EPA-600/8-77-004
FEBRUARY 1977
STATEMENT OF
SULFdTES
RESEARCH
dPPROdCH
OFFICE OF RESEARCH AND DEVELOPMENT
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON D.C.
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EPA-600/8-77-004
February 1977
Statement of
SULFATES RESEARCH APPROACH
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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TABLE OF CONTENTS
Page
1. INTRODUCTION 1
1.1 Scope of the Research Strategy 1
1.2 Background 2
1.3 Discussion of Research 3
1.4 Concurrent Sulfate Research 6
2. RESEARCH STRATEGY 8
2.1 Health Effects 10
2.1.1 Research Results 10
2.1.2 Research Strategy 12
2.2 Ecological Effects 17
2.2.1 Introduction 17
2.2.2 Research Strategy 17
2.3 Atmospheric Chemistry and Transport 18
2.3.1 Workshop on Regional Air Pollution Studies 18
2.3.2 Evlauation of Capabilities of Governmental-Industry Programs 19
2.3.3 Research Needs 20
2.3.4 Research Strategy 21
2.4 Measurement Methodology and Instrumentation 30
2.4.1 Background 30
2.4.2 Research Strategy 30
2.4.3 Anticipated Results 33
APPENDIX 1-BIBLIOGRAPHY 35
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DISCLAIMER
This report has been reviewed by the Office of Research and Development, U.S. Environmental
Protection Agency, and approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
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1. INTRODUCTION
The Environmental Protection Agency (EPA) has long been concerned about atmospheric suspended
sulfates. The recent energy-related program to convert power plants from oil or gas to coal, which will
increase S02 emissions, has heightened our interest in sulfates.
The Office of Research and Development (ORD), the research arm of EPA, has developed a strategy to
investigate the sulfate question in a way which would limit the research to manageable bounds. This
document defines the approach to be taken, lists the questions to be addressed, provides estimates of re-
sources needed, and time tables for accomplishing these goals.
Hence, the document presents a statement of an approach to sulfate research. It is a long-term planning
instrument to be considered by EPA program managers, Office of Management and Budget, research
managers in other agencies, Congress, and the public. It is intended as a tentative plan, and as such is sub-
ject to change and revision both in content and time frames. It does not attempt to present all the tech-
nical details of the proposed research, nor does it provide reference documentation.*
This strategy statement is logically divided into four research areas: Health Effects, Ecological Effects,
Atmospheric Chemistry and Transport, and Measurement Methodology and Instrumentation. The research
program that is to follow from this statement of approach will be an integrated compendium of these four
research areas and is to produce scientific evidence to:
1. Provide the scientific basis needed to determine whether regulatory action pertaining to total or
selected atmospheric sulfates is warranted.
2. If regulatory action is warranted, provide reasonable scientific bases for setting standards.
3. Define implementable control strategies.
1.1 SCOPE OF THE RESEARCH STRATEGY
As there are too many sulfate compounds in the atmosphere to study each singly and in combination,
EPA/ORD will focus its research in the next few years on those compounds and particle sizes likeliest to be
biologically significant and which are most commonly found. Prominent among these compounds are sul-
furic acid, ammonium bisulfate, ammonium sulfate, and two ionic species: vanadium and manganese. The
traditional water soluble sulfate measurement and the measurement of acid versus neutral sulfate relative
concentrations will also be evaluated to determine whether they provide adequate indices.
This research program deals only with atmospheric sulfur species, but it is important to recognize that
the sulfates problem is actually an integral part of the larger problem of atmospheric suspended aerosols.
That is, sulfates are a major component of atmospheric fine particulates, representing 40-60% of RSP in
most areas, and in a phased strategy to control fine particulates, the control of sulfates would constitute
the most important first step. Sulfates also may be only one of the agents responsible for acid precipita-
tion. However, in order to realistically cope with these larger problems, each component of the problem
must be examined.
Although the major contribution to sulfates in the atmosphere comes from stationary sources, some
research on emissions from mobile sources is relevant to the sulfates problem. The mobile source research
included in this strategy document plan is only that research specifically directed toward determining the
health effects of sulfuric acid or specific sulfates generated to simulate expected emissions from mobile
sources.
*Even though scientific statements made in this document are unreferenced, they are primarily based upon the references
listed in Appendix 1.
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Control technology has been developed and is commercially available for controlling significant
quantities of potential sulfate precursors such as S02 and particulates. Up to 90% of S02 emissions from
large stationary sources - principally electric generating utilities - can be removed by currently available
flue gas desulfurization (FGD) processes. Many major emission sources have already been equipped with
FGD processes and are using this technology, and many others are planning to do so. Similarly, particulate
emissions can be reduced significantly with available technology. Removal efficiencies in excess of 99%
are often achievable at reasonable cost.
Other technology is under development that will reduce total S02 emissions, especially in future years.
In addition, technology is being evaluated for smaller sources including smaller boilers and industrial pro-
cesses. EPA and ERDA are developing techniques for the removal of sulfur from fuel-prior to combustion.
Technologies under development address methods such as physical and chemical coal cleaning, liquified
coal, and clean synthetic fuels.
These technologies are under various stages of development, but in future years will minimize emissions
of sulfur oxides and other pollutants from increased energy production. The current technology and the
results of our ongoing research program could be extended to achieve increased S02 control should such a
need be identified and mandated.. Therefore, it is considered appropriate to leave S02 control technology
development in the base program, rather than initiate at this time a control technology program directed
specifically toward sulfates.
1.2 BACKGROUND
The data regarding causal relationships, biological mechanism, and dose-response relationships of sulfates
are extremely limited, particularly at concentrations to which the general population is normally exposed.
Epidemiological studies* have tended to show a statistical correlation between measured atmospheric sul-
fates and the frequency of asthmatic attacks and acute and chronic respiratory disease; however, the
quantitative results of these studies are confounded by a wide range of variables and uncertainties. Be-
cause of the limitations in available measurement methodology at the time these studies were done, the
studies do not distinguish between H2S04 and other sulfates, either acid or neutral. There are other
environmental factors, such as temperature stress, as well as other gaseous and particulate pollutants, which
are associated with the frequency of these illnesses.
The total sulfur in the atmosphere is probably distributed in a wide variety of gaseous and particulate
inorganic and organic compounds or complexes—the number may certainly be many hundreds. The
traditional definition of sulfates has been an operational one: material collected on a high-volume sampler
filter and analyzed as water soluble sulfates. This method does not distinguish between the various sulfate
or sulfite compounds that may be present, nor does it distinguish between the particle sizes. Thus the
chemical composition of the sulfate aerosol has not been characterized. Such characterization is important
because chemical structure, acidity and particle size of sulfates appear to be important factors related to
biological activities, that is the potential for producing adverse effects on humans or other living organisms.
Generally, suspended sulfates are submicron secondary aerosols derived principally from atmospheric
reactions of gaseous precursors. However, the observed sulfate concentrations, and in particular the acid
sulfates, are not always highly correlated with S02 concentrations. The occurrence of acid sulfates does
not appear to be linked closely with high S02concentrations at a given location. This suggests that factors
other than local S02 concentrations, such as long-range transport and transformation of primary S02
emissions, control the local level of sulfate concentrations. The acidity varies continuously over a wide
range, both day and night, within a 3-hour period in a given urban area. Meteorological factors, such as
*U.S. Environmental Protection Agency, Health Consequences of Sulfur Oxides: A Report from CHESS 1970-1971,
Research Triangle Park, N. C., National Environmental Research Center of U.S. Environmental Protection Agency, May
1974, EPA# 650/1-74-004.
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wind direction, indicative of the initial properties of the incoming air mass, are important. The extent of
atmospheric transformation and transport are critical relative to an understanding of population exposure
patterns and the development of control strategies.
Because of the critical lack of information in the many areas discussed above, the Office of Research and
Development (ORD) has in the past few years concentrated on:
1. Identifying through toxicological studies which components/compounds and what size particles in
the complex labeled sulfates are biologically active;
2. Developing instrumentation and measurement methodology specifically to identify and analyze
sulfur-containing particulate species; and
3. Developing the scientific data needed to relate sulfur oxide emissions to ambient air concentrations
of sulfates.
1.3 DISCUSSION OF RESEARCH APPROACH
Long-range planning is essential to assure that resources are best used during the needed long-term sulfate
research.
Such planning requires a careful examination of the research strategy so as to maximize the effectiveness
of the actual research. There are four general research questions that warrant specific attention.
1. To determine over a broad area the actual chemical composition of atmosphere's sulfates and other
sulfur-containing materials. This must include areas dominated by single S02 emitting industries,
areas dominated by single sulfate emitting industries, and areas with no heavy SC>2 or sulfate emitt-
ing industries. This is essentially a definition of the situation as it exists.
2. To provide information concerning the physical characteristics of the sulfates as well as the relation-
ships between the difficult to measure sulfate concentrations and the more easily measured TSP or
RSP.
3. Concurrent with 1 and 2, animal studies and human clinical studies where possible must be under-
taken to determine the adverse health effects resulting from exposure to those sulfate compounds
found to occur most abundantly in the ambient air (individually or in combination).
4. Conduct epidemiology studies to provide field verification of the laboratory studies by utilizing the
air pollution indices obtained with the kinds of field monitoring instruments that can be used on
control programs. To be useful these studies must demonstrate the most useful index of pollution
even though the adverse health effects may be caused by a specific compound, the level of which is
reflected fairly consistently, by the level of more easily measured materials.
The research strategy presented in this document is an interrelated series of scientific studies designed to
accomplish the Agency's research goals.
Table 1 summarizes the resources that are to be required in completing this research, by projecting fund-
ing estimates in the four areas of research: Health Effects, Ecological Effects, Atmospheric Chemistry and
Transport, and Instrumentation and Measurement Methodology.
Table 1
SULFATES RESEARCH STRATEGY FUNDING ESTIMATES ($M)
FY
77 78 79 80 81 82 83
Health Effects 5.4 4.6 7.5 7.5 6.8 6.8 3.5
Ecological Effects 0.9 0.4 1.4 1.4 1.4 1.4 2.0
Atmospheric Chemistry and Transport 4.5 4.5 5.2 5.5 5.3 5.0 2.4
Instrumentation and Measurement Methodology 1.3 1.3 2.3 2.0 1.6 1.3 0.8
TOTALS 12.1 10.8 16.4 16.4 15.1 14.5 8.7
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Some priorities are implicit in any funding statement. However, the interrelated nature of the research
areas make it very difficult to assign relative or absolute priorities in this research strategy. Figure 1 shows
this important interrelationship of the various components of the plan in how the objectives of the research
strategy are met.
To decide whether sulfates require regulatory action, the most critical question is whether sulfates cause
adverse health or welfare effects at levels found in the ambient air. Such health and welfare data is obvi-
ously crucial. No less important, however, are the Measurement Methodology and Instrumentation, and
the Atmospheric Chemistry and Transport research, as they provide the ability to characterize the "dose"
to the health and welfare effects research. These areas are also important in the initial phases of research to
indicate which materials might represent the greater hazards. At the same time, the Atmospheric Chemistry
and Transport research must proceed toward developing relationships between ambient levels of sulfates
and emissions of their precursors. This information will be required to develop control strategies if sulfates
warrant regulatory action.
