within the Valley indicate that significant pollutant variations
often occur in the horizontal and vertical during the night and early
morning. However, by midday, the gradients are significantly reduced,
except near the ground, where sulfate data obtained from high-volume
samplers indicate that ambient air concentrations average twice the air-
mass concentrations as measured by aircraft flights near ground level.
Additional research is needed to determine whether this is a sampling
artifact or a real phenomenon.
'"Prominent among the "sulfates" are sulfuric acid, ammonium bisulfate,
and ammonium sulfate. Within this report, the terms, sulfate, particulate
sulfate and S04 are synonymous and are defined as the traditional water
soluble fraction of the total filterable particulate analyzed and
expressed as micrograms of sulfate per cubic meter of sampled air.
IV
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Another interesting analysis involves aircraft sampling of the same
airmass as it enters the Tennessee Valley region and again as it leaves
(known as Lagrangian sampling). Analyses of measurements made on five
such days compared very well with an analytical model developed to simu-
late the transport and transformation processes. By using the model
simulations on six non-Lagrangian days together with the five measure-
ment days, some unexpected and interesting results were obtained. These
results need additional confirmation due to limits of the present data
set. One result shows that for the days with both inflow and outflow
measurements, the change in flux as the airmass passed over the region
was negligible.
When flow was from the south, sulfate flux, from inflow to outflow,
increased; however, sulfate concentrations were low at both boundaries.
Again, model estimates indicate that the region was a minor contributor
to this increase (only 12 percent); the remaining 88 percent increase in
sulfates resulted from conversion of gaseous sulfur compounds already in
the air before the airmass entered the region. An attempt to identify
the significant source region(s) that might be contributing to this large
inflow flux resulted in the conclusion that upwind anthropogenic sources
account for only about half of the gaseous sulfur flux, whereas biogenic
sources (i.e., wetland areas in and around the Gulf Coast States) could,
in theory, account for the other half. However, available data are insuf-
ficient to accurately quantify this biogenic source hypothesis.
One reason that our findings are significant is that this southwesterly
flow direction is the principal transport avenue over not only the Tennessee
Valley region but the entire United States east of the Mississippi River.
Also, this flow direction is frequently associated with summertime high
air pollution episodes over the eastern United States.
This study also indicates that, when wind speeds are light, TVA is
a principal source of pollution in the Tennessee Valley region.
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CONTENTS
Abstract
Executive Summary v
List of Figures ix
List of Tables xi
Acknowledgments xii
Nomenclature xiii
1. Introduction 1
Background 1
Scope of Research 2
2. Conclusions and Recommendations 4
Conclusions 4
Recommendations 5
3. Materials and Methods 7
Characterization of the Region 7
Physical characterization 7
Emissions characterization 9
Meteorological characterization 12
Synoptic weather patterns 12
Trajectory data 13
Sampling platforms 15
Meteorological measurements and support 23
Sampling procedures 23
1976 study 25
1977 study 25
Analytical methods 26
Continuous gas analyzers 26
Low-volume filters 27
High-volume filters 27
Transformation-transport model 29
Model development 29
Analytical model 29
Simple box model 32
Eulerian model 33
Model analysis 34
4. Results and Discussion 38
Sulfate Concentration and Flux Climatology 38
Seasonal concentration variations 38
Regional sulfate flux rose 42
Flux calculations 48
Estimating concentration and flux 48
Estimating U, H , and+H~ 51
Estimating SO and N04
concentrations 51
Estimating N03 and 03
concentrations 51
Flux measurement criteria 54
Tabular summary of flux calculations .... 58
VI
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Eulerian space and time variations 58
Eulerian space variations 58
Horizontal variations 61
Vertical variations 66
Eulerian time variations 72
Lagrangian flux analysis 72
Field results 73
Model results 77
Upwind sources 81
References 82
Appendixes
A. Synoptic Weather Typing A-l
B. Tabulation of TREATS 1976 and 1977 aircraft field
study data B-l
C. Altitude correction, Meloy model SH202 and SA285
sulfur analyzer C-l
D. Tabulation of TREATS 1976 and 1977 high-volume
field study data D-l
E. Inversion heights and average wind velocities
for Lagrangian and Eulerian days E-l
F. Synoptic meteorological summaries for
Lagrangian and Eulerian days F-l
vii
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LIST OF FIGURES
Figure Page
1 Physiographic divisions of the TREATS study region. . . 8
2 Annual average SQ% emission density map 10
3 Locations and emissions of major point sources .... 11
4 Favored 24-h airmass source regions for
Nashville, Tennessee 14
5 Percent occurrence of airmass movement out of the
Tennessee Valley region (1972) 16
6 deHavilland Beaver U6-A airplane 17
7 Airplane instrument layout 18
8 U6-A instrument package 19
9 Bell 47A helicopter 21
10 Helicopter instrument layout 22
11 Location and type of meteorological measurements ... 24
12 Region used in the development of the long-range
transport model 30
13 Schematic of the hox model 32
14 Comparison of Lagrangian and Eulerian boundary
conditions and solution domains_ 33
15 Predicted variation in SC>2 and 804 concentrations
as a function of transport time 35
16 Effect of variation in model parameters on predicted
response after 24 h of transport 36
17 Regional air quality trend stations 39
18 Monthly variations of TVA's 802 emissions and regional
sulfate concentrations, 1974-1977 40
19 Giles County sulfate concentration (|Jg m~3) vs the
average concentration of Cumberland, Gallatin,
and Giles 43
20 Annual frequency distributions of wind speed, wind
direction, sulfate concentration, and sulfate flux
for Nashville, Tennessee 44
21 Seasonal frequency distributions of Nashville sulfate
flux (ng nT2 s"1) 45
22 Relative frequency distributions 46
23 Schematic of typical flux calculation procedure .... 50
24 Typical early morning sulfur profiles 52
25 Typical midday sulfur profiles 53
26 Typical early morning and midday normalized ozone
profiles 55
27 Typical early-morning nitrate profiles 56
28 Airmass transport distance vs. inflow-to-outflow
sampling distance 57
29 Temporal variation of sulfate 62
30 Temporal variation of ammonium 63
31 Temporal variation of normalized total sulfur 64
32 Temporal variation of nitrate 65
33 Comparison of ground-level to upper-air sulfate
concentrations 69
vin
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Figure Page
34 Giles County sulfate concentration vs. Colbert .... 70
35 Comparison of inflow to outflow sulfate flux 74
36 Comparison of inflow to outflow total sulfur flux . . 75
37 Inflow to outflow concentrations and mole
ratio changes 76
38 Observed vs predicted outflow total sulfur (X 102)
and sulfate concentration 78
39 Relative change in total sulfur flux across the TREATS
field study region 79
40 Sulfate flux change across the TREATS field study
region 80
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LIST OF TABLES
Table Page
1 Airplane Instrument Package, Beaver U6-A 15
2 Helicopter Instrument Package, Bell 47A 20
3 Accuracy of Analytical Methods, 37-mm Millipore
Filters 28
4 Percent Variation in Model Response Resulting from
a ±50 Percent Change in a Single Parameter 34
5 Median Sulfate Flux and Concentration Values
Regardless of Sector 47
6 Summary of Lagrangian and Eulerian Measurements .... 59
7 Inflow-Outflow Concentrations (|Jg m 3) by Flow
Direction ^ 61
8 High-Volume Concentrations (pg m 3) by Flow
Direction 66
9 Comparison of Ground-Level and Upper-Air Sulfate
Concentrations 68
10 Suspended Sulfate Correlation Matrix 71
11 Sulfate Speciation 73
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LIST OF ABBREVIATIONS AND SYMBOLS
B --width of the region, m
b --subscript indicator of pollutant concentration above inversion,
(Jg m'3
C. --concentration, pg m~3
H --height of the capping inversion, m
i --indicator of S02 (i = 1) or 804 (i = 2)
j --indicator used with box formulation
k --first-order transformation rate constant for S02 to 864, s"1
kj k, s"1
k2 —3k/2, s"1
K , K , K --diffusivities along the principal axes, m2 s"1
x y z
Q --point-source S02 emission rate, |Jg s~l
t --time, s
t --age of airmass passing the outflow plane, s
3
t* --time at which the relative S04 concentration is maximum, s
U, V, W --mean wind speed components along the principal axes, m s"1
v. --deposition velocity, m s "-1
x, y, z --distances along the principal axes, m
Note: Subscript or superscript zero (0) indicates an initial value.
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ACKNOWLEDGMENTS
This work was primarily funded by the Federal Interagency Energy/
Environment Research and Development Program administered through the
Environmental Protection Agency under contract number EPA-IAG-DG-E721.
The support of this agency is gratefully acknowledged, as is the advice
and guidance of the Project Officer, C. W. Hall. However, without
additional funding by the Regional Air Quality Management Program of
the Tennessee Valley Authority and without the use of TVA's extensive
facilities, this work would not have been possible.
We wish to especially express our appreciation to Dr. Herbert
Jones, The TVA Project Director and Drs. James F. Meagher and Leonard
Stockburger of the Air Quality Research Section for their logistic and
design assistance before and during the two field studies and for their
thought-provoking input during data analysis. Also, we wish to express
our appreciation to William J. Parkhurst, Air Quality Monitoring Section,
for his input to the seasonal concentrations variations subsection; to
Malcolm C. Babb, Applied Research Staff, for his assistance in generating
plots; and to Hollis E. Lindley, Computer Applications Staff, for his
assistance in processing data. Finally, we wish to express our appreciation
to Elizabeth M. Bailey of the Air Quality Research Section for serving as
instrument operator during the 1977 study.
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SECTION 1
INTRODUCTION
The Tennessee Valley Authority (TVA) has long been concerned about
regional transport and transformation of atmospheric sulfur species
(Gartrell et al. 1963). The primary reason for this concern is that TVA
operates 12 large coal-fired power plants within the southeastern United
States, which constitute a major source of sulfur dioxide (802), the
precursor to sulfates (SO^).
In 1975, a program to study the regional atmospheric transport of
coal-fired power plant emissions, the Tennessee Regional Atmospheric
Transport Study (TREATS), was initiated by TVA as part of the Federal
Interagency Energy/Environmental Research and Development program being
administered through the Environmental Protection Agency. The primary
objective of the TREATS research is to develop an understanding of the
characteristics and mechanisms affecting regional pollutant levels and
interregional transport of primary and secondary sulfur pollutants. With
respect to this objective, the impacts of TVA emissions on the TREATS
study region and downwind regions are of primary concern.
BACKGROUND
Historically, when evaluating the impact of power plant emissions,
the region of concern was generally the immediate vicinity (within 20
km) of the power plant in question, and the pollutants of concern were
mainly particulates and S02. In most scientific work relating to atmos-
pheric transport of pollutants, little or no attention was given to the
intermediate (20 to 100 km) or regional (beyond 100 km) transport of
pollutants. Recently, however, emphasis has been placed on the evalua-
tion of intermediate and regional transport of power plant emissions.
Emphasis on the intermediate transport was changed abruptly by the
December 1974 publication of the Prevention of Significant Deterioration
(PSD) regulations (Federal Register 1978). Emphasis on the regional
transport of pollutants was changed by the gradually evolving regional
sulfate transport-transformation theory. This theory implies that remote
primary S02 emissions (preferentially from power plants with tall stacks)
are transformed to secondary particulate sulfates and transported over
long distances. Within the last 10 years, interest in regional transport
has steadily increased, as indicated by numerous international publica-
tions (e.g., Bolin et al. 1971; Eliassen and Saltbones 1974; Smith and
Jeffrey 1975; Bolin and Pearson 1975; Altshuller 1976; Wilson et al. 1977;
and Wilson 1978).
During the same period, researchers have been compiling an ever-
growing list of adverse effects that result from exposure of the human
population, biota, and materials to atmospheric sulfate particulate. In
particular, acid sulfate particulates have been implicated in the health
damage formerly attributed to S02 (EPA 1974a; Hausknecht and Ziskind 1975).
Other adverse environmental effects of atmospheric sulfates include acidic
deposition (wet and dry), with related adverse effects on the ecology of
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lakes, rivers, soils, and forests (Braekke 1976), and corrosion of mate-
rials (Yocom and Grappone 1976). More recently, visibility reduction
has also been related to increases in atmospheric S04 levels (Trijonus
and Kung 1978). Reduction in visibility and possible harmful health
effects are of special concern for aerosols in the 0.1- to l-|jm size range.
Sulfates are one of the more important contributors to atmospheric aerosols
in this size range.
The problem with controlling sulfates is that they are predomi-
nantly secondary pollutants transported to the receptor from usually
unknown source regions, and little is known about the transport-
transformation phenomenon. Even so, EPA is expected to promulgate
National Ambient Air Quality Standards for fine particulates, which are
mostly sulfates, within one to two years (Rowe et al. 1978). The
promulgation of fine particulate air quality standards is expected to
pose difficult problems for emission control and siting strategies for
future fossil-fired power plants—possibly more difficult than those for
PSD. The transformation and long-range transport of sulfates from
unknown sources make the problem of equity in sulfate control strategies
particularly acute. Thus, development of a physically realistic regional
transport-transformation modeling technology is an essential link in the
development of an equitable control strategy.
Development of a regional-scale modeling technology will require
submodels for gas-to-particulate conversion processes and various removal
processes. Also, detailed information on the time-dependent regional
emissions and diffusion and transport wind fields will be required to
drive the model.
Highly accurate models are expected to be complicated because of
the possible nonlinear dependence of sulfate production on the source
strength of S02. Another potential problem is the dependence of the
gas-to-particulate reaction on other trace atmospheric constituents
(e.g., OH radicals, cloud water pH, 03, and NH3). Also, the question of
biogenic (natural) sources of sulfur compounds is now an open area of
research, and active efforts are underway to understand it.
SCOPE OF THE RESEARCH
This report addresses not only the measurement and modeling of the
transport and transformation of sulfur species, but also the climatological
variations of aerometric and meteorological parameters, emission rates,
and their interrelationships. Other pollutant species are dealt with
primarily as they relate to the formation of particulate sulfates.
Prominent among the "sulfates" are sulfuric acid, ammonium bisulfate,
and ammonium sujfate. Within this report, the terms sulfate, particulate
sulfate, and S04 are synonyms and are defined as the traditional water-
soluble fraction of the total_filterable particulate analyzed and are
expressed as micrograms of 804 per cubic meter of sampled air.
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This report describes the results of the first three years of
studies into long-range transport of secondary sulfate pollutants.
Results from two discrete field studies that characterize long-range
transport and transformation into, within, and out of the Tennessee
Valley region, along with several other "paper" studies, are reported.
Although the results are politically and scientifically significant, the
limited resources require that they be considered only indicative and
not conclusive.
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
Our conclusions and recommendations are based on a limited number
of data collected during two long-range transport field studies conducted
in the Tennessee Valley region. Therefore, these findings, although sig-
nificant and in some cases totally unexpected, should be viewed as
preliminary and requiring confirmation by further research.
CONCLUSIONS
1. Although TVA and other power plants account for 90 percent of
the regional anthropogenic sulfur emissions, aircraft flux
measurements indicated that, during southwesterly flow, these
emissions are of the same magnitude as those advected into the
region. Therefore, with respect to interregional sulfur trans-
port, TVA emissions contribute about half of the outflow sulfur
burden. However, during light wind or calm conditions, TVA is
the principal contributor to regional pollutant levels. Within
the Valley such episode conditions are more frequent than in
the northeastern United States, but less severe with respect
to pollutant levels.
2. During transport from the southwest, only about 40 percent of
the measured sulfate influx can be explained by upwind anthro-
pogenic sources. The balance appears to be due to biogenic
sulfur emissions from the Gulf of Mexico and the extensive
wetland areas of the southeastern United States.
3. Eleven Lagrangian measurement days—fourjwith inflow and outflow
measurements of both total sulfur and 804— indicate that during
southwesterly flow, no significant change occurred across the
Tennessee Valley region in total sulfur flux or concentration.
Although the sulfate flux increased by a factor of two from
inflow to outflow, the actual concentrations were low--5.4 |Jg/m3
at the outflow boundary. Also, model estimates of the percentage
of sulfate flux attributable to regional emissions are small
(around 10 percent).
4. The 24-h airmass movement across the Tennessee Valley area
frequently originates in a broad band from southern Alabama,
Mississippi, and central Louisiana (the wetland areas of the
Gulf Coast). These airmasses typically exit the Tennessee
Valley, heading toward the northeastern part of the United
States.
5. Highest sulfate fluxes occur with southwesterly flow, whereas
highest sulfate concentrations occur with northeasterly flow.
Also, daily variation in sulfate and ammonium concentrations
are greater for northeasterly flow than for southwesterly flow.
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6. Nitrate concentrations show an opposite trend to the direction-
dependent concentration variations of sulfate and ammonium
(i.e., higher concentrations for southwesterly flow).
7. Model calculations (which did not consider wet deposition) indi-
cated that airborne SC>2 decays exponentially with transport
time. Its half-life of about 16 h results from the nearly equal
effects of removal by dry deposition and transformation to S04.
The decay rate is only a mild function of mixing height. The
model_also predicts that S04) aside from the initial presence
of S04 concentrations, increases, reaching a maximum after about
three days of transport, after which it decays almost exponen-
tially. Model calculations indicate that S04 is most sensitive
to changes in the transformation rate of S02 to S04. It is
relatively insensitive to changes in mixing height or deposition
rates. Comparison with data has shown that the model gives
reasonable results for a transport time of about 10 h.
8. Ground-level, high-volume measured S04 concentrations indicated
that ambient air concentrations were higher than those of air-
craft by a factor of two. This finding, which is contrary to
accepted dispersion theory and measurements, may represent an
artifact of the high-volume sampling technique.
9. Substantial vertical pollutant gradients often exist under
stable conditions (radiation inversions), especially during
the early morning (and night). However, these gradients often
dissipate by midday.
10. Total sulfur (mostly SC^) concentration measurements showed a
trend toward lower values from morning to afternoon; however,
the other pollutants analyzed (i.e., S04, NH4, and N03) showed
no such trend. This disparity could have resulted from differ-
ences in photochemistry and deposition velocities.
Although this research has allowed us to learn much about the charac-
teristics and mechanisms of long-range atmospheric transport of sulfur
pollutants, it also has raised several significant questions. The more
significant questions and recommended actions for answering them are
presented below.
RECOMMENDATIONS
1. Is the observed large total sulfur influx from the southwest
correct in magnitude, in speculated origin (i.e., biogenic),
and is it persistent in time? If so, then the TVA and national
emission reduction efforts may be limited in their potential to
reduce the sulfate, visibility, and acidic deposition problems
in the eastern United States. We strongly recommend that the
origin and magnitude be substantiated with a spring or summer
aircraft study over this region. If the speculation is con-
firmed, then additional studies will be required to define its
persistence in other seasons.
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Equitable regional control strategies relating to regional and
interregional formation and transport of sulfate pollutants--
the major contributors to adverse health effects, visibility
reduction, and acidic deposition--will be particularly difficult.
TVA emissions have been and will continue to be looked at closely
since they are the principle sources of regional pollution in
the Tennessee Valley and are occasionally transported toward the
northeastern United States. Evaluation of control strategies
(e.g., NAAQS, PSD, visibility degradation, cost-benefit) is
essential for both regional industrial siting and interregional
transport. However, these evaluations are nearly impossible
because no realistic regional transport-transformation models
relating remote emissions to regional air quality exist. There-
fore, we recommend that the TREATS program be expanded and redi-
rected to (1) collect additional data for submodel development
and model validation, (2) modify or develop a regional scale
transport-transformation model, and (3) validate the model.
In the next few years TVA will spend about 6 billion dollars
to remove 40 percent of its regional emissions. Considering
the magnitude of this initial control technology expenditure
and the likelihood of future expenditures, we recommend that
the subsequent extent of regional and interregional air quality
improvement and benefits be established.
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SECTION 3
MATERIALS AND METHODS
CHARACTERIZATION OF THE STUDY REGION
Because the TREATS program is focusing attention on the geographical
region encompassing the Tennessee Valley, unique regional characteris-
tics that will influence results must be considered. Physical, emission,
and meteorological characteristics are important.
Physical Characterization
The solid rectangle of Figure 1 outlines the Tennessee Regional
Atmospheric Transport Study region. The outer map border defines the
emissions inventory region, and the inner dashed box encompasses the
area in which field studies were carried out. The model region (solid
rectangular box) consists of parts of Illinois, Indiana, Kentucky, North
Carolina, South Carolina, Georgia, Alabama, Mississippi, Arkansas,
Missouri, and nearly all of Tennessee. Across this region, there are six
primary physiographic features. From east to west, they include the
(1) Appalachian Mountains, (2) valley and ridge subregion, (3) Cumberland
Plateau, (4) Highland Rim, (5) Central Basin, and (6) Mississippi
Embayment.
The Appalachian Mountain chain is comprised of folded and faulted
igneous and metamorphic rock. The characteristics of these types of
rocks make them particularly susceptible to the effects of acidic precipi-
tation. The Appalachians, which are very sparsely populated, contain
few anthropogenic pollution sources.
The valley and ridge subregion is characterized by northeasterly-
trending narrow parallel ridges and slightly wider intervening valleys.
Two large population centers, Knoxville and Chattanooga, and five TVA
coal-fired plants are found within this subregion. The topology and
meteorology of this subregion result in persistent up-valley, down-
valley winds. Under stable conditions, pollution tends to be trapped
and channeled in the valleys.
The Cumberland Plateau consists of a northeasterly-trending belt of
highlands bounded by abrupt escarpments. An unusual feature of this
region is the Sequatchie Valley. One TVA coal-fired power plant is
found in this subregion. The local pollution transport problems encoun-
tered in this region are similar to those in the valley and ridge region.
The Highland Rim consists of a rim or bench of highlands surrounding
the Nashville Basin. Three TVA coal-fired power plants are found in
this region. Because of the low terrain relief, pollution does not
become entrapped by physiographic restraints. The Highland Rim supports
one of the most fertile agricultural regions within the southeastern
United States.
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Mississippi Embayment
Modeling Area
1976 & 1977 Field Study Area
Cumberland Plateau
Highland Rim
Central Basin
Piedmont Plateau
Appalachian Mountain
Valley and ridge region
i
00
i
Figure 1. Physiographic division of the TREATS study regions.
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The Central Basin is an oval, northeasterly-trending depression
developed within the Highland Rim. One large urban center, Nashville,
and one TVA coal-fired power plant are found within this region.
The Mississippi Embayment is characterized by its low relief and by
the absence of consolidated rock outcroppings. One large urban center,
Memphis, and two TVA steam plants are located within this region.
Some of the physiographic subregions within the Tennessee Valley
exhibit topography capable of entrapping and channeling air pollutants.
For example, during the summer months, warm, moist tropical air is fre-
quently channeled from southwest to northeast between the Appalachian
Mountains and stationary cold fronts to the north (Smith and Nieraann 1977).
Most parts of the regions are heavily forested, with biota ranging from
subarctic coniferous forest biome to deciduous forest biome. Due to humid
conditions and a dense forest canopy, pollutant removal by dry deposition
should be greater than in many other regions of the United States. The
variety of topographical regimes and substrates has, of course, resulted
in a variety of edaphic biotic communities.
Emissions Characterization
An essential ingredient for any regional atmospheric transport study
or modeling effort is an up-to-date emissions inventory. For this reason,
a detailed inventory has been compiled for the TREATS region (Reisinger
and Sharma 1977).
