EPA-600/2-77-107a
July 1977
SOURCE ASSESSMENT:
AGRICULTURAL OPEN BURNING
State of the Art
by
C. T. Chi and D. L. Zanders
Monsanto Research Corporation
1515 Nicholas Road
Dayton, Ohio 45407
Contract No. 68-02-1874
ROAP No. 21AXM-071
Program Element No. 1AB015
EPA Project Officer: Dale A. Denny
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
Protect Aon
, Library
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PREFACE
The Industrial Environmental Research Laboratory (IERL) of
EPA has the responsibility for insuring that pollution con-
trol technology is available for stationary sources to meet
"~~ the requirements of the Clean Air Act, the Federal Water
,,/ Pollution Control Act and solid waste legislation. If control
technology is unavailable, inadequate, uneconomical or social-
ly unacceptable, then financial support is provided for the
development of the needed control techniques for industrial
and extractive process industries. The Chemical Processes
%
Branch of the Industrial Processes Division of IERL has the
•x" responsibility for investing tax dollars in programs to
5
C-5 develop control technology for a large number (>500) of
operations in the chemical industries.
Monsanto Research Corporation (MRC) has contracted with
EPA to investigate the environmental impact of various indus-
tries which represent sources of pollution in accordance with
EPA's responsibility as outlined above. Dr. Robert C. Binning
serves as MRC Program Manager in this overall program entitled,
"Source Assessment," which includes the investigation of sources
in each of four categories: combustion, organic materials,
inorganic materials, and open sources. Dr. Dale A. Denny of
the Industrial Processes Division at Research Triangle Park
serves as EPA Project Officer. Reports prepared in the Source
Assessment Program are of two types: Source Assessment
Documents, and State of the Art Reports.
111
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Source Assessment Documents contain data on emissions from
specific industries. Such data are gathered from the litera-
ture, government agencies and cooperating companies. Sampling
and analysis are also performed by the contractor when the
available information does not adequately characterize the
source emissions. These documents contain all of the infor-
mation necessary for IERL to decide whether a need exists to
develop additional control technology for specific industries.
State of the Art Reports include data on emissions from
specific industries which are also gathered from the litera-
ture, government agencies and cooperating companies. However,
no extensive sampling is conducted by the contractor for such
industries. Sources in this category are considered by EPA
to be of insufficient priority to warrant complete assessment
for control technology decision making. Therefore, results
from such studies are published as State of the Art Reports
for potential utility by the government, industry, and others
having specific needs and interests.
This study was undertaken to provide information on air
emissions from agricultural open burning. In this project,
Dr. R. A. Venezia served as EPA Project Leader.
IV
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CONTENTS
Section Page
Preface iii
Figures vi
Tables vii
Symbols viii
I Introduction 1
II Summary 2
III Source Description 5
A. Characteristics of Agricultural
Open Burning 5
B. Process Description 6
C. Factors Affecting Emissions 17
D. Geographical Distribution 18
IV Emissions 22
A. Selected Pollutants and their
Characteristics 22
B. Emission Factors 25
C. Definition of Representative Source 28
D. Source Severity 29
V Pollution Control Technology 38
A. State of the Art 38
B Future Considerations 45
VI Growth and Nature of the Source 46
VII Appendices 48
A. Sample Calculations for Data on
Burning Shown in Table 4 49
B. Equation Derivation and Input Data 52
VIII Glossary of Terms 58
IX Conversion Factors and Metric Prefixes 60
X References 62
v
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FIGURES
Number
1 Relative trace element content of dry
grass stubble. 11
2 Open burning of solid fuel. 11
3 Pyrolytic synthesis of B(a)P. 15
4 Illustration of agricultural open burning
seasons in the ten states with annual
burning greater than 400,000 metric tons. 21
5 Schematic diagram of mobile field sanitizer. 42
VI
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TABLES
Number Page
1 States Exempting or Not Regulating
Agricultural Open Burning 7
2 States Regulating Agricultural Open
Burning 8
3 Typical Analysis and Heating Value
of Straw 9
4 Summary of Agricultural Open Burning
Data (1973) 20
5 Characteristics of Emissions from
Agricultural Open Burning 24
6 Published and Calculated Emission Factors
* for Agricultural Open Burning 27
7 Maximum Ground Level Concentration and
Severity Factor of Different Emissions 30
8 Total Emissions of Criteria Pollutants
Resulting from Agricultural Open Burning
by State and Nationwide 34
9 Ratio of Criteria Pollutant Emissions
Resulting from Agricultural Open Burning
to Total State and Nationwide Emissions 35
10 Area and Population Exposed to Pollutants
for which x~/F > 1 and x"/F > 0.1 37
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SYMBOLS
Symbol Definition
c Flame height
e 2.72
F Primary ambient air quality standard for criteria
pollutants; corrected TLV (i.e., TLV • 8/24 • 1/100)
for noncriteria pollutants
H Effective emission height
k A system parameter for estimation of effective
emission height
Q, Heat emission rate relative to ambient temperature
Q Mass emission rate
m
max
max
Source severity =
j.
Averaging time
Burning duration
Short-term averaging time (= 3 min)
Average wind speed
Maximum ground level concentration of a pollutant
Time-averaged maximum ground level concentration
of pollutant emitted from a representative source
Vlll
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SECTION I
INTRODUCTION
Agricultural open burning in the United States is utilized
for field sanitation, residue removal and residue disposal.
This practice constitutes a source of air pollution. The
objective of this work was to assess the environmental impact
of agricultural open burning and to produce a State of the
Art Report summarizing available data on air emissions from
this source. This document was prepared by acquiring and
analyzing information on: (1) the basic agricultural open
burning process; (2) source sites; (3) emissions produced;
(4) effects on air quality; (5) the state of the art and
future considerations in pollution control technology; and
(6) the projected growth and anticipated technological
developments in this practice.
In this study, the effects on air quality resulting from
agricultural open burning were determined using estimated
emission factors derived from limited emission data available
in the literature. Major areas identified as needing further
characterization were: (1) sampling and analysis of poly-
cyclic organic matter (POM) emissions, (2) study of emissions
from all major types of agricultural burning, such as soybean
and tobacco residue, and (3) measurement of trace element
emissions.
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SECTION II
SUMMARY
Agricultural open burning is usually practiced for the pur-
pose of field sanitation, residue removal, and residue
disposal. It was estimated that the amount of agricultural
open burning totaled 13.2 x 106 metric tons (14.6 x 106 tons)
in 1973. Most of the burning occurred in the west and south
coastal states, and Hawaii. The combined tonnage of agri-
cultural open burning in California, Louisiana, Florida and
Hawaii constituted 59% of the national total in 1973.
Burning of agricultural wastes involves a series of repeated
pyrolysis and oxidation steps. Due to the poor mixing between
fuel and air and the quenching of combustion gases by sur-
rounding air, products of incomplete combustion such as smoke,
gaseous hydrocarbons, carbon monoxide, and polycyclic organic
matter are emitted in large amounts. Organic nitrogen com-
pounds in the fuel and part of the nitrogen gas present in
the high-temperature flame are converted to nitrogen oxides
during the burning process. In addition, trace metal elements
are also present in the effluent gas because of their content
in the wastes.
Emissions from agricultural open burning constitute 0.61%, 0.50%,
0.65%, and 0.06% of the national emissions of particulates,
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hydrocarbons, carbon monoxide, and nitrogen oxides, respec-
tively.3 The following 15 states have emissions of at least
one criteria pollutant from agricultural open burning which
exceed 1% of the state total emissions of that pollutant:
California, Florida, Georgia, Hawaii, Kansas, Louisiana,
Mississippi, Montana, Nebraska, North Carolina, North Dakota,
Oklahoma, Oregon, South Carolina, and South Dakota.9
Source severity (S) was defined to indicate the hazard
potential of the emission source:
_ xmax
S ~ ~f
where xmax is the time-averaged maximum ground level concen-
tration of each pollutant emitted from a representative
source of agricultural open burning, and F is the primary
ambient air quality standard for criteria pollutants and is
a "corrected" threshold limit value (TVL®«8/24•1/100) for non-
criteria pollutants. The representative source was defined
as an agricultural field of 105 m2 (25 acres) with a fuel
loading of 6.7 x 10"1* metric tons/m2 (3 tons/acre), a fire
propagation rate of 4.6 m/min (15 ft/min), and a fuel heating
value of 12.56 MJ/kg (5,400 Btu/lb). In agricultural open
burning, the source severity was found to be 1 for hydrocar-
bons, 0.2 for benzo(a)pyrene (B(a)P)," and less than 0.1 for
other pollutants. The population influenced by an average
ground level concentration (x) for which X/F>1 and X/F>0.1
is far below 20,000 persons for each of the above-mentioned
pollutants.
aBased on assumed emission factors.
'other reported POM compounds, whici
carcinogens, are not included in this study.
Other reported POM compounds, which are not suspected
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Control technology in- agricultural open burning consists of
practicing fire and fuel management to reduce the emission
of pollutants. The two most important factors that can be
controlled to minimize the emissions are backfire burning
and moisture content of the fuel. In addition to the reduc-
tion of emissions mentioned above, the effect of emissions
can be minimized by using meteorologically controlled
burning to maximize the dispersion of pollutants.
Among the alternatives to controlling emissions from open
burning are the combination of mobile field sanitation and
straw utilization, and incorporation of wastes into the soil,
The latter requires chemical control of weeds, pests, and
disease, and the potential environmental impact from these
chemicals must be considered.
