oERA
United States
Environmental Protection
Agency
Office of
Toxic Substances
Washington DC 20460
EPA-560/5-83-007
September. 1983
Toxic Substances
Comprehensive Assessment of
the Specific Compounds Present
in Combustion Processes
Volume 4
National Estimates of Emission
off Specific Compounds
from Coal Fired Utility Boiler Plants
-------
COMPREHENSIVE ASSESSMENT OF THE SPECIFIC COMPOUNDS
PRESENT IN COMBUSTION PROCESSES
VOLUME 4 - NATIONAL ESTIMATES OF EMISSION OF SPECIFIC COMPOUNDS
FROM COAL FIRED UTILITY BOILER PLANTS
by
Robert M. Lucas
George W. Kircher
Research Triangle Institute
SPECIAL REPORT
EPA Prime Contract No. 68-02-3938
Midwest Research Institute
MRI Project No. 8501-A(1)
August 8, 1985
Prepared for
U.S. Environmental Protection Agency
Office of Pesticides and Toxic Substances
Field Studies Branch
401 M Street, S.W.
Washington, DC 20460
Attn: Dr. Joseph J. Breen, Project Officer
Mr. Daniel T. Heggem, Work Assignment Manager
-------
DISCLAIMER
This document has been reviewed and approved for publication by
the Office of Toxic Substances, Office of Pesticides and Toxic Substances,
U.S. Environmental Protection Agency. The use of trade names or commercial
products does not constitute Agency endorsement or recommendation for use.
-------
PREFACE
The research and preparation of the draft of this report was per-
formed for the U.S. Environmental Protection Agency under Contract No. 68-01-
5848, Research Triangle Institute Project No. 1864-25. Mr. Joseph Carra was
the Contract Officer and Mr. Jerry Feinstein was the Task Manager. The final
revisions and preparations of this final report were completed by Research
Triangle Institute under subcontract to Midwest Research Institute under Prime
Contract No. 68-02-3938.
MIDWEST RESEARCH INSTITUTE
Clarence L. Haile
Deputy Program Manager
in E. Going
Program Manager
Approved:
James L. Spigarelli, Director
Chemical and Biological Sciences
Department
-------
CONTENTS
Page
I. Executive Summary. ........ 1
II. Introduction 1
A. Background 1
B. Overview. ....... . 2
III. Survey Design of Coal Combustion Study 2
A. Overview. 2
B. Target Population 2
C. Sample Selection and Stratification 3
D. Specimen Acquisition (Sampling) Plans 6
IV. Overview of Chemical Analysis Results 6
A. Target Compounds. 6
B. Qualitative Summary of the Data 6
V. Summary of Emissions Data 10
A. Overview 10
B. Summary of Flue Gas Emissions 10
VI. References 18
Appendix A - Statistical Methods 19
IV
-------
TABLES
Number Page
1 Strata of the Coal Combustion Survey and Sum of Size
Measures (in millions of tons) 6
2 Media Sampled by Plant 8
3 Target Polynuclear Aromatic Hydrocarbons and Phthalates ... 10
4 Detection of PAHs by Facility and Media 11
5 Detection of Phthalates by Facility and Media 12
6 Method Detection Limits for PCDDs and PCDFs for 5-Day
Composite Specimens 13
7 Detection of PCBs by Facility and Media 15
8 Method Detection Limits for PCB Isomers by Media 16
9 Average Emission Rates (g/hr) of Selected Compounds in the
Flue Gases by Facility 18
10 Estimates of Average National Emission Rates (g/hr) of
Selected Target Compounds 19
11 Summary of Total National Annual Emission of Selected Target
Compounds for Coal-Fired Utility Boilers 20
FIGURES
Number Page
1 Geographic strata of the coal combustion survey design. . . 5
-------
I. EXECUTIVE SUMMARY
Specimens were acquired from influents and effluents from seven
coal-fired utility boilers. The specimens were chemically analyzed for toxic
compounds in the polycyclic organic matter group. The specific target com-
pounds were polychlorinated dibenzo[p_]dioxins (PCDDs), dibenzofurans (PCDFs),
biphenyls (PCBs), selected polynuclear aromatic hydrocarbons (PAHs) and se-
lected phthalates. Twelve PAH compounds and six phthalate compounds were in-
cluded among the targetted compounds.
No PCDDs or PCDFs were detected in any of the acquired specimens.
PCBs were found in the flue gas emissions from each of the seven plants. The
average emission rate for the industry was estimated to be 1.12 g/h for each
boiler unit. The total annual national emissions of the industry was esti-
mated to be 7,500 kg. PCBs were only detected in one other media, the in-
fluent combustion air.