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Program on
Selected Species
Is
regulatory
action required
on most abundant
or widespread
species?
Begin program on
new selected species.
Can other species
be selected?
Program to
Evaluate Other
Species
.Implement
rest of
research
plan on
these
species.
Continue
evaluation
program and
consider
termination.
Figure 1. Su I fates Research Strategy
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1.4 CONCURRENT SULFATE RESEARCH
Other federal agencies are concurrently studying health effects of sulfates. The National Institute of
Environmental Health Sciences (NIEHS) is currently funding and supporting a number of significant
studies. Following is a brief compilation of the NIEHS sulfates research program:
Researcher(s)
HARVARD UNIVERSITY
Benjamin G. Ferris, M.D.
HARVARD UNIVERSITY
Mary D. Amdur, M.D.
NEW YORK UNIVERSITY
Albert F. Gunnison, M.D.
NEW YORK UNIVERSITY
Robert Shapiro, Ph.D.
JOHNS HOPKINS UNIVERSITY
Federick B. Bang, M.D.
SOUTHWEST FOUNDATION FOR
RESEARCH AND. EDUCATION
John R. Rowlands, Ph.D.
Brief Description of Research
Health effects on children and adults of S02 and respirable
particulates.
Factors affecting the irritancy potency of gases and aerosols on
guinea pigs.
Distribution and fate of inhaled sulfur dioxide or ingested
sulfites.
Damage to nucleic acids by bisulfite in rats and rabbits.
Interaction of S02 and virus on respiratory mucosa in chickens.
Effects of S02 upon alveolar macrophages in rats and baboon.
The Occupational Safety and Health Administration (OSHA) of the Center for Disease Control (CDC),
U.S. Public Health Service is also currently funding studies at the University of Washington on respiratory
effects of inhaled gases and aerosols. One study deals with S02 induction of peroxide formation.
Other current ongoing studies include work in California and Florida. The California Air Resources
Board (ARB) is carrying out a relatively small research effort on sulfates designed to concentrate on pro-
blems critical to and unique to California's environment. This program includes laboratory studies on
sampling and measuring methods, chemical transformations, and human and animal toxicology.
Following is a brief listing of ARB sulfate research activities:
Institution
Study Description
University of California
Irvine
University of Southern California,
School of Medicine
University of California
Santa Barbara
University of California
Davis
University of California at Los
Angeles (UCLA) School of Public
Health (and jointly with Calif.
State Health Department)
To examine the effects of simultaneous exposure to photo-
chemical oxidants and sulfate aerosols on respiratory function.
Rats and beagles are being used as subjects.
Studying exposure results of asthmatics to ozone and sulfur
dioxide, singly and in combination. Both respiratory and bio-
chemical responses are being measured.
To measure the response of healthy adults under physical stress
to ozone, and, later, to combinations of ozone and sulfate aerosol.
To study the effect of sulfates and sulfates combined with ozone
on lung resistance to bacterial infection. Mice and rats are sub-
jects in this study.
Study relationships between acute illness and ambient pollution
levels. This is to be a retrospective study using medical records
obtained from health care organizations in the Los Angeles area.
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University of California Study of the transformation of S02 to sulfate aerosol. Processes
Riverside of inherent and those occurring in a photochemically reacting
atmosphere containing hydrocarbons and nitrogen oxides.
Also in California, experimental exposures with special attention to SOo and ozone are being carried out
by Jack Hackney, M.D., of Rancho Los Amigos Hospital in Downey, California. In addition to normal
subjects, persons with relatively mild asthma are being exposed to these gases separately and in combina-
tion. As indicators of health effects of these pollutants, the Rancho Los Amigos program is recording
symptoms and measuring a number of biochemical and physiological parameters, including forced expira-
tory volume and forced vital capacity, flow/volume curves, and closing volumes.
In Florida, a statewide sulfur oxides group, funded by the state's electric and gas utility companies, has
funded a large sulphur oxides study to be carried out jointly by the University of Michigan School of
Public Health (Point of Contact, I.T.T. Higgins, M.D.) and the University of Florida College of Medicine
(P.O.C., Heinz J. Wittig, M.D.). The basic objective of this study is to clarify the issues of air quality and
human health in Florida, particularly related to the anticipated industrial growth and the accompanying
increased use of high sulphur fuel for power production. This study is expected to be completed during
1977. It includes work on health of adults, aged, children, and people with chronic respiratory disease. It
will also include studies on mortality and morbidity, as well as some experimental studies. Study sites will
primarily be in the Tampa area.
EPA is currently studying these sulfate research findings and is considering recommending an interagency
sulfate working group to coordinate sulfur compound research in government agencies. Such a group
would improve communication among researchers and protect the interest of both energy and environ-
mental groups.
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2. RESEARCH STRATEGY
This document lays out a strategy in developing and measuring the actual conduct of research. As ex-
plained in the Introduction, this document is a planning tool to be used in managing and guiding the more
detailed plans as the research program is implemented. Specific details including detailed protocols will be
worked out, pending management decision on the scope and strategy laid out here and actual resources
budgeted during the normal annual budget cycle.
The research strategy that follows is divided into four research areas: Health Effects, Ecological Effects,
Atmospheric Chemistry and Transport, and Measurement Methodology and Instrumentation. Welfare
effects other than ecological, i.e., visibility reduction and materials damage, are covered under Atmospheric
Chemistry and Transport, as is a portion of the acid rain research. Figure 2 is a graphic presentation of the
entire research strategy which shows the direction and structure of the research and how the four research
areas fit together to meet the program objectives.
Briefly outlined, the research is structured as follows:
1. Monitoring - I
2. Disciplines Involved - II - Toxicology
III - Epidemiology
IV - Clinical Studies
3. Effects- Mechanisms, Metabolic Pathways, New Health Parameters (II, III, and IV)
4. Dose Response Relationships - V.
5. Scientific Reports-VI.
The interrelationships of the disciplines involved in the research is illustrated in the figure, which shows
the flow of research from defining and identifying those sulfates to be studied to the culminating reports on
the health effects of the dose-response relationships. Detailed information and specific methodologies are
included in each section of specific areas in this research approach.
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CONTROLLED HUMAN
EXPERIMENTS ACUTE EXPOSURE
CHEMICAL AND PHYSICAL
CHARACTERIZATION
ENVIRONMENT LOADING
(0
H2S04
AMMONIUM BISULFATE
AMMONIUM SULFATE
TOTAL WATER SOLUBLE SULFATE
RELATIVE CONCENTRATIONS-
ACID VS NEUTRAL
SELECTED IONIC SPECIES
(VANADIUM & MANGANESE)
SHORT-TERM
CHAMBER EXPOSURE
BIOCHEMICAL PHYSIOLOGICAL
BEHAVIORAL RESPONSES
ACUTE HUMAN
DOSE I RESPONSE
EPIDEMIOLOGICAL STUDIES
BIOLOGICAL
SCREENING
TOXICOLOQIC MODEL SYSTEMS
WHOLE ANIMAL AND
ISOLATED CELL SYSTEMS
CHARACTERIZATION OF
HUMAN EXPOSURE
AEROMETRIC MEASUREMENTS AND
DEMOGRAPHIC ANALYSIS
APPROPRIATE
HEALTH INDICATORS
METABOLIC PATHWAYS
AND TARGET ORGANS
DOSE RESPONSE
RESPONSE
MECHANISMS
BIOLOGICAL MEASUREMENTS
SCIENTIFIC AND
-» TECHNICAL
ASSESSMENT REPORT
BIOCHEMICAL AND PHYSIOLOGICAL
MEASUREMENTS
MORBIDITY/MORTALITY
RESPIRATORY DISEASE
(ACUTE AND CHRONIC)
CARDIOVASCULAR DISEASE
CARCINOGENESIS
SPECTRUM OF BIOLOGICAL
RESPONSES
ANIMAL DOSE/
RESPONSE MODELS
BIOCHEMICAL
PHYSIOLOGIC
HISTOPATHOLOGIC
OTHER
CARCINOGENESIS
MUTAGENESIS
TERATOGENESIS
Figure 2. Health Effects Sulfate Research Strategy
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2.1 HEALTH EFFECTS
2.1.1 Research Results
EPIDEMIOLOGY-
Results of some epidemiological studies on su I fates identify an association between ambient sulfate
levels and adverse health effects. However, such statistical associations do not permit a firm conclusion
that a cause-effect relationship exists. An integrated program of lexicological, controlled human exposure,
and epidemiological studies is necessary to confirm or refute such a finding.
Study results to date indicate that exacerbation of symptoms and disease which suggest possible airway
irritation are more closely associated with exposure to suspended atmospheric sulfates (measured as water
soluble sulfates) than with exposure to sulfur dioxide or to total suspended particulate. However, the
range of concentrations of sulfates associated with a given health indicator varied considerably. In studies
of asthmatics in the Salt Lake Basin and the New York Metropolitan Area, the highest morbidity rates
were statistically associated with suspended sulfate concentrations ranging from 12 to 17 ng/m^ wnen the
air temperatures were -1.1° to + 10°C, and 1.4 to 7.3 jug/m3 when temperatures were above 10°C. Sub-
sequent asthmatic studies (not yet published) conducted in the Los Angeles Basin showed that sulfates
levels above 10 jug/m3 were most closely associated with the aggravation of asthma, and there appeared to
be an interaction between sulfates and ozone, when ozone levels were greater than 300 ^g/m3 (150 ppb)
(Air Quality Standard = 160 j/g/m3, or 80 ppb).
In a study of cardiopulmonary patients in the New York Metropolitan Area, the strongest and most con-
sistent pollutant association was found with sulfates. Annual average sulfate concentrations of 10 to 12
Aig/m3 were accompanied by a morbidity excess of about 6% when temperatures ranged from -1.1° to
+10°C and 32% when air temperatures were greater than 10°C.
At least some of the inconsistencies shown by these data might be expected. Air monitoring stations
have, in the past, been established at locations most convenient for the operator and with little or no re-
gard to criteria for developing a consistent index of exposure from community to community. Grid studies
with single communities have demonstrated significant variation in measurement of specific pollutant from
one point to another. It must be assumed, therefore, that the index of mean community exposure obtained
from a single monitoring station would vary considerably, depending on the particular site selected for
locating the station. Consequently, while each monitoring station would provide evidence of fluctuation in
the concentration of pollutants within a community, there is less reason to expect a consistent relationship
from one community to another.
There is also some scientific evidence, in both man and animals., to suggest that the co-carcinogenic
potential of sulfur oxides and their atmospheric products merit exploration.
TOXICOLOGY-
A substantially increased effort was begun in FY'75 to conduct targeted toxicological studies on sulfates.
Efforts have focused on developing biological screening systems, determining the metabojic pathways and
target organs, understanding responses and mechanisms, and establishing dose-response data. Within each
effort, consideration has been given to the various sulfate compounds and their relative toxicities, cation-
anion relationships, compound physical characteristics such as size and bioavailability, concentration and
time duration of exposure, and combined or synergistic effects with other pollutants.