Despite the continuing growth in crop harvest, agricultural
open burning has been declining since 1969. EPA's estimate
of burning was 29 x 106 metric tons (32 x 106 tons) of
residues for 1969. This figure dropped to 13.2 x 106 metric
tons (14.6 x 106 tons) for 1973 due to increasing concern
about air pollution from open burning, and development of
waste utilization, chemical sanitation, and modern tillage
and fertilization practices.
Although agricultural open burning will decline, burning
in several areas of the country will continue (due to
unavailability of alternatives) until more effective and
less harmful chemical control of pests, weeds, and disease
is available and until other economically viable techniques
for residue utilization or disposal are developed.
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SECTION III
SOURCE DESCRIPTION
A. CHARACTERISTICS OF AGRICULTURAL OPEN BURNING
Agricultural open burning is a portion of the overall open
burning segment of combustion sources of air pollution in
this country. This source of emissions includes the burning
of residues of field crops, row crops, and fruit and nut
crops for at least one of the following reasons: (1) resi-
due removal and disposal at low cost; (2) preparation of
farmlands for cultivation; (3) clearing of vines or leaves
from field to facilitate harvest; (4) disease control;
(5) direct weed control by incineration of weed seeds and
some weed plants; (6) indirect weed control by providing
clean soil surface for soil-active herbicides; and (7) de-
struction of certain mites, insects, and rodents. This
study of agricultural open burning does not include prescribed
burning which is defined as the use of controlled fire in
forests and on ranges to reduce the possibility of wildfire
and for other management goals.
Most of the crop residues are usually burned just before or
sometime after harvesting. Burning of orchard prunings and
natural attrition losses in the San Francisco Bay Area of
California is limited to the winter and early spring months
when the meteorological conditions permit rapid dispersal
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and when oxidant levels are normally low. The duration of
burning for each field ranges from a few minutes to several
hours per year, depending on the size of the field, type of
waste, and environmental conditions.
Because of the unavailability of alternatives which can be
applied economically and used to serve many purposes, the
burning of agricultural wastes still remains as a common
practice despite the growing concern about its contribution
to air pollution. The 12 states shown in Table 1 either
exempted or did not control agricultural open burning as
of 1974. In the other 36 states in the continental U.S.,
burning is controlled in varying degrees.1 For example,
New Jersey, which prohibits all open burning, has the most
restrictive regulations. Of the remaining states where some
control is imposed, 25 regulate agricultural open burning
directly while 10 regulate it only if a nuisance or hazard
is involved. Table 2 gives a summary of how each of these
states regulates agricultural open burning, how long the
regulations have been in effect, and whether or not a
regulation change is contemplated.
B. PROCESS DESCRIPTION
1. Source Composition
The types of agricultural wastes subject to open burning
include a variety of residues such as rice straw and stubble,
barley straw and stubble, wheat residues, orchard prunings
Walton, J. W. Disposal of Agricultural Waste by Controlled
Burning - A Regulatory Viewpoint. (Presented at Special
Conference, Air Pollution Control Association, Proc. Control
Technology for Agricultural Air Pollutants. Memphis, Tenn.
March 1974.)
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Table 1. STATES EXEMPTING OR NOT REGULATING
AGRICULTURAL OPEN BURNING3
State
Arkansas
Iowa
Kansas
Kentucky
Louisiana
Maine
Nebraska
Rhode Island
Tennessee
Virginia
West Virginia
Wyoming
Exempt
X
X
X
X
X
X
X
Not
regulated
X
X
X
X
X
Regulation
change
pending
No
No
No
No
Yesb
No
No
No
No
No
No
After Reference 1, through 1974.
Open burning regulations became effective July 1, 1975.
and natural attrition losses, grass straw and stubble,
potato and peanut vines, tobacco stalk, soybean residues,
hay residues, sugarcane leaves and tops, and farmland grass
and weeds. These various residues consist of chemically
different components called cellulose, hemicellulose, lignin
and a group of extractables (oils, pigments, minerals, and
other organic substances) in different proportions. Another
variation in the source composition is the moisture content
between different types of waste and in the same type of
waste due to different dryness. A typical ultimate analysis
of straw is shown in Table 3.2
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Table 2. STATES REGULATING AGRICULTURAL OPEN BURNING3
State
Alabama
Arizona
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
South Carolina
South Dakota
Texas
Utah
Vermont
Washington
Wisconsin
Type regulation
Directly
X
X
xb
X
X
X
X
X
X
X
X
X
X
X
X
As nuisance
or hazard
X
X
Xc
X
X
Regulated
since
1972
1969
1972
1970
1970
1971
1968
1969
1970
1970
1969
1967
1967
1970
1974
1968
1971
1971
1967
ALL OPEN BURNING PROHIBITED 1959
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
1971
1971
1970
1972
1972
1975
1962
1968
1972
1968
1969
1973
1969
Regulation
change pending
No
No
No
No
No
No
No
No
No
No
No
Yesd
No
Yes
No
No
No
Yese
No
Yesf
No
Yes
No
No
Yes
No
Yes9
No
No
h
Yes
No
Yes
Yes
No
No
After Reference 1.
Burning of ditches, fence rows, and weeds loosely regulated until evaluation can
be made into whether or not it is a significant source.
Open burning in grass-seed industry regulated directly.
Legislature passed bill suspending air quality control regulations for one
month each year for purpose of agricultural management.
Considering adding a one mile distance limit in urban areas.
fLegislature is acting to ease restrictions and permit agricultural burning. All
open burning is currently prohibited.
^Open burning prohibited in Willamette Valley since January 1, 1975. Legislature
may ease this restriction and permit grass seed field burning in some way.
Considering a permit system as soon as more manpower available.
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Table 3. A TYPICAL ANALYSIS AND HEATING VALUE OF STRAW2
Carbon
Hydrogen
Oxygen
Nitrogen
Moisture
Ash
Heating value
36.00%
5.00%
38.00%
0.50%
15.75%
4.75%
2,997 kcal/kg or 12.56 MJ/kg
(5,430 Btu/lb)
The chemical composition of the waste can also be subdivided
into combustible and noncombustible components. The latter
include inorganic ash and moisture and these are often
referred to as inerts. They do not contribute measurably to
the energy released upon combustion, but act as a thermal
sink and influence the peak temperature achieved during the
burning process. The combustible fraction of the solid fuel
(the waste subject to burning) consists of volatile and non-
volatile portions. The volatile portion is composed of low
molecular weight hydrocarbon compounds. The nonvolatile
portion contains high molecular weight carbonaceous material
and can be denoted by C H , usually with x » y.
Organic species other than those containing only carbon and
hydrogen (as mentioned above) may be present in either or
both the volatile and nonvolatile combustible fractions.
Examples are organically bound nitrogen, sulfur, and halo-
gens. Trace metal elements are also present in the waste.
2 Johnson, A. J., and G. H. Auth. Fuels and Combustion
Handbook. McGraw-Hill, New York, 1951.
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Their reported relative concentrations in dry grass stubble,
normalized to 10,000 for titanium, are shown in Figure I.3
2. Process Mechanism
The burning of agricultural wastes involves a series of
repeated steps. First, the volatiles near the surface are
evolved and burned, and then the residual solid nonvolatile
combustible structure burns out. As fresh unreacted solid
is exposed, these two steps are repeated.
The mechanism involved in the evolution and burning of vola-
tiles is shown in Figure 2. There are two types of reactions
taking place in this step. They are pyrolysis in the pre-
combustion zone and oxidation in the mixing and combustion
zone.4 In the precombustion zone, pyrolysis takes place in
the absence of oxygen. The driving force for these pyrolytic
reactions is the countercurrent transport of thermal energy
from the mixing and combustion zone.
Pyrolysis is a combination of thermal cracking and conden-
sation, and can occur in both the solid and vapor phases.5
In the solid phase, hemicelluloses decompose first, then the
cellulose, and then the lignin. The extractables evolve on
3Shum, Y. S., and W. D. Loveland. Atmospheric Trace Element
Concentrations Associated with Agricultural Field Burning
in the Willamette Valley of Oregon. Atmospheric Environ-
ment, £:645, December 1974.
^Edwards, J. B. Combustion - Formation and Emission of Trace
Species. Ann Arbor Science, Ann Arbor, Michigan, 1974.
5Orning, A. A. The Principles of Combustion. In: Principles
and Practices of Incineration, Corey, R. C. (ed.). New York,
Wiley-Interscience, 1969.
10
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10
10
o
o
10
o
cc
10
10
-1
GRASS STUBBLE
Al
Fe
Na
Ti
Mn
Cl
Cr
Ce
La
Co
Sc
Sm
Yb
Hf
Br
As
Eu
Lu
Sb
Hg
Figure 1. Relative trace element content of dry grass
stubble.3
Reprinted with permission from W. D. Loveland, Atmospheric
Trace Element Concentrations Associated with Agricultural
Field Burning in the Willamette Valley of Oregon, December
1974, Pergamon Press.
PRECOMBUSTIONZONE I MIXING AND COMBUSTION ZONE
PRIMARY
K- COMBUSTION
REGION
SOLID PHASE
PYROLYSIS
P§AE
PYROLYSIS
PRIMARY AIR
<
SECONDARY AIR
RECEDING INTERFACES
COLD AIR
V
POST FLAME
REGION
Figure 2. Open burning of solid fuel.4
Reprinted with permission of Ann Arbor Science Publishers, Inc.
11
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the basis of their volatility and reactivity at the higher
temperature.6 The volatile components are vaporized and
carried away from the solid surface where they mix with the
surrounding air. A diffusion flame is established within
the primary combustion region where the mixing of combustibles
and oxygen forms a flammable mixture.
Due to the poor mixing between air and fuel in agricultural
open burning, there is a region between the fuel surface and
the diffusion flame which contains little or no oxygen.