Naphthalene was the most prevalent PAH compound detected. It was
found in the flue gas emissions .from all seven facilities. The estimated
average emission rate was 1.6 g/h and estimate total national annual emis-
sions was 11,000 kg. Other PAHs were also detected in the coal at all seven
facilities but were only rarely detected in the other media.
Bis(2-ethylhexyl)phthalate was the most frequently detected phthalate
compound. It was detected in the flue gas emissions from all seven facilities.
The estimated average emissions rate was 17.5 g/h and the estimated total
annual national emissions was 104,000 kg. Phthalates were sparsly detected
in the other media.
II. INTRODUCTION
A. Background
The emission of several toxic compounds in the polycyclic organic
matter (POM) group, specifically polychlorinated dibenzo-p_-dioxins (PCDDs),
dibenzofurans (PCDFs), and biphenyls (PCBs) have been reported from stationary
conventional combustion processes (DC-USA 1978, 01ie et al. 1978 and Shin 1979).
These compounds are proposed to be ubiquitous in the aqueous environment and
it has been claimed that POMs are ubiquitous in air and are being formed from
many combustion sources (DC-USA 1978).
A study conducted for the U.S. Environmental Protection Agency (EPA)
(Shin 1979) demonstrates that a theoretical potential exists for POMs to be
formed during and as a result of conventional combustion processes. These
POMs may include PCDDs, PCDFs, and PCBs. The major combustion sources are
suspected to involve such fuels as coal-refuse, wood, municipal refuse, waste
oil, and coal. '•'•'-'
Because the acquisition of field specimens and their chemical deter-
mination are very costly, carefully planned studies were needed to ascertain
-------
the level and prevalence of the substances being emitted into the environment.
Because inadequate data were available on which to base a statistical design
for a national survey, a pilot study was specifically designed and conducted
to generate the appropriate data.
A description of the pilot study and its results can be found in a
report to the U.S. Environmental Protection Agency (USEPA) Office of Pesti-
cides and Toxic Substances (Haile et al. 1983a) and references therein. A de-
tailed description of the statistical analysis of the data collected in the
pilot study and the survey design for part of a nationwide survey of combustion
sources is presented in another report to the USEPA Office of Toxic Substances
(Lucas and Melroy 1985).
B. Overview
This report summarizes estimates of the prevalence and levels of
organic emissions from large coal-fired electricity generating facilities as
part of a nationwide effort to ascertain organic emissions from major sta-
tionary combustion sources. The principal compounds of interest are polynu-
clear aromatic hydrocarbons, phthalates and chlorinated aromatic compounds,
including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p_-dioxins
(PCDDs), and polychlorinated dibenzofurans (PCDFs).
Chapter III reviews the survey design employed to select sample fa-
cilities and describes the general sampling plans used to determine sampling
points and frequencies. Chapter IV presents the specific compounds targeted
for chemical analysis. Chapter V gives the statistical summary of the emis-
sions results. The technical discussion of the statistical analysis of the
data is given in Appendix A.
III. SURVEY DESIGN OF COAL COMBUSTION STUDY
A. Overview
$
The results given in this report are for large (greater than 10
BTU/h) coal-fired utility boiler facilities. Other types of coal burning
facilities and other facilities using different fuels were excluded from this
phase of the study. This section summarizes the statistical design used to
select facilities in the sample. The survey design was developed under another
contract and was originally documented in another report. The final report
was prepared under subcontract to Midwest Research Institute (Lucas and Melroy
1985). This section describes aspects of the survey design that directly im-
pact on the statistical analysis of the data.
B. Target Population
The target population for this phase of the cojnbustion study is all
coal burning utility boiler facilities greater than 10 BTU/h. To obtain a
sample of the target population, a sampling frame (inventory of facilities)
was constructed from the National Emissions Data Systems (NEDS) computer file.
A listing of the frame can be found in the design report (Lucas and Melroy
-------
1985). For the purposes of this study, each point source of emissions was
considered as a sampling unit. Hence, a facility with more than one stack
was considered to be more than one sampling unit.
Potential for biases result from facilities in the target population
that are not included on the frame. Also, inefficiencies could possibly result
from ineligible facilities (units not in the target population) being included
on the frame. Investigations to assess the magnitude of these potential pro-
blems were planned. However, because of funding limitations, the investiga-
tion was not performed. Because the NEDS file was updated routinely, particu-
larly for large facilities, the frame is felt to be substantially complete.