Biological Screening— Refinements have been made in previously developed rabbit alveolar macrophage
systems. Theses test systems permit rapid screening to determine relative toxicities of various sulfate com-
pounds believed to be present in the atmosphere.
Studies on rabbit alveolar macrophages comparing the relative toxicity of metallic sulfates and chlorides
indicate that the toxicity of the metal is the same with either the sulfate or chloride anion. On the basis of
quantitative determinations of the molar concentration of metal resulting in net cell death in 50% of cells
as compared to controls, the following ranking of toxicity was observed: Hg>Cd > V >Cu >Zn > Mn > Ni.
Zinc ammonium sulfate did not show a significantly different toxicity in this system from zinc sulfate.
Crude particulate samples being tested in the system contained several of these toxic trace elements. In
some cases the net toxicity of the crude material did not correlate well with the predicted toxicity based on
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the summation of the toxicities of the metals contained within or on the crude sample. For this reason it
is important to consider the interactions of toxic trace elements when evaluating the toxicity of environ-
mental samples. Preliminary experiments designed to elucidate and quantitate interactions between toxic
trace elements indicate that: (1) copper protects against vanadium cytotoxicity, and (2) selenium protects
against cadmium cytotoxicity.
Metabolic Pathways and Target Organs—The target organ for sulfur oxides is the lungs as well as the rest
of the respiratory tract. In Vitro experiments on normal guinea pig lung fragments exposed to sulfate ions
have shown that sulfate ions alone do not induce histamine release. However, ammonium ions may cause
histamine release. Studies are now being conducted to determine if immunologically sensitized lung frag-
ments have increased sensitivity to sulfate ions. The effect of h^SO^containing and (NH4+)- containing
sulfate salts on immunologically mediated reactions is also being investigated.
Responses and Mechanisms (Includes dose-response)-These studies indicate that small particle H2S04
aerosol is a greater respiratory irritant than is SC^, or other particulate sulfur oxides which have been
investigated. The irritant effects of HoSO^ are aerosol size dependent, i.e., at the same mass concentration
small particles which are ±0.3 jum diameter are more irritating to the respiratory tract than particles > 2.0
jjm diameter. The experimental evidence of the irritant effect of HoSC^ aerosol at low concentrations (as
low as 80 jjg/m^ at 0.3 jum Mass Mean Diameter (MMD)) is based principally upon the respiratory physio-
logic response of guinea pigs to short-term exposure to various specific sulfur oxide species. A principal
reaction product of h^SC^ neutralization, (NH^oSC^, is not a respiratory irritant in the animals that have
been studied except at concentrations which are high relative to ambient air levels. Preliminary unpublished
data indicate that ammonium bisulfate, an intermediate reaction product of K^SC^ neutralization, may
have an irritant effect intermediate between HoSC^ and (NH^SO^.
H2S04 inhalation has been found to affect the regional pattern of particle deposition in the respiratory
tract of guinea pigs. At a high mass concentration and large particle size (3000 jug/m^ and 2.0 jum MMD),
a total shift in the regional particle deposition rate occurred. At a low mass concentration and small part-
icle size (30 jug/rri3 anc| fj.34 jum MMD) no effect on total respiratory particle deposition was observed, but
a proximal shift in the regional deposition of inhaled particles occurred. Recent unpublished evidence in-
dicates that mass concentrations of 160-250 ^g/m3 of small particulate H2S04 (0.3-0.5 nm MMD) reduces
the mucociliary clearance rate of particles from the tracheo-bronchial region of the lung of donkeys, mice,
and guinea pigs.
The results of these studies indicate that the site of action of H2S04 aerosol is on the conducting airway
epithelium of the respiratory tract. This is the region of the lung in humans most affected by sulfur oxides
and which results in coughing, bronchitis and asthma. The conducting airway region seems to be affected
despite the fact that the small aerosol size, 0.3-0.5 /urn MMD, has a significant potential for deposition in the
alveolar region of the iung. This observation, and the fact that H2S04 and other sulfur oxide aerosols are
hygroscopic, or deliquescent, suggests that the inhaled particles may increase in size during transit through
the respiratory tract and deposit higher in the tract than would be expected based on their initial size. This
phenomena, and its implications for health, is the subject of investigations through a variety of experimental
approaches. The site of action of H2S04 inhalation demonstrated by experimental studies is supportive of
epidemiologic data which indicate that dieases of airways are the principal human responses which have
been associated with exposure to sulfur oxide air pollution.
The effect of H2S04, (NH4)2S04, and S02 on inhalation respiratory tissues and secretions from a
variety of animals has been studied using histophathologic and biochemical methods. Exposure regimens
up to 3-4 weeks duration have been used. The results of these studies indicate that inflammatory changes
in the lung or conducting airways of the respiratory tract do not develop except at very high mass concen-
trations relative to ambient air levels (8 mg/m3 in guinea pigs and higher in other animals). Thus it appears
that respiratory physiologic responses to SOX inhalation occur at concentrations much lower than those
that cause direct tissue injury.
The guinea pig appears to be the most sensitive animal to respiratory physiologic effects of SOX inhalation.
The comparative response of normal guinea pigs and humans to SC^-NaCI aerosol mixtures under high
humidity conditions which lead to acid aerosol formation indicates that most normal humans are not
adversely affected by 1 ppm S02-1 mg/m3 NaCI whereas this aerosol is irritant of guinea pigs at concentra-
tions as low as 0.25 ppm S02-0.5 mg/m3 NaCI. The high sensitivity of the guinea pig to SOX aerosol sug-
gests that it may be an analog to individuals who are highly sensitive to SOX inhalation, particularly
asthmatics.
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The role of 1^504 and (Nh^^SC^ as cocarcinogens with Benzo(a)pyrene during long-term exposure is
being investigated. These studies have been in progress for about one year and no data are available as yet.
CONTROLLED HUMAN STUDIES-
Clinical studies are just beginning and initial results should be available in late FY'77.
2.1.2 Research Strategy
The studies described have shown several sulfate species occurring in the ambient air are toxic to animals.
However, in these studies, sulfate concentrations were well above those in ambient air. Subsequent efforts
will attempt to determine the adverse health effects caused by exposures to ambient levels of the most
commonly occurring sulfur compounds, e.g., H2S04, ammonium bisulfate, ammonium sulfate, and selected
ionic species, singly and in combination with other sulfates and other pollutants. Significant adverse effects
will then require the development of human dose-response relationships for specific compounds. With such
information, in conjunction with results from the other research areas, it can also be determined whether
the water soluble measurement method or the relative concentration of acid versus neutral sulfates accurate-
ly reflects the concentration of these materials. It is anticipated that from these data acceptable indices of
the specific sulfate compounds found to contribute to adverse health effects may be developed for control
programs.
The gathering of this information requires a closely integrated program involving epidemiological,
toxicological and controlled human exposure study areas. Figure 2 shows the various components within
each study area and how results from each area are integrated to provide the data base necessary to permit
conclusions on specific sulfates, human adverse effects and cause-effect relationships. The approach as
shown in Figure 2 is to identify the composition and concentrations of sulfur compounds in the atmos-
phere, test the compounds in toxicological model systems (whole animal and isolated cell systems), conduct
controlled human experiments using short-term exposures, and finally to conduct epidemiological studies
in realistic ambient exposure conditions. The output from each of these investigative approaches will then
be integrated and assessed to arrive ultimately at a rate of human dose-response to atmospheric sulfates.
A critical pathway analysis of Figure 2 suggests that the epidemiologic studies including the characteriza-
tion of human exposure probably constitute the most critical aspect of the research effort. This is true
because the ambient conditions are the responsibility of EPA and these are studied only by epidemiology
technique. Each other aspect of the effort supplements and improves the potential for epidemiology, but
none, of themselves, can provide a definitive answer to questions about the need for controlling environ-
mental pollution.
Each of these items, plus atmospheric loading is briefly discussed and a summary of the funding for each
item is presented in Table'2.
Table 2
HEALTH EFFECTS RESEARCH FUNDING SUMMARY ($K)
FY
Research Area 77 78 79 80 81 82
Toxicology 1573 1065 1875 1575 1575 1575
Controlled Human Exposures 1986 2145 2300 2300 2300 2300
Epidemiology 1815 1380 3364 3600 2900 2900
TOTALS 5374 4590 7539 7475 6775 6775
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In addition to the principal strategy that concentrates on the few specific sulfates, a low level effort will
continue to develop toxicological data on other sulfur oxides, including sulfites, which occur in the atmos-
phere and which may cause adverse health effects.
The proposed research should be pursued concurrently in various other federal and university labora-
tories in addition to a concerted effort within EPA. Such efforts, however, must include, for maximizing
utility, a constant exchange of information and ideas to insure greatest possible support for the most
promising areas of effort and prudent redirection of programs at appropriate times. This type of informa-
tion exchange also will minimize undesirable duplication or overlapping of effort, provide for a consistency
of study design permitting comparability of study results, and assure the widest possible input and peer
review of proposed study objectives, methods and results.
CHEMICAL AND PHYSICAL CHARACTERIZATION OF ATMOSPHERIC LOADING-
Because the number of possible sulfate compounds is too large to study, a review was made of the current
data base to identify those compounds which are most likely to be found in the ambient atmosphere and
are believed to be biologically irritating or toxic. These compounds are sulfuric acid, ammonium bisulfate,
and ammonium sulfate. An initial part of the research program will be to confirm this preliminary finding.
Efforts will be made to collect aerometric data on these specific compounds especially in places where
population exposure data are required for epidemiological studies. Information on total water soluble
sulfate, relative concentrations of acid and neutral sulfates, and selected ionic species (e.g., vanadium, man-
ganese) will also be collected.
TOXICOLOGICAL MODEL SYSTEMS-
This overall toxicology program is designed to provide data necessary in the epidemiologic and controlled
human studies, as well as data which will contribute to development of dose-response relationships, to:
1. Assess the relative toxicity of H2S04, NH4HSO4, and (NH4)2S04 in whole animals; evaluate the
toxicity of other ionic species (HSOs, ^03=, trace metals) by in vitro methods; this information is
input to the design of targeted clinical and epidemiologic studies.
2. Determine the mechanism of biologic response to inhalation of these compounds.
3. Evaluate bio-indicators of response to determine whether or not they are suitable for use in
epidemiologic studies.
4. Determine the subacute and chronic toxicity of the compounds which cannot be ascertained by
direct human experimentation.
During FY'77-'78 the toxicological studies will be oriented specifically toward an evaluation of the com-
parative toxicity of strong versus weak acid or neutral sulfate aerosols. These comparisons will be made
using respiratory physiologic, pathologic, and microbiologic techniques. These specific compounds will
include H2S04 anc' ammonium bisulfate (NH4HS04) as strong acids and (NH4)2SO4 as a weakly acid or
neutral sulfate. A few studies of a neutral sulfate such as sodium sulfate, which is found predominantly in
the large particle fraction of atmospheric aerosols, may also be investigated. A dose-response relationship
will be determined on any sulfur oxides which are found to cause an adverse health response at moderate
or low levels. These priorities are flexible since it would be desirable to change them if initial studies of
ambient air indicate that other compounds or combinations might deserve more attention.
