EMISSION FACTOR DOCUMENTATION FOR AP-42 SECTION 11.16 (formerly 8.14)
Gypsum Manufacturing
1. INTRODUCTION
The document Compilation of Air Pollutant Emission Factors (AP-42) has been published by
the U.S. Environmental Protection Agency (EPA) since 1972. Supplements to AP-42 have been
routinely published to add new emission source categories and to update existing emission factors.
AP-42 is routinely updated by EPA to respond to new emission factor needs of EPA, State and local
air pollution control programs, and industry.
An emission factor relates the quantity (weight) of pollutants emitted to a unit of activity of
the source. The uses for the emission factors reported in AP-42 include:
1.	Estimates of areawide emissions;
2.	Estimates of emissions for a specific facility; and
3.	Evaluation of emissions relative to ambient air quality.
The purpose of this report is to provide background information from test reports and other
information to support preparation of AP-42 Section 8.14, Gypsum Manufacturing.
This background report consists of five sections. Section 1 is an introduction to the report.
Section 2 gives a description of the gypsum manufacturing. It includes a characterization of the
industry, an overview of the different process types, a description of emissions, and a description of
the technology used to control emissions. Section 3 is a review of emission data collection and
laboratory analysis procedures. It describes the literature search, the screening of emission data
reports, and the quality rating system for both emission data and emission factors. Section 4 details
revisions to the existing AP-42 section narrative and pollutant emission factor development. It
includes the review of specific data sets and the results of data analysis. Section 5 presents AP-42
Section 8.14, Gypsum Manufacturing.
1

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2. INDUSTRY DESCRIPTION12
Gypsum is calcium sulfate dihydrate (CaS04 • 2H20), a white or gray naturally occurring
mineral, and is used as a commercial and generic term for all calcium sulfate materials. Raw gypsum
ore is processed into a variety of products such as a portland cement additive, soil conditioner,
industrial and building plasters, and gypsum wallboard. The Standard Industrial Classification code
(SIC) for gypsum processing is 3275. The first six digits of the Source Classification Codes (SCC)
identifying pollution sources in gypsum processing are 305015.
2.1	CHARACTERIZATION OF THE INDUSTRY1
Between 1983 and 1989, sales of gypsum products increased between 5 and 10 percent
annually. The total value of gypsum products sold in the United States during 1988 was $2.1 billion.
This value dropped slightly in 1989 because lessening demand from construction industries made the
market more competitive and lowered prices. Several new gypsum plants are expected to become
operational in the early 1990's, thereby increasing competition even further.
In 1989, crude gypsum was mined by 36 companies at 65 mines in 21 States. The leading
producing States, in descending order, were Oklahoma, Iowa, Michigan, Texas, California, Nevada,
and Indiana. These seven States accounted for 76 percent of total domestic production. The three
companies leading in crude gypsum production were, in descending order, USG Corporation (USG),
National Gypsum Company (National Gypsum), and Georgia-Pacific Corporation (Georgia-Pacific).
Table 2-1 presents additional information about the geographies of crude gypsum production. Most
domestic gypsum is extracted from surface mines using standard open-pit methods.
In 1989, gypsum was calcined by 13 companies at 71 plants in 28 States. Leading States, in
descending order, were California, Texas, Iowa, Florida, Nevada, and New York. These six States,
with 29 plants, accounted for 48 percent of national output. Leading companies were USG, National
Gypsum, and Georgia-Pacific. Table 2-2 presents additional information about the geographies of
calcined gypsum production.
The United States is the world's largest miner of gypsum, accounting for about 16 percent of
total world output. Other leading countries, in descending order, include Canada, Iran, China, Japan,
France, Spain, and Thailand. Imports account for about one-third of crude gypsum processed in the
United States, making the United States, by far, the largest producer of gypsum products.
Table 2-3 summarizes, by general use, U.S. consumption of gypsum products in 1988. About
20 percent of consumed gypsum is uncalcined. Uncalcined gypsum (CaS04 • 2H20), crushed and
screened to specifications, is used mostly in portland cement manufacture (to retard the setting time of
concrete) and, to a lesser extent, in agricultural applications. Small amounts of very pure gypsum are
used as fillers and in glassmaking, papermaking, and pharmaceutical applications. Most calcined
gypsum (CaS04 • V2H20) products are prefabricated. Of the prefabricated products, 62 percent is
regular wallboard and 28 percent is fire-resistant wallboard.