Heating of the fuel vapors within this space promotes gas
phase pyrolytic reactions. The reactions involved in this
space consist of a competition between thermal cracking,
producing lighter and more stable products, and condensa-
tion reactions, producing heavier molecules. As the con-
densation goes on, the heavier molecules may be condensed
to liquid aerosols which are then converted to solid particles
eventually approaching carbon, and hydrogen is produced and
burned in the diffusion flame.
Once the particles are formed, their oxidation is a relatively
slow process (due to the heterogeneous reactions involved)
and the time that it takes for these carbonaceous particles
to pass through the oxidation region may be insufficient to
oxidize them. In the case of open burning, rapid quenching
of the combustion gases by the huge surrounding volume of
cold air further enhances the incompleteness of combustion,
thus permitting emission of a large amount of smoke and
unburned gaseous hydrocarbons in the effluent gas.
GYamate, G. Development of Emission Factors for Estimating
Atmospheric Emissions from Forest Fires. Publication No.
EPA 450/3-73-009, October 1972.
12
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The oxidation of unburned gaseous organic compounds and
smoke particles continues in the post flame region, provided
that sufficient secondary oxygen is present and the tempera-
ture is high enough. However, due to the quenching by large
unrestricted volumes of cold air, this post flame region
becomes relatively small in open burning.
Once the volatiles present near the fuel surface have been
evolved, oxidation of the nonvolatile portion of combustible
material (often referred to as char) occurs by a different
mechanism. This mechanism involves oxygen diffusion to a
gas-solid interface where oxidation occurs. This process of
"burnout" is a slow one since it involves several sequential
mass and heat transfer steps. No smoke is produced in this
step of burning.
Once the residual solid structure is burned out and the
fresh unreacted solid is exposed, the process described
above is repeated until all the wastes are burned.
3. Formation of Pollutants
The poor mixing between fuel and air and the quenching of
combustion gases by surrounding air contribute to the
emission of smoke, gaseous organic compounds, and carbon
monoxide, all of which are products of incomplete combustion.
Smoke is a suspension of very small (submicron) particulates
consisting of solid and liquid aerosols. The liquid aerosols
are white to brown in color and are formed from partial
condensation in the precombustion zone. These particles are
emitted in the effluent gas because they are neither ignited
nor heated to sufficient temperature to cause continuing
pyrolysis. Solid aerosols are black in color and are formed
when the liquid aerosols are heated to sufficient temperature
13
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in the absence of oxygen to cause continuing pyrolysis into
a solid form.
Another class of pollutants which may be contained in smoke
is polycyclic organic matter (POM), sometimes reported by
others as polynuclear hydrocarbons. These heavy hydrocarbons,
which may have carcinogenic properties, may be formed by a
sequence of pyrolytic reactions in the precombustion zone
shown in Figure 2. An example of POM formation is illus-
trated in Figure 3 where two paths are shown for the syn-
thesis of the polycyclic aromatic benzo(a)pyrene.^• 7 The
relative tendency for hydrocarbons to form polycyclic
species is:
aromatics > cycloolefins > olefins > paraffins
POM's may be emitted as liquid aerosols, condensed on the
solid particulates, or vaporized and remain as gases until
condensed in the sampling apparatus.
In addition to the particulates of submicron size mentioned
above, particulate matter can also be derived from fly ash
and fragments of partially burned fuel. However, these
particulates are not generally present in sufficient number
of particles per unit volume to produce dense smoke.5
Thermal cracking and condensation reactions are also the
source of a large variety of organic compounds. Any of
these compounds that are either not burned or incompletely
burned and are not condensed to smoke may escape as gaseous
organic compounds. These compounds include aldehydes,
7Chakroborty, B. B., and R. Long. The Formation of Soot and
Aromatic Hydrocarbons in Diffusion Flames - Part III.
Combustion and Flame, 12^:469, May 1968.
14
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15
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amines, organic acids, ketones, and gaseous hydrocarbons.8"11
Gaseous hydrocarbons include saturates, unsaturates (olefins,
acetylenes, and aromatics) , and possibly gaseous polynuclear
hydrocarbons. Olefins and aromatic compounds are the main
organic constituents in photochemical smog.
Carbon monoxide is formed when the air supply in the combustion
zone is below the theoretical requirement. Carbon monoxide
also forms by the gasification of smoke particles. Gasi-
fication reactions become possible when the environment in
the post-flame area becomes reduced due to insufficient
secondary oxygen supply. The reactions can be represented
by the following two equations:
C, . + C02 -»• 2CO (III-l)
C, . + H20 -»- CO + H2 (III-2)
\ s )
Note that for simplicity the particulate is depicted as
pure carbon. In reality it is CH with y « 1.0.
The residues also have a small content of organic nitrogen
compounds. Upon combustion these nitrogen compounds will be
oxidized to nitrogen oxides. Due to the high temperature of
8Gerstle, R. W., and D. A. Kenmitz. Atmospheric Emissions
from Open Burning. J. Air Poll. Cont. Assoc., 17:324-327,
May 1967.
^Sandburg, D. V., S. G. Pickford, and E. F. Darley. Emissions
from Slash Burning and the Influence of Flame Retardant
Chemicals. J. Air Poll. Cont. Assoc., 2_5:278, March 1975.
lODarley, E. F., F. R. Burleson, E. H. Mateer, J. T.
Middleton, and V. P. Osterli. Contribution of Burning of
Agricultural Wastes to Photochemical Air Pollution. J. Air
Poll. Cont. Assoc., 1^:685, December 1966.
11Boubel, R. W., E. F. Darley, and E. A. Schuck. Emissions
from Burning Grass Stubble and Straw. J. Air Poll. Cont.
Assoc., 19^497, July 1969.
16
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the flame, nitrogen oxides are also formed by the fixing of
nitrogen present in the air.
In the burning process the moisture contained in the waste
is simply evaporated along with the combustible volatiles.
A fraction of the energy produced by combustion must be
expended to vaporize this moisture and heat it to flame
temperature. This results in a reduction in flame temperature,
and thus a decrease in the formation of nitrogen oxides and
an increase in the particulate emissions.
For high moisture contents, especially associated with wet
pockets of waste, the vapor pressure of the water may almost
equal the atmospheric pressure. Under this extreme condition
oxygen is almost excluded from the area near the flame.
This insufficiency of oxygen for combustion enhances the
emission of pollutants.
C. FACTORS AFFECTING EMISSIONS
Factors affecting the completeness of burning and emission
of pollutants can be separated into the three categories
listed below where the factors of major importance are
indicated by an asterisk (*).
Environmental variables
Air temperature
Soil moisture
Relative and/or absolute humidity
*Wind speed and direction
Fuel conditions
Type of fuel (chemical composition)
*Waste moisture content
Density of fuel, kg/m3 (lb/ft3)
17
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Fire management
*Backfire or headfire
*Fuel loading, kg/m2 (lb/ft2) .
D. GEOGRAPHICAL DISTRIBUTION
Open burning is one of the principal methods for disposing
of agricultural wastes. As late as 1968, it was the most
widely accepted method especially in the west, due to its
low cost and effectiveness in control of weeds, pests, and
disease. However, open field burning has been eliminated
in some areas of the country because of the increasing
awareness of its contribution to air pollution, the
development of waste utilization, chemical control of weeds,
pests, and disease, and modern tillage and fertilization
practices.
According to a survey made for EPA in 1974, there were 13
states where agricultural open burning was negligible.12
Since then, Oregon has banned all open burning (as of
January 1, 1975). However, there are strong indications
that the state legislature of Oregon will reverse their
decision and burning will continue for several years.3'13
Table 4 gives a summary of agricultural open burning data
for the 37 states where agricultural open burning is practiced
significantly. Data on acres burned and fuel loading were
obtained from Reference 12 for 16 states; and the amount of
burning for 2 states was obtained from References 14 and 15,
as shown in the table. These data were reported in non-
metric units.
i2Yamate, G. Emissions Inventory from Forest Wildfires,
Forest Managed Burns, and Agricultural Burns. Publication
No. EPA-450/3-74-062, November 1974.
13Personal communication. H. M. Patterson. Department of
Environmental Quality, Portland, Oregon, 1975.
18
-------
The total amount of burning for the remaining 19 states was
determined from the difference between national total16 and
the total of the above-mentioned 18 states. This total
amount was then proportionated according to the crop acre-
age for each state to obtain the amount of burning for that
state. Sample calculations of the amount burned and the
area burned are shown in Appendix A.
As shown in Table 4, California, Louisiana, Florida, and
Hawaii are the major agricultural open burning states, each
burning in excess of 1,000,000 metric tons/yr. The tonnage
of burning in these states constitutes 59% of the national
total. As shown in Table 4, six states burn 400,000 to
1,000,000 metric tons/yr, twelve states burn 100,000 to
400,000 metric tons/yr, and fifteen states burn less than
100,000 metric tons/yr. Most of the burning occurs in the
west and south coastal states.
Since considerable agricultural open burning occurs in
states with low population density (such as North Dakota and
Kansas), a simple exposure factor was used to indicate the
combination effect of amount of burning and state population,
The exposure factor was defined as follows:
Exposure factor = (amount burned in the state,
in thousands of metric tons
per year) x (state population
fraction) (III-3)
The state population fraction is the ratio of the state
population to the national population. The exposure factor
represents the relative significance of agricultural open
burning for each state and is shown in Table 4.
19
-------
Table 4. SUMMARY OF AGRICULTURAL OPEN BURNING DATA (1973)
State
Alabama
a
Arizona
Arkansas
Ca lif orn la
Colorado
Delaware
f londa
Georgia
Hawaii
Idaho
Kansas
Kentucky
Louisiana
Maine
ID7 m2
36.