The toxicological testing program will also include an in vitro biological screening program to test other
sulfate compounds of unknown toxic potential that may be found in ambient air. The relationship of the
ionic composition of the compounds to toxicity and possible protective interactions of elements will be
determined. The toxic potential of HS03- and S03= will be evaluated. A complete evaluation of copper
protection against cadmium cytoxicity will be determined.
13
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There is also a need to develop more specific health indicators. The health indicators used in previous
epidemiologic studies have been non-specific, i.e., aggravation of asthma, cardiopulmonary symptoms, and
upper and lower respiratory disease. These same conditions may be statistically associated with exposure to
other specific pollutants. Therefore, in an urban atmosphere consisting of a wide variety of pollutants, it
is not possible, using non-specific health indicators, to determine reliably the contribution of specific
pollutants—particularly when there may be synergistic effects. Toxicologic studies will be conducted to
analyze possible biochemical changes that may be used as specific indicators of sulfur oxide exposure.
These specific response indicators will measure injury as well as physiological and biochemical responses
which reflect mechanisms by which the human body copes with a given stress.
The exposure regimen will include both short-term and long-term exposures in order to assess both acute
and chronic effects in a variety of animal species. Studies involving metabolic pathways and target organs,
and responses and mechanisms will be conducted as part of the short and long-term studies. These studies
will provide input to assembling dose-response data.
Table 3
TOXICOLOGY FUNDING ($K)
FY
_77 _78 79 80 81 82
Biological Screening 100 100 112 94 94 94
Metabolic Pathways and Target
Organs 123 100 138 116 116 116
Response and Mechanisms 641 330 718 603 603 603
Dose-Response 709 535 907 762 762 762
TOTAL TOXICOLOGY 1573 1065 1875 1575 1575 1575
CONTROLLED HUMAN EXPOSURE STUDIES-
Ethics prohibit the use of human subjects in the complete spectrum of research necessary to accomplish
the objectives of this research program. The experiments must be limited to short-term exposure (acute
biological responses) to concentrations approximating maximum ambient or occupational exposure condi-
tions. The objective of these studies will be to determine the level of short-term exposure at which bio-
chemical, physiological, and behavioral responses are observed in human subjects. Initial studies will center
on healthy subjects exposed to H2S04. Next, healthy subjects will be exposed to ammonium bisulfate and
ammonium sulfate. Studies will continue by exposing susceptible groups (i.e., asthmatics). These studies
will be concerned with the significance of factors such as particle size, humidity, temperature and syner-
gistic or inhibitory effects of a second compound. They will determine also the significance of time and
concentration factors included in total dose measurements. These data will assist with determining which
bio-indicators of response are most appropriate for epidemiological studies and will attempt to develop
human dose-response data for specific sulfate compounds.
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Table 4
CONTROLLED HUMAN EXPOSURE STUDIES FUNDING ($K)
FY
77 78 79 80 81 82
Low concentrations SOX exposure 292 300 368 338 338 338
Effects of H2S04 on human immunity 175 200 221 202 202 202
Effects of H2S04 on respiratory
function 1519 1645 1711 1760 1760 1760
TOTAL HUMAN STUDIES 1986 2145 2300 2300 2300 2300
EPIDEMIOLOGICAL STUDIES-
The principal aspects of the epidemiological studies are the characterization of human exposure patterns
and the use of appropriate health indicators to determine whether there are relationships between ambient
levels of the various sulfate compounds and adverse health effects. Epidemiologic studies also will be
utilized to determine those indices of air pollution that might best be utilized to implement control pro-
grams. Studies will be conducted in cities where sulfates are a major contributor to air pollution. Suffici-
ent preliminary monitoring will be conducted to determine appropriate sites for the health surveys,
appropriate locations for monitoring stations, and to assess the chemical and physical characterization of
the total atmospheric pollution. The various measurements of pollutants will be correlated to determine if
TSP, RSP, water soluble sulfa'tes, or any other readily measured component represents an acceptable index
for the toxic fractions (i.e., sulfates). The health surveys will utilize the most appropriate indicators of
biological response and health now existing or as they are developed. Studies will be designed to deter-
mine the statistical relationship between population exposure to specific sulfate compounds and adverse
health effects. Tentatively, studies are planned for Los Angeles, Salt Lake City, St. Louis, the Ohio River
Valley, and a northeast coast city to observe if variations in the composition of atmospheric sulfates affects
human health. Final selection will be made after detailed atmospheric assessment has been completed. The
results will be utilized for developing sufficient human dose-response relationships to indicate possible need
for and to support regulatory effort.
Table 5
EPIDEMIOLOGY FUNDING ($K)
FY
77 78 79 80 8J 82
Methodology to better characterize
human exposure to sulfates 345 370 436 415 415 415
Mortality and sulfates 0 50 50 0 0 0
Effects of short term intermittent
exposure to SOX 590 200 872 828 828 828
Conduct pilot study, then five
geographical area studies 535 510 1570 1942 1242 1242
Develop model for estimating human
dose-response curve for specific
sulfates exposure 345 250 436 415 415 415
TOTAL EPIDEMIOLOGY 1815 1380 3364 3600 2900 2900
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Table 6 summarizes the research projects and indicates expected completion dates for the major efforts
in the Health Effects Research Program. These dates are tentative and are dependent upon correlated
research efforts in all areas of the research strategy.
Table 6
Research Category
HEALTH EFFECTS RESEARCH ACCOMPLISHMENT STRATEGY
Time to Completion (FY)
77
78
79
80
81
Continuing
1. Toxicologic Model
Systems
a. Biological Screening
b. Metabolic Pathways and
Target Organs
c. Response Mechanism
d. Dose Response
e. Animal Dose Response
Model
2. Controlled Human
Experiments
a. H2S04 Acute Exposure
Healthy Males, Phase 1
b. Phase 2. Change Clima-
tic Conditions in
Chamber
c. Phase 3. Susceptible
Subjects
3. Epidemiologic Studies
a. Continuing Analysis
and Reassessment of
CHESS Data
b. Characterization of
Human Exposure
(1) Exposure model
(2) Assessment of
"total water
soluble su I fates"
as Index
c. Health Effects Field
Studies (Pilot)
(1)
(2) (sites
(3) to be
(4) selected)
(5)
d. Human Dose Response
Model
4. Cha cterization of
ambient air
Interim Report
Interim Report
Interim Report
Completion of major output date.
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2.2 ECOLOGICAL EFFECTS
2.2.1 Introduction
Sulfur-related welfare effects include ecological damage, materials damage, visibility deterioration, and
possible climatological alterations. Of principal concern is the suspected role of sulfur oxides in causing
acid precipitation. Existing information does not permit adequate quantification of these effects in order
to provide damage estimates. This section, however, deals only with ecological effects. The visibility
reduction and materials damage are addressed in the atmospheric chemistry and transport area.
The data elucidating the impact of sulfates on the environment are extensive but largely of recent origin.
The information available suggests that changes in the rate of nutrient leaching from plant foliage, acidifi-
cation of lakes and rivers, and changes in metabolism of organisms, are associated with the increased acidity
of precipitation.
Reduction in forest growth in Sweden and northern New England may be correlated with acidic precipi-
tation. Controlled studies indicate that herbaceous plant growth and reproduction are influenced by high
acidic precipitation. Pollen germination and pollen tube growth of tomatoes was retarded, resulting in
lower production. Timothy grass was also retarded. Studies also show that shifting of soils toward a lower
pH causes a shift from the less acid tolerant bacteria to the more tolerant fungi.
Aquatic ecosystems may also be significantly affected by acid precipitation if the input ratios of direct
precipitation to land drainage are high. The trend toward increasing acidity in lakes west of Sudbury in
Canada and in the lakes and rivers of Scandinavia has been attributed to acid precipitation. Serious fish
mortality, particularly of early age classes of salmonids, has been reported in the lakes of both areas.
Studies attempting to determine the specific effects of sulfates on plants are in the early stages. Inter-
polation, however, may be made from studies dealing with SO2 effects upon plants, particularly the
reactions which occur after SO2 has entered the leaf through the stomata. Indications are that the S02
upon entering the leaf reacts with the water in the air spaces. A major portion of the SO2 becomes SO4
ions. These ions then produce chemical reactions within the plant. The exact nature of these reactions is
still unknown. The point here is that it may be the sulfate ion which causes the reactions; therefore, similar
reactions may be expected from sulfate entering the plant leaf. The majority of these reactions produce
detrimental effects within the plant.
The ecological impact of sulfates and acid precipitation are just beginning to become known. Their
effects appear to be far-ranging. Increased S02 emissions resulting in increased sulfates and increased acid
precipitation can only accelerate the changes presently taking place.
2.2.2 Research Strategy
The research strategy consists of two parts: (1) continuation of current research on the direct effects of
sulfur oxides, including acid mist on selected crops, forest ecosystems, and terrestrial ecosystems, and (2)
an increased effort to study the effects of acid precipitation. A portion of the latter would supplement a
Department of Agriculture national acid precipitation monitoring system.
Short term research on acid precipitation could provide the basis for potential welfare standards, by
dealing with direct effects on annual and perennial horticultural and agronomic plants. Of course, forest
seedlings and more mature trees may suffer direct effects, but because of the long growth period, long-term
effort would be needed on forests. Perhaps the most important long-term work will be to determine acid
precipitation effects on soils: their chemistry, fertility, and biota. If the soil fertility is damaged, food
production would be damaged. Other effects of acid precipitation to be addressed in the long term should
be: (1) interactions between plant/animal growth, (2) changes in soil availability of metal to plants and
subsequent effects up the food web, and (3) direct and indirect effects of acid rain on aquatic organisms.
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Table 7
ECOLOGICAL EFFECTS FUNDING (SK)
77
860
78
380
FY
79
900
80
900
81
900
82
900
Current program on sulfur oxides
Increased program on acid
precipitation 0_ 0 500 500 500 500
TOTAL 860 380" 1400 1400 1400 1400
"For optimal implementation a S980K increase would be required for FY'78.
2.3 ATMOSPHERIC CHEMISTRY AND TRANSPORT
A major objective of the EPA sulfates research strategy is to develop the experimental output and the
empirical and deterministic relationship of sulfur oxide emissions to ambient air concentrations of sulfates.
Available experimental evidence indicates that almost all of the sulfate species measured on a regional scale
(100 to 1000.km) are formed through converting sulfur dioxide to sulfates in the atmosphere during trans-
port of polluted air volumes across regions. Analysis of available aerometric monitoring data and prelimi-
nary results on removal rates suggest that elevated point sources rather than low-level point or area sources
are the more important contributors to sulfates on a large regional scale (1000km). Within an urban area,
particularly during periods ol low-level inversions and restricted ventilation, lower level emissions of sulfur
dioxide and sulfur trioxide may make substantial contributions to sulfates in high density industrial and
commercial areas. The possibility that natural emissions of sulfides contribute to regional sulfate concentra-
tions through atmospheric oxidation to sulfates appears unlikely for many regions, but may contribute to
sulfates in certain specific areas. It also has been demonstrated that within the plume from an urban area
with high sulfur oxide emissions, high sulfate concentrations can be measured several hundred kilometers
downwind under some meteorological conditions. Finally, in the multiday periods during which stagnating
anticyclones persist in the northeastern and southeastern U.S., sulfates, along with ozone and other pollut-
ants, can accumulate over large regions in the U.S. Visibility reduction is commonly associated with sulfate
formation both in plumes and in stagnating anticyclones.