The annual average weight of anthropogenic S02 emissions for the
map area shown in Figure 1 is large--about 15,000 metric tons per day.
On a per-unit-area basis, this emission is nearly equivalent to the
national average; however, on a per-capita basis, it is about four times
the national average. This high emission results from a moderate popu-
lation density combined with a regional energy supply system, which depends
strongly on regional high-sulfur coal. Figure 2 places the regional sulfur
emissions in perspective with the rest of the nation. Some 75 percent
of the S02 emissions occur east of the Mississippi River, with the highest
emission density occurring near the Ohio River Valley (Ohio, Pennsylvania,
and Indiana).
Nearly 90 percent of the regional emissions result from 33 major
coal-fired power plants, which are irregularly scattered over the entire
region. Figure 3 illustrates the locations and relative magnitude of
S02 emissions for the power plants. TVA's 12 coal-fired power plants
account for one third of all sulfur emissions. By 1983 various S02
control technologies will reduce TVA regional emissions by 40 percent.
Figure 3 shows that many of the larger power plants are geographi-
cally grouped along the Ohio and Tennessee river valleys. This can lead
to one of several "source intensification" corridors, depending on the
synoptic meteorology (Smith and Niemann 1977). Such corridors become
significant when the airmass transport direction and the corridor direc-
tion coincide. When this happens, emission rates per unit area (along
these corridors) increase significantly.
-------
I
I—'
o
>20 tons/km
Figure 2. Annual average SC>2 emission density map.
-------
LABADIEH/SIL>lt"S •'••
V CJlfBAYSHORe
FESTuS-^Mx-N1 LLIN
0 I S
^ 'HrS* BALDWIN
^•^C CARBONDALE
PETERSBURG
GALLAGHER,
NO I ANA (\^*,- LOUISVILLE
. LOUISVILLE
NEWB
.' ftz- ST! ALBANS
V .CHARLESTON
WES-T V I RG I Nl A
LOUISA ' 5a.
Ml S SOUR I
ARKANSAS
UTICf HOCX
KENTUCKY
PARADISE— — —J
POP AR BLUFF NEW
MADRID
NORTH CAROL IN A
AS NEVILLE
LA
M I S S I S S I P P I
COLUMBUS,
ALABAMA
Q1RGAS
MIN6HAM,
f BWILSONVILLE
G EORGIA
0 ATLANTA
LWNAN
100-299
( J 300- 499*
\ 700-899*
LEGEND
900-1099*
ifl
MutS
MODEL AREA
500- • TVA STEAM PLANT
:- FIELD STUDY AREA
* metric tons/day
699"
LARGE NON-TVA STEAM PLANT
COLUMBIA
Figure 3. Locations and 862 emissions of major point sources.
-------
-12-
An example of a source intensification corridor is evident in the
locations of the TVA Colbert, Johnsonville, Cumberland, and Paradise
Steam Plants. These plants form a curved corridor oriented from the
south to the northeast through middle Tennessee and southern Kentucky.
Actual documentation of such a source intensification event along this
corridor was found during the recent Sulfur Transport and Transformation
in the Environment (STATE) Tennessee Plume Study (Private communication
with W. E. Wilson, Environmental Protection Agency, Research Triangle Park,
North Carolina, 1978).
Major population centers within the map area include Nashville,
Knoxville, Chattanooga, and Memphis, Tennessee; Birmingham, Alabama;
Atlanta, Georgia; and the area along the Ohio River from Evansville,
Indiana, to Louisville, Kentucky. Historical meteorologic records
indicate that average airmass trajectories emanating from this map area
have maximum frequency toward the NNE, with a second maximum toward the
ESE. Thus, cities such as Chattanooga and Knoxville, Tennessee, and
Louisville, Kentucky, are downwind of potentially high emission density
corridors.
The Cumberland, Paradise, Widows Creek, and Shawnee Steam Plants
are the largest TVA coal-fired plants. These plants, together with
TVA's Gallatin, Colbert, and Johnsonville Steam Plants, are base-load
plants and are all within the field study area sampled during the 1976
and 1977 studies. The average sulfur content of the coal burned in
these plants, most of which comes from the southern Appalachian area, is
3.4 percent.
Meteorological Characterization
In the following subsection, the climatological analyses of sig-
nificant meteorological variables in and around the Tennessee Valley
region are described. Specifically, analyses of seasonal and annual
variations in synoptic weather patterns and airmass trajectory analyses
are presented.
Synoptic Weather Patterns--
In an effort to objectively quantify the significant meteorological
variables that impact the Tennessee Valley region, a quasi-objective
weather typing scheme has been devised. This scheme classifies five
basic weather parameters identifiable on National Weather Service (NWS)
daily weather maps. The area of interest is defined within a 500-nautical-
mile (nmi) radius from Nashville, Tennessee. Daily weather maps were
tabulated every sixth day from November 5, 1973, through October 28, 1977.
Although meteorological cycles are known to exist, we felt that integrat-
ing the data base over four years would eliminate this bias. In doing
this, a total of over 235 data points were generated for each of the five
parameters. These five parameters describe (1) the predominant frontal
systems and associated pressure centers; (2) the distance (range) of the
most significant pressure center from Nashville, Tennessee; (3) the direc-
tion from Nashville, Tennessee (degrees from true north) of this pressure
-------
-13-
center; (4) the airmass type (e.g., maritime tropical, continental polar);
and (5) the relative frequency of measurable precipitation (£0.01 in.).
These parameters are further divided into categories. These categories
and their annual and seasonal distributions are presented in Appendix A.
All five parameters have significant departures from the mean during
summer, the peak sulfate season for eastern North America. These depar-
tures are all correlated with the strong influence of the Bermuda high
on weather patterns in the southeastern United States, especially during
the summertime. This influence results in reduced wind flow; moist, warm
air advection; and poor ventilation, which often leads to air pollution
episodes, not only in the southeast but over the entire eastern United
States.
Further work that substantiates the significance of the Bermuda high's
ability to produce elevated air pollution potential is presented by Korshover
(1976). He describes the most significant stagnation, or poor ventilation,
areas within the eastern United States on both an annual and seasonal
basis. For the high air pollution seasons of summer and fall, his analysis
shows that the most intense areas of stagnation are located in an arc
from West Virginia southward to central Georgia. The average distance
and location of this stagnation arc relative to the TREATS field study
region correspond well with the directional and distance analysis for
the high-pressure centers listed in Appendix A. This pressure orienta-
tion produces an annual airflow toward the northeastern United States
and leads to significantly reduced transport during the summer and autumn
months. Examples of this flow pattern producing high sulfate pollution
levels two to three times as high as the annual average are the TREATS
1977 field study days of late June and early July. However, significant
departures in this typical high pollution flow regime can occur (Reisinger
and Crawford 1979).
Trajectory Data--
Twice daily NWS 24-h surface and 850-mb back-trajectories for Nash-
ville, Tennessee, were analyzed for a 3-year period (1976-1978) to define
significant flow directions into the Tennessee Valley region. Also, for
a 1-year period (1972), 850-mb (~1500 m MSL) trajectory data were analyzed
for 14 cities surrounding the Tennessee Valley region to describe the
movement of airmasses out of the region.
Annual contour analyses of favored origination locations for 24-h
back-trajectories are presented in Figure 4. The numbers shown are the
occurrences for the period of record, 1976-1978. These analyses were
obtained by plotting the frequency of occurrence of 24-h back-trajectories
by 1-degree latitude-longitude boxes. The data show that on an annual
basis most trajectories originate in a sector from southern Alabama
through northwestern Tennessee. Seasonally, the winter pattern is quite
similar to the annual frequency pattern, whereas the spring pattern is
diffuse with numerous trajectories from the north and east. However,
the summer pattern indicates a more compact distribution, with 24-h tra-
jectory origins frequently occurring from west Tennessee. Fall trajec-
tories, like the spring trajectories, show a diffuse source region, with
significant maxima around the Ohio River Valley and eastern Tennessee.
-------
Figure 4. Favored 24-h airmass source regions for Nashville, Tennessee.
-------
-15-
The frequency of occurrence of trajectories originating within a
model area (defined by 38°N, 91°W, 33°N, and 82°W) and passing over eight
cities surrounding the area is shown in Figure 5. This model area roughly
defines the area within which TVA has coal-fired power plants. From this
figure, one can see that trajectories originating within this area rarely
affect regions to the south or west, whereas frequent airmass movement
occurs toward the north through east.
SAMPLING PLATFORMS
Two aircraft were used for the airborne sampling experiments. A
deHavilland Beaver (U6-A)--a single-engine, fixed-wing craft--was used
in both the 1976 and 1977 regional transport studies, and a Bell 47A
helicopter was also used during the 1977 study. The instruments installed
aboard the airplane are described in Table 1.
TABLE 1. AIRPLANE INSTRUMENT PACKAGE, BEAVER U6-A
Parameter
Detector
Instrument
Study
Total sulfur
Total hydro-
carbons
Ozone
NO, NO
' x
scat
Temperature
Dewpoint
S04, N03, NH4
Flame photometric Meloy Labs SH202 1976, 1977
Flame ionization
Chemiluminescence
(Os + C2H4)
Chemiluminescence
(03 + NO)
Integrating
nephelometer
Thermistor
Chilled mirror
Meloy Labs SH202
McMillan 1100
Thermo Electron
14D
Meteorological
Research
Custom
Cambridge 137-C3
Filter collection system
37 m Millipore See text
filters (Fluoropore)
1976, 1977
1976
1976, 1977
1977
1976, 1977
1976, 1977
1976, 1977
Power for the continuous monitors was provided by the aircraft
electrical system through two 1-kW Topaz inverters. The output from the
instruments was applied to Hewlett-Packard 7100B, dual-channel, strip
chart recorders.
The airplane, instrument layout, and instrument package are shown
in Figures 6, 7, and 8. The dual-line sampling probe was constructed
from two 0.635-cm-OD stainless steel tubes that extended 1.2 m above the
fuselage. This arrangement allowed for separate sampling streams for
-------
0\
I
Figure 5. Percent occurrence of airmass movement out of the Tennessee Valley region (1972).
-------
-17-
Figure 6. deHavilland Beaver U6-A airplane.
-------
-18-
H
ELECTRIC
INVERTERS
C2H4
CYLINDERS
PARTICULATE COLLECTION
/ SYSTEM
OPERATOR
STATIONS
PILOT DRY TEST
STATION METER
INSTRUMENT
RACKS
INLET
PROBE
INSTRUMENT
RACKS
Figure 7. Airplane instrument layout
-------
TS
°3
DEW PT.
RECORDERS
c
NO NOX
Figure 8. U6-A instrument package.
-------
-20-
particulate and continuous gas monitors while eliminating interferences
from the propeller wash and engine exhaust. Both probes were nearly
isokinetic--the gas sampling probe by allowing excess probe ram-air to
bleed out the end and the particulate sampling probe by matching probe
intake area and sampling flow rate to the aircraft sampling speed of 50 m
s-1. Vacuum for the particulate collection system was obtained from the
airplane vacuum system.
The integrating nephelometer was operated without a heater. For
relative humidity above about 70 percent, hygroscopic or deliquescent
particles grow. This enhances their scattering coefficient and leads to
increased b
scat
related to b
scat
Below about 70 percent, mass concentration can be
(Meteorological Research, Inc., 1972) by
Mass (g m"3) = 0.38 b
scat'
The second aircraft, a Bell 47A helicopter, was used in the 1977
regional transport study. The instruments installed aboard the helicopter
are described in Table 2.
TABLE 2. HELICOPTER INSTRUMENT PACKAGE, BELL 47A
Parameter
Detector
Instrument
Total sulfur
scat
Temperature
Dewpoint
S04,
, NH+
Flame photometric
Integrating nephelometer
Thermistor
Chilled mirror
Filter collection system
37 mm Millipore filters
(Fluoropore)
Meloy Labs Mo'del
SA-285
Meteorological
Research, Inc.
Custom
Cambridge 137-C3
See text
Power for the continuous monitors was provided by the helicopter
electrical system through a 1200-W Deltec inverter. The output from the
instruments was applied to Hewlett-Packard 7100B, dual-channel, strip chart
recorders.
The helicopter and the instrument layout are shown in Figures 9 and
10. The dual-line sampling probe was constructed from two 0.635-cm-OD
stainless steel tubes, which were mounted on the right landing strut and
extended forward about 1 m. This arrangement allowed for separate sampling
streams for particulates and gases while eliminating rotor downwash inter-
ferences. Airflow through the probes was nearly isokinetic. Vacuum for
the particulate collection system was obtained from two Cast model 1550
vacuum pumps.
-------
Figure 9. Bell 47A helicopter.
-------
-22-
TEMPERATURE AND DEW POINT PROBE
INSTRUMENT RACKS
GAS PROBE
NEPHELOMETER PROBE
POWER
INVERTER
PARTICIPATE
PROBE
PARTICIPATE
FILTER
PUMPS
Figure 10. Helicopter instrument layout.
-------
-23-
In both studies, particulate samples were collected on 37-mm Millipore
(Fluoropore) membrane filters. The 1976 study used Fluoropore filters
with 0.5-(jm pore size, whereas the 1977 study used filters with 1.0-(jm
pore size. Liu and Lee (1976) have shown that these filters have greater
than 99 percent collection efficiency for aerosols in the 0.03- to
1.0-pm diameter range. The volume of air sampled was measured with
Sprague dry test meters in 1976 and Matheson mass flowmeters in 1977.
The average flow rate through the filters was 50 L/min, and the average
volume of air sampled was 1.8 m3.
METEOROLOGICAL MEASUREMENTS AND SUPPORT
The study area for both the 1976 and 1977 aircraft measurement
programs was centered over the western Tennessee Valley region (dashed
area in Figure 11). As shown by Figure 11, this area has one of the
most densely instrumented meteorological networks in the Nation. TVA
operates seven upper-air stations, and the NWS operates one. Of the
stations, four are operated on a 24-h basis, with pibal and temperature
soundings taken four times throughout the day. Most of these soundings
are taken from early morning through midday. The NWS upper-air station
takes temperature and wind soundings at 0600 and 1800 CST. In addition
to these measurements, TVA measures wind and temperature at 13 meteorologi-
cal towers, and the NWS measures near-surface and cloud parameters at five
24-h weather observation stations. This wealth of meteorological data,
particularly the eight upper-air sites, has proven useful in accurately
defining the spatial and temporal variations of the planetary boundary
layer.
The TVA Meteorological Forecast Center (MFC) in Muscle Shoals,
Alabama, provided planning and operational forecasts of mixing-layer
heights and wind velocities, airmass trajectories, heights of radiation
and subsidence inversions, and general weather and cloud forecasts for
the study area. These forecasts were issued twice daily; an operational
forecast was issued on the morning of a sampling day, and an afternoon
planning forecast was issued for the following day. Updates of actual
wind and temperature profiles near the aircraft sampling paths were
frequently obtained on a near-real-time basis to evaluate the ongoing
experiment from a meteorological standpoint. To minimize variables and
still obtain a "typical" airflow pattern, the 1976 and 1977 studies were
designed so that sampling would be conducted during "favorable" meteorolo-
gical conditions. These favorable conditions included ceilings greater
than 305 m, identifiable subsidence inversions i2000 m, no measurable
precipitation within the study area, and persistent winds from the south
through west.
SAMPLING PROCEDURE
Two full-scale long-range transport field studies were conducted,
one during February and March 1976 and the other during June and July
1977. Because meteorology, chemistry, and biological activity differ
significantly from spring to summer, and knowledge gained from the 1976
study influenced the design of the 1977 study, the sampling procedure
description is divided by field study.
-------
A STU J,
WESTVIRGINIA
I ND I AN A
EVA|t:$VILLEOEVV
f^&L.
5 -NEB X
KENTUCKY
MISSOURI
POPQ
POPLAR BLUFF
T E N N E S S E|E
r inrvi
CAROlINA
CHARLOTTE
ARKANSAS
TH CAROL I NA
M I S SI S S I PPI
AGQR
BIRMINGHAM
BHM
• TVRRAOB PBAL8MET TOWER 0 SFC WX STA
A TM» PBAL MET TOWER A NON-TVA MET TOWER
Figure 11. Location and type of meteorological measurements.
-------
-25-
1976 Study
The sampling strategy during the 1976 study was to obtain Lagrangian
airraass measurements under fairly representative airflow conditions.
This and other meteorological conditions, described in the Meteorological
Measurements and Support subsection of Section 3, could be met only briefly
during prefrontal flow. Also, due to the variability of the wind, the
"window" during which the afternoon aircraft space coordinates were similar
to the Lagrangian airmass coordinates was also limited.
The Meteorological Characterization subsection, Section 3, indicates
that the principal flow direction is from the south through west. With
this in mind, we decided that the aircraft sampling strategy should be
to first make representative morning inflow measurements from south-central
Tennessee through northern Alabama. This was accomplished by flying two
horizontal traverses, one within the morning radiation inversion and one
between the tops of the radiation inversion and the subsidence inversion.
These traverses were flown at "constant altitudes" AGL; the within-inversion
measurements were typically made at an altitude of about 600 m AGL. Sulfate
sample requirements, more than airmass characterization requirements,
dictated that the traverses last at least 1.5 h, or be about 150 km long.
After the morning sampling traverses were completed, the aircraft
landed and refueled at the Muscle Shoals, Alabama, airport. At that time,
the forecasted wind and weather conditions at the outflow boundary were
updated. The aircraft then flew a "constant altitude" sampling flight
to the outflow boundary, which was typically near south-central Kentucky
and north-central Tennessee. Immediately after reaching the outflow field
study boundary, sampling began. The afternoon outflow sampling procedure
was similar to the morning procedure; that is, two (about 200-km) traverses
were flown at different altitudes to get representative readings within
the well-mixed layer. Typically, these measurements were near 600 and
1200 m AGL.
1977 Study
Three factors dictated that the single sampling strategy technique
used during the 1976 study be modified. The first factor was a need,
identified during the 1976 study, to determine whether significant vertical
or horizontal pollutant gradients existed, especially during early daylight
hours. The second factor was the availability of two aircraft; thus,
simultaneous measurements at two locations were possible. The third factor,
which probably proved greater than either of the other two, was the weather.
As with the 1976 study, favorable meteorological sampling conditions
were identified, as described in the Meteorological Measurements and Support
subsection. However, a climatological analysis of other summers and the
initial weather conditions observed in May and early June 1977 indicated
that obtaining all the desired conditions simultaneously would be impossible.
A combination of low wind speeds, lack of directional persistence, morning
ground fog, and airmass and frontal thunderstorm activity all contributed
to a modified sampling strategy. This modified strategy resulted in two
scenarios.
-------
-26-
Scenario 1 was defined as airmass Lagrangian or Eulerian measure-
ments. This scenario is similar to the 1976 sampling strategy, except
that separate aircraft sampled the atmosphere at the inflow or outflow
boundaries. Measurements were obtained by multiple-altitude traverses
(typically four levels) through the inversion layers and usually for
three time periods—early morning, late morning or midday, and afternoon.
This technique allowed for both Eulerian space and time measurements in
addition to the anticipated Lagrangian measurements.
In this report the terms "Eulerian" and "Lagrangian" refer only to
the basis of the coordinate system. If the coordinate system is particle
attached, the term "Lagrangian" is applied; the term "Eulerian" is properly
applied to all other cases.
Scenario 2 was defined as airmass stagnation, or blob measurements.
This scenario was similar to scenario 1 in that traverses were flown by
both aircraft. However, because wind flow cannot be defined under stag-
nation conditions, measurements cannot be evaluated for flux, and only
concentration variations in space and time can be analyzed.
The 1976 and 1977 data that were collected using these sampling
strategies are summarized in Appendix B.
ANALYTICAL METHODS
Continuous Gas Analyzers
The continuous gas analyzers used in the studies were calibrated
against standardized, wet chemical methods. The West-Gaeke (1956) pro-
cedure was used to calibrate the Meloy Labs flame photometric sulfur
analyzers before and after experiments. During sampling, all gas moni-
tors were continually checked for malfunctions.
The flame photometric detector is noted for its excellent sensitivity
to low background levels of sulfur and its linear logarithmic response
over several orders of magnitude. Unfortunately, it is also sensitive—in
an instrument-specific manner— to ambient pressure, which is a function
of altitude. The results from altitude tests on the Meloy 202 and 285
analyzers and the method used for adjusting the data to compensate for
pressure sensitivity are given in Appendix C. Caution should be observed
when using the resulting concentration numbers in an absolute sense,
since these tests were made after the two study periods.
The gas analyzers provide a continuous measurement in time (or dis-
tance) . To compare these continuous measurements with integrated-traverse
low-volume filter particulate measurements, the continuous measurements
must be integrated over the sampling traverse. The algorithm for this
integration is
c = i/(t2 - tx) ; fcl c(t)dt,
-------
-27-
where
C = integrated traverse equivalent concentration,
C(t) = time continuous concentration,
ti* fc2 - endpoint times of the traverse.
Because of large sample times (typically, t£ - tt = 15 min) and small
gradients of C(t) in time, instrument response time along a traverse was
not a problem.
Low-Volume Filters
The water-soluble fraction of particulate captured on the 37-mm
Millipore low-volume filters was extracted with Super-Q (prefiltered,
organics adsorbed, deionized, and membrane-filtered) water in an ultra-
sonic bath. The extracts were analyzed for 864, N03, and NH4 ions. The
S04 analyses for the 1976 study were performed by flash vaporization--
flame photometry (Roberts and Friedlander 1975; Husar et al. 1975). The
samples from the 1977 study were analyzed for 804 and NOs by ion chroma-
tography (Mulik et al. 1976). The NH4 analyses were performed by the
alkaline phenate method (EPA 1974b) with a Technicon autoanalyzer. The
accuracy to be expected from these techniques is shown in Table 3.
High-Volume Filters
Mine Safety Appliance filters were used during the 1976 field
study. Gelman Spectrograde filters were used in all TVA high-volume
samplers and in State of Kentucky high-volume samplers operated for the
1977 study. The Spectrograde filter was selected for the 1977 study
because of its low 864 background and lower alkalinity compared with most
other high-volume filter materials. Coutant (1977) has shown that lower
alkalinity filters produce significantly less artifact 804 formation.
Exposed filters were weighed for particul|te loading (Jutze and
Foster 1976) and analyzed for water-soluble 804, NOs, and NH4 ion concen-
tration. An extract for ion analysis was obtained from a 3.4-cm strip
of the filter, which was hot water refluxed for 90 min. Ion concen-
trations were determined with the methylthymol blue analytical finish
for SC>4, automated cadmium reduction method for nitrate-nitrite, and the
colorimetric phenate method for ammonium (analyzed as NHs). Because of
extraction problems with the 1977 Spectrograde filters and delays in
analysis, N03 and NH4 values are considered inaccurate and are not
reported. Checks on the accuracy of the sulfate extraction showed no
significant bias. Based on eight triplicate measurements (from three
collocated high-volume samplers), the standard error of estimate for the
precision of the measurement and laboratory analysis was found to be
±1.4 jjg m~3 or about 10 percent.
-------
TABLE 3. ACCURACY OF ANALYTICAL METHODS, 37-mm MILLIPORE FILTERS
Ion Method
S04 Flash vaporization
804 Ion chromatograph
NOg Cadmium reduction
NOs Ion chromatograph
NH4 Alkaline phenate
Typical blank
(M8/filter)
0.4
0.2
0.1
0.1
0.3
Concentration
(Mg/filter)
4.0
8.0
16.0
2.0
20.0
0.5
1.0
2.0
0.1
0.5
0.5
1.0
2.0
Recovery
91
100
98
81
93
118
104
98
100
97
84
87
92
Precision
tt)
4
4
3
25
5
40
18
10
19
20
36
24
8
I
M
oo
Based on seven replicate determinations at the given concentration level with a single
operator.