4.
26.
309.
32.
0.
109.
39.
44.
4.
243.
13.
142.
15.
Maryland i 0.
a
a
V i ch igan
a
M innesota
M 1 SSI SS 1 ppl
a
M i ssour i
Montana
Nebraska9
Nevada
New Mexico
North Carolina
North Dakota3
Ohioa
Oklahoma3
Oreqon
Pennsy Ivan La
^outh Carolina
South Dakota
Tennessee3
V i rqinia
Wnsh inqton
a
W i scons i n
Wyoming
National Total
0 .
21.
61.
138.
40.
34.
67.
0.
0.
138.
97.
32.
36.
107.
15.
8
59.
14.
9.
57.
32.
1
2,350
Area burned,
/yr (TO3 acre/yr)
( 89. ) '2
5 ( 11. )
( 64. )
( 763. ) 12
( 79. )
1 ( .2)12
( 270. I1'
5 ( 974. }1;
7 ( '08. )"
8 ( 12. )"
( 600. ) "
l 32. )
( 350. ) '-
( 36. ) 1?
6 ( 1.5) '"
6 { 1.5)
( 51. )
;> ( 151. i
( 340. ) ' '
5 ( 100. )
( 84. ) ''•
6 ( 167. )
8 ( 2 . ) ' "'
5 ( 1. ) ' "
( 341. ) "
( 242. }
( 79. )
( 89. )
( 264. ) I2
( 38. )
( 21. )
( 146. )
( 34. )
5 ( ?4. )
( 141. )"
I 80. )
3 ! 18. )
{ 5,804. )
fuel loading,
10"'1 metric ton'5/ir,2
( ton/aci e )
j
4
4
7
4
22
16
2
27
4
?
4
13
U
4
4
4
4
4
4
4
7
4
4
4
4
4
4
4
4
4
4
4
4
4
4
< 2) 1?
( 2)
( ?)
( 3)12
< 2)
(10) 1?
( 7) 1?
( I)12
(12) l'
1 2) "
( 1) 12
( 2)
( 6) 1J
( I)1'
( 5) 12
( 2)
( 2)
( 2)
( 2 ) < z
( 2)
( 2)'*
( 2)
( 3) "
( 2)l5
I 2)1?
( 2)
( 2)
( 2)
( 2)1?
( 2)
( 2)
( 2)
( 2)
( 2)
( 2)12
( 2)
( 2)
Amoui
103 metric
161
20
1J5
2,075
143
2
1,716
883
1,175
22
544
58
1,904
33
7
-,
93
274
617
181
152
303
5
2
619
438
142
161
479
69
38
265
61
4 i
256
145
3^
13,242
t burned,
tori/yr (103 ton/yr)
( 178}
( 22)
( 128)
Exposure
factor
2.74
0.18
1.09
( 2,289) ! 302.9
( 158)
( 2)
( 1,890)
( 974)
1.57
0.01
57.49
20.0
( 1,296) 4.47
( 22} 0.08
( 600) 6.04
( 64) i 0.93
( 2,100)
( 36)
( 8)
( 3}
( 102)
( 302)
( 680)
( 200)
( 168)
( 334)
( 6)
( 2)
( 682)
( 484)
I 158)
( 178)
( 528)
( 76)
( 42)
( 292)
( 68)
( 48)
( 282)
( 160)
( 38)
(14,600) 16
34.27
0.17
0.1
0. 1
4.1
5.15
6.79
4.16
0.52
2.21
0.01
0.01
15.5
1.31
7.47
2.03
4.0
4.02
0.49
0 . 87
1.2
0.99
4.30
3.16
0.06
Calculations shown in Appendix A.
!'(Air Pollution Emission Inventory for the State of Montana. NTIS Publication No. PB 204 383, 1971.
1 'Air Pollution Emission Inventory for the State of New Mexico. NTIS Publication No. PB 204 384, 1971.
1 '-Personal communication. Charles Mann. OAQPS, EPA, Durham, North Carolina, 1975.
20
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The seasons for burning and the types of waste burned in the
10 states with annual burning greater than 400,000 metric tons
(441,000 tons) are shown in Figure 4.
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT MOV DEC
CALIFORNIA
CALIFORNIA
CALIFORNIA
FLORIDA
FLORIDA
GEORGIA
GEORGIA
GEORGIA
HAWAII
KANSAS
LOUISIANA
- RICE RESIDUES17
• BARLEY RESIDUES17
- ORCHARD PRUNINGS & ATTRITION LOSS1
- SUGAR CAME RESIDUES12' 18
- ORCHARD PRUNINGS & ATTRITION LOSS
• HAY RESIDUES19
-PEANUT RESIDUES19
• SOYBEAN RESIDUES19
. SUGAR CANE RESIDUES12
12
18
-WHEAT RESIDUES
- SUGAR CANE RESIDUES
12
- WHEAT RESIDUES
20
-SOYBEAN RESIDUES
20
MISSISSIPPI
MISSISSIPPI
N CAROLINA TOBACCO RESIDUES 21
N DAKOTA -
N. DAKOTA —
OREGON
BARLEY RESIDUES
12-
12' 22
HAY RESIDUES
GRASS SEED RESIDUES1
Figure 4. Illustration of agricultural open burning seasons
in the ten states with annual burning greater
than 400,000 metric tons.
17Agricultural Solid Waste Disposal and Management in
California. Report of the Research Task Group, Division
of Agricultural Sciences. University of California,
Berkeley, California, 1973.
1 Department of Pollution Control, Tallahassee, Florida,
1975.
1 Environmental Protection Division, Department of Natural
Resources, Atlanta, Georgia, 1975.
20Mississippi Air and Water Pollution Control Commission,
Jackson, Mississippi, 1975.
2LOffice of Water and Air Resources, Department of Natural
and Economic Resources, Raleigh, North Carolina, 1975.
22Usual Planting and Harvesting Dates. Agricultural
Handbook No. 283, U.S. Department of Agriculture,
Washington, D.C., 1972.
21
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SECTION IV
EMISSIONS
A. SELECTED POLLUTANTS AND THEIR CHARACTERISTICS
The process mechanism and the formation of pollutants in
agricultural open burning have been described in detail in
Sections III.B.2 and III.B.3. Based on that information,
the major pollutants resulting from agricultural open burning
are: (1) particulates, derived from fly ash and partially
burned fuel, and smoke from incomplete combustion; (2) hydro-
carbons, from thermal cracking and condensation reactions;
(3) carbon monoxide, from incomplete combustion and from
gasification of smoke particles; (4) nitrogen oxides, from
oxidation of organic nitrogen compounds and from fixation of
nitrogen present in air; and (5) polycyclic organic matter
(POM), present in smoke and formed by pyrolytic reactions in
the precombustion zone. In addition, trace metal elements
including nickel, chromium, beryllium, cadmium, copper,
selenium, arsenic, mercury, titanium, manganese, and antimony
can be emitted. Due to their adverse health effects and
atmospheric reactivity which are described below, the above-
mentioned pollutants were selected for consideration in this
study. Sulfur oxides are not included here because their
emissions from agricultural open burning are negligible.23
2 Compilation of Air Pollutant Emission Factors (Revised).
U.S. Environmental Protection Agency, Office of Air
Programs, Research Triangle Park, N.C. OAP Publication
No. AP-42. April 1973.
22
-------
The health effects and atmospheric stability of emissions
from agricultural open burning are essentially the same as
those generally reported for air pollution sources, and these
are presented in Table 5. Due to insufficient data on trace
element emissions, the characteristics of these pollutants
are not listed in Table 5.
Most of the particulate emissions are solid and liquid aero-
sols of submicron size. In the burning of rice straw, the
mass median diameter of particulate emissions ranged from
0.11 to 0.13 ym.24 The data also showed a mass median
diameter of 0.025 to 0.10 ym for chloroform extractable
particulates and 0.025 ym for chloroform insoluble particu-
lates. Chloroform extractable particulates may be composed
of liquid hydrocarbon aerosol emitted during the pyrolysis
stage of the burning process. The chloroform insoluble
particles presumably consist of carbon particles and fly ash.
The small size of particulate matter emitted by agricultural
open burning was also reported in another study and the mean
size was found to be 0.5 ym for the burning of grass seed
residues.2 5
These fine particulates have the following effects: (1) they
absorb and scatter light and thus reduce visibility; (2) they
can penetrate the collection mechanisms of the human respi-
ratory tract and-lodge in the alveolar regions of the lung;
(3) some potentially hazardous trace elements may be enriched
24Goss, J. R., and G. E. Miller. Study of Abatement Methods
and Meteorological Conditions for Optimum Dispersion of
Particulates from Field Burning of Rice Straw - Spring Open
Field Burning Trials. Publication No. PB 235 796, June 1973
25Meland, B. R., and R. W. Boubel. A Study of Field Burning
Under Varying Environmental Conditions. J. Air Poll. Cont.
Assoc., 16:481, September 1966.
23
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in these submicron particles; and, (4) most of the particles
have the potential of remaining in the atmosphere for an
extended period of time, unless removed by rain or snowfall,
or by the slow process of coagulation and subsequent gravi-
tational settling.
B. EMISSION FACTORS
The quantities of emissions produced per unit of waste burned
have been reported by several authors. Table 6 is a compila-
tion of the information gathered from the literature and
includes only those articles containing emission factors or
data that can be used to calculate emission factors. Blanks
in Table 6 indicate that the particular data are not reported
in the cited references.