These physical, chemical and meteorological parameters are important factors to determine the relative
contributions of various sulfur oxide emission sources to air quality and also the required control strategies.
The experimental results and model predictions must delineate the relative effectiveness of different control
options, including usage of low sulfur fuel or reduced industrial activity, and various control technologies on
point and area emission sources at urban and non-urban sites. The ability to experimentally follow and to
model the effects of such parameters must be on the scale of 200 and perhaps up to 500 km by F Y'81.
2.3.1 Workshop on Regional Air Pollution Studies
On June 7-11, 1976, the Environmental Sciences Research Laboratory, RTP, EPA sponsored a workshop
on Regional Air Pollution Studies at the Appalachian State University Conference Center in Boone, N. C.
The workshop was coordinated by the Triangle Universities Consortium on Air Pollution (TUCAP). Four
panels were involved: (a) diffusion and transport (including meso scale meteorology), (b) transformations
(including removal processes), (c) measurement and operational strategies, (d) modelling and data manage-
ment. Members of the panels included university, industry, and government expert scientists including the
program managers for the related Electric Power Research Institute (EPRI) and Energy Research Develop-
ment Administration (ERDA) programs. Several members of the EPA Science Advisory Board Environ-
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mental Transport and Movement Advisory Committee participated, as well as EPA scientists from Office of
Research and Development laboratories, Headquarters, and Office of Air and Waste Management (OAWM).
The main conclusions follow:
(1)
(2)
(3)
The scientific problems discussed are extremely complex and require use of all currently available
large scale techniques to measure and trace pollutants.
An adequate scientific program requires combining resources of EPA, ERDA and EPRI.
Experimentation and modelling should be concerned with two different scales. The modelling panel
concluded the following:
Resolution
Maximum Scale
Model Type Distance (Km) Time Distance (Km)
Time
15 min
3hrs
Model Accuracy Goal
(95% Confidence Level)
Within a factor of 1.3
Within a factor of 2.0
Plume 500 24 hr 5
Regional 2,000 1 yr 50-100
(4) Relationships between single sources and air quality can be derived from plume studies but not in
• large regional studies.
(5) Transformation can be evaluated in plume studies but not in large regional studies in which steady
state conditions with respect to chemical composition and physical changes would be assumed.
(6) Two types of models are recommended: Diagnostic and Planning. Diagnostic models should be
used to design and evaluate results of field studies, particularly plume studies. Planning type models
are needed to use in developing sulfate control strategies.
Many more detailed recommendations also came from the four panels. The panels emphasized the total
national scientific effort needed in sulfate research.
2.3.2 Evaluation of Capabilities of Governmental - Industry Programs
As a result of the Boone workshop (EPA/ERDA/EPRI), project managers evaluated the major and
augmenting contributions of their organizations. EPA found major strengths in augmenting and combining
efforts to justify future funding on sulfate/nitrate research. A synopsis of such research areas follows:
Atmospheric Monitoring and Characterization
Surface Network
Source Characterization-Manmade
Source Characterization-Natural
Augment EPRI effort
Major EPRI effort
Major EPA-ORD effort
Physical and Chemical Characterization of
Aerosols
Fundamental Research
Instrument Research
Laboratory Kinetics
Transport, Transformation, Removal Field Studies
Point Source Plume
Urban Area Plume
Regional Sub-continental Pollutant Mass
Balance
Planetary Boundary Layer
Surfact Interaction (dry deposition)
Major EPA-ORD effort
Primary effort by EPA-ORD
Primary effort by EPA-ORD
Major effort by EPA-ORD
Primary effort by EPA-ORD
Augment EPRI and ERDA funding
Augment ERDA funding
Augment ERDA funding
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Modelling and Data Management
Numerical modelling-Plume Primary effort by EPA-ORD
Numerical modelling-Urban Plume Primary effort by EPA-ORD
Numerical modelling-Large Region subcontinent Augment ERDA and EPRI funding
Data Management Major effort by EPA-ORD
Data Analysis Major effort by EPA-ORD
EPA then would place its research emphasis on characterizing chemical and physical composition of
sulfate/nitrate species on a scale so that air quality could be related back to source emission strengths.
ERDA, through MAP3S and EPRI, would fund certain plume studies but also emphasize larger scale studies
in which sulfate concentration distributions can be related to synoptic weather patterns and climatological
factors.
2.3.3 Research Needs
To adequately define these parameters a range of studies are needed on the formation rates, size and
chemical composition of product particles and removal mechanisms. These studies include the following
types of investigations: (1) laboratory measurements of rates and mechanisms of reaction, (2) simulation
of atmospheric conditions in smog chambers or other modelling facilities, (3) an extensive group of field
studies, and (4) development of various statistical/empirical models and deterministic or mechanistic models.
Both types of models usually require substantial aerometric and meteorological assessment data. Modelling
progress is limited by the experimental outputs available on emissions, air quality, meteorological para-
meters, rates of physical and chemical transformations and removal rates. Adequate sets of experimental
outputs also heavily depend on adequate measurement techniques for the gases and aerosol species of con-
cern. Since three-dimensional profiles or fluxes are critical, measurements must be made both at the surface
and aloft using techniques with the desired sensitivity, precision and response time.
The primary objective is to determine on a regional scale of 1000 km or more the relative contribution of
each class of sulfur oxide emission source to ambient sulfates concentrations within urban areas. Sources
requiring investigation include low-level commercial and industrial point sources in urban areas, vehicular
emissions particularly in regions of California, high stack emission sources, large area industrial sources,
entire urban plumes, natural or biogenic sources, and maritime background in coastal areas.
More specifically, to develop experimental results for modelling the wide range of conditions, measure-
ments must cover individual and complex source plumes under various meteorological conditions: day,
night, warm-sunny, cool-overcast, varying humidity, stagnant and well-dispersed air masses, as well as over
various terrains.
Of all the biological and non-biological welfare effects, visibility reduction by finely divided aerosol
receives great attention by the public and press. In western states installing combustion sources that will
deteriorate visibility has been a major concern. Poor visibility is also one of the most aggravating aspects
of photochemical air pollution in Southern California.
Because visibility and visual range can be related to aerosol properties by well established physical relation-
ships, there is substantial reason to believe that visibility deterioration caused by sulfates is the most likely
welfare effect to be quantitated within the next several years. This could be the basis of a secondary air
quality standard.
This position is supported by actual empirical relationships between visual range and the chemical
composition of aerosol. This relationship was determined from the Characterization of Aerosols in
California (ACHEX) program. This research demonstrated that sulfate species are the most effective
scatterers of light, with nitrates being less effective, particularly at low humidities, and other aerosol con-
stituents being poor scatterers. As a result, finely divided sulfate and nitrate compounds contribute more
to visibility reduction than their mass concentration alone would indicate. In the eastern U.S., where sul-
fates dominate on a mass concentration basis, it follows that sulfates must dominate the visibility reduction
20
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problems of eastern regions. Therefore, establishing empirical relationships between visibility and sulfates
should be possible with an appropriate experimental program.
Two types of projects should be differentiated in terms of scale of effort. The first type of project is
concerned with characterizing sulfate species in specific urban and non-urban locations. One special
emphasis would be to differentiate sulfuric acid and other of the more acidic species from the total "water
soluble" sulfate and particulate sulfur. The proportion of acid species may vary between urban and non-
urban sites, geographic areas of the U.S., seasonal and associated synoptic weather changes, terrain and
other parameters. Therefore, representative measurements are needed over sufficient time periods to reflect
seasonal and other influences. Another emphasis should be to determine whether natural sources of
hydrogen sulfide and mercaptans do contribute significantly other than on a very local scale to sulfate
concentrations downwind of swampy areas and of shallow or polluted coastal waters. The resources for
such projects are reasonably modest.
The second type of project involves following the large scale movement of sulfur oxides from large
elevated stationary sources, extended industrial areas and urban plumes. These projects require tracers, air-
craft measurements, remote sensing, upper air meteorological soundings, and other components which
result in complex and costly projects. Since the range of environmental conditions of concern are sub-
stantial, the number of such projects which can be conducted are limited by total available resources as well
as the number of teams of scientific investigators available to participate.
Except in the St. Louis area, no projects currently exist to characterize ground level sulfate species. It
must be emphasized, as discussed in measurement methodology and instrumentation, that characterization
studies are essential to future planning of biological studies, particularly future population studies. Identify-
ing sulfate species in the atmosphere not currently considered in animal and human laboratory studies will
provide new emphasis to such studies. These ground level characterization projects must be integrated into
the regional monitoring system of the Electric Power Research Institute (EPRI) at least during intensive
periods for the large regional scale research effort (1000 km plus). Similarly, ground level characterization
measurements should be made concurrently with plume transport and transformation studies.
Two existing EPA programs provide the field capabilities needed for future studies of the second type.
The Regional Air Pollution Program (RAPS) will provide models of the distribution of pollutants in the St.
Louis urban area. This program is directed towards a number of criteria pollutants but with particular
emphasis on sulfur oxides, including sulfate species. The modelling approach depends on measurements at
fixed monitoring sites within and at the outer limits of the metropolitan areas as well as on vertical extens-
ions of these measurements through towers and aircraft. The Midwest Interstate Sulfur Transport and
Transformation (MISTT) program has emphasized measurements in the air downwind of St. Louis in the
St. Louis plume and following the plumes of the coal-fired power plants and industrial plumes downwind
of the St Louis area. Much of the measurement work must be done aloft or by use of remote instruments
to obtain the required flux data.
The choice of the St. Louis area for RAPS and MISTT has been productive because of the very large sul-
fur oxide emissions from power plants and industrial sources in this area. The required additional field
work will be completed in FY'76 and FY'77 with one possible winter field project in the MISTT program
in FY'78.
2.3.4 Research Strategy
The present RAPS approach will be modified in FY'78 and beyond. In fact, a new acronym, STATE
(Sulfur Transport and Transformation in the Environment), has been proposed. The present use of a 12-
month-a-year base measurement program with more extensive measurements during certain periods is too
demanding on available resources. Future field research in both STATE and MISTT will emphasize inten-
sive periods of field research activity with greater use of mobile ground units and aircraft rather than fixed
ground sites. This latter approach is essential to follow trajectories of various plumes over large distances.
A fixed regional surface network of the required density will be provided by the EPRI program. Further-
21
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more, the intent in future studies is to cover more field situations using several intensive measurement
periods in various regions. This method of field study will require greater flexibility than in the current
RAPS program, but should be more cost-effective.
At realistic current and projected (intramural and extramural) resource and manpower levels, a seven-
year program is needed to develop the minimal information base to devise and implement a sulfate standard
and control strategy. The period would cover the time span from FY'77 through FY'83. This projection
assumes only minimal contributions from other U.S. (EPRI, ERDA) or European programs up to 1977 but
substantial contributions after that, particularly from the results of large regional scale (1000 km) programs.