2.2	PROCESS DESCRIPTION2 3
A flow diagram for a typical gypsum process producing both crude and finished gypsum
products is shown in Figure 2-1. In this process, gypsum is crushed, dried, ground, and calcined.
2

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TABLE 2-1. CRUDE GYPSUM MINED IN THE UNITED STATES IN 1988a
State
No. of active
mines
Quantity mined,
103 Mg (103 tons)
Arizona, New Mexico
6
522
(574)
Arkansas, Kansas, Louisiana
5
1,504
(1,654)
California
7
1,355
(1,490)
Colorado, Montana, South Dakota, Washington,
Wyoming
9
615
(676)
Indiana, Ohio, New York, Virginia
5
2,035
(2,239)
Iowa
6
1,861
(2,047)
Michigan
5
1,780
(1,958)
Nevada, Utah
7
1,488
(1,637)
Oklahoma
8
1,975
(2,173)
Texas
6
1,766
(1,943)
Total
64
14,900
(16,390)
3 Reference 1. Data may not add to totals shown because of independent rounding.
3

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TABLE 2-2. CALCINED GYPSUM PRODUCED IN THE UNITED STATES IN 19881
State
Active
plants
Quantity calcined,
103 Mg (103 tons)
Arizona, Colorado, New Mexico, Utah
5
612
(673)
Arkansas, Louisiana, Oklahoma
7
1,572
(1,729)
California
6
1,773
(1,950)
Delaware, Maryland, North Carolina, Virginia
6
1,528
(1,681)
Florida
3
1,190
(1,309)
Georgia
3
711
(782)
Illinois, Indiana, Kansas
6
1,385
(1,524)
Iowa
5
1,155
(1,271)
Massachusetts, New Hampshire, New Jersey
4
750
(825)
Michigan
4
614
(675)
Washington, Wyoming
4
663
(729)
Nevada
4
1,116
(1,228)
New York
4
1,001
(1,101)
Ohio
3
441
(485)
Texas
7
1,193
(1,312)
Total
72
15,704
(17,274)
4

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TABLE 2-3. GYPSUM PRODUCTS (MADE FROM DOMESTIC, IMPORTED, AND BYPRODUCT
GYPSUM) SOLD OR USED IN THE UNITED STATES IN 1988a

Quantity,

Use
Mg (tons)
Value, $1,000
Uncalcined:
Portland cement
3,625
(3,987)
47,622
Agriculture and miscellaneous
1,262
(1,388)
27,851
Total
4,886
(5,375)
75,473
Calcined:
Plasters
720
(792)
98,411
Prefabricated products
17,414
(19,155)
1,916,901
Total calcined
18,135
(19,948)
2,015,313
Grand total
23,021
(25,323)
2,090,786
Reference 1. Data may not add to totals shown because of independent rounding.
5

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-------
Not all of the operations shown in Figure 2-1 are performed at all gypsum plants. Some plants
produce only wallboard, and many plants do not produce soil conditioner.
Gypsum ore, from quarries and underground mines, is crushed and stockpiled near a plant. As
needed, the stockpiled ore is further crushed and screened to about 50 millimeters (2 inches) in
diameter. If the moisture content of the mined ore is greater than about 0.5 weight percent, the ore
must be dried in a rotary dryer or a heated roller mill. Ore dried in a rotary dryer is conveyed to a
roller mill, where it is ground to the extent that 90 percent of it is less than 149 micrometers
(100 mesh). The ground gypsum exits the mill in a gas stream and is collected in a product cyclone.
Ore is sometimes dried in the roller mill by heating the gas stream so that drying and grinding are
accomplished simultaneously and no rotary dryer is needed. The finely ground gypsum ore is known
as landplaster, which may be used as a soil conditioner.
In most plants, landplaster is fed to kettle calciners or flash calciners, where it is heated to
remove three-quarters of the chemically bound water to form stucco (CaS04 • '/JTjO). Calcination
occurs at approximately 120° to 150°C (250° to 300°F) and 0.908 megagrams (Mg) (1 ton) of gypsum
calcines to about 0.77 Mg (0.85 ton) of stucco.
In kettle calciners, the gypsum is indirectly heated by hot combustion gas passed through flues
in the kettle, and the stucco product is discharged into a "hot pit" located below the kettle. Kettle
calciners may be operated in either batch or continuous mode. In flash calciners, the gypsum is
directly contacted with hot gases, and the stucco product is collected at the bottom of the calciner.
At some gypsum plants, drying, grinding, and calcining are performed in heated impact mills.