Particular attention was given to the data on the emission of
polycyclic organic matter (POM). The POM data shown in the
table are only those for benzo(a)pyrene. Although 10 more
POM compounds have been identified and measured in the
emissions from burning of grass clippings, leaves, and
branches,8/26/27 these 10 compounds were not included in the
table because they do not have potential carcinogenic
activity28 (defined as activity on animal tests). In addition
to the 11 compounds mentioned above, there might be large
26Hangebrauck, R. P., D. J. Von Lehmden, and J. E. Meeker.
Emissions of Polynuclear Hydrocarbons and Other Pollutants
from Heat-Generation and Incineration Processes. J. Air
Poll. Cont. Assoc., 14^:267, July 1964.
27Hangebrauck, R. P., D. J. Von Lehmden, and J. E. Meeker.
Sources of Polynuclear Hydrocarbons in the Atmosphere.
U.S. Department of Health, Education, and Welfare. Public
Health Service Publication No. 999-AP-33, 1967.
28Particulate Polycyclic Organic Matter. National Academy
of Sciences, Washington, B.C. 1972.
25
-------
amounts of other polynuclear aromatic hydrocarbons and their
alkyl derivatives, and polynuclear heterocyclic hydrocarbons
present in the emissions. Some of these compounds have been
found to be carcinogenic in animal studies.31'32 However,
the amount of these pollutants in the emissions is unknown
at the present time and therefore, the actual POM emission
may be higher than the data shown in the table.
The reported data on emissions of trace metal elements from
agricultural open burning is limited. The emission factors
for five elements from burning of sugarcane residue are listed
in Table 6.31 In another study, the emission of selenium
oxide in the burning of sugarcane has been reported.33
However, the data reported as selenium content in the smoke
cannot be used to calculate meaningful emission factors due
to the lack of data on CO2 concentration, air flow rate and
temperature.
In a recent study,3 the concentration of 26 trace elements
in gross air particulate samples taken from the burning of
residues from grass seed production were reported. It was
concluded that the atmospheric trace element abundances
associated with field burning were due to the trace element
content of the stubble being burned. The trace elements
concentrate in the larger sized particles having diameters
>11 ym. These data did not permit an evaluation of emissions
in terms of units of pollutant per unit of waste burned.
31Epstein, S. S., M. Small, J. Koplan, N. Mantel, H. L. Falk,
and E. Sawicki. Photodynamic Bioassay of Polycyclic Air
Pollutants. Arch. Environ. Health, 7_:531, November 1963.
32Hartwell, J. L. Survey of Compounds Which Have Been Tested
for Carcinogenic Activity. U.S. Public Health Service
Publication No. 149, 1951.
33Shendrikar, A. D., and P. W. West. Determination of
Selenium in the Smoke from Trash Burning. Environmental
Letters, 5_:29, January 1973.
26
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Table 6. PUBLISHED AND CALCULATED EMISSIONS FACTORS
FOR AGRICULTURAL OPEN BURNING
Geographic
area
California
California
CaLj forma
Bay Area
San Joaquin
Valley
Oregon
Willamette
Valley
Unknown
Unknown*1
Unknown**
Hawaii
Hawan
Fuel type
g p g
b
10% MC
25% MC
Agric. and forest
fuels, dry
Green fuels and
wet dead fuels
Grass
Woody materials
Fruit prunings, 11% MC
Fruit prunings, 35% MC
Rice straw
Barley straw
Grass stubble and
straw
Lab studies
Lawn clippings,
leaves, and tree
branches
Grass clippings,
leaves, and
branches, lab
studies
Grass clippings,
leaves, and
branches, field
studies
Suqar cane
Whole cane
Leaf trash
pineapple
Headf ires, 9.6 MC
16.9 MC
26.7 MC
Backfires, 9.3 MC
16.5 MC
24.4 MC
Participates
5 (10)
18 (36)
8 (16)
5.5-8.5 (11-17)
7.8 (15.6)
7.8 (15.6)
8.5 (17)
3.0-4.2 (6.0-8.4)
2.1-3.3 14.1-6.5)
3.2 b,4)
8.3 8.5)
11.7 23.3)
3.2 6,4)
3.9 7.7)
4.6 (9.1)
kg/motri
Hydrocarbons
(as CH4)
2-3 (4-18)
Av. 7 (14)
Increases
2.1 (4.2)C
4.9 (9.7)°
4.6 (9,1)C
7,3 (14.5)C
6.2 (12.3)
5.3 (10 6)
15 (30)
2.4-8 !4.7-16)C
1.2-7 (2.3-14)°
^-3 (4.6)';
3.0 (5.9)
6.2 (12.3)
1-9 (3.7)':
3.0 (6.01:;
3.6 (7.2)
Emis&iun
c ton (Ib/ton)
CO
20-70 (40-140)
Av. 46 (92)
Increases
23 (46)
33 (66)
37 (73)
51 (101)
66 (132)
33 (65)
30-42 (60-81)
24-36 (48-71)
50.1 (100.1)
52.8 (105.5)
65.0 (129.9)
53.7 (107.4)
56.3 (112.5)
58.4 (116.7)
fac torb
NO
2 (4)
POU"
0.00036 (0.00071)
0.000256 (0.00049)
0.00035 (0.00069)
0.00027 (O.OOOS3)f
0.00021 (0.00042)
Trace
Ug/metnc ton
(10~9 Ib/ton)
Ni. 0.155 (0.311}f
Cr: 0.052 (0.104)^
Be: 0.020 (0.039)-
Cd: 0.176 (0.351)-
Cu- 0.560 (1.120)
Mi; 0.115 (0.229)f
Cr: 0.036 (0.072)-
Be; 0 042 (0.083)^
Cd; 0.275 (0.549)f
Cu: 0.820 (1.64 )
Ref.
24
29
10
11
8
26
27
30
30
30
b
Moisture content
Total hydrocarbon as C
Specific geographic area i
e
Calculated from Reference
(a)pyrene
ot reported in referem
ferences 23 and ?6.
30. "
yDarley, E. F., H. H. Biswell, G. Miller, and J. Goss. Air Pollution from Forest and Agricultural Burning. (Presented at the
Western States Section. The Combustion Institute, Seattle, Washington. April 24-25, 1972.)
Darley, E. F., and s. L. Lerman. Air Pollutant Emissions from Burning Sugarcane and Pineapple Residues from Hawaii, special i
the Environmental Protection Agency. Amendment to EPA Research Grant R800711.
27
-------
The following emission factors, selected and assumed as
representative of agricultural open burning, were used in the
calculations of ground level concentration, mass emissions,
and affected population in Section IV.D:
Pollutant
Particulates2 3
Total hydrocarbons (as CHiJ23
Carbon monoxide23
Nitrogen oxides23
POM
Benzo(a)pyrene8,26,27,30
Trace metal elements
Nickel30
Chromium3 °
Beryllium3 °
Cadmium3 °
Emission factor,
kg/metric ton (Ib/ton)
8.5
10
50
1
( 17
( 20
(100
( 2
Copper
3 0
0.00029
0.14 x 10~9
0.044 x 10~9
0.031 x 10-9
0.23 x 10~9
0.70 x 10~9
( 0.00058 )
( 0.27 x 10~9 )
( 0.088 x 10~9)
( 0.061 x 10~9)
( 0.45 x 10~9 )
( 1.4 x 10-9 )
C.
DEFINITION OF REPRESENTATIVE SOURCE
A representative source of agricultural open burning was
defined in order to determine the source severity which is
described in Section IV.D. This representative source
consists of an agricultural field of 105 m2 (25 acres)13/34
3''Moore, J. , and C. D. Wolbach. Source Sampling of Sugarcane
Burning. Texas Air Control Board, Source Sampling Section.
May 1974.
28
-------
with a fuel loading of 6.7 x IQ~k metric tons/m2 (3 tons/
acre),24 a fire propagation rate of 4.6 m/min (15 ft/min),2U
and a fuel heating value of 12.56 MJ/kg (5,400 Btu/lb).2 The
following assumptions were made to characterize the burning
conditions: (1) burning starts from one side of the square
field; (2) there is a 20% heat loss to soil, ash, and water
evaporation; (3) flame height is 2 m (7 ft); and (4) wind
speed equals the national average of 4.5 m/s (10 miles/hr).
D. SOURCE SEVERITY
1. Maximum Ground Level Concentration
The maximum ground level concentration (XTT1_V) of each pollu-
-^ I Ud .A. *•
tant resulting from agricultural open burning was estimated
by Gaussian plume dispersion meteorology. Xmax values for
the average (representative), best, and worst cases (see
Appendix B.4) are shown in Table 7. For comparison, the TLV
and the ambient air quality standard for the criteria
pollutants are also listed.
The following formula was used for the calculation of Xmax:
2Q
= ' TTT T \
xmax ~"
where Q = mass emission rate, g/s
u = average wind speed, m/s
H = effective emission height, m
e = 2.72
The effective emission height was estimated by the following
equation (shown in the units reported by the authors
referenced in Appendix B):
29
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H = fcQ/ u + c (IV-2)
where k = a system parameter, m2/kcal ' s '
Q, = heat emission rate relative to ambient
temperature, kcal/s
c = flame height, m
Equation IV-2 was derived for particular application to
agricultural open burning. The derivation of Equation IV-2
and the evaluation of system parameter k are given in
Appendix B. Q and Q, are functions of field geometry, fire
propagation rate, fuel loading, and emission factor. Q, is
also proportional to the heating value of the fuel.
The input data for and a sample calculation of Q , Q, , H,
and Xmax are also given in Appendix B.