If the scope and timing of these other programs should become more directly compatible with EPA needs,
some reductions in program lengths are possible but not predictable. There is also anticipated support from
other sources, such as the National Science Foundation, for laboratory projects to investigate reaction
mechanisms and simulation studies.
The needs described above will be addressed by:
I. Laboratory Mechanistic Research and Simulation Studies
II. Chemical Characterization of Acid Sulfates
III. Regional Plume Studies (formation, dispersion, transport, transformation and removal processes)
and Regional Sub-continental Studies (Supplement EPRI Measurements at monitoring sites and
provide remote sensing capabilities)
IV. Environmental Energy Related Programs
V. Effects on Visibility Reduction
VI. Effects on Materials
VII. Association of Acid Rain Effects with Meteorological Parameters
VI11. Data Analysis and Modelling of Sulfates.
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Table 8a
ATMOSPHERIC CHEMISTRY AND TRANSPORT FUNDING FOR SULFATES ($K)
77
400
78
400
Zi
450
FY
80
450
81
450
82_
400
83
200
I. Chemical Mechanism
and Simulation8
II. Chemical Character!- 175 400 600 450 250 200 0
zation of Acid Sulfatesb
III. Experimental Regional 2255 1900 1900 2000 2000 1800 0
Plume Studies '
IV. Environmental Energy 900 900 1050 1075 1075 1050 1100
Field Studies
V. Visibility Reduction 50 125 200 175 100 50 0
VI. Materials Effects 20 100 150 150 150 150 0
VII. Acid Precipitation 50 50 100 150 150 100 100
Association with
Meteorological
Parameters
VIM. Model I ingc and Data 650 625 750 1050 1125 1250 1000
Analysis
Environmental
Energy Subtotal 1250 1275 1275 1275 1275 1275
TOTALS^ 4500 4500 5200 5500 5300 5000
including energy related projects, See Table 9
"not including measurement methodology and instrumentation research
Including energy related projects, See Table 16
^including resources for EPA technical staff involved in projects.
EPA resources included are only those considered directly relevant to understand the formation, dis-
persion, transport and removal of sulfate and their non-biological effects. Research, whether basic or
applied, which is not pollutant specific is not included. For example, laboratory research on the physics of
formation of aerosols not specific to sulfates is not included. Research on air pollution modelling, clima-
tology, or removal processes which is possibly applicable to a variety of pollutants but not specific to sul-
fates also would not be included in the resources. Similarly, research on nitrogen oxides arid nitrates are
available but not included in this plan. Separate activities covering these topics are provided within the
EPA program element structure on atmospheric chemistry and transport. This approach avoids duplicate
counting of resources or alternatively making the present plan an air pollution research plan rather than a
sulfate research plan. Finally, the resources do not include the substantial contribution made to the EPRI/
SURE (Sulfate Regional-Experiment) program because of the anticipated loan of a sizeable fraction of the
RAMS Stations and equipment from St. Louis to the SURE network.
The research components I through VIII in Table 8a respond to three major objectives: (A) Projects
supporting the health and welfare aspects of criteria development and an ambient air standard in
23
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determining what concentrations and compositions of various sulfate species cause responses or effects;
(B) Developing needed mathematical relationships between emission rates and air quality to initiate control
strategy whatever may be the standards pathway selected; (C) Energy technology related projects investigat-
ing the impact of new technologies on the composition of plumes. Table 8b reallocates by year the re-
sources listed in Table 8a.
Table 8b
ATMOSPHERIC CHEMISTRY AND TRANSPORT FUNDING BY OBJECTIVES ($K)
FY
72 78 ^79 80 £n 82 83
Objective A 170 475 600 625 400 300 100
Objective B 3080 2725 3300 3575 3600 3400 1000
Objective C 1250 1300 1300 1300 1300 1300 1300
Totals 4500 4500 5200 5500 5300 5000 2400
/. Chemical Mechanism and Simulation Studies—
These ongoing laboratory programs have the following objectives: (1) provide basic data on mechanisms
and processes related to oxidation of gaseous sulfur compounds to aerosols and the associated physical
changes in aerosols as they follow and grow; (2) simulate chemicals or physical processes occurring within
specific types of plumes to associate processes with effects of precursors, humidity, temperature and
catalysts on conversions of sulfur oxides to sulfates.
Table 9
CHEMICAL MECHANISM AND SIMULATION FUNDING ,($K)
77
250
150
78
250
150
79
300
150
FY
80
350
100(a)
81
350
100(a)
82
300
100(a)
83
100
100(a)
Base
Environmental-energy
Total 400 400 450 450 450 400 200
(a) assumes continuation of environmental-energy resources through FY82.
//. Chemical Characterization of Acid Sulfates—
Recent laboratory biological results reveal that initiating such characterization studies is essential for
selected sulfate species. As a result, a characterization project will be initiated during the first half of FY'77
to measure acid sulfates, total sulfates, and a number of elements by XRF, at sites both of interest for
future population studies as well as transport studies. The first group of sites will probably include a site in
Los Angeles, Utah, Missouri or Illinois (near St. Louis), and several other midwestern and east coast sites. A
small initial intensive project will be carried out on natural emissions in the Cape Hatteras area of coastal
North Carolina. The prototype instrumentation to optimize such investigations of natural emissions will
not be available until 1977, so only manual and research laboratory measurements can be made until then.
These characterizations at urban sites of interest to population studies will continue for several years.
Additional intensive measurement projects will be set up at non-urban EPRI/SURE monitoring sites. Such
characterization measurements will also accompany transport and transformation studies of larger plumes.
24
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A series of studies to determine whether natural emissions contribute significantly to regional problems
will continue through FY'78 to FY'80.
Table 10
CHARACTERIZATION OF ACID SULFATES FUNDING ($K)
FY
22 IB 79_ 80_ B± 82
1. Measurements at possible 100 200 250 150 0 0
sites for future population
studies.
2. Measurements to supplement 50 100 150 150 100 100
EPRI monitoring system
for regional studies.
3. Measurements to supplement 0 200 200 250 250 150
intensive regional plume studies3
4. Measurements of natural 25 100 250 150 150 100
emissions.
TOTALS 175 600 850 700 500 350
(a) Resources included in Regional Plume Studies (III)
///. Regional Plume Studies—
In FY 1973 a regional air pollution study (RAPS) was initiated in the St. Louis area by White House
initiative. The study was scheduled as a five-year program through FY'77. Funding has been at the 4 to
5 million dollar range per year during this study. The scope of the study was somewhat narrowed with re-
spect to the range of pollutants. Particular emphasis has been given to sulfur dioxide, sulfates and other
finely divided particulate species; however, a significant portion of the measurement program also has been
directed at obtained data related to ozone and its precursors. An extensive measurement system for gases
and particles has been set up in the St. Louis region, including nearby areas, on a scale not exceeding 100
km. A number of successful intensive periods of investigation have been conducted involving additional
specialized gas and aerosol measurements at ground level and from aircraft, also including upper air
meteorological soundings. A detailed "high resolution" emission inventory has been in development. The
final intensive field activities will be carried out in late fall or winter of 1976-77. The monitoring network
and meteorological network will be phased down in the second half of FY'77. During FY'76 and FY'77
increased emphasis has been given to data analysis and modelling. However, because of the phasing on
availability of emission inventory results and some other aspects, modelling will not be completed in FY'77.
Therefore, FY'78 modelling funding discussed below for the second phase of RAPS (STATE) must include
transitional funding to complete the utilization of RAPS from St. Louis.
As discussed above, the second phase of regional air pollution research (STATE) involves considerable
shift in emphasis. The efforts will concentrate on the contribution of elevated emission sources (stacks) of
sulfur oxides and nitrogen oxides to regional concentrations of sulfates and nitrates. Chemical compositional
efforts will emphasize acid sulfates and acid nitrates. The scale selected is the 100-500 km range since it is
within this range that there is a reasonable possibility of developing relationships between emissions and
the ambient air concentrations of total and acid sulfates and nitrates. Because the Electric Power Research
Institute (EPRI) is already committed to operating a large regional monitoring network, there is no need
for EPA to provide such a network. However, the EPA measurements capability does provide the
opportunity to supplement the measurements of the EPRI network by chemical characterization for
25
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sulfates and other species which EPRI will not measure in their basic monitoring program. Therefore, the
proposed program emphasizes following the movement and chemical and physical characteristics of plumes
from large utility complexes and their interactions with urban areas. In the first and possibly second field
study, a midwestern complex or one located on the boundary between midwest and southeast U.S. will be
selected. A complex is desired which will be so located that both polar and gulf maritime air trajectories
will pass over the complex. Among other reasons for this choice is the possibility of large variations in the
levels of acid sulfates with changes in frontal passage. Another aspect will be determining the interaction
of the plume(s) from the complex with an urban area well downwind of the complex. Later efforts will be
directed at impacts on the east coastal areas. It has been suggested that the combined efforts on plumes
and on the regional-subcontinental scale be termed STATE (Sulfate Transport and Transformations in the
Environment). Because of the programs to be funded by EPRI and ERDA on the regional-subcontinental
scale, EPA will emphasize the plume studies. The STATE program will be a five-year program on both sul-
fates and nitrates. In this strategy only the resources for sulfates are listed.
Resources listed cover the following aspects: (a) detailed chemical characterization in aircraft and at
mobile ground sites, (b) use of tracers to follow movement of plumes, (c) use of aircraft measurements
and remote sensors to obtain flux of pollutants at a number of downwind distances (times), (d) special
meteorological measurements needed aloft, and (e) data analysis.
Table 11
REGIONAL PLUME STUDIES FUNDING ($K)*
FY
71 78 79 80 81 82
1. Urban-regional 2190a 0 0 0 0 0
program (10-100 km)
RAPS
2. Plume intensive 0 1600 1600 1700 1850 1650
field programs
(100-500 km)
3. Regional-sub- 65 300 300 300 150 150
continental program
(1000-2000 km)
TOTALS 2255 1900 1900 2000 2000 1800
*RAPS and STATE both address pollutants other than sulfates. Shown here is that portion judged to
apply to sulfates only.
aNot including modelling or methods development
IV. Environmental Energy Major Field Programs—
Two major field programs have been funded by environmental energy resources. One of these programs,
MISTT, has been concerned with transport and transformation in plumes from various energy sources. How-
ever, the field work thus tar in practice has concentrated on coal-fired power plant plumes in the St. Louis
area and the urban plume of St. Louis. The scale has been in the 50 to 250 km range with the longer range
for the urban plume. Field projects in FY'78 and beyond will study specific types of plumes from single
sources. The second program is concerned with obtaining experimental data on a coal fired power plant
(Clinch River near Carbo, Va.) plume in complex terrain. A similar study should be conducted at an appro-
priate western site. The data will be used to improve modelling of plume behavior in complex terrain.