C. Sample Selection and Stratification
Because of the expense of sampling and chemical analysis, the sam-
ple was necessarily limited to one point source at each of the seven facil-
ities. The facilities were sampled for five consecutive days. Because of
the small sample size, an efficient sampling plan was very important to ob-
tain the most information about total emissions from such plants in the U.S.
from the limited data. An accurate size measure is useful in both the allo-
cation of samples and the selection of samples, for improving study efficency.
Because the total emissions was felt to be highly correlated with the amount
of coal burned by each plant, the number of tons of coal burned annually was
chosen as the measure of size of each point source. In order to disperse the
sample geographically, the U.S. was partitioned into seven groups (strata) of
contiguous States. The groups were arranged so that the sum of all the size
measures (reported or estimated amount of coal burned annually in such facil-
ities in the stratum) were approximately equal. Table 1 lists the States in
each stratum and the sum of the size measures for each State and stratum.
Figure 1 illustrates the strata.
One point source was selected at random from each stratum. The
probability of its selection was proportional to its size measure. This in-
creased the likelihood that the sample would contain a disproportionate number
of large emission sources.
Using a random selection technique results in estimates of the emis-
sions that are not subject to biases of the type that typically result from
judgement sampling. Also, such samples permits valid estimates of the preci-
sion of the survey results, that is, confidence intervals based on the survey
data will give ranges for the true emission values. During the planning stages
of the study, sampling of facilities in at least two combustion categories,
coal-fired boilers and refuse incinerators, was envisioned. Because the number
of coal-fired facilities was small (only 7), the precision of estimates for
that category was anticipated to be ±50 to ±60 percent. When other combustion
categories are investigated, their results can be combined with the results
of the present study to estimate emissions from their union. Precision of
these combined estimates is anticipated to be improved.
-------
Table 1. Strata of the Coal Combustion Survey and Sum of Size Measures
(in millions of tons)
North East
Maine
New Hampshire
Vermont
Massachusetts
Rhode Island
Connecticut
New York
New Jersey
Pennsylvania
Delaware
District of Columbia
Maryland
West Virginia
South East
Virginia
North Carolina
South Carolina
Georgia
Florida
Alabama
Ohio Valley
Ohio
Kentucky
Great Lakes
Michigan
Indiana
Wisconsin
79.5
0.0
0.8
0.0
0.0
0.0
0.0
6.3
2.4
38.5
0.7
0.0
4.4
25.8
72.5
4.8
20.4
7.8
17.7
6.1
16.7
74.5
44.9
30.0
64.2
21.3
31.2
11.7
North Central
Minnesota
Iowa
Missouri
Illinois
South Central
Tennessee
Mississippi
Arkansas
Louisiana
Oklahoma
Texas
West
North Dakota
South Dakota
Nebraska
Kansas
Montana
Wyoming
Colorado
New Mexico
Idaho
Utah
Arizona
Washington
Oregon
Nevada
California
Alaska
Hawaii
75.0
12.1
8.9
21.2
32.8
63.6
22.0
1.6
7.0
4.5
2.1
26.1
69.9
7.5
2.4
1.9
7.1
3.2
16.2
8.8
8.0
0.0
2.5
1.6
4.2
0.0
4.0
0.0
0.5
0.0
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Figure 1. Geographic strata of the coal combustion survey design.
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D. Specimen Acquisition (Sampling) Plans
Specimens were acquired for 5 days from each point source selected
in the sample. The specimen acquisition plans were based on the pilot study
that is described in detail in the design report (Lucas and Melroy 1985). In
general, the plan involved a complex multimedia design to collect specimens
of solid, liquid, and gaseous influents and effluents. Measurements of pro-
cess parameters were also recorded during the sampling periods.
All point sources had similar process flows of influents and efflu-
ents. However, each source was sufficiently unique to require site specific
adaptations of the general plan. The details of the site specific plans for
facilities are given in a report to the USEPA Office of Pesticides and Toxic
Substances (prepared by MRI (Haile et al. 1983b)). Table 2 presents a con-
cise summary of the media from which specimens were acquired by facility.
IV. OVERVIEW OF CHEMICAL ANALYSIS RESULTS
A. Target Compounds
The study objective was to estimate the total emissions of organic
compounds from major stationary combustion sources. The specific compounds
of interest belong to three general categories, polynuclear aromatic hydro-
carbons (PAHs) phthalates and chlorinated aromatic compounds (CACs). The
specific PAHs and phthalates targeted in the chemical analysis are given in
Table 3. The specific CACs are PCBs, PCDPs, and PCDFs. .