2 . Severity Factor
To obtain an indication of the hazard potential of the
emission source, the source severity (S) was defined as:
S = (IV-3)
where 7 is the time-averaged maximum ground level
^max
concentration of each pollutant emitted from a representative
source of agricultural open burning (see Section IV. C) , and
F is the primary ambient air quality standard for criteria
pollutants and is a "corrected" threshold limit value
(TLV« 8/24 -l/lOO) for noncriteria pollutants. This severity
31
-------
factor represents the ratio of. time-averaged maximum ground
level exposure to the hazard level of exposure for a
particular pollutant.
"x is the maximum ground level concentration (Y ) averaged
Amax ^ Amax y
over a given period of time. The averaging time is 24 hours
for noncriteria pollutants. For criteria pollutants, averaging
times are the same as those used in the primary ambient air
quality standards.
If t} represents the averaging time and t2 represents the
burning duration, the relationship between x and x can
max max
be expressed by the following two equations for agricultural
opening burning:
If t! < t
O.I/
*max = X(- ) dV-4)
If t! > t2
y~ = y to ° • 8 3 • t° • l 7/t 1 (IV-5)
xmax xmax 2 max ' l VAV 3;
where ^max is the short-term averaging time for which
equation (IV-1) is valid. The derivation of equations
(IV-4) and (IV-5) is given in Appendix B.3.
X and source severity for each pollutant emitted from
burning of a field under average conditions (see Appendix B.4)
are shown in the third and last column of Table 7, respectively.
It can be seen that the source severity is 1 for hydrocarbons,
between 0.1 and 1 for B(a)P, and below 0.1 for other pollutants.
It should be emphasized that these calculations were based on
the assumed emission factors mentioned in Section IV.B. There
32
-------
might also be emission of other toxic POM compounds and
trace metal elements for which the emission factors are not
available at the present time.
3. Contribution to Total Air Emissions
The contribution of agricultural open burning to statewide
and nationwide air emissions was measured by the ratio of
mass emissions from this source to the total emissions from
all sources.
The mass emissions of criteria pollutants resulting from
agricultural open burning were calculated by multiplying
the emission factors by the total burning done in the state.
The mass emission for each pollutant is shown in Table 8
for the states where agricultural open burning is usually
practiced, along with the nationwide emissions. There are no
figures for sulfur oxides in Table 8 because the emission of
sulfur oxides from agricultural open burning is negligible.32
Table 9 gives the ratios of criteria pollutant emissions
resulting from agricultural open burning to the total criteria
pollutant emissions in each corresponding state and the
nation. The total criteria pollutant emissions for each state
were obtained from the 1972 National Emission Report. The
states with at least one ratio greater than 1% are noted in
the table. On a nationwide basis, the emissions from agri-
cultural open burning constitute 0.1% or more of the total
emissions for the following criteria pollutants: particulates,
hydrocarbons, and carbon monoxide.
33
-------
Table 8. TOTAL EMISSIONS OF CRITERIA POLLUTANTS RESULTING FROM
AGRICULTURAL OPEN BURNING BY STATE AND NATIONWIDE3
Location
Alabama
Arizona
Arkansas
California
Colorado
Delaware
Florida
Georgia
Hawaii
Idaho
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Mexico
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
South Carolina
South Dakota
Tennessee
Virginia
Washington
Wisconsin
Wyoming
National Total
Particulates,
metric tons/yr
1,400
170
980
26,000
1,200
17
15,000
7,500
10,000
190
4,600
490
16,000
280
60
26
790
2,300
5,200
1,500
1,300
2,600
43
17
5,300
3,700
1,200
1,400
4,100
590
320
2,300
520
370
2,200
1,200
290
113,000
Hydrocarbons,
metric tons/yr
1,600
200
1,200
31,000
1,400
20
17,000
8,800
12,000
220
5,400
2,900
19,000
330
70
30
930
2,700
6,200
1,800
1,500
3,000
50
20
6,200
4,400
1,400
1,600
4,800
690
380
2,700
610
430
2,600
1,500
340
132,000
CO, metric
tons/yr
8,100
1,000
5,800
153,000
7,200
100
86,000
44,000
59,000
1,100
27,000
580
95,000
1,000
350
150
4,700
14,000
31,000
9,100
7,600
15,000
250
100
31,000
22,000
7,100
8,100
24,000
3,500
1,900
13,000
3,100
2,200
13,000
7,300
1,700
662,000
NOX, metric
tons/yr
160
20
120
3,100
140
2
1,700
880
1,200
22 •
540
58
1,900
33
7
3
93
270
620
180
150
300
5
2
620
440
140
160
480
69
38
270
61
43
200
150
34
13,200
aBased on assumed emission factors.
34
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Table 9. RATIO OF CRITERIA POLLUTANT EMISSIONS RESULTING
FROM AGRICULTURAL OPEN BURNING TO TOTAL STATE
AND NATIONWIDE EMISSIONS9
Location
Alabama
Arizona
Arkansas
California
Colorado
Delaware
Florida
Georgia
Hawaii
Idaho
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
b
Montana
Nebraska
Nevada
New Mexico
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
South Carolina
South Dakota
Tennessee
Virginia
Washington
Wisconsin
Wyoming
Nationwide
Particulates,
%
0.11
0.21
0.64
2.4
0.55
0.04
5.8
1.7
15.
0.31
1.2
0.08
3.9
0.52
0.01
0.03
0.10
0.79
2.8
0.69
0.43
2.4
0.04
0.02
0.99
4.3
0. 06
1.3
2.2
0.03
1.3
3.9
0.11
0.07
1.2
0.27
0.35
0.61
Hydrocarbons ,
%
0.23
0.77
0.53
1.3
0.67
0.03
2.5
1.7
12.
0.24
1.6
0.81
0.90
0.24
0.02
0.006
0.12
0.61
2.9
0.40
0.51
2.2
0.09
0.01
1.3
5.7
0.11
0.43
1.9
0.07
0.58
2.7
0.15
0.11
0.67
0.25
0.56
0.50
CO,
%
0.39
0.11
0.62
1.7
0.74
0.04
2.9
2.0
19.
0.29
2.5
0.04
1.5
0.40
0.03
0.008
0.13
0.71
3.4
0.44
1.1
2.4
0.11
0.02
1.6
6.2
0.12
0.50
2.3
0.08
0.65
3.1
0.19
0.13
0.7
0.42
0.51
0.65
NO ,
X
%
0.04
0.02
0.06
0.17
0.09
0.003
0.24
0.22
2.4
0.04
0.21
0.01
0.41
0.04
0.002
0.001
0.004
0.08
0.32
0.04
0.09
0.27
0.005
0.001
0.14
0.46
0.01
0.07
0.32
0.002
0.007
0.49
0.01
0.01
0.12
0.32
0.04
0.06
Based on assumed emission factors.
States which have at least one ratio greater than 1%.
35
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4. Population Exposed to High Pollutant Concentrations
To obtain a quantitative evaluation of the population influ-
enced by a high concentration of emissions resulting from
burning a typical agricultural field, the areas exposed to
the time-averaged ground level concentration (x) for which
X/F > 1 and x/F > O.I were obtained by determining the area
within the ispoleth for ~x,37 and the number of people within
the exposed area was then calculated by using a proper
population, density.
The representative population density used in the calculation
of affected population was the average state population den-
sity, weighted by the amount of burning in each state. For
hydrocarbons, which have source severity (S) greater than or
equal to 1, the area and population exposed to a time-averaged
ground level concentration for which x/F ^_ 1 an<^ X/F 21 ^ • ^
are shown in Table 10. For benzo(a)pyrene, which has
0.1 < S < 1, affected area and population are shown only for
"x/F _> 0.1. In addition to the average exposed population,
two extreme cases were also examined and these are listed in
the same table. The extreme values were obtained by using
the state population density of Massachusetts and Montana
because these two states have the highest and lowest popu-
lation density among the states where agricultural open
burning is usually practiced.
It can be seen from Table 10 that for the average case, the
population influenced by high ground level concentration is
far below 20,000. However, it should be noted again that
there may be some other POM compounds and trace metal elements
emitted and not reported.
37Turner, D. B. Workbook of Atmospheric Dispersion Esti-
mates. U.S. Department of Health, Education, and Welfare,
Public Health Service. Cincinnati, Ohio. 1969.
36
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SECTION V
POLLUTION CONTROL TECHNOLOGY
A. STATE OF THE ART
The adverse impact on the environment from agricultural open
burning can be reduced by proper fire and fuel management,
meteorologically scheduled burning, or by the substitution
of other alternatives.
Better fire and fuel management can result in a reduction in
the amount of air emissions from open burning. The practice
of meteorologically scheduled burning can facilitate maximum
pollutant dispersion and reduce the ground level pollutant
concentration. These two types of control and several
alternatives to open burning are discussed below.
1. Fire and Fuel Management
It has been shown, in the burning of rice residues, that
single line backfiring (wherein a fire progresses in a direc-
tion opposite to that of the wind) could reduce particulate
emissions by approximately 50% over single line headfiring
(wherein a fire progresses in the same direction as the
wind) because backfiring provides a longer residence time
for more complete combustion.21* The backfire ignition
technique was also recommended after an investigation of
38
-------
plume rise and smoke characteristics from open field burning
of agricultural residues.38 However, it should be noted
that the use of backfiring for fire management has limitations
when fuel loading is low. In this case headfiring may become
the only method that can produce an effective burn.
Among the field condition variables (air temperature,
humidity, wind speed, fuel loading, and residue moisture
content) it has been reported that residue moisture content
is the primary variable controlling particulate emissions.24'25
It was shown that residue with 10% moisture content emitted
only 1/3 as much particulates upon burning as residue with
25% moisture content.24 Therefore, the control of residue
moisture in open burning can be used to reduce air emissions.