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-29-
TRANSFORMATION-TRANSPORT MODEL
This section presents the derivation and exploration of simple
Eulerian and Lagrangian models of the SOg-to-SC^ transformation and trans-
port processes to a receptor along a mean trajectory. The pollutants are
considered to be confined between the ground and a capping inversion.
Diffusion in the horizontal is allowed. Simple linear models of the
transformation and the dry deposition processes are used. Wet removal
processes are not considered, but could be easily added to either the
analytical or numerical formulations. A sensitivity analysis of the
Lagrangian 1-dimensional analytic formulation illustrates not only the
importance and functional relationship of various model parameters, but
also the integral characteristics of the long-range transport process.
Model response is compared with field data in Section 4.
Model Development
The equation that describes the mean turbulent transport, diffusion,
and transformation of any conservative, gas-like, airborne substance is:
(2)
The term on the left side of this equation is the mean rate of increase
of C. per unit time. The first three terms on the right side define the
increase of C. resulting from 3-dimensional differential advection
transport. Trie next three terms define the 3-dimensional turbulent
flux-convergence for C.. The last term specifies chemical transformation.
Equation (2) becomes specific to a substance when appropriate conversion
parameters and boundary conditions are specified (Monin and Yaglom
1971). Although it is of limited utility as it stands, Equation (2) is
a useful starting point for model development, provided appropriate
assumptions are made and applied with suitable boundary conditions. This
apgroach was used to develop a simple regional transport model for S0£ and
864. Variables used in this subsection are defined in the List of
Abbreviations and Symbols located at the front of this report.
Analytical Model--
Consider a region of varying width (Figure 12), oriented so that its
length is parallel to the mean boundary-layer wind direction. It is
bounded above by an elevated inversion, below by the ground, and on either
end by the vertical inflow and outflow planes. Sulfur, as S02 and S04, is
carried into the region at the inflow by the mean wind and is augmented by
regional sources of S02, both natural and man-made. The regional airborne
sulfur is subjected to turbulent transport and diffusion, chemical
transformation, and deposition.
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-30-
INVERSION
Figure 12. Region used in the development of the long-range transport model.
Equation (2) can be greatly simplified to describe this situation.
To do so, eight assumptions are made.
ac.
1. —i = 0 (steady state).
at
2. U = constant; V = W = 0.
ac.
4. C. is independent of y and z.
ac.
.
5 K i is independent of x and z within the region.
8C.
u*-> .
6 K i is independent of x and y within the region.
7. K
8. K
9Ci
ac.
y = B/2
y = -B/2
8Ci
9C.
.
= - K
z = 0
z3l
= 0.
z = H
Letting i = 1 and integrating Equation (2) twice, once with respect to y
and once with respect to z, over the region yields
(3)
(4)
+ Hk)BC!.
Similarly, for i = 2, the resulting equation is
UH-(BC2) = -v2BC2 + SHkBCi/2-
-------
-31-
Equations (3) and (4) may be considered Lagrangian by virtue of the relation
x = Ut. These equations can be derived directly from first principles, as
Scrivin and Fisher (1975) did to obtain an Equation similar to Equation (3).
The analytical solutions for Equations (3) and (4) are
Ci = C° (BQ/B) exp {-[(Vl/H) + k](t - tQ)}, (5)
and
C2 = C?(Bo/B) exp [-(v2/H)(t - tQ)]
+ (3/2)C?(Bo/B) {[(V! - v2)/Hk] + I}'1
• {exp [-(v2/H)(t - to)] - exp {-[(vj/H) + k](t - tQ)]}. (6)
B /B is the factor defining dilution due to crosswind diffusion.
For single plumes Scriven and Fisher (1975) use B = B + 20Ut, where 0
is the (constant) angle of horizontal regional growth; Gifford (1976)
suggests that, over larger distances, B is proportional to t3 2 so that
B = bt3 2, where b is the proportionality constant. For regional transport
it is appropriate to set B to a large value, and B /B = 1 since multiple
plumes exist within the region, crosswind gradients are small, and the
mass that is diffusing out is nearly balanced by that which is diffusing
in.
In this form, Equations (5) and (6) do not account for sources of
S02 within the region. This deficiency can be remedied by using the
principle of superposition. If a source having emission rate Q is
encountered at x1, x < x1 < x, assume that the effluent is spread uniformly
within a plane that passes through the source and is normal to the wind.
Then the S02 concentration in this plane, which is now taken as the
initial plane, is Q/UHB1, where B = B' when x = x', and x' is taken as
the initial distance. The solution at the outflow plane is the sum of
the individual solutions.
Equations (5) and (6) likewise do not apply to a region having a
variable mixing depth. This deficiency can be overcome either by
(1) deriving Equations (5) and (6) by assuming H is a function of x, or
(2) applying Equations (5) and (6) in their present form in a stepwise
manner, requiring H to be constant during any step, but allowing H to
change from step to step. With this approach, the region is modeled by
stacking "boxes" of possibly different dimensions end-to-end along the
trajectory and modeling transport, diffusion, chemical transformation,
and deposition through each box in a piecewise-continuous manner.
Additional details are given in the following subsection. For complex
situations, the latter method is more versatile because obtaining a
closed-form solution by method 1 may not be possible when H is variable.
The box method can also be used to handle the presence of S02 sources
within the region.
-------
-32-
Simple Box Model--
With the "box" approach, the region is modeled by stacking "boxes"
end-to-end along the trajectory and modeling, in a piecewise-continuous
manner, transport, diffusion, chemical transformation, and deposition
through each box. Figure 13 illustrates how boxes are stacked to vary
mixing height and handle multiple sources.
When Equations (4) and (5) are applied across a "box," they become
for S02
C = (1 - H /H )C + (H /H )C exp [-(v /H +
1 >J J -1 J I)" *• x J ^JJ •*• -1 J
k)At]
+ Q./H.U ;
J J
(7)
BOX FOR THE
PREVIOUS
TIME STEP
BOX FOR
CURRENT
TIME STEP
LID
Figure 13. Schematic of the box model.
and for S04
v2/H.k) + I]"1 exp [-
-i + 3/2
.. + k)]At
(8)
Equations (7) and (8) are simple algebraic equations, which are
Lagrangian in nature and allow for varying mixing height and sources
along the trajectory. Again, the dilution term for crosswind spread has
been neglected in this formulation; the solution process proceeds simply
by solving Equation (7) for the J box S02 concentration and then using
this concentration in Equation (8). This solution procedure is repeated
as "boxes" are stacked end-to-end along the trajectory.
-------
-33-
Eulerian Model—
Equation (2) could be solved (as is) with implicit finite-difference
techniques since they demand nothing about the flow or diffusion situation.
Unfortunately, if assumptions are not imposed, such procedures make signi-
ficant demands on computer resources and knowledge of boundary conditions
(Crawford 1977). If the same assumptions used to obtain Equations (7)
and (8) are imposed, except that X ^ Ut, the following Eulerian finite-
difference model is obtained:
[I/At + U/Ax +
(l/At)C° + U/Ax(l-H ,/H )C
*->j J A J
+ k]
+ H /H C + 2/3 kC
J •"• J *•
(9)
>J [I/At + U/Ax + v2/H.]
Equations (9) and (10) are similar to the previous box model, and
oo
C . and C0 . are the box concentrations of S02 and S04 at the previous
i >J ^>J
time step.
Lagrangian finite-difference equations similar to Equations (7) and
(8) can also be obtained:
(10)
2/At [(1-H._1/H.)C1 b + H._1/H.C1 .]
[2/At + Vi/H. + k] +
2/At
2/3
v2/H
(11)
(12)
*'J [2/At
These finite-difference equations follow the analytic ones remarkably
well. For example, Equations (11) and (7) agree within a few percent
for a time step of 1 h for typical values of model parameters. But for
Lagrangian modeling, the truly analytic Equations (5) and (6) or (7) and
(8) are preferred because they are exact within model assumptions and
functionally tell more about the transport process. Figure 14 compares
the boundary conditions required and solution region obtained with
Lagrangian vs Eulerian models. As can be seen, the Lagrangian model
requires much less input information, but also yields less predictive
information.
\
POINT
BOUNDARY
CONDITION
SOLUTION ONLY
ALONG LAGRANGIAN
TRAJECTORY
t
SLOPE s
\
SOLUTION FOR.
THE ENTIRE
TIME /DISTANCE
DOMAIN
LINE BOUNDARY
CONDITION
Figure 14. Comparison of Lagrangian and Eulerian boundary conditions and
solution domains.
-------
-34-
Model Analysis
A sensitivity analysis of Equations (5) and (6) is useful because
it reveals the functional behavior of the model relative to its various
parameters and the theoretical behavior of the transport, transformation,
and deposition processes insofar as they are properly described by the
assumptions made to derive the model. In Equations (5) and (6), t (or
x IT1) is the independent variable, and H, V^, V2, and k, along with the
initial conditions Cx and €2, control the model response, Cj and C2.
Following the usual approach to sensitivity analysis, we varied each of
the four parameters and two initial conditions independently over a
range of possible values, centered about their normal values, while the
other parameters and initial conditions were held fixed at their nominal
values. The effect on model response with B /B = 1 is presented in
Table 4 and Figures 15 and 16. For these results, typical midday parameter
values were used: H = 1500 m, Vj = 1 cms'1; v2 = 0.1 cms"1; and k = 5.6
x 10~6 s"1 (2 percent per hour). Table 4 shows the effect of a 50 percent
change from the nominal value of each parameter.
TABLE 4. PERCENT VARIATION IN MODEL RESPONSE RESULTING
FROM A ±50 PERCENT CHANGE IN A SINGLE PARAMETER
Relative response (%) due to
parameter variation
Model parameter Typical value
k 2% h
v1 I cm s"1
v2 0.1 cm s"1
H 1500 m
Plus 50%
C j C2
-21 +36
-25 -11
-2
+23 +10
Minus 50%
C/">
1 ^2
+27 -45
+33 +13
+2
-44 -23
Figure 15 illustrates the effect of transport time on model response.
The Cj/Cj curve is exponential and is characterized by a time constant of
[(vj/H) + k]"1. For typical midday parameter values, dry deposition of
S02 is slightly more important than transformation of S02 to 804. These
processes together imply a half-life for SQ2 of about 16 h.
On the other hand, the
curve of Figure 15 is not exponential.
In fact, for B /B = 1, C2/C1 reaches a maximum value at
t* = to + in
- v2)/H] + k},
(13)
or about three days for typical parameter values. For Figure 15, we
assumed no initial sulfate (i.e., C2 = 0) and that t =0. Beyond t =
t* Cg/Ci decays more slowly—approximately exponentially at a rate
-------
10'
TRANSPORT TIME (s)
Figure 15. Predicted variation in S02 and SO, concentrations as a function of transport time.
-------
-36-
2 _ 4 6 8
S02 TO SOi CONVERSION RATE CX/h)
«) EFFECT OF VARIATIONS OF K>THE REACTION RATE CONSTANT,
ON SOZ AND SO? CONCENTRATIONS
100
1 2
SO, DEPOSITION VELOCITY lcm/6)
C) EFFECT OF VARIATIONS OF V,, S02 DEPOSITION VELOCITY,
ON S02 AND SO; CONCENTRATIONS
100
90
Ife/C*
V|-t.O m/dVrO.t
K *• UC/H T •
I
_L
800 12OO 1 BOO 2OOO
MIXING DEPTH (m)
240O
b) EFFECT OF VARIATIONS OF H, THE MIXING DEPTH, ON S02
AND SO; CONCENTRATIONS
too
0.5 1.0 1.5
SO^" DEPOSITION VELOCITY (cnv/s)
d) EFFECT OF VARIATIONS OF V2, SQ~ DEPOSITION VELOCITY,
ON SO2 AND SO7 CONCENTRATIONS
Figure 16. Effect of variations in model parameters on predicted response
after 24 h of transport.
-------
-37-
characterized by a half -life, due to dry deposition, of around 12 days.
Therefore, as shown in the meteorological characterization subsection,
precipitation occurs frequently enough to indicate that wet-sulfate
removal processes are probably dominant.
Without wet removal, the model confirms that long-range transport
over great distance is possible. Because C2/Ci is unique for each value
of t, the average age of an airmass passing the outflow plane can be
computed when this ratio is known. Assuming C2 = 0, the age is
ln[l + 2/3{[(Vl-v2)/Hk] + lUCa/Ct)]
t = - - t
3
Figure 16 illustrates the effect of individual parameter variation
on model response after 24 h of transport. This figure shows that k and
V! have the greatest control over response and v2 has the least. The
figure also shows that increases in either H or k will increase the
C2/Ct ratio.
Finally, the form of any of the models presented is such that the
effect of a single phenomenon cannot be separated or therefore estimated.
For example, the simplified form of Equation (5) is C/C = exp {(-vjYH
+ k) t}. It is apparent (based on the present best guess at the parame-
ters vx and k) that the effect of deposition is equivalent in magnitude,
direction, and form to that of chemical transformation. The sulfate
equations are even more transcendental in nature. This illustrates the
need for physical understanding and study of separate deposition and
transformation phenomena. Comparisons with data are presented in
Section 4.
In summary, the model predicts that airborne S02 decays exponentially
with transport time. Its half-life of about 16 h results from the yearly
equal effects of removal by dry deposition and transformation to 804. The
decay r^te is only a mild function of mixing height. The model also shows
that 864, aside from the initial presence of S04 concentrations increases
until it reaches a maximum after about three days of transport, after which
it decays almost exponentially. The model indicates tha| S04 is most sensi-
tive to changes in the transformation rate of S02 to S04. It is relatively
insensitive to changes in mixing height or deposition rates.
-------
-38-
SECTION 4
RESULTS AND DISCUSSIONS
SUL¥ATE COHCHWRMIOH MTO TLUX CLIMATOLOGY
Although the regional field studies supplied unique and informative
field data, these data are limited to only a few specific spring and summer
days. Long-term climatological data do not suffer from this deficiency,
and much can be learned from •variations in and interrelationships between
aerometric and meteorological parameters.
Seasonal Concentration Variations
The seasonal fluctuation of a pollutant is usually the most prominent
feature of a long-term data set. The analysis of four years of sixth-day
suspended sulfate data taken from the five rural Tennessee Valley monitor-
ing sites (Figure 17) reveals the strongly seasonal configuration shown
in Figure 18. Suspended sulfate concentrations are lowest in the winter,
highest in the summer, and intermediate in the spring and fall. The mean
summer concentration of 10,4 ^g m~3 is more than double the mean winter
concentration of 4.5 pg m"3. This pattern of summer suspended sulfate
maxima is consistent with the observations found in other sulfate research
conducted in the eastern United States and Canada (Garvey 1975; Hitchcock
1976; ERT 1976; Lioy et al. 1977; Tony and Batchelder 1978; and Melo 1978).
Although the seasonal patterns found in these studies are similar,
significant differences in magnitude do exist, with the highest sulfate
levels occurring at urban sites in the northeastern United States
(Altshuller 1973; Frank 1974; ERT 1976).
Many factors may be related to the seasonal pattern of suspended
sulfate values. These factors fall into three major categories—
emissions, transformation, and transport-related phenomena.
The anthropogenic contribution to sulfur in the atmosphere is well
quantified, particularly in the industrialized regions of the world. In
the past, the release of anthropogenic sulfur from these regions was strongly
seasonal—high emissions in the winter when much fossil fuel (particularly
coal) was used for space heating and low emissions in the summer months
when space heating was not required. However, the advent of cleaner fuels,
such as natural gas and low-sulfur coal, for space heating and industrial
processes and the promulgation of strict air quality regulations resulted
in an overall reduction in total sulfur emissions per kilowatt. During
this same period, however, total sulfur emissions were not reduced, pri-
marily because of the increased demand for fossil-fuel-generated electrical
power. Across the country and particularly in the Tennessee Valley, coal-
fired generating units provide the main source of electrical power. These
units provide base load generating capacity, and although peak demands
occur in heating and cooling seasons, the relative seasonal variation in
the rate of sulfur emissions can explain only a small percentage of the
-------
LBL
TRIGG COUNTY
KENTUCKY
LOVES MILL
WASHINGTON COUNTY
VIRGINIA
GILES COUNTY
GILES COUNTY
TENNESSEE
HYTOP
JACKSON COUNTY
ALABAMA
LOUDON
MONROE COUNTY
TENNESSEE
Figure 17. Regional air quality trend stations.
-------
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•°E 10.0
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Figure 18. Monthly variations of TVA's S02 emissions and regional sulfate concentrations, 1974-1977,
-------
-41-
seasonal sulfate variation (Figure 18). Therefore, anthropogenic sulfur
emissions are not significantly related to the seasonal pattern of sus-
pended sulfates in the Tennessee Valley region.
The natural contribution of sulfur to the atmosphere is not well
quantified. Several researchers (e.g., Robinson and Robins 1972; Lovelock
et al. 1972; Friend 1973; Hitchcock 1975) have estimated natural emissions
on a global scale, but little additional information exists.
Biological emissions of atmospheric sulfur, thought to be mostly
hydrogen sulfide (H2S), are undoubtedly related to seasonal fluctuations
in temperature. Biological activity and emissions of H2S are greater
with increasing temperature. This source of emissions may be partly
responsible for the seasonal sulfate pattern—particularly in the TREATS
region, where typical summertime southwesterly transport allows sulfur
input from the potentially large natural sulfur-producing regions of low-
lying marshes and swamps found in east Texas, Louisiana, and Mississippi.
Natural sulfur sources and their contribution to regional airsheds are
of paramount concern.
Various transformation processes and their respective rates may also
be partly responsible for the high summer levels of suspended sulfate.
The conversion rate for S02 to S04 is greater in the summer (about 1.4
percent per hour) than in the winter (about 0.3 percent per hour) (Meagher
1977). The increase in summer conversion rate is believed to result from
increased photochemical activity. The difference in conversion_rates
and the relative deposition velocities of S02 (1 cm s"1) and S04 (0.1
to 0.5 cm s"1) indicates that high summer sulfate levels result at least
partly from seasonal variations in transformation processes.
High sulfate concentrations are usually associated with stagnating
anticyclonic airmasses (ERT 1976; Teknekron 1977). Within the TREATS
region these stagnating conditions are more prevalent in the summer and
fall months than in the other seasons (Korshover 1976). Of either con-
tinental or maritime origin, these conditions are associated with high
temperature, humidity, and insolation and with low precipitation and
ventilation. Meteorological factors present in these airmasses seem to
provide optimal conditions for both sulfate generation and its atmospheric
buildup. Some airmass characteristics are thus related to optimization
of the transformation process (i.e., high temperature, insolation, and
humidity), whereas others relate to concentration of the end product
(i.e., low precipitation and poor ventilation). The strong frontal
activity associated with the winter months exhibits contrary factors,
which result in less transformation and concentration buildup.
In summary, the factors resulting in the seasonal summer sulfate
concentration maxima may be relegated to three major categories:
(1) increased natural and anthropogenic emissions; (2) enhanced gaseous
sulfur to particulate sulfate transformation; and (3) poor transport con-
ditions, resulting in atmospheric sulfate buildup.
-------
-42-
Regional Sulfate Flux Rose
To better describe the flux of sulfate pollution through the TREATS
region and the significant variables that influence it, a sulfate trajec-
tory climatology analysis is presented. This analysis summarizes three
years of sulfate flux data, gathered every sixth day beginning on January 4,
1976. It incorporates (1) sulfate data obtained from three TVA high-volume
sampler sites centered around Nashville, Tennessee; (2) boundary-layer
meteorologic parameters obtained from the NWS site at Nashville, Tennessee;
and (3) synoptic weather typing (as described in the Meteorological Charac-
terization subsection of Section 3). These parameters have been analyzed
seasonally and annually. Correlations between and among variables are
described, and significant findings are discussed.
The sulfate concentration numbers used are the averages from three
TVA monitoring locations—Cumberland and Gallatin Steam Plants and Giles
County trend station—that surround Nashville, Tennessee. A logical
question is whether the proximity of the power plants to the high-volume
samplers leads to spurious sulfate readings. However, as described in
more detail in the Eulerian Space and Time subsection of Section 4, the
sulfate measurements obtained at the plants are thought to be represen-
tative of regional levels. Also, a plot (Figure 19) of the concentration
values from the Giles County trend station vs. the average of all the
sites supports this conclusion. Figure 19 shows a slope of near one and
a high correlation coefficient.
The meteorological parameters include average wind velocity and dew-
point temperature through the first 1500 m AGL averaged from twice daily
NWS radiosondes. Also included are the weather typing parameters as
described in the Meteorological Characterization subsection, Section 3.
Analysis of the data (Figures 20 and 21) graphically shows that the south-
west sector dominates as the favored sector for mass transport through
the Tennessee Valley region. The dominance of this sector for transport
is also supported by the trajectory and meteorological analyses presented
earlier. An analysis of 24-h back-trajectory data shows that the favored
source origination region for this southwesterly flow sector is located
in southern Louisiana and Mississippi. Implications of this region as a
potentially major biogenic source region are discussed in the Lagrangian
flux analysis subsection.
The relative distribution of the range of aerometric and meteoro-
logical variables within sectors is also of interest. The frequency of
occurrences of a given parameter by sector have been divided into three
ranges.
Intercomparisons between sectors show the relative importance of
each in producing elevated pollutant and wind speed levels. Due to a
limited data base, the individual 22.5-degree sectors have been grouped
into 90-degree sectors for analysis purposes. Even when this is done,
the southeast sector still has insufficient data (8 observations) for
inclusion in the analysis. The results of these annual relative fre-
quency distributions are shown in Figure 22.
-------
-43-
25,
15
CO
CO
CJD
10 20
TOTAL SO ;
Figure 19. Giles County sulfate concentration (|Jg m"3) vs. the average
concentration of Cumberland, Gallatin, and Giles.
-------
-44-
-E W-
(A) WIND SPEED (m/s)
(C) WIND DIRECTION (degrees]
-E W-
s s
(B) SULFATE CONCENTRATION (Mg/m3) (D) SULFATE FLUX (pg m2 s'1)
Figure 20. Annual frequency distributions of wind speed, wind direction,
sulfate concentration, and sulfate flux for Nashville,
Tennessee.
-------
-45
-E W
:AJ WINTER
(B) SPRING
(C) SUMMER
(D) FALL
Figure 21. Seasonal frequency distributions of Nashville sulfate flux
(|Jg m~2 s""1).
-------
-46-
ctr
ct:
CJ
CJ
CD
CD
>-
CJ
C3
LU
CrT
201
ctr
LEGEND
COMCENTRAION
-> s«
:0-32
«?c
WIND SPEED (m sl)
NUMBER OF OBSERVATIONS PER SJCja? IN PARENTHESIS
CONC
NE SV NV
iViV
:»T*i»r<
Figure 22. Relative frequency distributions.
-------
-47-
An analysis of the data presented in Figure 22 shows that, although
most sulfate is transported into the Valley from the southwest, the
greatest concentration maxima occur with northeasterly flow. Reisinger
and Crawford (1979) have shown that this trend can result from the
transport of modified continental polar air from the high emission
density region along the Ohio River valley into the study area. Also,
the southwest and northwest sectors have almost identical concentration
distributions, probably indicating a lesser, more diffuse source region
than is associated with northeasterly flow. As will be shown subse-
quently, aircraft data from the two field studies also support this
analysis.