In these mills hot gas contacts gypsum as it is ground. The gas dries and calcines the ore and then
conveys the stucco to a product cyclone for collection. The use of heated impact mills eliminates the
need for rotary dryers, calciners, and roller mills.
Gypsum and stucco are usually transferred from one process to another by means of screw
conveyors or bucket elevators. Storage bins or silos are normally located downstream of roller mills
and calciners but may also be used elsewhere.
In the manufacture of plasters, stucco is ground further in a tube or ball mill and then batch-
mixed with retarders and stabilizers to produce plasters with specific setting rates. The thoroughly
mixed plaster is fed continuously from intermediate storage bins to a bagging operation.
In the manufacture of wallboard, stucco from storage is first mixed with dry additives such as
perlite, starch, fiberglass, or vermiculite. This dry mix is combined with water, soap foam,
accelerators, and shredded paper or pulpwood in a pin mixer at the head of a board forming line. The
slurry is then spread between two paper sheets that serve as a mold. The edges of the paper are
scored, and sometimes chamfered, to allow precise folding of the paper to form the edges of the board.
As the wet board travels the length of a conveying line, the calcium sulfate hemihydrate combines
with the water in the slurry to form solid calcium sulfate dihydrate, or gypsum, resulting in rigid
board. The board is rough-cut to length, and it enters a multideck kiln dryer, where it is dried by
direct contact with hot combustion gases or by indirect steam heating. The dried board is conveyed to
the board end sawing area and is trimmed and bundled for shipment.
7
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2.3 EMISSIONS24
Potential emission sources in gypsum processing plants are shown in Figure 2-1. While
particulate matter (PM) is the dominant pollutant in gypsum processing plants, several sources may
emit gaseous pollutants also. The primary sources of PM emissions include rotary ore dryers, grinding
mills, calciners, and board end sawing operations. Other significant PM sources include the following:
-- Scoring and chamfering
-- Plaster mixing and bagging
-- Conveying systems
-- Storage bins
Uncontrolled PM emissions from these sources are not well quantified. The major sources of gaseous
emissions include dryers and calciners.
Other sources of PM emissions resulting from gypsum processing that may not be classified as
part of the plant operations are primary and secondary crushers, screens, stockpiles, and roads. If
quarrying is part of the mining operation, PM emissions may also result from drilling and blasting.
Gaseous emissions from gypsum processes result from fuel combustion and may include
nitrogen oxides, sulfur oxides, carbon monoxide, and carbon dioxide (C02). Processes using fuel
include rotary ore dryers, heated roller mills, impact mills, calciners, and board drying kilns. Although
some plants use residual fuel oil, the majority of the industry uses clean fuels such as natural gas or
distillate fuel oil. Emissions from fuel combustion may be estimated using emission factors presented
in AP-42 Sections 1.3, 1.4, and 8.14.
2.4 CONTROL TECHNOLOGY2
For control of PM, fabric filters are the most prevalent type of technology. Particulate matter
emissions from some gypsum sources may be controlled with electrostatic precipitators (ESP's).
These sources include rotary ore dryers, roller mills, kettle calciners, and conveying systems.
Although rotary ore dryers may be controlled separately, emissions from roller mills and conveying
systems are usually controlled jointly with kettle calciner emissions. Moisture in the kettle calciner
exit gas improves the ESP performance by lowering the resistivity of the dust.
Equipment for controlling gaseous pollutants is generally not used in gypsum processing. In
large part, this is due to the use of clean fuels by the industry.
It is important to note that emission control devices are frequently needed to collect the
product from some gypsum processes and, thus, are commonly thought of by the industry as process
equipment and not as added control devices.
REFERENCES FOR SECTION 2
1. L. L. Davis, "Gypsum," Minerals Yearbook, Vol. 1, U. S. Department of the Interior, Bureau of
Mines, 1989.
8
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2.	Gypsum Industry - Background Information for Proposed Standards (Draft). U. S. Environmental
Protection Agency, Research Triangle Park, NC, April 1981.
3.	Kirk-Othmer Encyclopedia of Chemical Technology. Volume 4, John Wiley & Sons, Inc., New
York, 1978.
4.	S. Oglesby and G. B. Nichols, A Manual of Electrostatic Precipitation Technology. Part II:
Application Areas. APTD-0611, U. S. Environmental Protection Agency, Cincinnati, OH,
August 25, 1970.