26
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Table 12
MAJOR ENERGY-RELATED FIELD PROJECTS FUNDING ($K)
FY
22. 78 79 80 81 82
MISTT project 575 700 850 875a 1075a 1095a
Complex terrain- 325 200 200 200a 0 0
project
TOTALS 900 900 1050 1075a 1075a 1095a
aAssumes energy funding will continue after FY'79
V. Effects of Sulfates on Visibility Reduction—
The dominant role of finely divided sulfates on visibility reduction has been discussed. Concurrent
measurements of sulfates and visual range will be made at a number of urban and non-urban sites including
some EPRI sites and sites where population studies also will be conducted. Varying visual conditions also
will be related to meteorological parameters.
Table 13
VISIBILITY REDUCTION FUNDING ($K)
77
50
78
125
79
200"
FY
80
175
81
100
82
50
Visibility Studies
VI. Effects of Acid Sulfates on Materials
EPA has made field measurements to evaluate deterioration of construction materials in St. Louis. How-
ever, present and past evaluations have not been designed to separate effects of sulfur dioxide from effects
of acid sulfates. The distribution of damage on a regional scale may well be different depending on the con-
tributions of sulfur dioxide compared to acid sulfates in causing damage. Selected paired urban and non-
urban sites should be evaluated.
Table 14
MATERIALS DAMAGE FUNDING ($K)
77
0
20
78
100
0
79
150
0
FY
80
150
0
81
150
0
82
150
0
Base
Energy
TOTALS 20 100 150 150 150 150
VII. Association of Acid Precipitation Effects with Meteorological Parameters—
Increased acidity of soil and inland waters has been observed in Sweden, Norway, Canada, and the U.S.
The effect has been associated to a large extent with acidity of sulfure particulate matter often transported
distances of 1000 to 2000 km and transferred from the air to soil or water bodies by precipitation. The
most consistent effect has been on spawning and growth of trout and salmon in lakes and streams. In the
27
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U.S. this effect occurs in high altitude lakes in the Adirondack mountains with extinction or alterations in
density, size, structure, and growth rates of trout populations. Evidence has accumulated that one parti-
cularly adverse condition is the extremely high acidity of spring snow-pack runoff. However, high levels of
acidity also occur during certain types of individual precipitation episodes. An evaluation of these types of
conditions will be related to meteorological conditions and emission sources over the eastern North
American Continent. The resources for ecological research are included elsewhere in this strategy.
Table 15
ACID PRECIPITATION FUNDING ($K)
FY
77 78 79 80 81 82 83
Acid Precipitation Studies 50 50 100 150 150 100 100
VIII. Data Analysis and Modelling of Sul fates—
Data analysis is needed of RAPS results as well as of the experimental results from the new regional pro-
grams (STATE) proposed to develop empirical relationships between emission sources and ambient air sul-
fates. Evaluation of urban-regional scale models (10-100 km) using St. Louis RAPS experimental results
will be emphasized in FY'77 and FY'78. Development of deterministic plume models (100-500 km) and
regional subcontinental models should be emphasized in FY'77 and FY'78 to permit evaluation and modi-
fication in FY'79 and later. Both diagnostic and planning type models are needed. It should be emphasized
that a different set of models are required to deal with the plume and regional-subcontinental scales. The
plume models will include modules for chemical and physical changes and will involve much higher spatial
and temporal resolution than the regional-subcontinental models. It should again be emphasized that sup-
porting research on model development techniques not of a pollutant specific character also will be in pro-
gress but the resources are not included in this strategy.
Table 16
DATA ANALYSIS AND MODELLING FUNDING ($K)
£Y
77 78 79 80 81 82 83
1. Development and 350 325 400 650 700 700 600
evaluation of
urban regional
plume models
2. Development of 100 150 250 300 325 450 300
regional subcon-
tinental models
3. . Environmental 200 150 100 100b 100b 100b 100b
Total resources 650 625 750 1050 1125 1250 1000
including those
in III
bAssumes continuation of environmental energy funding beyond FY'79
28
-------
Table 17 summarizes the nine research areas and major milestones in each, for the Atmospheric Chemis-
try and Transport Research Strategy.
Table 17
ATMOSPHERIC CHEMISTRY AND TRANSPORT
Research Category
I. Chemical mechanism
and simulation studies
II. Chemical characteri-
zation of ambient acid
suIfates
111-1 Urban-regional
air pollution study
III-2 Plume intensive
studies
III-3 Regional-Subcon-
tinental program
IV-1 MISTT project
IV-2 Complex terrain
project
V. Effects of sulfates on
visibility reduction
VI. Effects of sulfates
on materials
VII. Association of acid
rain effects with
meteorological para-
meters
VIM. Characterization
of emission sources
IX. Data analysis and
modelling
76
77
Time to Complete (FY)
78 79 80
I ' ' • I ' ' ' I ' '
81
82
•—h
83
The ability to meet the completion dates shown in Table 18 depends as much on the continued availa-
bility of key ORD-EPA scientists as on dollar resources. With the continuing reductions in laboratory staff
in ORD-EPA, there is no assurance that the key atmospheric scientists needed to manage and implement
this portion of the strategy can be replaced if they resign or are transferred. The completion dates listed
are based on actual laboratory staffing at the beginning of FY'77. Losses of staff will require that various
of the individual completions be shifted to later dates or deleted entirely. This uncertainty as to future
staffing also is one reason why it is unrealistic to propose higher levels of dollar resources in these research
areas despite the realization that the present EPA strategy is less than optimum.
29
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2.4 MEASUREMENT METHODOLOGY AND INSTRUMENTATION
A critical need in the present research strategy is to develop methods for monitoring specific sulfur com-
pounds in ambient air. Epidemiological, toxicological, clinical, and atmospheric formation studies depend
on the availability of such methods. Any effort to understand the relationship between the emission of
sulfur compounds and sulfates and ambient air quality also depends upon the adequacy of the measuring
methods.
2.4.1 Background
The measurements made to date in both monitoring network activities and population studies have been
for total "water soluble" sulfates. This measurement includes individual sulfate species which are in both
the coarse and fine particle size range and which may or may not be acidic in nature in aqueous solution.
However, the accumulating experimental results from biological studies with individual sulfate species in-
dicate that sulfates such as sodium, calcium, and magnesium sulfate which are not acidic and which occur
predominately in the coarse particle size range are not of concern. In fact, no experimental evidence is
available to suggest that any of the sulfates present predominantly in that size range are of biological con-
cern. Some biological results also indicate that the more strongly acidic, finely divided sulfates may have
greater adverse biological effects than less strongly acidic ones. Therefore, biological effects may be found
to be associated with the presence in the atmosphere of the more strongly acidic sulfates.
The "water soluble" sulfate method may not be an adequate indicator of acid sulfates. This tentative
conclusion urgently needs verification. It is based on observations of variation in acid sulfate reported in
Sweden and in the St. Louis area which were not at all proportional to the "water soluble" sulfate concen-
trations. Therefore, the completion of related measurement research is essential to permit initiating a char-
acterization project at selected sites in FL'77-'78 to quantitatively relate acid sulfates to "water soluble"
sulfates.
There-is a similar need to include characterization of acid sulfates as an element of the transport and
transformation research projects in FY'78 and beyond. These projects also require the capability to
measure total gaseous and total particulate sulfur accurately to obtain mass balances. Such mass balances
are critical to develop reliable relationships between emissions of sulfur compounds and ambient sulfur
concentrations. Ammonia measurements are also needed to test kinetic mechanism of sulfate formation.
To develop the capabilities discussed above, it is essential that artifact sulfate caused by converting sulfur
dioxide to sulfate on some collection substrates be minimized or completely eliminated. Similarly the re-
action of ammonia with acid sulfate on the collection substrate must be minimized to avoid underestimat-
ing acid sulfate concentrations present in the atmosphere.
2.4.2 Research Strategy
The considerations discussed result in eight project activities discussed below. A summary of funding
for each is presented in Table 19.
Discussions with representatives of EPRI and ERDA as well as knowledge of European programs indicate
that only limited efforts on sulfate laboratory measurement techniques and little if any instrumentation
development can be expected by other sources. The only major instrumentation program is being con-
ducted by EPA. Currently several of the measurement research activities in ERDA laboratories are sup-
ported as part of the EPA program. In addition, NSF has funded a number of basic measurement projects
with some general relationships to this plan. Therefore, the described research and funding is essential not
only for EPA, but for the total national effort on sulfates.
The items included are those specifically related to sulfates and not air pollution or environmental
measurements in general. For example, measurement projects to analyze for specific elements usually
reflect concern about the specific toxicity of these elements. Unless the element has a reasonable
30
-------
association with su I fates and current methodology is inadequate to meet the needs in the sulfate strategy,
it was considered inappropriate to include such resources as pertinent to sulfates. To include research on
even less directly related measurements on organics, oxidants, and nitrogen oxides would turn a sulfates
research strategy into a non-specific catch-all environmental research effort.
/. Particle Sizing—
Sulfates must be separated into fine and coarse fractions by use of an appropriate particle sizing device.
As discussed, this separation is required because of the lack of biological response to coarse particles. This
separation is also useful because it eliminates or reduces the interference of alkaline substances present pre-
dominantly in the coarse particle size range with acid sulfate measurements. The collection surfaces in the
particle sizing device must be compatible with subsequent analysis for acid sulfates and "water soluble"
sulfates.
Table 18a
MEASUREMENT METHODOLOGY AND INSTRUMENTATION FUNDING ($K)
I. Particle sizing
II. Key sulfate species
111. Other sulfate species
IV. Other particle sulfur
V. Inst. for Transf.
& Transp. Res.
VI. Natural sources 20 50 50 0 0 0 0
VII. Develop monitoring 135 125 225 200 200 200 200
techniques
VIII. Source Character- 135 135 315 300 250 150 150
ization
IX. Standardization 100 100 375 450 200 150
X. Env. Energy Pass-Thru 300 300 300 300 300 300
77
245
165
30
25
145
78
175
165
50
50
150
79
175
310
150
150
250
80
125
150
150
175
150
81.
100
150
150
100
150
82
75
150
50
50
125
83
0
0
0
0
0
TOTALS3 1300 1300 2300 2000 1600 1250
Including resources for EPA technical staff involved in projects.
The research components I through X in Table 18a respond to three major objectives: (A) projects sup-
porting the health and welfare aspects of criteria development and an ambient air standard in determining
what concentrations and compositions of various sulfate species cause responses or effects; (B) develop-
ment of the mathematical relationships between emission rates and air quality needed to initiate control
strategy development whatever may be the standards pathway selected; (C) energy technology related
projects investigating the impact of new technologies on the composition of plumes. In Table 18b the re-
sources listed in Table 18a are reallocated by year among these objectives.
31
-------
77
220
780
300
78
265
735
300
79
610
1390
300
80
475
1225
300
81
400
900
300
82
250
700
300
83
0
500
300
Table 18b
MEASUREMENT METHODOLOGY AND INSTRUMENTATION
FUNDING BY OBJECTIVE ($K)
FY
77 78 79 8C
Objective A
Objective B
Objective C
Total 1300 1300 2300 2000 1600 1250 800
//. Key Sulfate Species—
Analytical and instrumental techniques capable of providing for separation and analysis of sulfuric acid,
ammonium bisulfate and ammonium sulfate are essential. Techniques which measure compounds directly
are desired, but these techniques, which involve estimating of individual compounds by deducting from a
set of acid sulfate measurements, are acceptable.