The relative annual flux distribution by sector is also shown in
Figure 22. Contrary to the concentration analysis, this figure indicates
that the cumulative flux distribution shown in Figure 20 is a good
indicator for the relative magnitude of flux by sector. An analysis of
the relative flux distribution shows that, within the southwest sector,
flux values are greater than 66 (Jg m"2 s"1 on 30 percent of the days.
This is almost twice the relative occurrence of the other two sectors
analyzed. Naturally, since pollutant flux is inherently tied to wind
speed, the close similarity between the relative flux plot and the wind
speed plot shown in Figure 22 is not surprising. Also, the wind speed
plot is well correlated with the other pollutant frequency distributions,
especially for the southwest sector.
An analysis of the seasonal variation in both flux and concentra-
tion, regardless of sector, is shown in Table 5.
TABLE 5. MEDIAN SULFATE FLUX AND CONCENTRATION VALUES REGARDLESS OF SECTOR
Flux Concentration
Season (ug m~2 s'1) (|Jg m~3)
Winter
Spring
Summer
Fall
42
50
44
38
5
6
11
7
This table shows that sulfate flux peaks during the spring, whereas
sulfate concentration peaks during the summer. Variations in these varia-
bles depend at least partly on variations in airmass type, wind velocity,
solar radiation, and biogenic and anthropogenic emission. In an attempt
to determine the relative importance of one of these parameters, airmass
type, a joint frequency distribution analysis was performed. This analy-
sis indicates that concentration and flux levels differ only slightly when
the airmass type is either maritime tropical or modified continental polar.
However, when modified maritime polar airmasses are present, high pollutant
-------
-48-
levels rarely occur. This, no doubt, results partly from low natural and
man-made sulfur emission rates in the upwind areas of the Great Plains.
Analysis of the relationship between high sulfate flux levels and meteoro-
logical characteristics indicates that the highest sulfate flux values
(2 100 |Jg m"2 s"1) occur during southwesterly flow of maritime tropical air.
This flow occurs, almost exclusively, in response to gradients related to
prefrental or Bermuda high pressure patterns.
FLUX CALCULATIONS
Measurements of regional mass transport (or flux) of a pollutant
are very useful for assessing not only the impact of the studied area on
itself and adjacent regions, but also the impact of adjacent regions on
the studied region. Ideally, pollutant flux can be defined at any
location, but measurements at inflow and outflow locations relative to
the study region are the most informative. An inflow measurement defines
the impact of an upwind region on the study area, whereas an outflow
measurement defines the combined impact of the upwind and study regions
on the downwind region. The net impact of a studied area on a downwind
region is defined by differences in these measurements (i.e., outflow
minus inflow). This difference, when complemented with meteorological
and source information, is also useful in studying characteristics and
mechanisms of the long-range transport phenomenon.
Few researchers have attempted regional flux measurements because
of the measurement difficulties imposed by the large space and time
scales. This section presents the methods and results of two modest
field studies that attempted such measurements within the Tennessee
Valley region. Our intent is not that these measurements be considered
exact (no measurement is), but that they are reasonable estimates from
which several significant conclusions can be made.
Estimating Concentration and Flux
The variable that describes net pollutant mass transport is pollutant
flux. Pollutant flux can be defined at a point, over a line, or through
a plane. The appropriate method for assessing regional impact is the
pollutant flux through a plane. This is defined as
Ft(x,t) = /;c.Udyd2/(H-L), (15)
where
C. = concentration of pollutant species i,
U = transporting wind speed (ideally normal to the measurement
plane),
H = height of the plane,
L = length of the plane,
F. = transported mass of pollutant species i per unit area per unit
1 time.
-------
-A9-
Unfortunately, Equation (15) is impossible to evaluate rigorously because
C. and U vary, not only as a complex unknown function of position coordinates
x, y, and z, but also as a function of time t. Therefore, assumptions
must be made about the spatial and temporal variations of C. and U.
By assuming that variation in time is "slow" compared with the time
scale required for the measurement (about 2 h) and the horizontal
inhomogeneity can be integrated out by long horizontal sampling traverses
(about 150 km), then Equation (15) can be approximated as
HR + SUS _
H was used in the F. approximation. Values of C~ for SOz ar*d 864 were
max i D
obtained by averaging the limited number of actual measurements made above
the subsidence inversions with the 10 percentile values determined from an
analysis of all measurements made by the two aircraft. This correction
allows for mass conservation when comparing mass flux during the diurnal
cycle and is especially important when comparing early morning to midday
measurements. When the morning subsidence inversion height is greater
than the afternoon mixing height, mass concentration is assumed to result
from meteorological subsidence of superior air. Thus, no corrections are
made under these conditions. Also, so that intercomparison between days
can be made, the sulfur flux values for all days have been normalized to
the grand mean subsidence inversion height measured on all field study
-------
MORNING
Figure 23.
AFTERNOON
Schematic of typical flux calculation procedure.
I
(^
o
-------
-51-
sampling days, H (1600 m). In the following subsections, the methods of
approximating the variables listed in Equation (16) are discussed.
Estimating U, HR, and H_--
Any accurate calculation of mass flux inherently depends on a good
estimate of wind speed. In like manner, an accurate estimate of the
mass balance depends on a good estimate of mixing height. For both the
1976 and 1977 studies, the TVA and NWS upper-air stations closest to and
most representative of the airmass sampled were used to estimate actual
mixing height and resultant wind speeds. These stations and their
representative wind speed and mixing height values for the Eulerian and
Lagrangian days are listed in Appendix C. HR was simply defined as any
surface-based inversion with 9T/3z ^ 0. To determine the best estimate
of the actual average mixing height for a group of measurements, the
representative sounding was plotted, and the near-surface temperature
measured at midsampling time was used to find the dry adiabatic inter-
section of the sounding. Variation can possibly occur when estimating
the actual mixing height, especially during midmorning, which is the time
when the radiation inversions usually dissipate. However, on the average,
this method is a good approximation to the true mixing height (Holzworth
1972).
After the mixing height was determined, the layer resultant wind
velocity was determined. This velocity multiplied by the mean layer
concentrations and normalized for H produces the flux values presented
in the following analyses.
Estimating SO and NH4 Concentrations--
A.
Sampling limitations necessitated estimation of CR, €„, and C, the
mean transport layer concentration, from a few (two to four) discrete
horizontal integrated average values and "typical" pollutant profile
shapes. Figures 24 and 25 show the typical profiles of sulfate and total
sulfur, as determined from actual measurements during the TREATS 1976 and
1977 field studies. The observed sulfur values were interpreted by con-
sidering the appropriate profile and were averaged both within and between
inversion layers to obtain the most representative estimates for C-, Cc,
+ Kb
and C. Because most of the NH4 is assumed to be in the form of (NH4)2S04,
the typical sulfate profiles were also used to estimate the average for
KH4. CR for NH4 was assumed to be the stoichiometric amount needed to react
with the background S04 (i.e., 0.3 |Jg m"3 of NH4).
Estimating N03 and 03 Concentrations--
In a manner similar to the estimation for sulfur and ammonium
salts, discrete horizontal integrated values were obtained for nitrate
and ozone. The most significant differences between these pollutant
profiles and the typical sulfur profiles were their high scatter and
-------
1.5
1.4
1.3
1.2
X 1.1
tEGEND
Z
o
1.0
.8
.7
2
OL
O -5
Z
PREVIOUS _DA_YS
MIXED LAYER
TYPICAL RADIATION
I NVERSION HEIGHT
D
SYM DATE
H C 3
(m) Qig/m )
D 6/03/77 2800
-K- 6/04/77 1520
• 6/05/77 1480
+ 6/08/77 2010
X 7/06/77 1570
A 7/07/77 1160
H PREVIOUS BAYS MIXED
IAYER DEPTH
2
4
8
2
15
12
AVERAGE CONCEHTRATIOH
VJITHIH H
C;C^ 1.55 -I.24IZ/H)
F : to.*
n
.8
LLj
LLJ
.7
Q
uj
hJ
Z -6
OC
O
2
.4
.3
.2
P R_E VJOUS _DA^S
MlXED LAYE R
SYM DATE
6/04/77
6/05/77
6/08/77
7/06/77
7/07/77
X
A
H
I£gEND
H
(m)
1520
1480
2010
1570
1160
C 3
Qig/m )
55
24
57
46
40
PREVIOUS DAYS
IAYER DEPTH
HOED
AVERAGE CONCENTRATION
WITHIN H
C/C =1.98-1.65 (I/HI
TYPICAL RADIATION
i NVERSION HEIGHT
C/C=0.2J + S.4HZ/H)
i i i i
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2
NORMALIZED TOTAL SULFUR PROFILES (C/C~)
Figure 24. Typical early morning sulfur profiles.
-------
2.0
1.8
1.6
I
LEGEHD
SYM DATE H
£m)
• 12/19/75 762
+ 2/24/76 1060
O 3/11/76 1200
X 3/23/76 1750
• 3/24/76 1800
# 6/03/77 1220
Oil *- 6/04/77 1430
r D 6/24/77 2000
A 7/07/77 1900
c" ,
Oifi/ni )
1.8
2.8
7.0
3.2
4.7
3.7
7.2
1.9
17.1
-^ j H MIXED LAYER DEPTH
— 1.4 L C AVERAGE MIXED LAYER
Z \±t COHCEMTRATIOH
P C
< L
> U •
u, 1 +
UJ
Q
i: i.o
IVJ
<
I 0.8
O
Z
0.6
0-4
0.2
• SUBSIDENCE
u -° ' 1 N VERSION 1
I
A Di-
•xi
• *-
i
T
#-*-»
i
f
I D
' A
. , , , . , , , , 1 ,• i + i i i i lO j i tf
[
!
KED
/ER
A* , , ..
2.0
1.8
1.6
I
IN
~ 1.4
Z
O
\ u
UJ
UJ
2 i.o
M
<
oc 0.8
O
Z
o.«
0.4
0.2
LEGEHD
SYM DATE -EL ,03.
# (£) Qag/m )
• 3/11/76 1200 69
X 3/23/76 1750 56
O 3/24/76 1800 60
+ 6/24/76 1800 60
# 6/03/77 1220 38
*- 6/04/77 1433 25
H 6/24/77 2000 216
A 7/07/77 1910 80
H MIXED LAYER DEPTH
C AVERAGE MIXED LAYER
CONCERTRATIOlf
#
1
1 S U B SI DE NCE
I 1 N VERSION 1
:
A
t i
# !
«x i
*
i
MIXED 1
I
0 LAYER j
i * '
*x * i
j,
*
t
1 E
o ,
i
O i
' o'? ' n'^ ' r>V ' «'. ' .'o ' .' ' '. ' -T^-^-A- ' J. '.'.'. t
W
I
0.8 1.0 1.2 1.4 1.6 1.8 7.0 2.2
NORMALIZED SULFATE C ONC E NTRA T ION (C/C)
1A
«... w.u W.B i.u i.* 1.4 1.6 1.8 2.0 2.2
NORMALIZED TOTAL SULFUR CONCENTRATION (C/C)
Figure 25. Typical midday sulfur profiles.
-------
-54-
lack of shape, as illustrated by Figures 26 and 27. Because of this scatter,
a vertical weighing factor, based on actual measurement location within
the mixed layer, was considered to be more representative of the mean
layer concentrations than any other estimation technique. No attempt
was made to correct for background concentrations above the subsidence
inversion when calculating C.
Flux Measurement Criteria--
For the flux analysis to be reasonably accurate and useful, certain
criteria are required:
1. The direction of airflow has to be relatively steady; that is,
the directional variation of the mean transport wind in both
space and time must be less than or equal to ±45°.
2. Both inflow and outflow measurements must be made to obtain
daily Eulerian or Lagrangian concentration values. These
measurements must be made over a sufficiently wide spatial
extent, in both the horizontal and vertical, to be represen-
tative of the airmass sampled.
3. The meteorological conditions specified in the Meteorological
Measurements and Support subsection of Section 3 must be met.
These criteria were met on five Lagrangian days and six Eulerian
days during the two studies. Only one Lagrangian day was sampled during
the 1977 summer study, whereas four Eulerian days were sampled. Three
of the inflow-outflow Eulerian measurement days in 1977 were made during
northerly wind flow.
A Lagrangian event (day) is defined as outflow aircraft measurement
of the same airmass that was previously sampled at the inflow end, plus
or minus 1 h. All other airmass measurements were defined as Eulerian.
The average time of a set of aircraft traverses at both inflow and outflow
is the time used for Lagrangian-Eulerian calculations.
For the Lagrangian days, the second criterion usually imposed an
airmass age of 7 h to the outflow sampled airmass. This occurred for
two reasons: (1) The aircraft had limited performance capabilities, which
restricted them to daytime hours and limited cruise speeds (<100 knots);
and (2) the large distance (~250 km) between inflow and outflow measure-
ment points required a fairly rapid airmass inflow-to-outflow traverse
time so that darkness would not curtail sampling operations. Because
inflow measurement times usually averaged 0800 h these requirements
limited Lagrangian operations to a fairly narrow "window" of favorable
wind flow speeds of from 8 to 12 m s"1 (i.e., airmass age of 6 to 8 h).
Figure 28 graphically shows both the Lagrangian and Eulerian measurement
regimes. Here the earliest measurement defines the relative origin for
other measurements for the same day.' Only days with both inflow and
outflow measurements are plotted.
-------
=Y180L DATE
I
\
N
Z
a
LL
J
UJ
D
U
O
Z
6 —
I •» -
J
»
O
_>
G
2/20/7P
5/1 i/7f
V18/7C
V24/7C
e/O^/77
C/18/77
fV^tt/77
f/TO/77
7/OCV77
7/C.7/77
1 981
1219
(y q/m 5
IBb
177
m
ea
9=;
42
MI_XED_
LA YER
8 -
TYPICAL RADIATION
INVERSION HEICMT
2 -
1-2!-
f SUBSIDENCE
1 D
^ i INVERSION
0 '
( . 1 —
1
8 i—
LU i-
Cu f-
|_
a . i
LU 0 t—
r^Kj —
5 h
21 i
a: •* 1-
i L
i—
K
LEGEND
DATE H
t> 2/19/76 1900
O 3/11/76 12BO
» 3/18/76 1372
O 3/23/76 1767
O 3/2V76 1 829
a 6/02/77 280S
•+- 6/28/77 1372
* 6/30/77 1629
• 7/06/77 1067
H-MIXED LAYER DEPTH
«
O
o
c.
Z07
163
180
170
196
20S
114
162
151
(ml
C-AVERACE M;XED LAYER
CONCENTRATION tug
/m3)
D
0 o» +
1 •
D
* 00
•
o °
* * D
Ln
C/i
1
! 2
MORNING OZONE PROFILES (C/C)
2 1 6 8 I 0 I 2
MID DAY OZONE PROFILES (C/C)
Figure 26. Typical early morning and midday normalized ozone profiles.
-------
2.0
o
i—i
i—
LU
_J
LU
Q
LU
rM
i—i
_J
4- D
r o
**
i i ill
LEGEND
DATE H C DATE H C
t> 6/03/77 1676 .35 0 6/18/77 25OO .30
O 6/0^/77 1219 .^0 X 6/28/77 152^ .18
•ft 6/CH/77 128O .^8 ^ 6/ZO/77 1220 .33
<> 6/05/77 1159 .25 • 6/30/77 1220 .95
O 6/08/77 18Z9 .Z3 * 7/06/77 990 .30
D 8/08/77 1*28 ,*S • 7/06/77 137Z .33
+ 6/18/77 2SOO .1Q * 7/O7/77 1676 .25
H-MIXED-LAYER DEPTH Cm)
C-AVERA^GE MIXED-LAYER CONCENTRATION (Mg/m3)
SUBSIDENCE
INVERSION
O
»
t>
*K * *
x o
<-> D
m t> TYPICAL RADIATION
w <-> INVERSION HEIGHT
o
^ •%
• 21 x£<> ^01 +
i i i i ili^itili
I
Ul
0
.4 .8 1.2 1.6 2.0
NORMALIZED NITRATE PROFILES (C/C)
Figure 27. Typical early morning nitrate profiles.
-------
LU
U
z
<
h-
O)
1—I
Q
H
a:
o
Q_
U)
z
<
cr
D
Z
CJ)
3OO
250
2OD
150
1 DO
50 -
0
LEGEND
- Z/ 10/76
O - 2/ 1 9/76
O ~ 3/11 /76
[> - 3/18/76
^ - 2/22/76
O - 2/24/76
NOTE-DAYS OF INFLOW AND OUTFLOW
MEASUREMENTS PLOTTED WITH EARLIEST
INFLOW POINT AT ORIGIN
> - 6/03/77
O - 6/0^/77
O - 6/Z8/77
D - 6/30/77
+ - 7/06/77
LANCRANCIAN
MEASUREMENT
REGION
EULERIAN
MEASUREMENT
REGION
O
O
O
50 1OO 150 200 250 3OO
OUTFLOW MEASUREMENT DISTANCE Ckm)
Figure 28. Airmass transport distance vs. inflow-to-outflow sampling distance.
-------
-58-
The bias toward sampling during southwesterly flow conditions results
from three factors:
1. As stated previously, "typical" meteorological conditions were
desired. As evidenced from Section 3, flow from the southwest
is typical.
2. High sulfate pollution episodes have been documented with southwest-
to-northeast flow of maritime tropical air from the Gulf of
Mexico (Perhac 1977; Smith and Niemann 1977).
3. Wind velocity sufficiently steady and strong enough to allow
for Lagrangian measurements occurred almost exclusively with
flow from the southwest.
Tabular Summary of Flux Calculations--
The Lagrangian and Eulerian aircraft sampling data for both 1976
and 1977 are summarized in Table 6. All days when Valley-wide measure-
ments were made are listed in this table. The complete data set for all
aircraft measurements is given in Appendix D. Due to instrument problems,
only relative changes can be analyzed for the 1977 measurements made by
the Meloy 202 total sulfur instrument. This instrument was almost exclu-
sively used for measurements at the northern end of the Valley (i.e.,
Scottsville, Kentucky, area), and its readings are identified by a super-
script "i" after the total sulfur reading. In the following sections,
the data from Table 6 are analyzed by measurement type. A detailed
synoptic meteorological summary for the Lagrangian and Eulerian days is
given in Appendix E.
EULERIAN SPACE AND TIME VARIATIONS
The Eylerian space and time variations of four pollutants--total
sulfur, S04, N03, and NH4--are explored. Eulerian space variations are
explored by grouping measurements that were made at similar times, but
in different horizontal or vertical space locations. Similarly, Eulerian
time variations are explored by grouping measurements that were made at
the same locations, but at different times. Aircraft measurements fitting
into these two groups occurred exclusively during the 1977 summer study.
The aircraft data used in these analyses are taken from Table 6.
High-volume measurements of total suspended particulates and 864
are taken from both study periods. The high-volume sulfate is analyzed
separately from the aircraft sulfate because of an interesting discon-
tinuity between the two measurements. This discontinuity is discussed
further in the Vertical Variations subsection.
Eulerian Space Variations
Eulerian measurements were separated in both horizontal and vertical
space. Typically, measurements were made at two locations separated by
an average horizontal distance of over 200 km. These sampling locations
-------
TABLE 6. SUMMARY OF LAGRANGIAN AND EULERIAN MEASUREMENTS
Sampling Days With Both Inflow and Outflow Measurements
Pollutant concentration
Date
2/10/76
2/19/76
3/1J/76
3/18/76
3/23/76
3/24/76
6/3/77
6/4/77
6/28/77
6/30/77
7/6/77
Time3
0916
1526
0927
1455
0908
1425
083S
1418
0834
1345
0800
1332
0743
1030
1110
1440
1505
0726
0717
1030
1453
1518
0723
1025
1025
1345
1335
1651
0637
0713
1033
1000
1345
1406
0646
0815
1030
1240
1425
1533
b c d
Sampling WD WS DST
methodology (•) (m/s) (tern) SO,
L 217 13.6 293 1.8
L 274 9.8 200 1.2
E 200 3.6 278 4.5
L 226 10.5 234 3.2
E 210 2.5 250 2.9
I 198 9.5 242 2.8
E 021 3.5 190 1.5
3.6
1.6
E 004 1.3 190 3.8
4.1
6.6
E 240 8.7 234
3.4
3.9
3.4
L 233 9.7 234 1.9
2.6
3.2
E 357 2.0 234
19.3
11.7
16.3
Inflow
WH,
0.5
0.4
1.3
0.8
1.8
0.9
0.4
0.9
LR
1.1
1.5
1.8
0.7
0.5
0.5
0.4
0.5
0.9
2.1
2.0
2.6
rat/so; TS' ml o3
1.5
1.9
1.6
1.4
3.2
1.7
1.3
1.4
LR
1.6
2.0
1.4
1.0
0.7
0.8
:. i
0.9
1.4
0.6
0.91
0.84
42
67
49
71
85
52
LR
37
LR
LR
31
22
237
134
93
63
76
62
40
51
45
-------
TABLE 6 (continued)
Other Eulerian Days
Date
6/5/77
6/8/77
7/7/77
Time3
0702
1137
1500
0658
1045
1430
0716
1105
0645
1015
0721
1115
1100
1428
Sampling
class
0
0
0
N
N
N
N
N
B
B
N
N
0
0
WD WS
(°) (m/s)
327 5.0
285 2.9
287 4.4
VRB
274 4.9
317 3.2
Pollutant concentration (\ig m 3)e
S04
22.7
7.8
10.8
5.9
7.4
13.1
1.3
2.0
3.6
1.8
8.5
9.2
12.1
22.8
-f.
NH4 NH4/S04
3.0
2.9
1.6
1.3
2.2
3.7
0.4
0.9
1.3
0.7
1.3
2.1
3.2
2.9
0.7
2.0
0.8
1.2
1.6
1.5
1.7
2.4
2.0
2.2
0.8
1.2
1.4
0.7
TS1 N03 03 H (m)*
186
57
52
21
42
30
45
34
89
61
25
31
103
80
0.3
0.6
0.5
0.2
0.7
0.4
0.2
0.3
0.4
0.3
0.2
0.1
0.5
0.5
_
-
-
215
246
267
LR
141
-
-
98
111
-
—
1677
1677
1677
1677
1677
1677
1829
1829
1829
1829
1900
1900
1900
1900
Pollutant
fluxE
(Mg m'2 s"1)
• S04
114.2
41.7
61.9
16.6
31.8
28.8
9.0
9.6
NA
NA
40.9
48.9
41.7
105.7
.
TS1
934
307
300
60
180
66
323
161
NA
NA
160
167
355
369
Center point
of traverse
Threet, AL
Center Star,
Anderson, AL
Scottsville,
Scottsville,
Portland, TN
Franklin, KY
Franklin, KY
Red Bank, AL
Wolf Springs
AL
KY
KY
, AL
Lewisburg , KY
Central City
Waterloo, AL
Red Bank, AL
, KY
Midtime of sampling traverses.
L = Lagrangian; E = Eulerian; B = blob; 0 = outflow; N = neither.
Mean wind direction and speed for the sampling day.
Distance in kilometers between average midpoint of inflow and outflow sampling traverses.