The residue moisture content is strongly related to solar
radiation, relative humidity, air temperature, wind speed,
and residue loading. In order to have low moisture content
at the time of burning, the day and time of the day for
burning should be carefully selected. To facilitate quick
residue drying, it would be best to spread the residues
evenly in the field. Uniformly spread residues also provide
better disease control when burned.
2. Meteorologically Scheduled Burning
The pollutants, once emitted, can be effectively dispersed
under certain meteorological conditions, and the environmen-
tal impact can be reduced to some extent. One way of
achieving this is to permit burning only when the inversion
base and the maximum mixing height are at prescribed levels,
38Carroll, J. J. Determination of Temperature, Winds, and
Particulate Concentrations in Connection with Open Field
Burning. Final Report, Contract ARB-2114, Air Resources
Board, State of California, November 1973.
39
-------
and at specified wind velocities and directions. This type
of control has been practiced in the San Francisco Bay Area
for several years.39/40
In the Willamette Valley of Oregon, the climatology and pre-
dictive equations have been studied for management of smoke
from field burning.41 According to the study, the number of
acres of field residue that may be burned on a given day with-
out overburdening the air can be predicted. The predictions
were based on the vertical temperature change, relative humid-
ity, pressure gradient, wind speed, and existing visibility.
3. Mobile Field Sanitizer
One alternative to open burning is controlled incineration
in a mobile field sanitizer. The development of these
sanitizers was started in early 1970 by the Oregon State
University, funded by the State Emergency Board. It was
determined that the volatile portions of the crop residue
burned in less than 1/2 second but 10 seconds were necessary
to completely burn all the carbon particles.42 The sanitizer
was designed to burn all residue in its path within a self-
sustaining combustion chamber. Particulate emissions were
39Johnson, H. C., and H. A. James. Controlled Open Burning
in the San Francisco Bay Area. J. Air Poll. Cont. Assoc.,
20^:530, August 1970.
40Osterli, V. P. Waste Disposal. In: Combustion-Generated
Air Pollution, Starkman, E. S. (ed.). New York, Plenum
Press, 1971.
41Bates, E, M. Smoke Management in the Willamette Valley.
NTIS Publication No. COM-74-11277, May 1974.
42Research Relating to Agricultural Field Burning. Progress
Report, Agricultural Experiment Station and Air Resources
Center, Oregon State University, Corvallis, Oregon.
February 1971.
40
-------
estimated to be reduced by 80-90% and unburned hydrocarbon
emissions by 99% when compared with open burning.^ 3
The mobile field sanitizer consists of two sections as shown
in Figure 5.112 The front section is a converted combine
which picks up straw and conveys it to the main incinerator.
A large fan is fitted to the combine to supply combustion
air to the single combustion chamber. Additional draft is
supplied by a round stack on top of the fire box. A hopper
on the front of the combustion chamber contains augers to
convey fuel onto a stainless steel grate in the combustion
chamber. Hinged steel tube drags are installed in the front
and rear of the firebox to prevent fire spread. Because of
the high temperature involved, the sanitizer is equipped
with steel wheels and tires. A propane burner is used to
provide the starting temperature.
Field testing in 1971 and 1972 on grass seed fields suggests
that under ideal conditions the mobile field sanitizer will
provide effective field sanitation and straw combustion with
smoke emissions under the limits of the Department of
Environmental Quality of the state of Oregon.43 However,
the reliability of the sanitizer in the control of weeds,
pests, and disease, and in the thermal stimulation of soil
for various crop species is still questionable.13 Because
of engineering and economic problems, the field sanitizer is
still not commercialized, despite the banning of open
burning in the Willamette Valley, effective January 1, 1975.
3Farmer Alternatives to Open Burning: An Economic Appraisal,
Special Report 336, Agricultural Experiment Station,
Oregon State University, Corvallis, Oregon. October 1971.
41
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The field sanitizer was also tested in California rice and
barley fields in 1971 and 1972.^ and some difficulties were
experienced. Due to the high silica content of rice straw,
machine operation was unsatisfactory. Wild fires occurred in
the field operation. The study also concluded that high
particulate emission levels will still be a problem unless
some provisions were made to remove particulates at the in-
cinerator discharge. If the technical problems can be solved,
the field sanitizer with its controlled temperature can pro-
vide more uniform and complete weed/disease control than can
be attained by open burning.
4. Other Alternatives
Field burning can be used to simultaneously accomplish
field sanitation, residue removal, and residue disposal. In
the grass seed land in the Willamette Valley of Oregon, field
burning also provides a thermal treatment to the soil which
raises the production yield substantially. Therefore, in
the study of alternatives, the above-mentioned factors must
be considered.
The most common method of disposing of crop residues is to
incorporate the material directly into the soil. This can
be accomplished by disking or by chipping or shredding for
subsequent working into the soil. The main problems miti-
gating against the extension of soil incorporation of the
remaining residues now burned in some areas of the country
are: (1) poor soil conditions for cultivation as exist
^Miller, G. E., and J. R. Goss. Study of Abatement Methods
and Meteorological Conditions for Optimum Dispersion of
Particulates from Field Burning of Rice Straw: Rice Straw
Incinerator Evaluation. Publication No. PB 236 405,
June 1973.
43
-------
for California rice where the water table is high and the
residue occurs late in the year when temperatures are low,
biodegradation is slowed, and disease or pest problems may
be great; (2) the occurence of bulky materials not capable
of incorporation, such as large prunings, or removed fruit
trees; (3) a requirement for rapid removal of the residue
to permit planting of the following crop; and, (4) possible
soil nitrogen depletion due to the residue decomposition.
Another alternative to field burning is the mechanical
removal of residues. This method is generally expensive
unless the residue commands a satisfactory price. Oregon
State University has conducted extensive research on
the potential uses of residues generated in the Valley.
Among the products found to be technically feasible were
paper, hardboard, insulation material, animal feeds, fuel,
and microbial protein.143 At the present time, a major crop
residue is used for stubble-mulch farming to protect fallow
lands against the erosive forces of wind and water.
In the event that field burning is not employed, chemical
methods would be required to control weeds, disease, and
pests. The subsequent effect in air and water pollution
resulting from the application of herbicides, fungicides,
and pesticides would also have to be evaluated.
In grass disease research, an intensive program of testing
available fungicides for control of major grass disease,
underway for years, has not produced a practical chemical
control.45 More stringent federal standards have decreased
the number of new fungicides being developed and fewer new
chemicals are available for further evaluation.
45Field Burning. Agricultural Experiment Station, Oregon
State University, Corvallis, Oregon. February 1973.
44
-------
B. FUTURE CONSIDERATIONS
Due to the continuous expansion of urban communities, the
reduction in agricultural land, and the increase in the
intensity of agricultural planting, pollution controls on
open burning as described in Sections V.I and V.2 may not be
sufficient to reduce the environmental impact in the future.
Further research is therefore needed in the following areas
in order to reduce the practice of agricultural open burning:
(1) improve the mobile sanitizer for better control of
disease and weeds, for maintaining crop yields, and for
safer operation; (2) study the environmental impact of the
extensive use of chemical control of disease, weeds, and
pests; (3) identify the domestic and foreign markets for
utilization of crop residues; and, (4) develop more effective
and less harmful (to mankind) means of chemical control of
disease, weeds, and pests.
Straw residue is high in cellulose and can be used in manu-
facturing many different products. In a few years, this
straw may be a very valuable raw material for other indus-
tries.46 In the future, the solution to open field burning
of cereal crop and grass seed residues may be a combination
of straw utilization and mobile field sanitation.
Until less harmful and more effective chemical controls are
available and until other economically viable techniques for
residue utilization or disposal are developed, control of
the environmental degradation of air quality will depend on
fire and fuel management and on meteorologically controlled
burning.
46Sherman, C. J. Is the Industry Going Up in Smoke? Crops
and Soils Magazine, 25:18, April 1974.
45
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SECTION VI
GROWTH AND NATURE OF THE SOURCE
Open burning is one of the principal methods of disposing
of agricultural wastes. Despite the continuing growth in
crop harvest, agricultural open burning has been declining
since 1969 due to increasing awareness of its contribution
to air pollution and development of waste utilization,
chemical control of weeds, pests, and disease, and modern
tillage and fertilization practices. EPA's estimated
agricultural open burning was 29 x 10 6 metric tons
(32 x 106 tons) for 1969. This figure dropped to 13.2 x 106
metric tons (14.6 x 106 tons) for 1973. 14
In some cases there are no alternatives to open burning at
the present time. Examples are sugarcane burning in Florida,
Louisiana, and Hawaii, grass seed burning in Oregon,
Washington, Arizona, and Idaho, and rice and barley residue
burning in California.
In 1971, the Oregon State Legislature passed a bill banning
open burning in the Willamette Valley, effective January 1,
1975. However, due to the unavailability of effective
alternatives, it is possible that the lawmakers will
eventually reverse their decision.13
46
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Although agricultural open burning will continue to decline,
the burning in several areas of the country will continue until
more effective and less harmful chemical control of pests,
weeds, and disease is available, and until other economically
viable techniques for residue utilization or disposal are
developed.
47
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SECTION VII
APPENDICES
A. Sample Calculations for Data on Burning
Shown in Table 4.
B. Equation Derivation and Input Data
48
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APPENDIX A
SAMPLE CALCULATIONS FOR DATA ON BURNING SHOWN IN TABLE 4
The burning data were usually reported in nonmetric units.
Calculations were made using nonmetric units, and then the
results were converted to metric units.