///. Other Sulfate Species—
Efforts will continue to determine whether other sulfate species in the finely divided particulate matter
with potential to cause adverse biological effects actually occur in the atmosphere. One such possible
species has been identified in the stacks of oil-fired power plants. This species appears to be a compound of
vanadium and sulfur, possibly vanadyl sulfate, VOS04- Special research techniques must be applied to
verify this result and to seek other possible species in the atmosphere.
/ V. Other forms of Particulate Sulfur—
Other valence states of particulate sulfur may be of significance. Sulfites especially have been suggested
as of possible importance. Therefore, measurement techniques acceptable for air quality research on
valence states and molecular compounds of sulfur need to be developed and applied.
V. Instrumentation for Transformation and Transport Research—
For transformation and transport research there is an additional need for real time or semi-real time
instrumentation to measure total particulate sulfate, as well as sulfur dioxide and ammonia at the concen-
tration levels of concern in regional scale studies.
VI. Natural Sources—
Natural emissions of hydrogen sulfide and mercaptans are frequently discussed as contributors to
ambient sulfate concentrations as a result of oxidation mechanisms. To conduct adequate studies of
natural emissions a measurement system must be develop which will be adequate to differentiate among
the sulfur species involved in the process of conversion of such reduced sulfur vapors to sulfate.
VII. Monitoring Needs—
There is a need for low cost devices for measurement of sulfur dioxide, sulfuric acid and other acid sul-
fates. Continuing research is needed to develop devices that will be practicable for routine monitoring.
32
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VIII. Characterization of Emission Sources—
This characterization strategy is primarily concerned with chemical and physical characterization of sul-
fates from oil-fired stationary sources. Recent experimental results have demonstrated that directly emitted
sulfate emissions in the form of sulfuric acid and a vanadium/sulfur species, probably vanadyl sulfate, are
larger than indicated by experimental results obtained a number of years ago. The sulfate levels obtained
are sufficiently higher to be of possible concern if unstable meteorological conditions exist immediately
downwind of the source (1-10 km). Additional evaluations are needed of oil-fired combustion sources
utilizing a range of fuels under various operating conditions. The emission factors thus obtained can be
used with single source meteorological diffusion equations to estimate ground level concentrations near
the sources. Concurrently, ground level concentrations of total and acid sulfates need to be measured under
adverse, meteorological conditions near oil-fired emission sources. Additional resources related to measure-
ment aspects are included in that portion of the strategy.
Table 19
SOURCE CHARACTERIZATION FUNDING ($K)
FY
77 78 79 80 81 82
Source Studies 150 250 250 275 250 150
IX. Standardization of Measurement Methodology—
If it is determined that specific sulfates require regulatory action, there will be a need for standardized,
routine monitoring instrumentation and measurement methodology. This effort must begin in FY'77 for
those specific sulfates which are the focus of this strategy.
2.4.3 Anticipated Results
Many of the objectives described above are already being addressed by the EPA program. Current pro-
gress and anticipation of the funding levels presented in Table 18 permit the following projections. Table
20 summarizes the eight project areas and the expected results, which are described below:
In mid-1978, (1) final designs of both manual and automated dichotomous samplers needed for com-
mercial units should be available; (2) evaluation and utilization of second generation prototype sulfuric
acid analyzers in determining H2SO4 in the atmosphere will have been in progress for over one year and
final design for commercial units should be in progress; (3) methodology for strong acid, ammonium, and
sulfate in the fine paniculate fraction will have been evaluated and applied to samples from selected sites
for over a year; (4) a prototype total particulate sulfur analyzer system will be available for field evaluatior
(5) evaluation of a group of research type samplers and particle sizing devices will have been completed
(low pressure cascade impactors, "two mass" and streaker); (6) performance of tandem filter particle/gas
prototype collectors for H2S and SO2 for natural source studies will be completed and automated units
will be in process of fabrication; (7) final prototype design will be completed on the chemiluminescence
NH3 analyzer.
In mid-1979 a number of additional developments could be available: (1) lower cost dichotomous
samplers could be commercially available; (2) sulfuric acid analyzers could be commercially available;
(3) second generation prototype total particulate sulfur analyzers could be available; (4) high sensitivity
S02 analyzers (0.1 ppb detection limit) should be commercially available; and (5) ammonia analyzers
should be available for routine field use in research programs.
33
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Table 20
MEASUREMENT METHODOLOGY AND INSTRUMENTATION
ACCOMPLISHMENT STRATEGY
Research Category
1. Specifications
developed for commercial
particle sizing devices
for collection of sulfate
2. Specifications
developed for commercial
sulfuric acid analyzers
3. Prototype particle
sizing sulfuric acid
and strong acid tech-
niques for characteri-
zation studies available
4. Total sulfate
monitors
5. Automated strong
acid monitor
6. Spectrometers for
other sulfur species
7. Automated
collectors for studies
of natural emission
sources
8. Specifications
developed for high
sensitivity S02
analyzers
9. Ammonia analyzers
available for research
needs
10. Manual H2S04
Collectors
11. Standardization
and support
76
77
Time to Complete (FY)
78 79
80
—h
81
34
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APPENDIX 1
35
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BIBLIOGRAPHY
* This bibliography reflects information in published literature that was used in developing this research approach.
36
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Air Quality Criteria for Sulfur Oxides. Washington, D.C.: U.S. Department of Health, Education, and Welfare, National
Air Pollution Control Administration. January 1969. 178 pp.
Altshuller, A.P. "Atmospheric Sulfur Dioxide and Sulfate: Distribution of Concentration at Urban and Nonurban Sites in
United States." Environ. Sci. Technol. 7: 709-712, August 1973.
Alfshuller, A.P., R.J. Charlson, A.P. Waggoner, D.S. Covert, N.C. Ahlquist, A.M. Vanderpol. "Sulfate Background Aerosol
Optical Detection In St. Louis Region:' Atmospheric Environment. 9(8) 1975, p. 765.
Amdur, M.O. "The Impact of Air Pollutants on Physiologic Responses of the Respiratory Tract." Proc. Am. Phil. Soc.
14: 3-8, 1970.
Amdur, M.O. "Toxicological Appraisal of Paniculate Matter, Oxides of Sulfur, and Sulfuric Acid," Air Pollut. Contr. Assoc.
19(9) :638-644, September 1969.
Amdur, M.O. and M. Corn. "The Irritancy Potency of Zinc Ammonium Sulfate of Different Pontrile Size S." Am. Ind. Hyq.
Assoc. J. 24:326-333, 1963.
Atkins, D.H.F., R.A. Cox, and A.E.J. Eggleton. "Photochemical Ozone and Sulfuric Acid over Southern England." Nature
235: 372-376, 1972.
Battigelli, M.C., J.F. Gamble. "From Sulfur to Sulfate: Ancient and Recent Considerations." J. Occup. Med. 18(5) 1976
pp. 334-341.
Brosset, C. "Particle-borne Strong Acid; Occurence, Effects and Determination Methods." (Presented at the Division of
Water, Air, and Waste Chemistry Meeting of American Chemical Society. New York, August 1972.)
Brosset, C. "Airborne Particles Black and White Episodes." Ambio. 5(4) 1976, pp. 157-163.
Buchanan, D.R. "The Corrosion or Deterioration of Concrete." Australian Corrosion Engineering. 14(5): 5, May 1970.
Burns, G.R. "Oxidation of Sulfur in Soils." Washington, D.C. The Sulfur Institute. Technical Bulletin No. 13, Vol. 8,
No. 1. 1967. pp. 9-15.
Butcher, S.S. and R.J. Charlson. An Introduction to Air Chemistry. New York: Academic Press, 1972.
Cadle, R. D. and P. L. Magill. "Chemistry of Contaminated Atmospheres." In: Air Pollution Handbook. Magill, P. L., F.R.
Holden, and C. Ackley(eds.), New York: McGraw-Hill, 1956. pp. 3-21.
Cadle, R. D. and R. C. Robbins. "Kinetics of Atmospheric Chemical Reactions Involving Aerosols." Faraday Soc. Disc.
30:155-161, 1960.
Charles, Jeffrey M. and D. 8. Menzel. "Ammonium and Sulfate Ion Release of Histamine from Lung Fragments." Arch.
Envir. Health Vol. 30, June 1975, pp. 314-316.
Cheng, R.T., J. 0. Frohliger, and M. Corn. "Aerosol-Gas Interactions." J. Air Pollut. Contr. Assoc. 21: 138-142, March
1971.
Chronic Exposures of Cvnomologus Monkeys to Sulfuric Acid Mist and Fly Ash Mixtures. Hazelton Laboratories, Inc. for
Electric Research Council. Project RP-74. December 1973.
Crowther, C., and H. G. Rustan. "The Nature, Distribution and Effects Upon Vegetation of Atmospheric Impurities in and
Near an Industrial Town." J. Agric. Sci. 4:25-55. 1911.
37
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Covert, D. S., R. J. Charlson and N. C. Ahlquist. "A Study of Chemical Composition and Humidity to Light Scattering by
Aerosols." J. Appl. Meteorol. VI (6)-.968-976. 1972.
Cox, R': Z. and S. A. Penkett. "Oxidation of Atmospheric SC^ by Products of the Ozone-Olefin Reaction." Nature. 230:
321-322,1971.
Dochinger, L.S., T. A. Seliger, editors. Proceedings of the International Symposium on Acid Precipitation and the Forest
Ecosystem (1st). Held at Columbus, Ohio, May 12-15, 1975. Columbus, Ohio: Ohio State University Atmospheric
Sciences Program, 1035 pp. August 1976.
Driscoll, J. N. and A. W. Berg. Improved Chemical Methods for Sampling and Analysis of Sulfur Oxides Emissions from
Stationary Sources. Research Triangle Park, N.C.: U.S. Environmental Protection Agency: APTD 1162, June 1971.
Prepared for EPA by Walden Research Corporation, Cambridge, Massachusetts under Contract No. CPA-22-69-95. 270
PP-
Driscoll, J.N., J. Becker, R. Hebert, K. Horbal, and M. Young. Validation of Improved Chemical Methods for Sulfur Oxides
Measurements from Stationary Sources. Research Triangle Park, N. C.: U.S. Environmental Protection Agency: EPA— R2-
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
i. REPORT NO.
EPA-600/8-77-004
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Statement of SULFATES RESEARCH APPROACH
5. REPORT DATE
February 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
I. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
10. PROGRAM ELEMENT NO.
1AA601
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/00
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This document presents a strategy to investigate the sulfate question.
It defines the approach to be taken, lists the questions to be addressed,
provides estimates of resources needed, and time tables to accomplish these
goals. It is intended to serve as a long-term planning instrument.
The strategy statement is divided into four research areas: Health
Effects. Ecological Effects, Atmospheric Chemistry and Transport, and
Measurement Methodology and Instrumentation.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
sulfates
research
04 A
06 T
06 F
3. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report/
20. SECURITY CLASS (This page)
UNCLASSIFIED
21. NO. OF PAGES
43
22. PRICE
EPA Form 2220-1 (9-73)
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