Abbreviations: - = pollutant not measured; LR = lost record; NA = not applicable;
-------
-61-
were typically in south-central Kentucky and northwestern Alabama. These
locations characterized either inflow, outflow, neither, or blob (stag-
nation) conditions, depending on meteorology. Such measurements were
also made at various elevations.
Horizontal Variations--
When winds were steady enough, inflow and outflow measurements were
made. Five such days were sampled during the 1977 summer study. Again,
the limitation of this data base_to just five summer days allows only
tentative findings. Plots of 864, NH4, total sulfur, and NOg aircraft
values, listed by measurement type and flow direction, are presented in
Figures 29 through 32. Intercompari|on by pollutant shows that, with
northerly flow, average values of S04 concentrations (Figure 29) vary
significantly from inflow to outflow and from day to day. However, with
southwesterly flow the situation is reversed. Little spatial or temporal
variation is evident. Although this difference may be due only to the
limited number of days sampled, it could also be due to the variation in
SOg emission density. Large sulfur sources are immediately upwind from
the inflow (northern) boundary during northerly wind flow, whereas just
the opposite is the case for the inflow (southern) boundary with south-
westerly flow. Similarly, for ammonium (Figure 30) the northerly inflow
boundary shows greater variability and higher concentrations vs. those
at the southern inflow boundary. Nitrate concentrations (Figure 32)
show an opposite correlation, indicating that its major source regions
differ significantly (possibly natural vs man-made). The average
inflow and outflow concentrations and standard deviations by pollutant
for three days with northerly flow and for the two days with south-
westerly flow are shown in Table 7.
TABLE 7. INFLOW-OUTFLOW CONCENTRATIONS (pg m"3) BY FLOW DIRECTION
Flow direction
North-northeast
Pollutant
S04
NH4
NO;
Inflow
7.6 (6.6)
1.5 (0.7)
0.3 (0.2)
Outflow
11.2 (5.0)
2.6 (1.3)
0.6 (0.2)
South- southwest
Inflow
3.1 (0.7)
0.6 (0.2)
2.0 (1.0)
Outflow
2.6 (1.0)
0.6 (0.5)
0.5 (0.2)
Q
Standard deviations in parentheses.
Significant increases occur in the average concentrations of all
three pollutants from inflow to outflow with northerly winds, whereas
no significant change occurs from inflow to outflow with southwesterly
flow, except for the nitrates. The nitrates show a large inflow concen-
tration with southerly flow and a small outflow concentration.
-------
\
ON
10
7/07/77
O NW
Figure 29. Temporal variation of sulfate (I = inflow, 0 = outflow, N = neither, B = blob; wind
direction in upper right corner of each axis).
-------
X
I
o
U>
Figure 30. Temporal variation of ammonium (I = inflow, 0 = outflow, N = neither, B = blob; wind
direction in upper right corner of each axis).
-------
6/08/77
N • w
I VB6
7/07/77
O- Nw
Figure 31. Temporal variation of normalized total sulfur (I = inflow, 0 = outflow, N = neither,
B = blob; wind direction in upper right corner of each axis).
-------
N- w
Figure 32. Temporal variation of nitrate (I = inflow, 0 = outflow, N = neither, B = blob; wind
direction in upper right corner of each axis).
-------
-66-
Traditionally, total filterable sulfates have been measured as water-
soluble sulfates from glass-fiber, high-volume filters. Although serious
questions as to the adequacy of this sampling method have often been raised,
governmental agencies and private industry continue to use the high-volume
method. Therefore, establishment of a relationship between high-volume
concentrations, upper air concentrations, and interregional transport
would be useful.
High-volume filter data, mostly for daytime periods, from the two
studies are presented in Appendix D. These data are obtained from fixed
monitors, most of which are located near TVA power plants (Figure 3).
Depending on wind flow conditions, these sites are designated as being
representative of inflow, outflow, or neither (in between). A presenta-
tion of inflow-outflow-neither high-volume measurements by wind direction
is shown in Table 8.
TABLE 8. HIGH-VOLUME CONCENTRATIONS (ug m~3) BY FLOW DIRECTION
Number
of days
7
3
Average
4
12
Average
Weighted
Wind
direction
WNW (270-329°)
N (330-029°)
S (150-209°)
WSW (210-269°)
grand average
Inflow
TSP
79
92
85
62
76
69
75
_
S04
12
15
13
6
8
7
9
.1
.1
.6
.6
.0
.3
.7
Outflow
TSP
93
86
89
86
60
73
79
-~
S04
17
17
17
8
6
7
11
.5
.3
.4
.0
.6
.3
.2
Neither
TSP
79
85
82
55
50
53
65
^
S04
15.4
17.5
16.5
7.2
6.4
6.8
10.5
Average
TSP
84
88
85
68
62
65
71
so;
15.0
16.6
15.8
7.3
7.0
7.2
10.5
Analysis of these data shows that, similar to the aircraft data,
sulfate concentrations differ significantly with various wind flows.
West-northwesterly through northerly flow is accompanied by high sulfate
concentrations at both inflow and outflow, whereas the opposite is true
for southerly or west-southwesterly flow. Total suspended particulates
follow the same pattern; only the relative magnitude of the changes are
less. For all days, the average increase in sulfate from inflow to
outflow is 15 percent, whereas total suspended particulates show no
significant change.
Vertical Variations—
Typical early morning and midday sulfur profiles are illustrated in
Figures 24 and 25 respectively. To generate these plots, data were norma-
lized and pooled, regardless of location. Both plots illustrate a somewhat
unexpected behavior. The early morning profiles scale well in the vertical
when the previous day's mixed-layer depth is used. At the lower boundary
(Z/H = 0), the data suggest that through the night SO?, (the main component
-------
-67-
of the total sulfur plot) is selectively removed, whereas S04 shows no
apparent tr.end. This could indicate a significant difference in nighttime
SC-2 vs. S04 deposition velocities. The midday sulfur profiles of Figure
25 illustrate jyst what is expected—a uniformly mixed layer—except for
ground-level S04, which was determined by high-volume sampling.
The difference between similar spatial and temporal measurements of
aircraft and ground-level sulfate is graphically shown in Table 9 and
Figure 33. A paired-t test shows that this difference—aircraft concen-
trations nearly half the high-volume concentrations—is statistically
significant (p = 0.99). Because most monitoring sites are located at
the power plants, a bias was at first believed to have been introduced
by local source effects. This bias might result from primary sulfate
emissions, artifact sylfate formation, or a more frequent exposure to
secondarily formed SO.. However, Bailey and Ruddock (1978) have shown
that primary sulfate emissions from TVA power plants are typically low
(~1 percent by molar ratio), and artifact sulfate formation on Gelman
Spectrograde filters, as discussed in the Analytical Methods_subsection,
is also low. Also, the average conversion rate of 862 to 804 [<2 percent
per hour (Meagher et al. 1977)] and the relatively low deposition velocity
of S04 indicate that this pollutant is long-lived and therefore widely
dispersed. This is supported by an analysis of high-volume data from
the two field studies.
A high-volume sampler located at the Giles County trend station was
compared with the average of four samplers located at the nearest TVA
coal-fired power plant, the Colbert Steam Plant. These two measurement
sites are separated by over 100 km. A plot of the Giles sulfate data
vs. the Colbert data for 18 simultaneous measurements obtained during
the two studies is shown in Figure 34. A slope statistically not dif-
ferent from one and a high correlation coefficient (r2 = 0.77) indicate
the regional nature of the sulfate pollution and the representativeness
of the power plant sulfate values in indicating regional sulfate levels.
Additional correlations among five trend stations and between Giles
County and the average of Cumberland and Gallatin Steam Plants, as tabu-
lated in Table 10, show that, although all correlations are good, the
correlation between Giles and the average of the two power plants is better
than the correlations between trend stations. This result is probably
due to the variabilities inherent in the measurement technique itself.
Thus, because two or more high-volume samplers exist at each power plant,
the resultant smoothed or averaged measurement concentration may be more
representative of regional sulfate levels.
Terra and Hilst (1978) of the Electric Power Research Institute's
SURE program reported midday ozone bulges near the ground (surface to
200 m AGL) during their summer measurement program. These ozone bulges
are an indication of photochemical reactions and may be tied to hydroxyl
radical production, a favored reactant with S02 that probably leads to
sulfate formation. Unfortunately, our study had no ground-level or near-
ground-level ozone measurements; thus, this hypothesis for explaining
the high S04 readings measured near ground level for the TREATS data
could not be checked.
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-68-
TABLE 9. COMPARISON OF GROUND-LEVEL AND
UPPER-AIR SULFATE CONCENTRATIONS
Date
6/03/77
6/05/77
6/08/77
6/24/77
6/28/77
6/30/77
7/06/77
7/06/77
7/07/77
Sample
class
0
N
B
I
I
I
N
0
N
Aircraft measured Closest High-volume
concentration high-volume concentration
(pg m~3) station(s) (|jg m"3)
5.5
9.3
4.0
2.8
2.8
3.0
19.8
17.9
14.4
Colbert
Colbert
Colbert
Colbert
Johnsonville
Colbert
Paradise and
Gallatin
OACD and
Colbert
Cumberland and
Paradise
17.0
17.0
9.0
4.5
13.0
5.3
27.1
28.7
27.2
I = inflow, 0 = outflow, B = blob, and N = neither.
Each air concentration is an average of at least two measurements
spanning at least 4 h and within 50 to 305 m AGL.
Results from at least two high-volume monitors were averaged. Both
9- and 24-h results are presented; values for 6/24/77, 6/30/77, and
7/6/77 are 24-h samples.
-------
E
\
O)
20
16
CO
h-
LL
CJ
8
0
AIRCRAFT S0^=0.57(HIGH-VOLUME
r2= 0.86
0
8 12 16 20 24 28 32 36
HIGH-VOLUME SO^(Mg/rn3)
I
CT>
VO
Figure 33. Comparison of ground-level to upper-air sulfate concentrations.
-------
/^v
«•
E
U)
X
II
o
O)
o
CJ
UJ
-J
in
COLBERT S04 CMg/ma)
Figure 34. Giles Couaty sulfate concentration vs Colbert.
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-71-
TABLE 10. SUSPENDED SULFATE CORRELATION MATRIX
Air quality trend
Loves Mill
Loudon
Hytop
Giles County
Land Between
the Lakes
Valley-wide
Giles County
Cumberland
Gallatin
Average
Loves
Mill
86b
92
82
93
97
Giles
County
112b
112
112
Loudon Hytop
0.58a 0.55
(250) (320)
0.69
(185)
89
80 217
89 227
93 98
Selected trend
Giles
County
0.54
(450)
0.58
(225)
0.66
(80)
222
88
and power
Cumberland
0.713
(125)
113
112
stations
Land Between
the Lakes
0.47
(520)
0.45
(350)
0.51
(260)
0.46
(175)
100
plant stations
Gallatin
0.78
(115)
0.85
(110)
112
Valley-
wide
0.73
0.83
0.83
0.83
0.67
Average
0.89
0.93
0.95
Based on high-volume data collected simultaneously every sixth day;
parenthesized numbers are the distance between sites in kilometers.
Number of data points in correlation.
£
Data from around a power plant were averaged.
-------
-72-
These analyses do not indicate the reason for the large discontinuity
evident in the aircraft vs. ground-level sulfate measurements. However,
dispersion and deposition theory would indicate that this phenomenon is
an aberration; therefore, we speculate that this phenomenon results from
artifact 804 formation on the Gelman Spectrograde filters. Until such
time as an explanation is forthcoming, the two data sets will be analyzed
separately.
Eulerian Time Variations
Analyses of the time dependence of the various pollutant concentra-
tions are presented in this section. The data shown in Figures 29 through
32 also show temporal variations for the various pollutants measured at
different locations throughout the Valley. A temporal analysis of the
data indicates diurnal variations between and within pollutants. For
instance, the sulfate concentration plots show a fairly flat profile with
southwesterly wind flow, whereas large variations usually occur with westerly
through northerly flow. However, the flux of sulfate generally increases
throughout the day, with significant departures evident on June 3 and
5, 1977. Ammonium, an ion thought to be strongly tied to the sulfates,
also shows a fairly flat profile on the southwesterly flow days, but has
significant departures from the sulfate profile shapes on other days.
The molar ratio (JO^/SO^) presents no identifiable temporal trend. How-
ever, a relatively high ratio occurred on the stagnate or blob day, June 8,
1977, indicating that a much more aged airmass was sampled. The normalized
measurements of total sulfur concentration definitely show a trend toward
lower values from morning to afternoon, whereas nitrate values show no
discernible pattern. However, as previously mentioned, the inflow nitrate
values measured during southwesterly flow are significantly higher than
any other inflow or outflow nitrate values measured.
Some of these phenomena a*e explainable. For instance, the decrease
in total sulfur concentration with time may be related to an increase in
turbulent mixing, thus leading to increased removal. Conversely, the
sulfate concentration data do not follow any pattern; due to its longevity,
it should be a more regional and uniformly distributed pollutant. The
high inflow concentrations of nitrate during southwesterly flow indicate
a significantly different source region than that within or north of the
field study area. Because no large anthropogenic NO sources exist within
500 km upwind from the southwestern field study boundary, it seems probable
that a natural area type source region is responsible for this anomaly.
LAGRANGIAN FLUX ANALYSIS
This section presents (1) the results of Lagrangian field study data,
(2) comparisons of model predictions vs. actual data, and (3) additional
predictions based on measured inflow boundary conditions and model simula-
tion of transport to the outflow. Both the field study data and model
predictions support several unexpected conclusions concerning TVA's
regional and interregional impact and the significance of upwind sources.
-------
-73-
Field Results
Five Lagrangian days (Figure 28) were sampled during the two field
studies—four during the 1976 spring study and one during the 1977 summer
study. A breakdown of the Lagrangian days and the flux calculations is
shown in Table 6. This analysis shows that all Lagrangian measurements
were made under relatively brisk southwesterly through westerly flow.
Four of the five Lagrangian measurement days occurred during prefrontal
flow of maritime tropical air. The only exception was on February 19,
1976, when a weak front moved through the area early in the morning and
westerly flow occurred thereafter. No significant rainfall occurred on
any of these days; however, cloud ceilings at <2000 m were present on
February 10, 1976, and June 30, 1977. Also, solar radiation was consider-
ably limited on February 10, 1976, March 24, 1976, and June 30, 1977,
due to high cloud cover.
Analysis of these limited field data shows that, for the four Lag-
rangian days with both inflow and outflow total sulfur and sulfate mea-
surements, the average daily sulfate flux from inflow to outflow increased
by 47 percent, with a standard deviation of 35 percent, whereas the total
sulfur (gaseous and particulate) flux decreased. Plots of both the Lagran-
gian and Eulerian inflow-outflow sulfate and total sulfur flux measurements
are shown in Figures 35 and 36. Although both the inflow and outflow
sulfate concentrations are relatively low, there appears to be a significant
percentage increase in outflow sulfate flux. Also, total sulfur flux
decreases slightly from inflow to outflow. However, neither of these
conclusions is statistically significant (due to a high standard deviation
and a limited number of data points).
The average measured mole ratios of NH4/S04 are 1.5±0.3 at the inflow
vs 1.910.7 at the outflow. This is a 27 percent increase from inflow to
outflow. Although this difference may be real, statistically it is not
significant. The scatter (Figure 37) for the composite of Lagrangian
and Eulerian sulfate and ammonium measurement comparisons is large.
If the measured sulfate is assumed to be derived only from ammonium
sulfate [(NH4)2S04], ammonium acid sulfate (NH4HS04), and sulfuric acid
(H2S04) and if all ammonium is associated with sulfate, then limits can
be placed on the relative abundance of these compounds. The minimum and
maximum percentages of each compound that could yield the observed ratios
are given in Table 11. The sulfur acid data includes all sulfate compounds
other than the ammonium salts.
TABLE 11. SULFATE SPECIATION
Compound
(NH4)2S04
NH4HS04
H2S04
Inflow
(%)
50-75
0-50
0-25
Outflow
(%)
91-96
0-9
0-5
-------
CO
o 60
(M
? 50 i-
X
D
_J
LL
UJ
I—
<
LL
_l
13
LL
h-
D
O
30 -
20
10
OUTFLOV = 1.3(INFLOW)
INFLOW = OUTFLOW
LEGEND
FLOW
2/1O/7Q
O 2/1S/7O
3/18/76
D 6/28/77
0/30/77
N
NE FLOW
O/O3/77
6/04/77
7/06/77
0
10 20 30 40 50 60
INFLOW SULFATE FLUX (pg/(m2°s))
I
-vl
Figure 35. Comparison of inflow to outflow sulfate flux.
-------
CO
O)
1
X
CO
O
1 OOO
800
OOO
4OO
ZOO -
O
INFLOW = OUTFLOW
LEGEND
t> 2/10/76 - 1_ O 3/1 8/76 - 1_
n 2/ie/7e - L *• 3/23/70 - E
+ 3/11/70 - E O 3/2t/76 - L
L - L^GRANGIAN E - EULERIAN
O
2OO 4OO 6OO 8OO 1 OOO 1 2OO 1 4OO
INFLOW-TOTAL SULFUR FLUX (ng/ (mz•s ) )
Ln
I
Figure 36. Comparison of inflow to outflow total sulfur flux.
-------
-1 2.5
1- 2/10/76
2- 2/19/76
3- 3/11/76
3/18/76
6- 3/24/78
7- e/04/77
8- 0/28/77
9- 6/30/77
5- 3/23/7B 10- 7/06/77
MOLE RATIO = 0 (hLSO.J
6
8
10 12 14 16 18
CONCENTRATION (pg/m3 )
Figure 37. Inflow to outflow concentrations and mole ratio changes.
-------
-77-
Nitrate (N03) concentrations are all below the minimum detectable
limit for the 1976 samples, whereas for the one Lagrangian day in 1977,
the nitrate averaged 1.1 |jg m 3 at inflow and 0.6 Mg m 3 at outflow.
Model Results
Equations (5) and (6) of the Transformation-Transport Model subsec-
tion of Section 3 are the analytical models used for the comparisons and
predictions of this subsection. Given a set of inflow boundary conditions,
superposition was used to account for multiple sources along a trajectory
path. The parameters used were specified as B /B = 0.0, V: = 1.0 cm/s,
V2 = 0.5 cm s , K = 0.3 percent per hour; and H was specified as observed
for the given day being simulated. The deposition velocities are as sug-
gested by Hicks and Wesley (1978). Although their sulfate deposition
velocity is high in comparison with other reported values, it has minor
influence on model simulations (see Model Analysis subsection). The S02
to 864 transformation rate of 0.3 percent per hour is intentionally low
with respect to the recommended value of 2 percent per hour (Husar et al.
1977). This lower rate was selected because it is more representative of
actual measurements made within TVA power plant plumes at lower atmospheric
temperatures (5 to 10°C) and higher plume dilution ratios (Meagher et al.
1977). Also, chemical transformations within the Tennessee Valley region
should proceed at a somewhat slower rate because of the relatively low
levels of urban pollutants.
Figure 38 illustrates observed vs. predicted outflow total sulfur
(symbols) and sulfate concentrations (small letters). The five days pre-
sented were characterized by wind speeds around 8.5 m s 1, mixing heights
of 1530 m, and trajectory lengths of 300 km. The predictions are surpris-
ingly good considering the simplicity of the model and model input.
The relative change in total sulfur flux across the TREATS field study
region is illustrated in Figure 39. Here the observed data points are
represented by circled letters, and the predicted data points (using
inflow measured values as boundary conditions) are shown by noncircled
letters. Although some of these predicted points are noted as Eulerian,
this is only because of the data tagging system used. That is, the model
can only yield Lagrangian results. When the modeled results are added,
the range of inflow-to-outflow flux values is significantly increased.
If the outflow total sulfur flux decreases, as indicated by the limited
observed data, then the removal by deposition exceeds TVA's rate of
emission, a conclusion supported by the model.
Both observed and predicted inflow-to-outflow sulfate flux are illus-
trated in Figure 40. This plot indicates that, although the outflow sulfate
flux is about twice the inflow flux, the average outflow sulfate concentra-
tion is only 5.4 pg m 3.
Model results indicate that sulfur emissions from upwind sources
are primarily responsible for the gaseous and particulate flux values
measured. The following subsection integrates the results from this and
previous subsections in an attempt to identify emission rates and locations
of significant upwind sulfur sources.
-------
-78-
ro
en 7
CD
LJ
CD
LJ
CD
CD
CD
LU
CJ
h—t
CD
or
Q_
2/10/76
2/19/76
3/18/76
3/24/76
6/30/77
k-l/4*/h V,-1.0cm/s
Vo=0.4cm/s
oo
OBSERVED OUTFLOW CONCENTRATION (ug/V)
Figure 38. Observed vs. predicted outflow total sulfur (X 102) and
sulfate concentrations.
-------
-79-
2000.
1500 ,
CN
I
CO
D
X
1000
CO
CD
SPRING 1976 TREATS DATA
E EULERIAN
L LAGRANGIAN
(X-454?, Y=
SUMMER 1977 TREATS DATA
e EULERIAN
1 LAGRANGIAN
CIRCLED LETTERS ARE
MEASURED DATA
INFLOW
Figure 39.
Relative change in total sulfur flux across the TREATS
field study region.
-------
CO
CM
CD
D
X
o
en
o
_i
U_
h-
Z)
o
175
150 ..
125 ..
100 ."
75 ..
50 ..
25 ..
0
SPRING 1976 TREATS DATA
E EULERIAN
L LAGRANGIAN
SUMMER 1977 TREATS DATA
e EULERIAN
1 LAGRANGIAN
CIRCLED LETTERS
ARE MEASURED DATA
00
o
i
(9
O)
(9
in
(O
INFLOW S0= FLUX
4
Figure 40. Sulfate flux changes across the TREATS field study region.
-------
-81-
Upwind Sources
A large influx of total sulfur pollutants occurs when the flow is
southwesterly. This influx is evident from both aircraft (spring and
summer studies) and seasonal and annual ground-level sampling (high-volume
sulfate data). These inflow (and outflow) fluxes are typically of the same
order of magnitude as the regional emission flux contribution. The obvious
question is, "What is the location(s) and magnitude of the upwind source
region(s)?" In trying to answer this question, we look first at the upwind
anthropogenic source regions and second at possible biogenic sources.
An analysis of man-made SC>2 emissions from the southwest quadrant (Fig-
ures 2 and 3) shows that no large sulfur sources exist within 500 km of the
inflow field study boundary. Further analysis (private communications with
B. Gilbert, EPA, Region IV, 1979) reveals that the area from central Texas
eastward to the Alabama-Mississippi border, including the States of Arkansas,
Louisiana, and Mississippi, has about the same daily S02 emission rate as all
12 TVA coal-fired power plants (i.e., ~5000 metric tons/day). To evaluate
the significance of these emissions on the inflow measurements made for the
four Lagrangian days, the transformation-transport model was used. Average
meteorologic and aerometric parameters were used, and all emissions were
assumed to originate at the approximate center (i.e., central Louisiana) of
the land area included in the upwind source region. Using typical deposi-
tion velocities (Vj = 1.0 cm s *, V2 = 0.5 cm s 1), Equations (5) and (6)
show that, on the average, the upwind anthropogenic sources contribute
about 50 percent to the measured sulfate flux. Other man-made sources
farther upwind also probably contributed to the measured inflow values;
however, due to the relatively short half-life of S02 (~16 h) and the low
measured inflow sulfate flux, emissions from any other sources farther
upwind would not be likely to have a very significant effect.