The reader interested in a detailed presentation of the chemical
analysis results is referred to the MRI reports (Haile et al. 1983b) previ-
ously mentioned. In the sections below, only a qualitative summary of the
data is presented to give a feel for the frequencies of which classes of
compounds were detected. Chapter V presents the summary of the estimated
emissions of the target compounds of the study for which a consequential
amount of data was collected.
B. Qualitative Summary of the Data
1. Polynuclear Aromatic Hydrocarbons
At least one of the PAH target compounds was found in flue gas spe-
cimens collected at all seven facilities. They were found much less frequently
in the other effluent media. Table 4 presents the facilities and media at
which PAHs were detected. Napthalene was the only PAH detected at all seven
facilities. Phenanthrene was found at all facilities except No. 5. Four com-
pounds, acenaphthene, benzo[k]fluoranthene, dibenz[a,h_]anthrene and benzo-
[g_,h_,i_]perylene were not detected in the flue gas at any of the seven facil-
ities. The other compounds were detected in from two to five facilities.
-------
Table 2. Media Sampled by Plant
Facility Number
Influents
Air
Water
Coal
Effluents
Flue gas
Water
Fly ash
Bottom ash
Economizer ash
1
S
sa
S
S
sc
S
S
NS
2
S
Sb
S
S
sc
S
S
NS
3
S
S
S
S
NS
S
S
NS
4
S
S
S
S
Sd
S
S
NS
5
S
S
S
S
Sd
S
S
NS
6
S
S
S
S
sd
S
S
NS
7
S
se
S
sd
S
S
S
Note: S denotes media from which samples were acquired; NS denotes media for
which JTO samples were acquired.
.Make-up water and influent water to bottom ash hopper.
Influent river water and boiler seal water.
^Overflow water.
Sluice water collected simultaneously with bottom ash.
Quench water from cooling tower.
-------
Table 3. Target Polynuclear Aromatic Hydrocarbons and Phthalates
Category
Compounds
Polynuclear
aromatic hydrocarbons
Phthalates
Naphthalene
Acenaphthylene
Acenaphthene
Fluorene
Phenanthrene
Fluorathene
Pyrene
Chrysene
Benzo[k]f1uoranthene
Benzo[a]pyrene
Dibenz[a,h]anthracene
Benzo[c[,h,ijperylene
Dimethyl phthalate
Diethyl phthalate
Di-rrbutyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl)
phthalate
Di-n-octyl phthalate
-------
Table 4. Detection of PAHs by Facility and Media
Facility number
Media
Influents
Air
Water
Coal
Ef luents
Flue gas
Water
Fly ash
Bottom ash
Economizer ash
1
ND
ND
D
D
ND
ND
ND
-
2
ND
ND
D
D
ND
' ND
ND
-
3
ND
ND
D
D
- .
ND
ND
-
4
ND
ND
D
D
ND
ND
ND
-
5
ND
D
D
D
D
ND
D
-
6
D
D
D
D
D
ND
ND
-
7
ND
D
D
D
ND
ND
D
D
Legend: D denotes detection of one or more of PAH target compounds.
ND denotes no PAH target compound detected.
- indicates media for which no specimens were acquired.
Source: Compiled by the Research Triangle Institute from information supplied
by the Midwest Research Institute.
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2. Phthalates
At least one of the phthalate target compounds was detected in the
flue gas from each of the seven facilities. Bis(2-ethy1hexyl) phthalate was
detected at all seven facilities. Dimethyl phthalate (the least frequently
detected) was detected at the plants 1, 6, and 7. The other phthalate com-
pounds were detected at four of the seven facilities. Table 5 summarizes the
detection of phthalates by facility and media.
3. Chlorinated Aromatic Hydrocarbons
No PCDDs or PCDFs were detected in any of the media sampled from
any plant. Table 6 gives the method detection limits for these compounds by
media. PCBs were detected in the flue gas specimens collected from each of
the seven facilities. PCBs were detected in the influent air (combustion) at
six of the seven facilities. Facility number 3 was the only one for which no
PCBs were detected in the influent air. PCBs were not detected in any of the
other media from which specimens were acquired. Table 7 presents the detec-
tion of PCBs by facility and media. Table 8 presents the method detection
limits for PCBs by media.