9
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3. GENERAL DATA REVIEW AND ANALYSIS
3.1 LITERATURE SEARCH AND SCREENING
Data for this investigation were obtained from a number of sources within the Office of Air
Quality Planning and Standards (OAQPS) and from outside organizations. The AP-42 Background
Files located in the Emission Inventory Branch (EIB) were reviewed for information on the industry,
processes, and emissions. The Crosswalk/Air Toxic Emission Factor Data Base Management System
(XATEF) and Volatile Organic Compound (VOC) PM Speciation Data Base Management System
(SPECIATE) data bases were searched by SCC code for identification of the potential pollutants
emitted and emission factors for those pollutants. A general search of the Air CHIEF CD-ROM also
was conducted to supplement the information from these two data bases.
Information on the industry, including number of plants, plant location, and annual production
capacities, was obtained from the Minerals Yearbook. Census of Minerals, Census of Manufactures,
and other sources. The Aerometric Information Retrieval System (AIRS) data base also was searched
for data on the number of plants, plant location, and estimated annual emissions of criteria pollutants.
A number of sources of information were investigated specifically for emission test reports and
data. A search of the Test Method Storage and Retrieval (TSAR) data base was conducted to identify
test reports for sources within the gypsum industry. Copies of these test reports were obtained from
the files of the Emission Measurement Branch (EMB). The EPA library was searched for additional
test reports. A list of plants that have been tested within the past 5 years was compiled from the
AIRS data base. Using this information and information obtained on plant location from the Minerals
Yearbook. Census of Manufactures, and Census of Minerals. State and Regional offices were
contacted about the availability of test reports. However, the information obtained from these offices
was limited. Publications lists from the Office of Research and Development (ORD) and Control
Technology Center (CTC) were also searched for reports on emissions from the gypsum industry. In
addition, the Gypsum Association, a representative trade association, was contacted for assistance in
obtaining information about the industry and emissions.
To screen out unusable test reports, documents, and information from which emission factors
could not be developed, the following general criteria were used:
1.	Emission data must be from a primary reference:
a.	Source testing must be from a referenced study that does not reiterate information from
previous studies.
b.	The document must constitute the original source of test data. For example, a technical
paper was not included if the original study was contained in the previous document. If the exact
source of the data could not be determined, the document was eliminated.
2.	The referenced study must contain test results based on more than one test run.
3.	The report must contain sufficient data to evaluate the testing procedures and source
operating conditions (e.g., one-page reports were generally rejected).
10
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A final set of reference materials was compiled after a thorough review of the pertinent
reports, documents, and information according to these criteria.
3.2 EMISSION DATA QUALITY RATING SYSTEM
As part of the analysis of the emission data, the quantity and quality of the information
contained in the final set of reference documents were evaluated. The following data were excluded
from consideration:
1.	Test series averages reported in units that cannot be converted to the selected reporting
units;
2.	Test series representing incompatible test methods (i.e., comparison of EPA Method 5 front
half with EPA Method 5 front and back half);
3.	Test series of controlled emissions for which the control device is not specified;
4.	Test series in which the source process is not clearly identified and described; and
5.	Test series in which it is not clear whether the emissions were measured before or after the
control device.
Test data sets that were not excluded were assigned a quality rating. The rating system used
was that specified by EIB for preparing AP-42 sections. The data were rated as follows:
A—Multiple tests that were performed on the same source using sound methodology and
reported in enough detail for adequate validation. These tests do not necessarily conform to the
methodology specified in EPA reference test methods, although these methods were used as a guide
for the methodology actually used.
B~Tests that were performed by a generally sound methodology but lack enough detail for
adequate validation.
C~Tests that were based on an untested or new methodology or that lacked a significant
amount of background data.
D~Tests that were based on a generally unacceptable method but may provide an order-of-
magnitude value for the source.
The following criteria were used to evaluate source test reports for sound methodology and
adequate detail:
1.	Source operation. The manner in which the source was operated is well documented in the
report. The source was operating within typical parameters during the test.
2.	Sampling procedures. The sampling procedures conformed to a generally acceptable
methodology. If actual procedures deviated from accepted methods, the deviations are well
documented. When this occurred, an evaluation was made of the extent to which such alternative
procedures could influence the test results.
11
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3.	Sampling and process data. Adequate sampling and process data are documented in the
report, and any variations in the sampling and process operation are noted. If a large spread between
test results cannot be explained by information contained in the test report, the data are suspect and are
given a lower rating.
4.	Analysis and calculations. The test reports contain original raw data sheets. The
nomenclature and equations used were compared to those (if any) specified by EPA to establish
equivalency. The depth of review of the calculations was dictated by the reviewer's confidence in the
ability and conscientiousness of the tester, which in turn was based on factors such as consistency of
results and completeness of other areas of the test report.