The above results seem to point to a large biogenic source region as
the only possible explanation for the high influx readings observed. Vari-
ous large wetland areas (e.g., inland and tidal marshes, bogs, etc.) exist
along the Gulf Coast region of east Texas, Mississippi, Alabama, and Loui-
siana and in Arkansas (Shaw and Fredine, undated). However, quantification
of the relative importance of each type of wetland in producing natural
sulfur emissions is limited (Adams et al. 1979). Thus, in a crude attempt
to determine whether these extensive wetlands (about 8.6 x 104 km2) could
supply the needed gaseous sulfur, the transformation-transport model was
run (using the boundary conditions used in making the anthropogenic calcu-
lations) backward in time to estimate the emission rates, airmass age, and
average source location needed to explain the concentrations measured.
These calculations result in an estimated rate of emission of 2.02 Tg y 1
(as S02), a mean age of 10 h, and a source distance of about 300 km. The
age and distance results compare well with the central location and mean
transport times from the principal swampland areas of Louisiana (~500 km).
Also, when the estimated emission rate is applied evenly across the wet-
land areas,_the average sulfur emission flux rate from wetlands alone is
~10 g m 2 y"1. This estimate is one to two orders of magnitude higher
than current approximations of wetland emissions (Adams et al. 1979).
However, our estimate does not include emissions from nonwetland soils or
emissions from the Gulf of Mexico. Also, as stated by Adams et al., their
approximations likely underestimate actual natural emissions due to
sampling system losses.
-------
-82-
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energy systems. Vol. Ill: Air quality impact model and results.
Teknekron, Inc., Berkeley, California.
Terra, S., and Hilst, G. 1978. SURE takes to the air. EPRI J. 12:14-17.
Tony, E. Y., and Batchelder, R. B. 1978. Compilation and analysis of data
sets for the evaluation of regional sulfate models. Teknekron, Inc.,
Berkeley, California.
Trijonis, J., and Yvan, K. 1978. Visibility in the Northeast—long-term
visibility trends and visibility/pollutant relationships. EPA
600/3-78-075, Environmental Protection Agency, Research Triangle Park,
North Carolina.
West, P. W., and Gaeke, G. C. 1956. Fixation of sulfur dioxide as sulfi-
tomercurate III and subsequent colorimetric determination. Anal. Chem.
28:1816.
Yocom, J. E., and Grappone, N. 1976. Effects of power plant emissions on
materials. EC-139, Summary report prepared for Electric Power Research
Institute, Palo Alto, California.
-------
A-l
APPEKDIX A
SYNOPTIC WEATHER TYPING
-------
A-2
APPENDIX A
SYNOPTIC WEATHER TYPING
A quasi-objective weather typing scheme has been devised. The area
of interest is defined by a 500-nautical-raile (nmi) radius from Nashville,
Tennessee. Data for five parameters were obtained from NWS daily weather
maps for every sixth day for a 5-year period beginning on November 5,
1973. Thus, over 235 data points were generated for each parameter. These
five parameters describe (1) predominant frontal systems and associated
pressure centers; (2) distance (range) of the most significant pressure
center from Nashville, Tennessee; (3) direction from Nashville, Tennessee
(degrees from true north) of this pressure center; (4) airmass type (e.g.,
maritime tropical, continental polar); and (5) relative frequency of
measurable precipitation (>0.01 in.).
These parameters are further divided into categories. These
categories and their annual and seasonal distributions are presented in
Tables A.I through A.5.
Annually, 27 percent of the frontal system-pressure center parameter
can be described by the high-pressure center (HPC) without front category,
while the next most frequent occurrence is divided almost equally between
HPC associated with cold fronts west of Nashville or with stationary
fronts (~16 percent each). Seasonally, the only significant variation
occurs during the summer months, when stationary fronts account for 36
percent of the weather occurrences.
Joint frequency distributions (JFD) between some of the parameters
were analyzed. First, comparisons between the distance and pressure-
frontal parameters indicate that, although HPC without cold fronts occur
most frequently, their relative distance from Nashville is often within a
100- to 399-nmi range (53 percent). Directional considerations indicate
that most of the pressure centers within this range (28 percent) occur in
the 045- to 089-degree sector. Also, for pressure centers greater than
500 nmi, 46 percent occur within sectors 2 and 3 (045 to 134 degrees),
whereas an additional 31 percent occur within sectors 7 and 8 (270 to 359
degrees). Seasonally, the annual JFD varies only slightly for the pressure
system defining parameters 1, 2, and 3.
An analysis of the direction and airmass parameters shows that, when
pressure centers are southeast of Nashville, there is an 81 percent
chance that the airmass type affecting the Tennessee Valley region will
be of maritime tropical origin. This, no doubt, is in response to the
summertime Bermuda high (48 percent occurrence). For the approximately
50 percent of the time when pressure centers are within a 500-nmi radius
of Nashville, Tennessee, the most favored range is from 300 to 399 nmi
(16 percent). Except for the range from 0 to 99 nmi (3 percent), the
other three categories all occur at about the same frequency (11 percent).
Seasonally, summer has the largest frequency (23 percent) for the 300- to
399-nmi range.
-------
A-3
TABLE A.I. PERCENT FREQUENCY DISTRIBUTION FOR PRESSURE-FRONTAL PARAMETER
a
Weather type
Cold front west with HPC
Cold front east with HPC
Cyclone with or without front
HPC without front
Stationary front with HPC
Stationary front with LPC
Stationary front without
pressure center
East-west cold front south
of BNA with HPC
East-west cold front north
of BNA with HPC
Season
Winter
16
15
5
38
11
8
0
3
3
Spring
20
8
8
26
16
7
0
7
8
Summer
11
2
7
20
23
13
7
8
10
Fall
17
16
0
26
17
6
0
6
12
Annual
16
10
5
27
17
8
2
6
8
a
Abbreviations: HPC = high-pressure center; LPC = low-pressure center;
BNA = Nashville station.
-------
A-4
TABLE A.2. PERCENT FREQUENCY DISTRIBUTION FOR RANGE PARAMETER
Season
Distance (nmi)
0-99
100-199
200-299
300-399
400-499
>500
Winter
2
11
8
13
16
49
Spring
3
18
7
13
13
46
Summer
2
9
11
23
14
41
Fall
3
7
12
17
9
52
Annual
2
11
9
17
13
47
-------
A-5
TABLE A.3. PERCENT DISTRIBUTION FOR DIRECTION PARAMETER
Direction
(degrees from
true north)
0-44
45-89
90-134
135-179
180-224
225-269
270-314
315-359
Season
Winter
5
23
13
7
10
13
15
15
Spring
7
25
16
8
10
5
20
10
Summer
4
29
23
13
4
5
9
14
Fall
3
28
16
3
3
10
14
23
Annual
4
26
17
7
6
9
15
16
-------
A-6
TABLE A.4. PERCENT DISTRIBUTION FOR AIRMASS TYPE PARAMETER
Season
Airmass type
Continental polar
Modified maritime polar
Maritime tropical
Modified continental polar
Modified maritime tropical
Winter
21
25
25
25
5
Spring
8
15
44
30
3
Summer
0
3
75
18
3
Fall
10
20
28
36
6
Annual
10
16
42
27
4
-------
A-7
TABLE A.5. PERCENT FREQUENCY DISTRIBUTION FOR RAINFALL PARAMETER
Number of stations
recording precipitation
0
1
2
3
4
Season
Winter
48
15
10
11
16
Spring
41
10
20
11
18
Summer
39
23
18
16
3
Fall
57
12
16
6
10
Annual
46
15
16
11
12
-------
A-8
Pressure center locations occur most frequently (26 percent) in the
045- to 089-degree sector from Nashville; three other sectors (090 to
134 degrees, 270 to 314 degrees, and 315 to 359 degrees) all have occur-
rences at about the same frequency (16 percent). Again, the most signi-
ficant departure occurs during the summer, when 52 percent of all pressure
centers are located in the 045- to 089-degree and 090- to 134-degree sectors.
Also, during the autumn, 51 percent of the directional location is defined
by two sectors, the 045- to 089-degree and the 315- to 359-degree sectors.
These results indicate the strong influence of the Bermuda high on weather
patterns in the southeastern United States.
Annually, the airmass typing parameter is dominated by maritime tropical
airmasses (42 percent), with the next most frequent type being modified
continental polar (27 percent). Wide variations occur seasonally. Winter
is almost equally divided among all the airmass types; spring shows a
bias toward maritime tropical (44 percent) and modified continental polar
(30 percent); summer is strongly dominated by maritime tropical (75 percent);
and autumn has a slight bias toward modified continental polar (36 percent).
Annually, an analysis of the rainfall parameter indicates that 46
percent of the time no rainfall occurs at any of the four stations, and
that an almost equal probability exists of having either one or two
stations recording measurable precipitation (16 percent).
JFD analysis of the frequency of precipitation vs. airmass type indi-
cates that, when maritime tropical airmasses are affecting the area, a
70 percent chance exists that at least one station will receive measura-
ble precipitation. Conversely, when other airmass types are influencing
the area, only a 40-percent chance exists of at least one station receiving
measurable precipitation.
-------
B-l
APPENDIX B
TABULATION OF TREATS 1976 and 1977
AIRCRAFT FIELD STUDY DATA
-------
B-2
ABBREVIATIONS AND UNITS FOR APPENDIX B
DATE Date of sample, month, day, year
TIME Midpoint time of sample, h and min
SHIP Aircraft used for sample, B-deHavilland Beaver U6-A, H-Bell
47A helicopter
XFROM X-coordinate* at start of sample, km
YFROM Y-coordinate at start of sample, km
XTO X-coordinate at end of sample, km
YTO Y-coordinate at end of sample, km
ELEV Typical elevation of sample, m AGL
STYPE Sample type, T (traverse), S (spiral)
SCLASS Sample classification, I (inflow), 0 (outflow), N (neither I or 0),
B [blob (no significant airmass transport)], T (travel from inflow
location to outflow and vice versa)
804 Sulfate ion concentrations, pg m 3
N03 Nitrate ion concentrations, pg m 3
NH4 Ammonium ion concentrations, |Jg m 3
TS Total sulfur concentrations, pg m 3 as SOg
Oa Ozone concentrations, |Jg m 3
BSCAT Atmospheric extinction coefficientjdue to light scattering by
both gases and particulate, E-4 m
TEMP Ambient temperature, °C
DP Dewpoint temperature, °C
*The origin of the coordinate system is Nashville, Tennessee. The Y-axis
is rotated 1.8 degrees east of true north.
-------
THEATS AIHCHAFT FIELD STUDY DATA
DATE TIME SMP XFROM YFRCM XTO YTu tLEV STYPt SCLAiS SO* N03 NH4 TS 03 BbCAT TF.MP DP COMMENT
10676 1214
10676 1511
21076 915
21076 917
21076 1312
21076 14*2
21076 1611
21176 1205
? i Q7 A R A A
c 1 ** r O O * II
21976 1015
21976 1*07
21976 150*
21976 1544
22076 754
22076 927
22*76 1307
22*76 1307
31176 901
31176 915
31176 122?
31176 13*0
31176 1510
31176 163B
31876 819
31876 857
31876 1213
31876 133*
31876 1502
31876 1636
31976 709
31976 739
31976 1125
32376 823
32376 845
32376 1119
32376 1239
32376 1452
32376 1630
32476 751
32*76 806
32*76 1111
32*76 1221
32*76 1*36
32*76 1610
52077 13*1
52077 142?
5?077 1451
52077 15!5
52077 1541
60177 1650
60177 1750
60277 1*15
60?77 1505
60277 1535
e
B
B
a
B
B
B
B
Q
B
H
B
ft
B
B
B
B
B
R
R
B
B
B
Q
R
B
B
B
B
P
e
R
B
B
P
R
H
B
H
R
P
B
B
P
p
a
P
H
H
B
e
B
p
p
-204
-HP
-e
-182
-76
30
126
30
l n i
— 1 u 1
-147
7V
-If
75
-76
92
-6
-18?
-6
-182
-76
-13
126
-13
-US
-7H
-76
113
-14
113
-119
-76
-76
-p
-1?2
-76
-14
126
- 14
93
-119
-76
-8
126
-14
-76
-31
-76
-61
-27
-78
40
30
101
76
-16.6
-184
-219
-60
-156
92
146
9'
"'ts
-151
-156
93
-156
-160
-?1S
-60
-21S
-60
-156
6e
146
be
-156
-156
-156
-12
140
2
-156
-156
-156
-21S
-60
-156
75
14t
75
-Ind
-156
-156
75
146
75
-156
-Ib3
-156
-15C
-171
-156
70
92
167
1Z4
-«B
-204
-182
-£
30
126
30
-7e
-101
75
T~i
7V
92
-76
-1»2
-tf
-1S2
-e
-13
12e
-13
-7e
V j
VJ
113
-14
113
-7e
83
93
13
-1N2
-e
-14
126
-14
-7e
-m
93
-14
1 ,14
*3 V14
-151 1676
-151 l»-7b
-lr>0 152
-iDb 914
-CO MO
-219 ItlS
-60 152
-21V 6.10
6" \i 1*
14*1 1E19
DM M 0
- lab 610
-leO \^
-------
TREATS AIKCKAFT FIELD STUDY DATA
DATE TIKE SHIP XFROC YFKOM XTO YTO ELEY STYPE SCLASS SO* N03 NH* TS 03 BSCAT TEwH
DP COMMENT
60377 1615
60377 705
60377 730
60377 755
60377 625
60377 1015
60377 1045
60377 1115
60377 1425
60377 1*55
60377 1525
60377 1040
60377 1115
60377 1135
60377 1425
60377 1455
60377 1530
60377 1555
60477 640
60477 715
60477 740
60477 810
60477 1015
60477 1045
60477 1115
60477 1145
60477 1425
60477 1450
60477 1525
60477 1550
60477 610
60477 645
60477 725
60477 755
60477 1455
60477 1540
60577 630
60577 655
60577 730
60577 800
60577 1015
60577 1045
60577 1115
60577 1145
60577 1415
60577 1*45
60577 1515
60577 615
60577 645
60577 720
60577 750
60577 1125
60S77 1150
60577 1*30
B
B
B
B
e
B
B
B
8
B
B
H
H
K
H
H
H
H
B
B
B
B
e
a
B
B
B
8
B
B
H
h
H
H
h
H
B
B
e
B
B
B
e
a
B
B
B
H
H
H
f
H
H
H
101
30
83
30
83
30
76
30
30
64
30
-If
-131
-US
-78
-99
-132
-105
30
27
51
?7
56
28
56
28
51
27
51
27
-78
-112
-78
-112
-77
-29
30
99
30
99
30
99
30
99
30
2P
30
-87
-124
-87
-111
-76
-*fi
-78
167
92
46
92
46
92
7
92
92
23
92
-156
-105
-37
-156
-117
-72
-114
92
25
101
25
101
20
101
20
101
2S
101
25
-1S6
-104
-156
-104
-165
-162
92
23
92
23
92
23
92
23
92
20
92
-152
-115
-152
-115
-156
-125
-156
30
«3
30
*3
JO
76
30
76
64
30
53
-131
-144
-114
-99
-1J2
-105
-B4
27
51
<;7
51
£8
56
28
56
27
bl
27
51
-112
-78
-112
-78
-29
-78
99
30
99
30
99
30
99
JO
26
30
16
-124
-b7
-\e<>
-a l
-46
-78
-15
92 3048
46 152
92 457
46 1067
92 Ib24
7 610
92 1214
7 lfj«b
23 610
92 1128
27 Ib46
-117 305
-87 305
-13* 1067
-117 305
-72 305
-114 762
-152 762
25 152
101 *57
25 1067
101 1524
20 457
101 91*
20 1372
101 1629
2b 457
101 91*
25 1372
101 1829
-10* 122
-156 305
-10* 610
-156 914
-162 762
-156 305
23 122
92 2**
23 *57
92 1372
23 *57
92 91*
23 1372
92 213*
20 610
92 121V
40 1829
-115 152
-152 305
-115 762
-152 152*
-125 305
-156 762
-123 1219
S
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
r
T
T
T
T
T
T
T
T
7
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
I
I
1
0
0
o
0
0
0
0
N
fc
N
N
I
I
I
I
0
0
0
0
N
N
N
N
N
N
H
N
N
N
N
0
0
0
0
0
0
0
6.4 0.* 1.7
1.* 0.* 0.3
1.* 0.* 0.5
1.8 O.o 0.3
3.1 0.2 0.6
3.2 0.* 0.0
4.2 0.3 1.1
0.2 0.2 0.0
0.7 0.6 0.3
i.5 0.9 3.0
1.8 0.8 0.*
. O.I 0.0
S.6 0.8 2.1
4.3 0.6 1.5
. 0.1 1.6
•..3 0.5 1.5
5.8 0.6 1.8
2.9 0.2 0.9
3.0 O.I 1.0
0.3 0.1 0.0
O.h 0.* 2.1
4.3 0.1 1.3
1.9 0.1 0.5
0.1 0.1 0.0
7.1 0.3 1.9
7.9 0.2 2.2
6.1 0.3 1.6
0.0 0.2 0.0
6.5 0.7 1.8
2.5 0.3 O.b
*.5 0.5 1.2
*.2 0.4 1.1
7.0 0.6 2.2
6.3 O.b 2.0
6.9 0.3 1.8
7.7 0.3 1.8
11.9 0.3 2.3
0.5 0.1 0.0
3.9 0.8 0.9
11.9 1.1 3.6
9.6 0.2 3.0
0.9 0.1 0.0
14.3 0.5 4.1
11.9 0.3 3.3
1.4 0.0 0.4
7.6 0.6 1.8
11,7 0.1 1.6
. 0.0 0.0
1.1 0.7 1.3
B.7 0.6 2.5
9.2 0.6 3.3
10. -i 0.* 2.6
. *51
* •
• *
• *
• «
*9
26
12
• *
• »
• •
• •
*6
68
82
88
• •
• •
* »
• •
*9
26
15
» •
32
1*
* »
• •
31
51
67
70
55
6*
16 17
32 284
** 279
6 200
56 <:97
35 273
. 1S6
.106
36 292
2* 237
. 267
37
330 .
73
77
53
62
52
150
100
76
MS
121
111
111
71
b.O 1.0 SPlRAL-lOtOOO' TO 3700
ItJ.b 8.0
19.0 7.5
1S.O *.S
9.0 4.0
1B.O 8.S
14.5 7.0
12.0 -2.0
i
. 21.5 8.5 FIDE EXTINGUISHED DISCHARGED
8*
8*
100
121
ry
71
66
71
76
150
129
iei
61
139
ISO
89
55
150
171
161
55
100
71
76
79
82
8*
300
200
200
50
261
250
79
61
261
326
221
116
139
116
239
1*5
134
229
17.0 7.5 FlrtE EXTINGUISHED DISCHARbED
13.0 1.0 FIRE EXTINGUISHER PROBLEMS
22. b 3.0 POKER SUPPLY PROBLEMS
22. b 3.0 POMER SUPPLY PROBLEMS
16.0 7.0 POHER SUPPLY PROBLEMS
2*.S 9.S
24. b 9.0
20.0 8.5 SO* QUESTIONABLE
20. S 6.S
30. 5 10.5
21.0 9.5
15.5 T.U
16.5 -20.0
21.0 10.5
17.0 9.0
16.0 -2.5
15.5 -20.0
2*.0 10.0
20.0 9.0
16.0 7.5
16.6 -20.0
22.0 10.0
23.0 8.5
20.5 8.5
17.5 7.0
22.0 6.5
37.0 7.0
19.1) 14.0
24. b 11.0
24.0 9.5 0732 SALLATIN PLUME
19.0 -14.0
24.0 10.5
20.0 10.0
19.0 7.0
15.0 2.0 SLIDES 5-8
25.5 13.0
20.0 12.0 SLIDES 9 1 10
15. 0 10.5
25.0 10.0
25.0 9.5 COLBERT PLUME
22.0 8.0
15.5 10.5
26.0 13. 0
21.0 12.0
16.5 11.5
-------
TREATS AIRCRAFT FIELD STUDY DATA
DATE TI^E SHIP XFRO YFrtOM XTO YTO F_LEv STYPE SCLASS S04 N03 NH4 TS 03 BSCAT TEMP OP COMMENT
60577 1530
60777 1700
60777 900
60877 635
60877 70S
60877 730
60877 755
60877 1020
60877 1050
60877 1120
60877 1150
60877 1530
60877 1420
60877 545
60877 625
60877 700
60877 730
60877 1015
60877 1050
60877 1120
60877 1155
60877 141B
60877 144E
60877 1550
60877 1615
61377 1115
61377 1145
61377 1215
61377 1250
61377 1305
61377 1230
61377 1305
61877 645
61877 715
61877 1155
61877 1220
61877 1310
61877 1335
61877 625
61877 710
61877 1220
61877 1305
61877 1405
62477 1110
62477 1135
62477 12(15
62477 1350
62477 1415
62477 1440
62477 1520
62477 1550
62477 1655
62477 1725
62477 1610
H
R
H
R
R
R
e
R
R
R
R
R
H
H
h
M
H
H
H
H
H
H
H
H
H
8
R
H
H
f>
H
H
H
R
H
f>
R
H
H
H
H
N
H
a
R
ft
R
U
R
R
n
R
H
9
-IS
-78
-78
30
16
19
16
19
16
19
16
30
14
-78
-30
-78
-30
-7fi
-45
-7?
-*5
-52
-SO
-SI
-ei
-77
-4%
-7M
-36
-77
-78
-*5
-77
-40
-7B
-47
-11
-11
-78
-39
-? H
-119
-77
-29
-55
-4?