V. SUMMARY OF EMISSIONS DATA
A. Overview
This chapter summarizes emission results of selected target PAHs,
phthalate compounds and PCBs. PAH or phthalate compounds that were rarely
detected are excluded from the summaries. Also, because of the small sample
size, estimates for even the frequently detected compounds are less precise
than is usually desirable. The emissions are summarized by calculating sev-
eral intervals for estimates of the true emission rates. These intervals will
have different confidence levels (probability of coverage) ranging from 50 to
95 percent.
B. Summary of Flue Gas Emissions
Table 9 summarizes the average emission rates of PCBs and PAHs, and
phthalates detected during the study by facility. Table 10 summarizes the
data of selected compounds given in Table 9. Only compounds detected at four
or more facilities are included. Table 11 summarizes the estimated total
annual emissions of selected target compounds. The statistical methods used
to calculate the estimates are based on theory presented in Hansen et al.
(1953) and described in Appendix A.
10
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Table 5. Detection of Phthalates by Facility and Media
Media
Influents
Air
Water
Coal
Ef luents
Flue Gas
Water
Fly ash
Bottom ash
Economizer ash
1
NO
ND
ND
D
ND
ND
ND
-
2
ND
ND
ND
D
ND
ND
ND
-
Facil
3
ND
ND
ND
D
-
ND
ND
-
lity number
4
ND
ND
ND
D
ND
ND
ND
-
5
ND
D
D
D
D
D
ND
-
6
D
D
D
D
D
D
D
-
7
ND
ND
ND
D
D
D
ND
D
Legend: D denotes detection of one or more of phthalate target compounds.
ND denotes no phthalate target compound detected.
- indicates media for which no specimens were acquired.
Source: Compiled by the Research Triangle Institute from information supplied
by the Midwest Research Institute.
11
-------
Table 6. Method Detection Limits for PCDDs and PCDFs for
5-Day Composite Specimens
Dioxin and furan isomers
Sample Type
Flue gasa
Bottom ash
Fly ashb
Economizer ash
Plant background
Units
pg/dscm
pg/g
pg/g
pg/g
pg/dscm
Clx-Clj,
250
25
25
25
50
C14
100
10
10
10
20
an
5> L-M>
500
50
50
50
100
C17, Cl,
700
70
70
70
140
ar
Aqueous samples
500
200
1,000
1,400
Source: Reproduced from a report to the U.S. EPA Office of Pesticides and
Toxic Substances prepared by the Midwest Research Institute (Haile
et al. 1983b).
All flue gas specimen diluted 1:10 for HRGC/MS-SIM analysis. The 5-day
composite was calculated as equivalent to 10 dscm.
The 5-day composite is equivalent to a 100-g specimen.
.The 5-day composite is equivalent to a 50-dscm specimen.
The 5-day composite is equivalent to a 5-£ specimen.
12
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Table 7. Detection of PCBs by Facility and Media
Facility number
Media
Influents
Air
Water
Coal
Efluents
Flue gas
Water
Fly ash
Bottom ash
Economizer ash
1
D
NO
NO
D
ND
ND
ND
-
2
D
ND
ND
D
ND
ND
ND
-
3
ND
ND
ND
D
-
ND
ND
-
4
D
ND
ND
D
ND
ND
ND
-
5
D
ND
ND
D
ND
ND
ND
-
6
D
ND
ND
D
ND
ND
ND
-
7
D
ND
ND
D
ND
ND
ND
ND
Legend: D denotes PCBs detected.
ND denotes PCBs not detected.
- indicates media for which no specimens were acquired.
Source: Compiled by the Research Triangle Institute from information supplied
by the Midwest Research Institute.
13
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Table 8. Method Detection Limits for PCB Isomers by Media
Sample type Detection limit
Bottom asha 1 ng/g
Fly asha 1 ng/g
Economizer ash 1 ng/g
Aqueous samples 20 ng/£
Plant background airc 2 ng/dscm
Source: Reproduced from a report to the U.S. EPA Office
of Pesticides and Toxic Substances prepared by
the Midwest Research Institute (Haile et al. 1983b).
•Five-day composite equivalent to a 100-g specimen.
Five-day composite equivalent to a 5-L specimen.
Five-day composite equivalent to 50 dscm.