3.3 EMISSION FACTOR QUALITY RATING SYSTEM
The quality of the emission factors developed from analysis of the test data was rated using
the following general criteria:
A—Excellent: Developed only from A-rated test data taken from many randomly chosen
facilities in the industry population. The source category is specific enough so that variability within
the source category population may be minimized.
B—Above average: Developed only from A-rated test data from a reasonable number of
facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a random
sample of the industries. The source category is specific enough so that variability within the source
category population may be minimized.
C—Average: Developed only from A- and B-rated test data from a reasonable number of
facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a random
sample of the industry. In addition, the source category is specific enough so that variability within
the source category population may be minimized.
D—Below average: The emission factor was developed only from A- and B-rated test data
from a small number of facilities, and there is reason to suspect that these facilities do not represent a
random sample of the industry. There also may be evidence of variability within the source category
population. Limitations on the use of the emission factor are noted in the emission factor table.
E—Poor: The emission factor was developed from C- and D-rated test data, and there is
reason to suspect that the facilities tested do not represent a random sample of the industry. There
also may be evidence of variability within the source category population. Limitations on the use of
these factors are always noted.
The use of these criteria is somewhat subjective and depends to an extent upon the individual
reviewer. Details of the rating of each candidate emission factor are provided in Chapter 4 of this
report.
REFERENCES FOR SECTION 3
1. Technical Procedures for Developing AP-42 Emission Factors and Preparing AP-42 Sections
(Draft). Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency,
Research Triangle Park, NC, March 6, 1992.
12
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4. AP-42 SECTION DEVELOPMENT
4.1	REVISION OF SECTION NARRATIVE
Because of the lack of new information on processes and emissions, only editorial changes
were made to the narrative of Section 8.14.
4.2	POLLUTANT EMISSION FACTOR DEVELOPMENT
Two major changes were made to the emission factors of Section 8.14. First, new emission
factors were developed for C02. Second, the quality of all existing emission factors was reevaluated;
the results of this reevaluation are given in Section 4.2.4 of this document.
All data reviewed for this revision were taken from the existing background file; no new test
reports or emission data could be located. Four test reports were found in the background file that
provided information for the development of new emission factors for C02. Those four references are
described in detail below.
4.2.1 Review of Specific Data Sets
4.2.1.1	Reference 1. This reference is a test report sponsored by EPA's EMB to determine
various emission parameters relating to milling, drying, and packaging operations. The tests were
conducted by Roy F. Weston, Inc., at the Gold Bond Building Products plant in Wilmington, North
Carolina, from May 19 to 27, 1980.
Carbon dioxide emission data were available from four sampling locations: the inlet and outlet
of a fabric filter controlling emissions from a flash calciner, and the inlet and outlet of a fabric filter
controlling emissions from a rotary ore dryer. Three tests were conducted at each location that yielded
C02 emission data.
Because all tests followed EPA protocol, no major problems were reported, and sufficient
process and analytic information was presented for validation of results, this reference was rated A.
4.2.1.2	Reference 2. This reference is a test report sponsored by EPA's EMB to determine
various emission parameters relating to gypsum ore processing. The tests were conducted by Roy F.
Weston, Inc., at the U. S. Gypsum Company's plant at Shoals, Indiana, from June 3 to 19, 1980.
Carbon dioxide emission data were available from the inlet and outlet of a fabric filter
controlling emissions from a gas-fired rotary ore dryer. No other C02 emission data were available.
All tests followed EPA protocol, and no major problems were reported. Ample background
data were also presented, with the exception of a detailed process flow diagram. Since PM was the
only pollutant of concern, no attempt was made to quantify C02 emissions in the calciner combustion
gases—the main source of C02 emissions in the plant. Overall, the tests and the test report were
comprehensive and were rated A.
4.2.1.3	Reference 3. This reference is a test report sponsored by EPA's EMB to gather data
to establish standards for new and substantially modified sources. The tests were conducted by York
13
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Research Corporation at the Gold Bond Building Products plant in Richmond, California, from July 15
to 16, 1980.
Carbon dioxide emission data were available from the inlet and outlet of a fabric filter
controlling emissions from a gas-fired flash calciner. The quality and level of detail of this reference
are identical to those of References 1 and 2. Thus, the data of this report were rated A.
4.2.1.4 Reference 4. This reference is a report of a New Mexico compliance test. The test
was conducted in April 1979 at Western Gypsum's Rosario Facility.