16
-5
16
51
74
51
H
11
-123
-156
-156
92
35
114
35
114
35
11*
35
92
62
-156
-162
-15b
-Ib2
-156
-1%9
-16B
-18*
-153
-146
-123
-123
-165
-1H9
-156
-195
-Ifcb
-1S6
-ln76
35 30b
114 610
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-------
TREATS AIRCRAFT FIELD STUDY DATA
DATE TIME SMP XFRO^ YFflOf XTO YTO ELEY STYPt SCLASS S04 N03 NH4 TS
03
BSCAT TtHP DP COMMENT
62*77 1115
62*77 11*5
63*77 1225
62*77 13*5
62*77 1*15
62*77 1*55
62*77 1625
62*77 16*5
62777 1715
62877 710
62877 T35
62877 955
62877 1055
62877 1320
6Z877 1350
62877 1000
62877 1050
62877 1325
62877 1*05
62877 1*30
62877 1620
62877 1650
62877 1725
63077 6*0
63077 715
63077 7*5
63077 1000
63077 13*0
63077 13*5
63077 1*20
63077 1*50
63077 600
63077 625
63077 650
63077 715
63077 950
63077 1020
63077 1050
63077 1115
63077 1320
63077 1*10
70177 11*5
70177 1225
70177 610
70177 650
70577 1020
70577 10*5
70577 1115
70577 1*10
70577 1»*0
70577 1510
70577 1535
70577 1120
70577 1200
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-198
-179
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-75
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-66
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-144
-130
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-123
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1067
1067
610
1676
152
610
610
1067
305
S14
457
762
457
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914
457
457
914
152
610
610
152
457
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610
1128
152
152
610
610
305
305
610
610
762
305
305
457
152
610
610
610
610
305
305
914
914
610
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2.0 1.5 0.6 310
3.0 1.7 0.6 260
2.3 1.7 0.2 195
2.3 1.6 0.1 193
3.4 1.6 0.1 155
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1.2 0.5 0.2 . 88.0
1.6 0.5 0.2 33 94.0
1.6 0.1 0.0 35 126.0
2.3 0.6 0.3 16 122.0
1.9 0.5 0.3 . 111.0
4.1 0.9 1.0 16 104.0
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3.4 3.1 0.3 232
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4.2 3.3 0.6 132
3.6 3.2 0.7 140
3.9 2.7 0.1 133
3.9 2.6 0.4 89
2.6 1.9 0.0 91
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2.5 0.2 0.9 20 157.0
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1.9 1.7 0.2 60
13.2 0.4 2.1 43 2B.3
18.6 0.2 2.8 55 338.9
11.6 0.4 2.0 55 237.0
10.6 0.1 1.0 52 284.0
10.7 0.2 0.9 30 19*. 0
19.1 0.0 0.7 . 176.0
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13.0 0.4 4.4 173
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166
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211
221
97
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316
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22.0 15.5
29.0 20.5
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23. b 17.0
29.0 17.0
27.5 18.5
2b« 0 18.0
17.0 7.0
24.0 19.5
22.5 18.0
23.0 18.0
20.5 17.0
27.0 20.5
22. b 17.0
23.0 19.5
21.5 18.5
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21.0 17.0
21.5 17.5
2b.O 18.5
26.0 18.5
22.0 17.0
2b.O 21.0
24.0 19.5
24.5 19.0
26.0 20.5
28. b 19.0
25.0 18.5
21. 5 8.5
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23.5 20.0
24. b 19.0
24.0 19.0
25.0 21.5
25.0 22.0
22.5 20.5
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28.5 21.0
2b.5 16.5
25.0 18.0
25.0 19.5
22.5 18.5
2B.5 21.0
26.5 20.5
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28. b 21.0
26. b 21.0
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UP AND DOWN OF COLBERT
UP AND DOWN OF COLBERT
UP AND DOWN OF CULbERT
UP AND DOWN OF COLBERT
UP AND DOWN OF COLBERT
3500* TO 100>
3500« TO 100«
UP AND DOWN OF COLBERT
PASS THROUGH GALLATIN PLUME
W
CLOUDS AND RAIN (BNA PLUME)
CLOUDS AND RAIN (BNA PLUME)
K*VILLE 4 POSSIBLY GALL. PLUME
-------
AlkC^AH FIELD STIA'Y UATA
DATE TIKE SHIP XFOO YFRCM XTO YTO tLEV STYPt bCLASS SU* NOJ Nn* TS 03 ObCAT TtMK CP COMMENT
70577 1*05
70577 1*30
70577 1*55
70577 1525
70677 7*5
70677 815
70677 8*5
70677 920
70677 1225
70677 1255
70677 1510
70677 1540
70677 1550
70677 555
70677 630
70677 705
70677 735
70677 1010
70677 1050
70677 1*00
70677 1*50
70777 635
70777 710
70777 715
70777 805
70777 1050
70777 11*0
70777 1*50
70777 1525
70777 1550
70777 1015
70777 1100
70777 13*5
70777 1*15
70777 1**5
70777 1510
70877 915
70877 950
70877 1030
121875 832
121875 1126
121P75 1452
121875 1546
121975 925
121975 1027
121975 1228
121975 1316
121975 1*05
121975 145?
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-153 -96
-117 -123
36 86
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27.0 16.5
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24.0 18.0
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26. b IB. 5
27. b 18.5
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-------
C-l
APPENDIX C
ALTITUDE CORRECTION, MELOY MODEL SH202
AND SA285 SULFUR ANALYZER
-------
C-2
APPENDIX C
ALTITUDE CORRECTION, MELOY MODEL SH202 and SA285 SULFUR ANALYZER
The flame photometric detector (FPD) is noted for its excellent
sensitivity to low background levels of sulfur and its linear logarithmic
response over several orders of magnitude. Unfortunately, it is also
sensitive—in an instrument-specific manner—to ambient pressure, which
is a function of altitude. As a result of this altitude sensitivity, a
study was conducted to develop altitude corrections for the Meloy model
SH202 and SA285 sulfur analyzers used in the TVA TREATS studies.
Both sulfur analyzers were mounted in an aircraft. The analyzers
were connected in parallel with a tee connection and through a 4-way
valve to three bags. The Teflon bags were filled with zero air, and low
and high background concentrations of S02. The fourth valve position
sampled cabin air.
An initial reference response was obtained from each bag while
sitting on the runway at 152 m MSL. Additional responses to the three
bagged gases were obtained at 762 and 1370 m MSL. Results from the test
are given in Table C.I.
TABLE C.I. MELOY SH202 ALTITUDE TEST
Analyzer response (ppb as S02)
Elevation
(m MSL)
152
762
1370
Model SH202
Zero
4.4
2.3
2.6
Low
20.2
20.4
16.7
a
High
127
116
110
Model 285
Zero
0
-5.1
-0.65
Low
23
16.5
15.8
High
125
120
115
SH202
response based on March 4, 1976, calibration (i.e., c = 2706A ' )
Modeling Altitude Response
The change in response (parts per billion as S02) of the flame
photometric detector as pressure drops is characterized by a decrease in
baseline current and a reduction in detector sensitivity. For the SH202
FPD, both the zero shift and reduction in sensitivity were significant.
These effects were most severe at low concentrations. For the SA285,
only the zero shift with altitude was significant.
-------
C-3
The corrected SH202 response is well described by the equation,
C = C1 + 0.46 + 0.000128 (Z - 152) CT,
where
C1 = uncorrected response, ppb,
C = altitude corrected response, ppb, and
Z = elevation, m MSL.
This model explains 98 percent of the altitude variation, and has a
standard error of 1.2 ppb. This is well within the accuracy of the
instrument and usual calibration procedures.
The corrected SA285 response is well described by the equation,
C = C1 - 0.6 + 0.00716 (Z - 152),
where
C1 = uncorrected response, ppb,
C = altitude corrected response, ppb, and
Z = elevation, m MSL.
This model explains 95 percent of the altitude variation, again well
within the accuracy of the instrument and usual calibration procedures,
All total sulfur readings were corrected with these models.
-------
D-l
APPENDIX D
TABULATION OF TREATS 1976 AND 1977
HIGH-VOLUME FIELD STUDY DATA
-------
D-2
ABBREVIATIONS AND UNITS FOR APPENDIX D
DATE Date of sample, month of year
STATION Name of station
LOCATION Classification, I (inflow), 0 (outflow), N (neither I nor 0)
X,Y* Coordinate location of high-volume sampler, km
TSP Total suspended particulate concentration, |jg m~3
804 Suspended water-soluble sulfates, (Jg m"3
N Number of samples averaged for station
DURATION Average duration of sample, h
*The origin of the coordinate system is Nashville, Tennessee. The Y-axis
is rotated 1.8 degrees east of north.
-------
D-3
TREATS 1976 C 1977 HIGH-VOLUME FIELD STUDY DATA
DATE STATION LOCATION X V TSP S04 N
21076 LBL
21076 JOHNSONVILLE
21076 CUMBERLAND
21076 PARADISE
21076 GALLATIN
21076 WIDOWS CREEK
21976 LBL
21976 JOHNSONVILLE
21976 COLBERT
21976 CUMBERLAND
21976 GILES
21976 GALLATIN
21976 WIDOWS CREEK
22076 LBL
22076 JOHNSONVILLE
22076 COLBERT
22076 CUMBERLAND
22076 PARADISE
22076 GILES
22076 GAUATIN
22076 WIDOWS CREEK
22476 LBL
22476 JOHNSONVILLE
22476 COLBERT
22476 CUMBERLAND
22476 PARADISE
22476 GILES
22476 GALLATIN
22476 WIDOWS CREEK
31176 LBL
31176 JOHNSONVILLE
31176 COLBERT
31176 CUMBERLAND
31176 PARADISE
31176 GILES
31176 GALLATIN
31176 WIDOWS CREEK
31876 LBL
31876 JOHNSONVILLE
31876 COLBERT
31876 CUMBERLAND
31876 PARADISE
31876 GILES
31876 GALLATIN
31B76 WIDOWS CREEK
31976 LBL
31976 JOHNSONVILLE
31976 COLBERT
31976 CUMBERLAND
31976 PARADISE
31976 GILES
31976 GALLATIN
31976 WIDOWS CREEK
32376 LBL
DURATION
0
N
N
0
N
0
0
N
I
N
N
0
N
0
N
I
N
0
N
N
I
N
N
I
N
0
N
N
N
N
N
I
N
0
N
N
0
N
N
I
N
0
N
N
D
0
N
I
N
D
N
N
I
D
-118
-105
-83
-30
27
90
-118
-105
-99
-83
-24
27
90
-118
-105
-99
-83
-30
-24
27
90
-118
-105
-99
-83
-30
-24
27
90
-118
-105
-99
-83
-30
-24
27
90
-US
-105
-99
-B3
-30
-24
27
90
-118
-105
-99
-63
-30
-24
27
90
-118
71
-18
24
114
24
-144
71
-18
-159
24
-108
24
-144
71
-18
-159
24
114
-108
24
-144
71
-18
-159
24
114
-108
24
-144
71
-IS
-159
24
114
-108
24
-144
71
-18
-159
24
114
-108
24
-144
7i
-18
-159
24
114
-108
24
-144
71
18.0
33.5
36.5
29,5
39.0
30.5
41.0
76,0
37,5
61.5
54,0
53.0
50.5
50.0
39,0
44,5
45.0
77.5
34.0
49.0
38.0
23.0
24.0
19,0
30.0
87.0
32,0
34.0
29.5
14,0
27,5
28.0
38.5
63.5
12.0
47.0
189.5
33.0
48.0
35.5
43.0
70.0
37, 0
72.0
43.0
24.0
68,5
24.5
67.0
60.5
47.0
55.5
11.0
30,0
9.0
7,5
7.5
7,5
8.5
10,5
5,0
15,0
3.0
3.0
4.0
2,5
3.0
8.0
5.0
7.0
6.0
6.5
13,0
6.0
9,0
2.0
3.0
2.5
2,5
4.0
4,0
4.0
3.5
5.0
8.5
5.5
9.0
13.0
4,0
12.0
12,5
3.0
5.5
5.5
5,0
5,5
6.0
5.0
6,5
6.0
9.5
5.5
9.0
9.5
11,0
11.0
5.0
10,0
1
2
2
2
2
2
1
1
2
2
1
2
2
1
i
2
2
2
1
1
2
1
2
2
2
2
1
2
2
1
2
2
2
2
1
2
2
1
2
2
2
2
1
1
2
1
2
2
1
2
1
2
1
1
9.0
9,0
9,0
9,0
9,0
9.0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9.0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
9,0
4,5
9.0
9,0
9,0
9,0
4,5
9,0
9,0
-------
D-4
TREATS 1976 C 1977 HIGH-VOLUME FJCLO STUDY DATA
DATE STATION
32376 JOHNSONVILLE
32376 COLBERT
32376 CUMBERLAND
32376 PARADISE
32376 GILES
32376 GALUTIN
32376 WIDOWS CREEK
32*76 LBL
32*76 JOHNSONVILLE
32476 COLBERT
32*76 CUMBERLAND
32*76 PARADISE
32*76 GILES
32*76 GALLATIN
32*76 WIDOWS CREEK
60277 SHAWNEE
60277 JOHNSONVILLE
60277 COLBERT
60277 CUMBERLD.
60277 HENDERSON
60277 OWENSBORO
60277 BOWLING GREEN
60277 WIDOWS CREEK
60277 KINGSTON
60377 SHAWNEE
60377 JDHNSONVILLE
60377 COLBERT
60377 CUMBERLD.
60377 HENDERSON
60377 OWENSBORO
60377 PARADISE
60377 GILES COUNTY
60377 BOWLING GREEN
60377 WIDOWS CREEK
60377 KINGSTON
60*77 SHAWNEE
60*77 JOHNSONVILLE
60477 COLBERT
60477 CUMBERLO,
60477 PARADISE
60477 GILES COUNTY
60477 WIDOWS CREEK
60477 KINGSTON
60577 SHAWNEt
60577 JOHNSONVILLE
60577 COLBERT
60577 CUMBERLO.
60577 PARADISE
60577 CUES COUNTY
60577 WIDOWS CREEK
60577 KINGSTON
60877 SHAWNEE
60877 JOHNSONVILLE
60877 COLBERT
LOCATION
N
I
N
0
M
N
I
0
N
I
N
0
N
N
1
I
N
0
N
0
0
D
N
0
N
I
I
I
0
I
0
N
N
N
0
N
I
N
0
N
I
N
N
N
N
0
0
0
I
I
B
TSP
SO* N DURATION
-105
-99
-83
-30
-24
27
90
-118
-105
-99
-83
-30
-24
27
90
-176
-105
-99
-83
-72
-36
29
90
203
-176
-105
-99
-83
-72
-36
-30
-24
29
90
203
-176
-105
-99
-83
-30
-2*
90
203
-176
-105
-99
-83
-30
-24
90
203
-176
-105
-99
-18
-159
24
11*
-108
24
-1*4
71
-18
-159
24
114
-108
24
-1*4
101
-18
-159
24
166
176
92
-1*4
-26
101
-18
-159
2*
186
176
11*
-108
92
-144
-26
101
-18
-159
24
114
-108
-144
-26
101
-18
-159
24
114
-108
-144
-26
101
-18
-159
29,5
74.0
31.0
50.0
29,0
50.0
67,0
35.0
42.0
43.5
41.5
66.0
50.0
53.0
37.0
77,5
58,5
57,0
27,0
58,0
118.0
46,0
53.5
40.0
81.0
61.5
75.5
60.0
0.0
117,0
69.0
49.0
45,0
109.0
82.5
114.5
77.0
75.0
64.0
97.0
18.0
96.0
76,5
94,0
71.5
103.5
77,0
98.0
63,0
205.5
65,0
165.5
54,5
50.5
4.5
7,0
4.0
4.0
7,0
6.5
9,0
4.0
6,0
7,0
5.0
6.0
5,0
5,5
5,3
9.0
10.0
12,0
5.5
1,0
9.0
6,0
6.0
8.5
10.5
8.0
17.0
9.0
0.0
11.0
3.0
13.0
1.0
11.0
11,0
18.5
19,5
12,0
12,0
14,5
4,0
14,0
10,5
11,5
12.5
17.0
8,5
9.5
18,0
23.0
14,0
7.5
6.0
9.0
2
2
2
2
1
2
2
1
2
2
2
1
1
2
2
2
2
2
2
1
I
1
2
2
2
2
2
2
I
1
2
1
1
2
2
2
2
2
2
2
1
2
2
2
2
2
2
2
I
2
I
2
2
2
9,0
9,0
9,0
9,0
9,0
9,0
9,0
24.0
24,0
24,0
24,0
24,0
24,0
24,0
2't,0
9.0
9,0
9,0
9,0
«,0
8.8
8,0
9,0
9,0
9,0
9,0
4,0
9,0
0,0
9,3
6,7
9,0
0,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9.0
9,0
9,0
-------
D-5
TREATS 1976 t 1977 HIGH-VOLUME FIELD STUDY DATA
OATE STATION LOCATION X Y TSP SD4 N
60877 CUM6ERLO.
60877 HENDERSON
60877 OWENS80RD
60877 PARADISE
60877 GILES COUNTY
60877 BOWLING GREEN
60877 WIDOWS CREEK
60877 KINGSTON
61377 HENDERSON
61377 DWENSBQRO
61377 BOWLING GREEN
61777 SHAWNEE
61777 JOHNSONVILLE
61777 CUMBERLO.
61777 HENDERSON
61777 aWENSBORO
61777 PARADISE
61777 GILES COUNTY
61777 BOWLING GREEN
61777 WIDOWS CREEK
61777 KINGSTON
61877 SHAWNEE
61877 LBL
61877 JOHNSONVILLE
61877 COLBERT
61877 CUMBERLAND
61877 OACD
61877 PARADISE
61877 GILES
61877 GALLATIN
61877 HYTQP
61877 WIDOWS CREEK
61877 KINGSTON
62477 SHAWNEE
62477 LBL
62477 JOHNSONVILLE
62477 COLBERT
62477 CUMBERLAND
62477 OACD
62477 HENDERSON
62477 OWENSBORO
62477 PARADISE
62477 GILES
62477 GALLATIN
62477 BOWLING GREEN
62477 HYTOP
62477 WIDOWS CREEK
62477 KINGSTON
62877 SHAWNEE
62877 JOHNSONVILLE
62877 COLBERT
62877 CUMBERLO.
62877 HENDERSON
62877 OWENSBORO
DURATION
I
N
N
N
N
N
B
0
I
I
1
N
N
I
0
0
D
0
0
N
0
I
I
I
I
I
N
0
N
0
N
D
0
I
I
I
I
I
N
0
a
D
N
a
D
N
0
0
N
N
0
N
I
I
-83
-72
-36
-30
-24
29
90
203
-72
-36
29
-176
-105
-83
-72
-36
-30
-24
29
90
203
-176
-118
-105
-99
-83
-81
-30
-24
27
63
90
203
-176
-118
-105
-99
-83
-81
-72
-36
-30
-24
27
29
63
90
203
-176
-105
-99
-83
-72
-36
24
186
176
11*
-108
92
-144
-26
186
176
92
131
-18
24
166
176
114
-10B
92
-144
-26
101
71
-18
-159
24
-156
114
-108
24
-138
-144
-26
101
7i
-18
-159
24
-156
186
176
114
-108
24
92
-138
-144
-26
101
-18
-159
24
166
176
85.0
97,0
163,0
115,0
62.0
110. 0
130.5
38.5
69,0
118.0
408.0
31.5
20.0
22.0
78,0
140.0
39,0
29.0
66.0
32.0
51.5
65.3
39,0
30,2
33,0
45.3
36,0
63.3
35,0
32,3
35,0
60,2
55.5
50,5
40,0
44.2
63,4
64,0
96,0
41,0
163,0
42,0
82.0
63.8
71.0
89.0
100.7
36,0
120. 0
126,0
127.0
144,0
125.0
259,0
7,5
5.0
2,0
8.5
11.0
4.0
14,5
7.0
10,0
31,0
5,0
6.5
7,5
6.5
2.0
3.0
11.5
7.0
6,0
9.5
14.0
8.6
7,9
8,7
8.4
10,6
9,3
13.3
10,6
9.8
10,2
14,1
17,1
6.2
4,5
7.1
4.5
6.0
5.8
7,0
4.0
6,8
6,8
8.7
12,0
4.6
9.4
9,8
8,5
6.0
20,0
8,5
12,0
6.0
2
1
1
2
1
1
2
2
1
I
1
2
2
2
1
1
2
1
I
2
2
4
1
!>
4
6
2
6
1
4
1
6
2
4
1
5
5
7
2
1
1
5
i
4
1
1
6
4
2
2
I
2
1
1
9,0
8,0
8,7
9,0
9,0
8.0
9,0
9,0
24,0
9,3
8,0
9,3
9,0
9,0
B,2
9,0
B,9
9.0
8,0
8,8
9,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
24, 0
24.0
24,0
24, 0
24,0
24, 0
24,0
24,0
24,0
6,5
9,1
24,0
24, 0
24,0
6,0
24,0
24,0
24,0
9,0
9,0
9,0
9,0
8,8
8,3
-------
D-6
TREATS 1976 C 1977 HIGH-VOLUME FIELD STUDY DATA
DATE
STATION
LOCATION
TSP
SU4 N
DURATION
62877
62877
62877
62877
62877
63077
63077
63077
63077
63077
63077
63077
63077
63077
63077
63077
63077
63077
63077
63077
70577
70577
70577
70577
70577
70577
70577
70577
70677
70677
70677
70677
70677
70677
70677
70677
70677
70677
70677
70777
70777
70777
70777
70777
70777
70777
70777
PARADISE
GILES COUNTY
EfOwLING GREEN
WIUOWS CREEK
KINGSTON
SHAWNEE
LBL
JOHNSONVILLE
COLBERT
CUMBERLAND
OACD
HENDERSON
QWENSBORCJ
PARADISE
GILES
GALLATIN
BOWLING GREEN
HYTOP
WIDOWS CREEK
KINGSTON
SHAWNEE
JOHNSONVILLE
COLBERT
CUHBERLD.
PARADISE
GILES COUNTY
WIL'OWS CREEK
KINGSTON
SHAWNEE
JOHNSONVILLE
COLBERT
CUMBERLAND
QACO
PARADISE
GILES
GALLATIN
HYrop
rtlUQWS CREEK
KINGSTON
SHAWNEE
JOHNSONVILLE
COLBERT
CUMBERLD.
PARADISE
GILES COUNTY
WIDOWS CREEK
KINGSTON
I
N
I
N
N
I
I
I
I
I
N
G
0
0
N
0
0
N
0
0
0
N
I
N
0
I
I
N
I
N
0
N
D
I
0
N
0
0
N
I
N
0
N
N
N
0
0
-30
-24
29
90
Z03
-176
-118
-105
-99
-83
-81
-72
-36
-30
-24
27
29
63
90
203
-175
-105
-99
-83
-30
-a*
90
203
-176
-105
-99
-83
-81
-30
-2*
27
63
90
203
-176
-105
-99
-83
-30
-24
90
203
11*
-108
92
-144
-26
10;
71
-IB
-139
24
-156
186
176
114
-108
24
92
-138
-144
-26
101
-18
-159
24
11*
-108
-144
-26
101
-18
-159
24
-156
11*
-108
24
-138
-144
-26
101
-18
-159
24
11*
-108
-144
-26
151.5
136.0
69,0
120,5
71.0
59,5
46.0
45.5
63.6
39.4
64.5
110.0
200.0
65.0
44.0
58.5
76.0
39.0
63,8
60,8
92,0
90.0
116,5
91.3
132.3
97.0
123.0
88.5
101.5
131.7
101.8
123.4
108,0
129.8
88.0
99,3
66.0
97.5
103,3
80,7
90,0
134,5
116,5
141.0
146,0
207,0
91,5
7,5
15,0
2,0
7.0
6,0
7.1
3.7
7,6
5.3
6.9
4.7
13,0
4.0
10,2
B.4
10,0
2,0
5,0
9.4
12,7
19.0
30.0
25.0
27,5
29,5
29.0
24,0
25.0
25,9
38,2
27,6
32.6
29.8
25.2
27,6
29,0
17,9
27.8
26,8
13,3
28,0
25,5
29,5
25.0
42.0
33.5
29.5
2
1
1
2
2
4
1
6
5
7
2
1
1
5
1
4
1
1
5
4
2
2
2
2
2
1
2
2
4
6
5
5
1
5
1
3
1
6
4
3
2
2
2
2
1
2
2
9,0
9,0
a,o
9(0
9,0
24,0
24,0
24,0
24,0
24,0
24,0
8.2
9,0
24,0
24,0
24,0
8,0
24,0
24,0
24,0
9,0
9,0
9,0
9,0
6,9
9,0
9,0
9,0
24,0
24,0
24.0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
24,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
9,0
N«209
-------
E-l
APPENDIX E
INVERSION HEIGHTS AND AVERAGE WIND VELOCITIES
FOR LAGRANGIAN AND EULERIAN DAYS
-------
E-2
ABBREVIATIONS AND UNITS FOR APPENDIX E
Sampling class: I = inflow, 0 = outflow
Inversion type: R = radiation; S = subsidence
Station : BNA = Nashville, TN (NWS)
JSV = Johnsonville Steam Plant, New Johnsonville, TN
KIN = Kingston Steam Plant, Kingston, TN
COL = Colbert Steam Plant, Pride, AL
PAR = Paradise Steam Plant, Drakesboro, KY
GAL = Gallatin Steam Plant, Gallatin, TN
WID = Widows Creek Steam Plant, Bridgeport, AL
Wind velocity : Angle defines average direction from which wind is blowing.