14
-------
Table 9. Average Emission Rates (g/hr) of Selected Compounds
in the Flue Gases by Facility
PCBs
Napthalene
Acenaphthylene
Fluorene
Phenanthrene
Fluoranthene
Pyrene
Chrysene
Benzo[a]pyrene
Dimethylphthalate
Diethylphthalate
Di[n]butyl-
phthalate
Butyl benzyl -
phthalate
Bis(2-ethylhexyl)-
phthalate
Di[n]octyl-
phthalate
No. 1
8.5
1.4
0.038
0.036
0.81
0.19
0.088
0.034
0.007
0.039
25
23
3.4
41
10
No. 2
0.40
1.5
0.072
0.12
1.8
0.21
0.058
0.16
4.6
13
0.92
0.86
Facility number
No. 3 No. 4 No. 5 No. 6
S 0.005 3.1 0.048 0.32
0.470 1.7 5.0 2.7
0.035
0.045 0.25 0.20
0.047
0.11 0.005 0.033
0.16
0.62 9.6
0.019 0.60 .
0.21 0.55
11 16 57 15
2.2
No. 7
0.031
0.58
0.003
0.061
0.017
6.7
Source: Report to the U.S. EPA Office of Pesticides and Toxic Substances by
the Midwest Research Institute (Haile et al. 1983b).
15
-------
Table 10. Estimates of Average National Emission Rates per Plant (g/h) of Selected Target Compounds
Compound
PCBs
Naphthalene
Fluorene
Phenanthrene
Chrysene
Diethylphthalate
Di[n]butyl
phthalate
Butyl benzyl
phthalate
Bis(2-ethylhexyl)
phthalate
Standard
Mean deviation
1.
1.
0.
0.
0.
3.
2.
0.
17.
12
76
021
35
046
72
91
45
5
0.66
0.32
.012
0.15
0.022
1.94
0.12
0.13
4.41
Confidence intervals
Median
0.32
1.5
0.0
0.20
0.033
0.62
0.019
0.21
15
( o.
( 1.
( o.
( o.
( 0.
( 2.
( 2.
( o.
(14.
50%
63 ,
52 ,
012,
23 ,
029,
28 ,
82 ,
35 ,
3 ,
1.62 )
1.99 )
0.030)
0.46 )
0.062)
5.16)
3.00)
0.55)
20.8 )
( o.
( 1.
( -
( o.
( o.
( 1.
( 2.
( 0.
(11.
75%
23 ,
33 ,
005,
14 ,
016,
12 ,
75 ,
27 ,
6 ,
2.02 )
2.18 )
.037)
0.55 )
0.075)
6.32 )
3.07 )
0.63 )
23.4 )
90% 95%
* *
(1.08, 2.43) (0.88, 2.64)
* *
(0.02, 0.67) *
*. . .. *
*
(2.66, 3.16) (2.58, 3.24)
(0.16, 0.74) (0.08, 0.82)
(8.1 , 26.9 ) (5.3 , 29.8 )
* These entries were excluded where the calculation would result in inadmissible results. For example, the normal
90% confidence interval for PCBs is (-0.29, 2.53). The lower bound being less than zero implies that the data is
too variable to accept the validity of the 90 percent confidence statement.
-------
Table 11. Summary of Total National Annual Emission of Selected Target Compounds for Coal-Fired Utility Boilers
Compound
PCBs
Naphthalene
Fluorene
Phenanthrene
Chrysene
Diethylphthlate
Oi[n]butyl
phthalate
Butylbenzyl ..
phthalate
Bis(2-ethylhexyl)
phthalate
Mean
(kg)
7,500
11,000
140
2,200
300
25,000
19,000
2,900
104,000
Standard
deviation
(kg)
4,400
2,000
51
980
150
18,000
670
790
31,000
Confidence interval
50%
( 4
( 9
(
( 1
(
(12
(18
( 2
(81
,200,
,200,
100,
,500,
190,
,000,
,500,
,300,
,000,
10,000)
12,000)
180)
2,900)
410)
38,000)
19,500)
3,500)
127,000)
75%
( 1,500.
( 8,000.
( 72,
( 900,
( 100,
(10,000,
(18,000,
( 1.800,
(63,000,
13,400)
13,000)
210)
3,500)
500)
49,000)
20,000)
4,000)
145,000)
90% 95%
* *
( 6,700, 15,000) ( 5,100, 16,000)
( 32, 250) *
( 100, 4,300) *
* *
* *
(17,500, 20,500) (17,000, 21,000)
( 1,200, 4,600) ( 700, 5,100)
(-38,000, 170,000) (19,000, 189,000)
'These entries were excluded where the calculations would result in inadmissible results. For example, the nominal 90% con-
fidence interval for PCBs is (-1,900, 16,900). The lower bound being less than zero implies that the data are too variable to
accept the validity of the 90% confidence statement.