Stack gas from a fabric filter controlling the emissions of a gypsum calciner were tested three
times for PM and C02. The type of calciner was not specified, nor was the process well described.
However, because EPA-standardized methods were followed and field and laboratory data were
presented, this test report was rated B.
4.2.2	Review of XATEF and SPECIATE Data Base Emission Factors
The XATEF and SPECIATE data bases were searched for emission factors relevant to the
gypsum processing industry. No pertinent information was found.
4.2.3	Review of Test Data in AP-42 Background File
As mentioned above, the AP-42 background file was the only source of data for this revision.
Four references—all emission test reports—were found in the file that provided emission data for C02.
Three of these references were sponsored by EPA and were rated A. One reference was a State
compliance test and was rated B.
4.2.4	Results of Data Analysis
Section 8.14 was revised because it contained air pollution emission factors for only filterable
PM. In this revision, emission test reports in the background file were reviewed for data relevant to
C02 emissions. Also, the quality of existing emission factors was reevaluated.
Four test reports in the background file were found to contain C02 emission data. Table 4-1
presents a summary of this data, and Table 4-2 presents a summary of the emission factors developed
from this data. Although the data are of good quality, they do not represent a good sample of the
gypsum industry. Thus, all new emission factors developed in this revision are rated D.
Based upon a review of the gypsum processing industry as described in Reference 5, it was
determined that the existing emission factors did not represent an accurate sample of the gypsum
industry. In the development of any one emission factor, no more than five test reports, representing
five different plants, were used. The total number of gypsum plants is at least 73. Therefore, all
emission factors previously developed for Section 8.14 were down-rated from either B or C to D.
Particle size distribution data in the 1983 version were also down-rated to D.
14
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TABLE 4-1. SUMMARY OF TEST DATA FOR GYPSUM PROCESSING
Source
Control
device
Pollutant
No.
of
runs
EF range,
kg/Mg
(lb/ton)a
EF average
kg/Mg
(lb/ton)a
Data
rating
Ref.
No.
Flash
calciner
None
C02
3
60-65
(120-130)
60
(120)
A
1
Flash
calciner
(fuel
unknown)
Fabric
filterb
co2
3
60-65
(120-130)
60
(120)
A
1
Rotary ore
dryer
None
co2
3
21-25
(41-49)
23
(45)
A
1
Rotary ore
dryer
Fabric
filterb
co2
3
15
(29-30)
15
(30)
A
1
Rotary ore
dryer
(gas-fired)
Cyclone0
co2
3
3.9-4.8
(7.8-9.6)
4.3
(8.6)
A
2
Rotary ore
dryer
(gas-fired)
Cyclone/
fabric
filter1"
co2
3
3.5-4.5
(7.0-8.9)
4.1
(8.1)
A
2
Flash
calciner
(gas-fired)
None
co2
3
42-49
(84-98)
45
(90)
A
3
Flash
calciner
(gas-fired)
Fabric
filterb
co2
3
48-55
(95-110)
50
(99)
A
3
Calciner
Fabric
filterb
co2
3
55-75
(110-150)
65
(130)
B
4
aEmission factors presented as pounds of pollutant emitted per ton of yield.
bFabric filters generally achieve negligible control of C02.
cCyclones generally achieve negligible control of C02.
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TABLE 4-2. SUMMARY OF EMISSION FACTORS FOR GYPSUM PROCESSING
Source
Control
device
Pollutant
No. of
tests
Average
EF, kg/mg
(lb/ton)a
Emission
factor rating
References
Calciner (110)
None
O
O
5
55
D
1, 3,4
Rotary ore dryer
None
O
O
4
12
(23)
D
1,2
aEmission factors presented as pounds of pollutant emitted per ton of yield.
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REFERENCES FOR SECTION 4
1.	Source Emissions Test Report. Gold Bond Building Products. EMB-80-GYP-1, U. S.
Environmental Protection Agency, Research Triangle Park, NC, November 1980.
2.	Source Emissions Test Report, United States Gypsum Company. EMB-80-GYP-2, U. S.
Environmental Protection Agency, Research Triangle Park, NC, November 1980.
3.	Source Emissions Tests, Gold Bond Building Products. EMB-80-GYP-5, U. S. Environmental
Protection Agency, Research Triangle Park, NC, December 1980.
4.	Particulate Analysis of Calcinator Exhaust at Western Gypsum Company. Kramer, Callahan and
Associates, Rosario, NM, April 1979.
17
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