Directions in degrees from true north, speed in meters per
second. Numbers in parentheses are the resultant wind
through the transport layer.
-------
E-3
TABLE E.I INVERSION HEIGHTS AND AVERAGE WIND VELOCITIES
FOR LAGRANGIAN AND EULERIAN DAYS
Sampling
Date class Time (L)
2/10/76
2/19/76
I :
3/11/76
3/18/76
3/23/76
I
0
0
I
I
I
I
I
0
I
I
I
I
0
I
I
I
I
0
0
I
I
I
I
I
0
0
0515
1345
1715
0810
0930
0810
0930
0930
1643 (avg)
0815
0830
1015
0923 (avg)
1530 (avg)
0655
0815
0655 (avg)
0655 (avg)
1340
1700
0815
0810
0815
0810
0810
1705
1415
Inversion
Upper air height (type)
station (m AGL)
BNA
JSV
BNA
COL
JSV
COL
JSV
JSV
BNA & WID
COL
COL
JSV
COL & JSV
JSV & BNA
WID & COL
COL
WID & COL
WID & COL
JSV
BNA
COL
COL
COL
BNA
JSV
626 (S)
915 (S)
244 (R)
1829 (S)
1900 (S)
366 (R)
1829 (S)
1250 (S)
519 (R)
1524 (S)
1372 (S)
305 (R)
1219 (S)
1767 (S)
Wind
velocity (m s"1
(219/14.0)
(215/13.2)
237/4.7
278/13.8
(276/12.4)
(269/6.9)
232/2.0
235/2.7
(235/2.6)
(183/5.2)
230/8.4
249/10.3
(243/9.5)
(212/12.2)
086/2.1
021/1.3
(043/1.3)
(213/6.6)
Layer
) (m)
SFC-626
SFC-915
SFC-915
SFC-244
245-1829
SFC-1829
SFC-1900
SFC-366
367-1829
SFC-1829
SFC-1250
SFC-519
520-1524
SFC-1524
SFC-1372
SFC-305
306-1219
SFC-1219
SFC-1767
-------
E-4
TABLE E.I (continued)
Sampling
Date class
3/24/76 I
I
I
I
0
0
6/03/77 I
I
I
I
I
I
I
0
0
0
0
0
0
0
0
0
6/04/77 I
I
I
I
I
I
I
I
I
Time (L)
0655 (avg)
0825 (avg)
0655 (avg)
0655 (avg)
1332
1315 (avg)
0640 (avg)
0615
0630 (avg)
0950
0805
1600 (avg)
1605
0845
1110
0845
1110
1110
0950
1110
1400
1510
0650
0630
0650
0630
0630
1015
1200
1435 (avg)
1325
Upper air
station
COL & WID
COL & WID
COL & WID
COL & WID
JSV
JSV & KIN
PAR & SNA
PAR
PAR & BNA
JSV
JSV
JSV & BNA
JSV
COL
COL
COL
COL
COL
JSV
COL
JSV
COL
GAL
GAL
GAL
GAL
GAL
JSV
JSV
JSV, COL,
BNA
JSV
Inversion
height (type)
(m AGL)
564 (R)
1752 (S)
1829 (S)
305 (R)
1646 (S)
1646 (S)
1524 (S)
366 (R)
1645 (S)
1646 (S)
1524 (S)
457 (R)
1219 (S)
1128 (S)
& 1433 (S)
Wind
velocity (m s"1)
192/6.9
197/9.9
(196/8.9)
(201/10.6)
061/6.0
348/6.3
(358/5.6)
(064/3.9)
(046/2.2)
068/2.7
009/5.2
(016/4.4)
(016/4.4)
(009/2.8)
125/2.9
145/1.0
(132/1.7)
(020/1.4)
(349/2.3)
Layer
On)
SFC-564
565-1752
SFC-1752
SFC-1829
SFC-305
306-1676
SFC-1676
SFC-1646
SFC-1524
SFC-366
SFC-1645
SFC-1645
SFC-1646
SFC-1524
SFC-457
458-1219
SFC-1219
SFC-1128
SFC-1433
-------
TABLE E.I (continued)
E-5
Sampling
Date class
6/04/77
(Cont . )
6/28/77
6/30/77
0
0
0
0
0
0
0
I
I
I
I
0
0
0
0
0
0
I
I
I
I
I
I
I
I
I
0
0
0
0
0
Time (L)
0845
0725
06lO(avg)
0725
0725
1235
1510
0940 (avg)
1110
1400
1510
0700
0620
0700
0700
1040 (avg)
1140 (avg)
0430
0710
0430
0710
0710
1220
1140 (avg)
1650 (avg)
1445 (avg)
0650
0655 (avg)
0650
0655 (avg)
0655 (avg)
Inversion
Upper air height (type) Wind
station (m AGL) velocity (m s~l]
COL
COL
COL (2)
COL
COL
COL
COL
COL & JSV
COL
JSV
JSV
GAL
JSV
GAL
KIN & JSV
KIN, WID &
JSV
COL
COL
COL
COL
COL
COL & JSV
COL
JSV & COL
GAL
GAL, PAR, &
KIN
GAL
GAL, PAR, &
KIN
GAL, PAR, &
KIN
366 (R)
1280 (S)
1524 (S)
1524 (S)
1372 (S)
365 (R)
1524 (S)
1372 (S)
366 (R)
1220 (S)
1524 (S)
1524 (S)
548 (R)
1220 (S)
(124/2.6)
315/2.7
(322/1.2)
(005/2.9)
(239/9.0)
(232/8.1)
244/10.6
266/11.8
(262/10.8)
(237/9.0)
234/7.9
240/9.8
(238/9.2)
(234/9.8)
(233/10.0)
223/8.5
240/9.3
(233/8.8)
Layer
) (m)
SFC-366
367-1280
SFC-1200
SFC-1524
SFC-1372
SFC-1372
SFC-365
366-1524
SFC-1524
SFC-1372
SFC-366
367-1220
SFC-1220
SFC-1524
SFC-1524
SFC-548
549-1220
SFC-1220
-------
E-6
TABLE E.I (continued)
Date
6/30/77
7/06/77
Sampling
class
-0
0
0
0
I
I
I
I
I
I
I
0
0
0
0
0
0
0
0
0
Time (L)
1145
1155 (avg)
1510
1420
0810
0800
OSOO(avg)
0750
0755(avg)
1005
1415
0820
0715
0820
0715
0715
1230
1110
1700(avg)
1510
Upper air
station
KIN
KIN & JSV
KIN
JSV
GAL
GAL
PAR & GAL
PAR
PAR & GAL
JSV
JSV
COL
COL
COL
COL
COL
COL
COL
COL (2)
COL
Inversion
height (type)
(m AGL)
1220 (S)
1829 (S)
365 (R)
990 (S)
1067 (S)
366 (R)
1372 (S)
1372 (S)
1036 (S)
Wind
velocity (m s"1)
(234/8.5)
(230/12.0)
057/0.6
014/0.9
(026/0.7)
(333/1.9)
082/2.9
012/4.6
(024/3.8)
(020/2.2)
(355/3.2)
Layer
(m)
SFC-1220
SFC-1829
SFC-365
366-990
SFC-990
SFC-1067
SFC-366
367-1372
SFC-1372
SFC-1372
SFC-1036
-------
F-l
APPENDIX F
SYNOPTIC METEOROLOGICAL SUMMARIES
FOR LAGRANGIAN AND EULERIAN DAYS
-------
F-2
APPENDIX F
SYNOPTIC METEOROLOGICAL SUMMARIES FOR LAGRANGIAN AND EULERIAN DAYS
Meteorology for the two field studies is analyzed for the Lagrangian
and Eulerian measurement days shown in Table 6. Thus, six days were
analyzed for the 1976 spring study and eight for the 1977 summer study.
The following analyses describe by study and date the most significant
meteorological parameters.
1976 STUDY
In the Tennessee Valley region, February and especially March are
typically characterized by spring type weather; that is, frequent frontal
passages are the rule, with good ventilation (wind speed times mixing
height) and rapidly changing airmass characteristics. Typical inversion
heights and wind speeds are about 600 m and 5.5 m s"1 in the morning and
1800 m and 7 m s"1 in the afternoon. Typical daily maximum temperatures
average 15°C, whereas daily minimum temperatures average around 3°C.
Surface wind speeds average 5 m s"1; this represents the strongest average
flow for any period during the year. Precipitation typically occurs on
one out of every three days, and mean cloud cover averages 65 percent.
Analysis of weather types (see the Meteorological Characterization subsec-
tion of Section 3) indicates that the spring season has similar charac-
teristics to the annual average weather. High-pressure systems occur
most frequently (27 percent), with the centers of these systems typically
located northeast and east of Nashville. Maritime tropical and modified
polar airmasses occur equally during this time of the year and account
for 80 percent of all airmass types.
February 10, 1976
As noted previously, February (and March) weather is typified by
strong ventilation and frequent frontal passages. This is exemplified by
the weather pattern of February 10, 1976. On the morning of February 10,
1976, a developing low-pressure center and associated cold front were
located in the Great Plains area of Iowa and Kansas, while at the same
time, a large modified continental polar airmass was centered over central
Florida. The combined effect of these two systems produced an influx of
maritime tropical air, with accompanying clouds. Early-morning inflow
ceilings (near Muscle Shoals, Alabama) were around 1000 m AGL, but gradually
rose above 1500 m AGL at the afternoon outflow boundary (near Bowling
Green, Kentucky). No significant rainfall occurred during the sampling
day, and the maximum average surface temperature was 20°C (68°F). Tempera-
ture soundings showed that warm air advection produced a morning mixing
layer (~600 m AGL) nearly equal to the climatological average, whereas
the afternoon mixing height (~900 m AGL) was significantly below the
afternoon climatological average. As might be expected, winds under this
pressure configuration were southwesterly and strong; Valley-wide mixing-
layer wind velocity averaged 215 degrees at 13 m s~l throughout the sampling
-------
F-3
period. The average of the surface and 850-mb 24-h back-trajectory for
February 10, 1976, showed that the airmass originated along the Louisiana-
Texas border area (Figure F.I).
February 19, 1976
The weather pattern on this date was characterized by a weak surface
frontal passage through the study area during the daylight hours, which
caused little change in the prevailing modified maritime polar airmass
weather characteristics. Generally, fair skies with southwesterly surface
winds early in the morning and westerly winds by midday characterized the
prevailing weather conditions. Areawide temperatures were warm, with
highs generally around 20°C (68°F). Winds aloft were westerly from near
surface to 1800 m AGL, the top of the afternoon mixed layer. The morning
radiation inversion was about 300 m AGL. The 24-h back-trajectory for
February 19, 1976, indicated the source region to be eastern Kansas
(Figure F.2).
March 11, 1976
The synoptic weather pattern for March 11, 1976, was predominantly
influenced by an east-west-oriented stationary front located through
central Kentucky and a high-pressure center located along the Georgia-
South Carolina border. This combination produced high cloud ceilings
over the field study area and an influx of maritime tropical air. Winds,
both surface and aloft, were southwesterly during the morning hours,
whereas a gradual backing produced a more southerly component by after-
noon. The morning radiation inversion height was about 400 m AGL, and
the morning subsidence inversion height was about 1800 m AGL. Due to
warm air advection, the afternoon inversion height decreased by about 500
m. No precipitation occurred during the measurement period, and high
temperatures were again around 20°C. Also, the 24-h back-trajectory
indicated that the airmass originated in central Mississippi (Figure F.3).
March 18, 1976
Somewhat similar to the weather of March 11, 1976, a high-pressure
center was located along the Georgia-South Carolina border, with a warm
front through northern Kentucky. Again, southwesterly flow of maritime
tropical air occurred across the study area. Partly cloudy skies prevailed,
with temperatures again reaching 20°C. The morning radiation and subsi-
dence inversions were about 500 and 1500 m AGL respectively.
By afternoon, the subsidence inversion had decreased to about 1400 m
AGL due, again, to warm air advection. The 24-h trajectory analysis
indicated that the source region included southern Louisiana and Mississippi
(Figure F.4).
-------
Figure F.I. The 24-h boundary-layer back-trajectories for 1800 h CST, February 10, 1976.
-------
Figure F.2. The 24-h boundary-layer back-trajectories for 0600 h CST, February 19, 1976.
-------
Figure F.3. The 24-h boundary-layer back-trajectories for 1800 h CST, March. 11, 1976.
-------
Figure F.4. The 24-h boundary-layer back-trajectories for 1800 h CST, March 18, 1976.
-------
F-8
March 23, 1976
A meteorological pattern different from the previous two occurred
on this date. A modified continental high-pressure airraass was centered
over the Chesapeake Bay area, with a very weak pressure gradient over
the study area. Boundary-layer winds were light and northeasterly early
in the morning, but became stronger and southwesterly by afternoon. Skies
were generally clear throughout the sampling period, with the area tempera-
ture again peaking around 20°C. Morning radiation and subsidence inversion
heights averaged 300 and 1200 m AGL, respectively, whereas the afternoon
subsidence inversion height rose to about 1800 m AGL. The 24-h back-
trajectory shows a complex trajectory path resulting from the changing
nature of the high-pressure center's location (Figure F.5).
March 24, 1976
The high-pressure center of the previous day was well off the eastern
seaboard by the morning of March 24, 1976. An approaching cold front
with a pressure-frontal orientation similar to that described on February
10, 1976, caused an influx of warm, moist tropical air. Middle and high
cloud cover increased throughout the day; however, rainfall did not occur
in the study area until after dark. Morning radiation and subsidence
inversion heights were about 600 and 1750 m AGL respectively with the
afternoon subsidence inversion height rising slightly to about 1800 m
AGL. The 24-h trajectory shows that once again the source region was
southern Louisiana and Mississippi (Figure F.6).
1977 STUDY
Summertime (June and July) weather in the Tennessee Valley region,
as in most of the eastern United States, is typified by infrequent frontal
passages and slow-moving high-pressure systems. Due to increased solar
insolation, vertical mixing is usually good, with cliraatological morning
and afternoon averages being about 450 and 1900 m AGL respectively. How-
ever, total ventilation is significantly less, on the average, than the
spring season due to reduced wind speeds. Transport layer speeds average
only 3.5 m s"1 in the morning and 5ms1"1 in the afternoon. The average
daily maximum temperature is 31°C (twice the daily springtime average
maximum), whereas the daily minimum averages 20°C. Typical surface wind
speeds average 3 m s l, the slowest average wind speed of any season.
Precipitation occurs on an average of one third of the days, and mean
cloud cover averages about 55 percent. Analysis of weather typing indi-
cates that stationary fronts and high-pressure centers without associated
frontal systems predominate. Most pressure centers fall within a 300-
to 399-km radius of Nashville or are greater than 500 km and favor the
45- through 134-degree sector (northeast through southeast of Nashville).
Maritime tropical airmasses cover the area 75 percent of the time and
either one or more of the four Tennessee weather stations record
measurable precipitation 60 percent of the time.
-------
Figure F.5. The 24-h boundary-layer back-trajectories for 1800 h CST, March 23, 1976.
-------
Figure F.6. The 24-h boundary-layer back-trajectories for 1800 h CST, March 24, 1976.
-------
F-ll
June 3, 1977
Early in the morning of June 3, 1977, a weak continental polar front
lay east-west across northern Alabama and Georgia. Behind it, to the
north, was a modified continental airmass centered over central Michigan.
This high-pressure system produced northerly winds, no precipitation,
and morning radiation and subsidence inversion heights that averaged
about 350 and 1650 m AGL respectively. The average field study after-
noon inversion level decreased to about 1500 m due to subsidence of
superior air. The average maximum temperature was 30°C, with mostly
sunny skies prevailing. The 24-h trajectory data showed that the source
region was in southern Indiana and Illinois (Figure F.7).
June 4, 1977
The high-pressure center of the previous day moved southeastward
and was centered over West Virginia on the morning of June 4, 1977. Again,
airflow was light and from a northerly direction. Average morning radiation
and subsidence inversion heights were 400 and 1250 m AGL respectively.
The afternoon inversion height rose to around 1400 m AGL. Again, no signi-
ficant cloud cover was present over the study area, and the average maximum
temperature was 31°C. The trajectory data indicated that the airmass
originated along the Ohio River Valley area (Figure F.8).
June 5, 1977
By the morning of June 5, 1977, the high-pressure center of the previ-
ous two days dissipated and began merging with the Bermuda high. Winds
were west-northwesterly throughout the boundary layer. Inversions averaged
350 and 1400 m AGL during the morning hours and 1750 m AGL during the
afternoon. Again, no significant cloud cover was present and the average
high temperature reached 33°C. The 24-h trajectory data indicated that
the airmass originated along the Mississippi River west of the study region
(Figure F.9).
June 8, 1977
A modified continental high-pressure airmass was centered over northern
Alabama on June 8, 1977. Morning radiation and subsidence inversion heights
averaged 300 and 1600 m AGL respectively. By afternoon, the subsidence
inversion rose to about 1800 m AGL. Boundary-layer winds were light and
variable over northern Alabama and west-northwesterly over the northern
half of the field study area. Trajectory analysis shows that the 24-h
airmass source region was in central Indiana and Illinois (Figure F.10).
Temperatures rose to around 27°C under fair skies.
-------
Figure F.7. The 24-h boundary-layer back-trajectories for 0600 h CST, June 3, 1977.
-------
Figure F.8. The 24-h boundary-layer back-trajectories for 0600 h GST, June 4, 1977.
-------
I
I—I
*-
Figure F.9. The 24-h boundary-layer back-trajectories for 1800 h CST, June 5, 1977.
-------
Figure F.10. The 24-h boundary-layer back-trajectories for 0600 h CST, June 8, 1977.
-------
F-16
June 28, 1977
A significant departure from the earlier June northerly wind flow
regime was evident during the last one third of the month. On June 28,
1977, an approaching cold front located in the Great Plains combined with
the Bermuda high to produce steady southwesterly flow of maritime tropical
air. Boundary-layer winds throughout the study area were southwesterly
and relatively strong (7 to 10 m s'1). Morning radiation and subsidence
inversion heights averaged about 400 and 1500 m AGL, respectively, whereas
afternoon inversion heights were around 1400 m AGL. Despite the approaching
frontal system, only mid-level small cumulus and altocumulus clouds were
evident. Average high temperatures reached 32°C. Significant rainfall
did not materialize until after sunset, and most of that was confined to
the western part of the field study area. The 24-h trajectory data indi-
cated that airmass source regions included the Gulf Coast area of eastern
Texas and southern Louisiana (Figure F.ll).
June 30, 1977
By the morning of June 30, 1977, the southward moving cold front of
June 28, 1977, was located over Kentucky and had begun moving northward
as a warm front in response to the approach of a second maritime polar
airmass. This new frontal system was situated through central Iowa, then
southwestward to southern Colorado. Again, warm moist tropical air accom-
panied relatively strong (8 to 11 m s"*1) southwesterly winds. Morning
radiation and subsidence inversion heights averaged 450 and 1200 m AGL,
respectively, with the afternoon subsidence inversion rising to about
1650 m AGL. Hazy but fair skies were prevalent in the morning; however,
by midafternoon isolated cumulus congestus and cumulonimbus clouds pro-
duced shower activity near the northern study area boundary. Maximum
temperatures were around 35°C. The 24-h trajectories indicated that the
airmass originated in the northern Louisiana area (Figure F.12).
July 6, 1977
Weather conditions within the Tennessee Valley area and, in fact,
across most of the eastern United States were dominated by a large,
sprawling high-pressure system on July 6, 1977. The surface center of
this maritime tropical airmass was located over southern Louisiana,
whereas the upper-level core was located over the bootheel area of
Missouri. Boundary-layer winds were light (<4 m s"1) and northerly.
Morning radiation and subsidence inversions were relatively low, with
values averaging 350 and 1100 m AGL, respectively, whereas afternoon
subsidence inversion levels remained relatively stable. Maximum tem-
peratures peaked around 35°C while subsiding air effectively eliminated
cloud cover. Trajectory data indicated that the little air movement
present came from the northwest (Figure F.13).
-------
Figure F.ll. The 24-h boundary-layer back-trajectories for 0600 h CST, June 28, 1977.
-------
i
<—i
Co
Figure F.12. The 24-h boundary-layer back-trajectories for 1800 h CST, June 30, 1977.
-------
I
l->
vo
Figure F.13. The 24-h boundary-layer back-trajectories for 0600 h CST, July 6, 1977.
-------
F-20
July 7, 1977
Similar to July 6, 1977, this day's weather was characterized by a
continuation of the Bermuda high-pressure system over much of the eastern
United States. The upper-level high-pressure cell was centered over the
study area. Maritime tropical air continued to pervade the area. Boundary-
layer winds were again light (<5 m s"1) and generally from the WNW. Morn-
ing radiation and subsidence inversion heights averaged 200 and 1700 m AGL.
Skies were generally fair, and average maximum surface temperatures once
again reached 35°C. The 24-h trajectories indicated that the airmass
affecting the study area once again originated near the Mississippi River
(Figure F.14).
-------
Figure F.14. The 24-h boundary-layer back-trajectories for 0600 h CST, July 7, 1977.
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-80-126
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
TRANSPORT AND TRANSFORMATION OF SULFUR OXIDES
THROUGH THE TENNESSEE VALLEY REGION
5. REPORT DATE
June 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
T. L. Crawford and L. M. Reisinger
8. PERFORMING ORGANIZATION REPORT NO.
N581
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Natural Resources
Tennessee Valley Authority
Muscle Shoals, AL 35660
10. PROGRAM ELEMENT NO.
1NE-832
11. CONTRACT/GRANT NO.
81 BDL
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office cf Research & Development
Office of Energy, Minerals & Industry
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
Milestone
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
This project is part of the EPA-planned and coordinated Federal Interagency
Energy/Environment R&D Program.
16. ABSTRACT
This report is directed to scientists interested in the long-range atmospheric
transport and transformation of sulfur compounds.
Statistical and climatological analyses of historical data and the results of
two long-range transport studies are presented. The^two long-range atmospheric
transport field studies were conducted over a 300-km area of the southern United
States centered on the Tennessee Valley region The first study was conducted dur-
ing the spring of 1976, and the second was conducted during the summer of 1977. The
field study region contains seven large coal-fired power plants and one large city.
Results indicate that the predominant flow and mass transport direction is from
the southwest to the northeast. Also, aerometric measurements obtained by aircraft
and ground sampling compared favorably with results obtained with an analytical
transport-transformation model developed for this study. Results indicate that,
during prevailing southwesterly airflow, large sulfur influxes are present. These
influxes, which are at the same order of magnitude as the Tennessee Valley regional
emission fluxes, can only partly be explained by upwind anthropogenic sources.
Natural source emissions are hypothesized to account for about half of this sulfur
influx.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Earth Atmosphere
Transport Processes
Charac..Meas. & Monit.
6F 8A 8F
8H 10A 10B
7B 7C 13B
8. DISTRIBUTION STATEMENT
19. SECURITY CLASS (ThisReport>
Unclassified
21. NO. OF PAGES
153
Release to public
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
-------
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