-------
VI. REFERENCES
DC-USA. 1978. Dow Chemical U.S.A. The trace chemistries of fire - A source
of and routes for the entry of chrlorinated dioxins into the environment.
The Chlorinated Dioxin Task Force, the Michigan Division.
Haile CL, Stanley JS, Lucas RM, Melroy DK, Nulton CP, Yauger WL, Jr. 1983a.
Comprehensive assessment of the specific compounds present in combustion pro-
cesses: Vol. 1. Pilot study of combustion emission variability. Final re-
port. Environmental Protection Agency. Contract 68-01-5915. EPA 560/5-83-004,
NTIS PB-84-140-870.
Haile CL, Stanley JS, Walker,T, Cobb GR, Boomer BA. 1983b. Comprehensive
assessment of the specific compounds present in combustion processes. Volume
3. National survey of organic emissions from coal-fired utility plants. EPA
Publication EPA-560/5-83-006.
Hansen MH, Hurwitz WN, Madow WG. 1953. Sample survey methods and theory.
Vol. I. John Wiley and Sons.
Lucas RM, Melroy DK. 1985. A survey design for refuse and coal combustion
processes. Research Triangle Institute, Research Triangle Park, NC. RTI/1864/
11-01F. Prepared under subcontract PO No. 71180 for Midwest Research Institute,
Kansas City, MO.
01ie K, Vermeulen PL, Hutzinger 0. Chlorodibenzo-p-dioxins and chlorodibenzo-
furans are trace components of fly ash and flue gas of some municipal incin-
erators in The Netherlands. Chemosphere. 2. p. 105-172.
Shin C, Ackerman D, Scinto L, Moon E, and Fishman. 1979. POM emissions from
stationary conventional combustion processes with emphasis on polychlorinated
compounds of dibenzo-p_-dioxin (PCDD's), biphenyl (PCB's) and dibenzofuran
(PCDF's). Draft report prepared by TRW, Inc. for the U.S. Environmental Pro-
tection Agency.
18
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APPENDIX A
STATISTICAL METHODS
19
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OVERVIEW
The purpose of this appendix is to supplement the materials presented
in Chapter V of the text.
A. Estimation of Means and Totals
Because the facilities in the study were selected with probability
proportional to their size, the calculation of statistical estimates must in-
corporate this probability. Let Z(i) denote an observation from plant i,
i =1,... 7. Then the estimated total of the Z's is calculated using the
formula:
7
Z = I W(i)Z(i) (A.I)
1=1
where W(i) is the sampling weight, the inverse of the probability that facil-
ity i was selected in the sample. The probability that unit i was selected
in the sample was calculated using the expression
S(i)/S+(i) i = 1, 2, 3, ... 7
where S(i) denotes the size measure for the facility selected in stratum i
an S (i) denotes the sum of all the size measures for facilities in stratum
i. The sampling weights are given in Table A.I. To estimate the total annual
emission, the average hourly emission rate for plant i (say X(i)) is multi-
plied by H(i) (the total annual operating hours given in Table A.I) and sub-
stituted into equation A.I for Z(i). This was done for the targeted compounds
with sufficient information to produce reliable information. The summary of
the total annual emissions is given in Table 11 in the text.
To estimate the average hourly emission rate, X(i) is directly sub-
stituted for Z(i) in equation A.I and the result divided by the sum of the
weights, giving the equation
7 7
Z = ( Z W(i)Z(i))/( I W(i)) (A.2).
i=l i=l
To estimate the proportion of the plants emitting detectable levels, an indi-
cator (define 0 for not detect or 1 for detected) random variable can be sub-
stituted for Z(i).
20
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Table A.I Sampling Weights and Operating Hours Per Year
for the Seven Study Facilities
Facility
number
(i)
1
2
3
4
5
6
7
Sampling3
weight
(W(i))
45.93
87.10
226.46
125.42
68.11
175.16
50.61
Operating
hours/year
( \\f -I \ ^
v rl \ I ) )
8,400
8,400
7,200
8,736
6,552
8,064
8,736
Calculated by the Research Triangle Institute from the probability mechanism
used to select the sample.
Obtained from the National Emission Data System (NEDS) computerized data
file.
21
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B. Variance Estimation
Because of the small sample size of one facility per stratum, a
variance approximation suggested by Hansen et al. (1953) was used to estimate
the variance of the total annual emissions and average emission rate. The
equation is
o * 3 L(g)
/(Z) = I (L(g)/(L(g)-l)) I (Y(g,h) - A(g,h) Y(g,+)/A(g,+)r. (A.3)
g=l h=l
The terms in the expression are defined and their values given in Table A.2.
This essentially involves collapsing the seven strata into three groups of 2,
2, and 3 facilities. To estimate the variance_of Z, equation A.3 is used with
Z(i) = H(i)X(i). To estimate the variance of Z, the equation
V2(Z) = V2(Z)/( I W(i))2
.1=1
is used where Z(i) = X(i).
C. Interval Estimator
Confidence intervals are estimated using the expression:
A. S\ A. /S •
(Z - V(Z)t(a,4) , Z + V(Z) t(a,4))
or
(Z - V(Z)t(a,4) , Z - V(Z)t(a,4))
/\ y\
where Z, Z, V(Z), and V(Z) are given above. The t(a,4) denotes the table value
of students t distribution with 4 degrees of freedom. The degrees of freedom
are calculated by taking the number of strata (7) minus the number of groups
(3).
22
-------
Table A.2 Definition and Values of Terms for Equation A.3
Facility Number
1
2
3
4
5
6
7
ga
2
2
3
1
1
1
3
hb
1
2
1
1
2
3
2
L(g)c
2
2
2
3
3
3
2
Y(g,h)d
Z(D
Z(2)
Z(3)
Z(4)
Z(5)
Z(6)
Z(7)
A(g,h)e
69.9
72.5
64.2
74.5
79.5
75.0
63.6
?g denotes the group number
h denotes the unit number within group g
.L(g) denotes the number of units in group g
Y(g,h) denotes the values of the Z renumbered by group and unit within group.
Y(g,+) denotes the sum of the Y(g,h) over the levels of h in group g.
A(g,h) is the size measure of the stratum renumbered by group and unit within
group. A(g,+) denotes the sum of the Y(g,h) over the levels of h in group g.
23
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REPORT DOCUMENTATION .»•_ REPORT NO- *•
PAGE 560/5-83-007
4. Title and Subtitle
Comprehensive Assessment of the Specific Compounds Present in
Combustion Processes, Volume 4. National Estimates of Emission
of Specific Compounds from Coal Fired Utility Boiler Plants
7. Authors)
Robert M. Lucas and Denise K. Melroy
9. Performing Organization Name and Address
Midwest Research Institute with subcontract to
Research Triangle Institute
P.O. Box 12194
Research Triangle Park, NC 27709
12. Sponsoring Organization Name and Address
Field Studies Branch
USEPA
401 M Street, S.W.
.Washington, DC 20460
3. Recipient'* Accession No.
5. Report Date
August 1985
6.
8. Performing Organization Rept. No. ..'«
o. .
10. Project/Task/Work Unit No.
1A
11. Contracl(C) or Grant(G) No.
(o 68-02-3938
(G)
13. Type of Report & Period Covered
Final
14.
IS. Supplementary Notes
J. J. Breen, Project Officer
D. T. Heggem, Work Assignment Manager
16. Abstract (Limit: 200 words)
Specimens were acquired from influents and effluents from seven coal-fired utility
boilers. The specimens were chemically analyzed for toxic compounds in the polycyclic
organic matter group. The specific target compounds were polychlorinated dibenzo[£]-
dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls {PCBs), selected polynuclear aromatic
hydrocarbons (PAHs) and selected phthalates. Twelve PAH compounds and six phthalate
compounds were included among the targetted compounds.
Naphthalene was the most prevalent PAH compound detected. It was found in the flue
gas emissions from all seven facilities. The estimated average emission rate was 1.6 g/h
and estimate total national annual emissions was 11,000 kg. Other PAHs were also de-
tected in the coal at all seven facilities but were only rarely detected in the other
media.
No PCDDs or PCDFs were detected in any of the acquired specimens. PCBs were found
in the flue gas emissions from each of the seven plans. The average emission rate for
the industry was estimated to be 1.12 g/h for each boiler unit. The total annual nationa
emissions of the industry was estimated to-be 7,500 kg. PCBs were only detected in one
other media, the influent combustion air.
17. Document Analysis a. Descriptors
Combustion,
Emission estimates,
PAH, PCB, PCDD, PCDF
b. Identifiers/Open-me'ed Terms
L. COSA'l'l Kul(!,'Grr>ui>
IS. Avallibilily n.!tr.-n~nt
Release to Public
L:
\K.
\
f.rciiiity Cl.liS (Tl\is Report)
Unclassified
Soci.'rily Clasi (Tliis f'jy.rl
Unclassified
21.
2:.
No. of Pages
28
fvicc
orno .-.si. FCI:M r.7i i-s-7?)
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