Total number of states in
which agricultural open
burning is practiced12 = 37
Total burning in the
U.S.11* = 14,600 x 103 tons/yr
Total burning reported for
18 states12/14'15
(excluding the nonsugarcane
burning in Florida for
which data were not
available) = 11,746 x 103 tons/yr
.'. Total burning in the remain-
ing 19 states (including
the nonsugarcane burning
in Florida) = 14,600 x 103 - 11,746 x 103
= 2,854 x 103 tons/yr
49
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For Florida
Total burning was calculated by estimating the nonsugarcane
burning and adding that value to the sugarcane burning, the
latter calculated from reported information.
Nonsugarcane
crop average = 2,089 x 103 acres47
Nonsugarcane
burning
= 2,854 x 103 tons/yr x 2,089 x 103 acres
161,531 x 103 acres
= 37 x 103 tons/yr
where 161,531 x 103 acres represents the total crop
average in the remaining 19 states.
Sugarcane acres burned
Tons sugarcane burned per year
Sugarcane burning
Estimated nonsugarcane burning
Total burning
= 265 x 103 acres/yr12
= 7 tons/acre12
= 1,855 x 103 tons/yr
= 37 x 103 tons/yr
(calculated above)
= 1,892 x 103 ton/yr or
1,716 x 103 metric
tons/yr
^Agricultural Statistics. Statistical Reporting Service,
U.S. Department of Agriculture, 1974.
50
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For Arizona
State crop acreage = 1,251 x 10 3 acres17
Burning = 2,854 x 103 tons/yr x 1.251 x 103 acres
161,531 x 103 acres
= 22 x 10 3 tons/yr or 20 metric tons/yr
Estimated fuel
loading
= 2 tons/acre
Are, burned
4.5 x 107 m2/yr
51
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APPENDIX B
EQUATION DERIVATION AND INPUT DATA
1. DEVELOPMENT OF EQUATION (IV-2)
The behavior of plumes from agricultural open burning is
different from that of plumes from elevated stacks in the
following respects: (1) the emissions from open burning
are a progressing line source, with large amounts of heat
release, rather than a near-point source as is the case
emissions from elevated stacks; and (2) the only driving
force for plume rise in the case of open burning is the
buoyancy force created by the burning process. Thus, the
effective plume height is totally controlled by environmen-
tal factors (especially wind speed). In stack emissions,
the buoyancy rise is only one of the factors used in
estimating the effective emission height.
A number of empirical equations are available in the lit-
erature for predicting the plume rise in stack emissions.
However, due to the differences between the two types of
emission sources, the application of these equations to open
burning becomes questionable.
After examining the relative ground level concentration
between a one-unit and a ten-unit power plant, it was con-
cluded that due to the separation of emission stacks, the
52
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plume rise becomes proportional to the 0.25 power of heat
emission.1*8 This separation of emission points in the
power plant is similar to the line source in the agricultural
open burning. Thus, an equation similar to the Lucas,
Moore, and Spurr formula1*9 was used to predict the effective
emission height, H, in this document:
H = kQhV u + c (B-l)
where Q, = heat emission rate relative to ambient
h
temperature, kcal/s
u = average wind speed, m/s
k = a system parameter, m/kcalV^s3/4
c = the flame height, m
A relationship of this type is essentially unchanged for
wind direction normal to or in line with the burning line.
The larger buoyant effect for in-line winds approximately
compensates for the dilution effect of wind normal to the
burning line. However, it should be noted that although
the wind direction does not affect the plume rise, it does
change the emission rate (due to the difference between
backfire and headfire).
2. EVALUATION OF THE SYSTEM PARAMETER, k
The value of the system parameter, k, in Equation (B-l) was
estimated using the data listed below:
'tSThomas, F. W. , S. B. Carpenter, and F. E. Gartrell. Stacks
How High? J. Air Poll. Cont. Assoc., 13_:198, May 1963.
't9Lucas, D. H. , D. J. Moore, and G. Spurr. Intern. J.
Air Water Poll. 7_:473, July 1963.
53
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Size of field:24 2,500 m2 or 50 m x 50 m
(0.25 acre or 160 ft x 160 ft)
Fuel loading:24 6.72 x 10~4 metric ton/m2
(3 tons/acre)
Fire propagation rate:24 4.6 m/min (15 ft/min)
Fuel heating value:2 3,000 kcal/kg or 12.56 MJ/kg
(5,400 Btu/lb)
Flame height:3 2 m (7 ft)
Effective emission height:24 210 m (690 ft)
Wind speed:24 1.34 m/s (3 miles/hr)
Burning: starts from one side of
the square field.
Heat loss to soil, ash, and
water evaporation: 20%
Q, was calculated by the following formula:
Q, = (length of one side of the square field)
x (fire propagation rate) x (fuel loading)
x (heating value) x (1.0 - 0.2) (B-2)
With the listed data above, Q, becomes:
Q, = 50 m x 4.58 m/min x 1 min/60 s
x 6.72 x 10~4 metric ton/m2 x 3,000 kcal/kg
x 0.8 x 1,000 kg/metric ton
= 6,149 kcal/s
aAssumed.
54
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With Q, , H, and c known, Equation (B-l) was then used to
back-calculate k value.
I H — f** I 1*1 *^ / " •*• / "
k = vtl c; u = 31.5 m2/s kcal (B-3)
Note that this k value is dimensional and the value shown is
based on the quantity of Q, in units of kcal/s, and H and c
in meters. Conversion factors are presented in Section IX.
3. Derivation of Equations (IV-4) and (IV-5)
The maximum ground level concentration (x ) calculated
max
from Equation (IV-1).is the value for short term averaging
time during which the Gaussian plume diffusion equation is
valid. The short term averaging time was found to be 3
minutes in a study of published data on lateral and vertical
diffusion.50 The estimate of maximum ground level concentra-
tions for time intervals greater than 3 minutes can be
obtained by using the following formula for a continuously
emitting source:37
t x 0.17
max
xmax xmax I ti (B-4)
where ti = the averaging time
the short ten
(= 3 minutes)
t = the short term averaging time
max
In the case of agricultural open burning, a field is burned
for only a short duration each time, ranging from a few
minutes to several hours. If the averaging time is smaller
50Nonhebel, G. Recommendations on Heights for New Industrial
Chimneys. J. Inst. Fuel, 3_3_:479, July 1960.
55
-------
than the burning duration, then this source can be treated
as a continuously emitting source, and Equation (B-4) can
be used to obtain the time-averaged maximum ground level
concentration. Note that Equation (B-4) is essentially the
same as Equation (IV-4).
If the averaging time is greater than the burning duration,
then the concentration has to be averaged over the burning
duration (as a continuously emitting source) and then
averaged over the averaging time (as a non-continuous source)
This treatment can be expressed by the following equation:
/t \Q-17 t2
v = v (_5>ax) . ±
Amax Amax \ t2 / tj
0.83 0.17
* to * t /ti (B-5)
2 max / i
where t2 = the burning duration
Equation (B-5) so derived is the same as Equation (IV-5)
which is applicable when t^ > t2.
4. INPUT DATA FOR CALCULATION OF x
max
The maximum ground level concentration, x t °f pollutants
max
resulting from agricultural open burning was described in
Section IV.D.I of this document. Input data used to
calculate Q , Q, , H, and x a^e provided below for the
m n max
average, worst, and best cases.
a. Average Case
The input data used for the average case are the same as
those listed in Section 2 of Appendix B except for the
following variables:
56
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Size of field:13'34 io5 m2 (25 acres)
Wind speed:3 4.5 m/s (10 miles/hr)
b. Worst Case
The input data used for the worst case are the same as those
listed in Section 2 of Appendix B except for the following
variables:
Size of field:13 80 x IO4 m2 (200 acres)
Fuel loading:12 2.69 x 10~3 metric ton/m2
(12 tons/acre)
Wind speed: 9.0 m/s (20 miles/hr)
c. Best Case
The input data used for the best case are the same as those
listed in Section 2 of Appendix B except for the following
variables:
Size of field:13 IO4 m2 (2.47 acres)
Fuel loading:12 2.24 x lO"4 metric ton/m2
(1 ton/acre)
Wind speed: 0.9 m/s (2 miles/hr)
National average wind speed.
Estimated value.
57
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SECTION VIII
GLOSSARY OF TERMS
AFFECTED POPULATION - The number of people around a repre-
sentative source who are exposed to a source severity greater
than 0.1 or 1.0 as specified.
BACKFIRE BURNING - Fire progression in a direction opposite
to that of the wind.
BURNOUT - Smokeless combustion which occurs after oxygen has
diffused to a gas-solid interface of the nonvolatile portion
of combustible material (often referred to as char).
CRITERIA POLLUTANT - Pollutant for which ambient air quality
standard has been defined (these are: particulate, hydro-
carbons, carbon monoxide, sulfur dioxide, and nitrogen oxides,
EMISSION FACTOR - Quantity of emissions per quantity of mass
burned.
EXPOSURE FACTOR - A value used to indicate the combination
effect of amount of burning and state population.
FUEL LOADING - Mass of material burned per unit of area
burned.
HEADFIRE BURNING - Fire progression in the same direction
as the wind.
NONCRITERIA POLLUTANT - Pollutants for which ambient air
quality standards have not been defined.
POLYCYCLIC ORGANIC MATTER - Heavy hydrocarbons which may
have carcinogenic properties.
REPRESENTATIVE SOURCE - An agricultural open burning field
defined for use in calculating the source severity.
SANITIZER - Mobile field unit used for controlled incinera-
tion of residue.
58
-------
SMOKE - A suspension of submicron particulates consisting of
solid and liquid aerosols.
SOURCE SEVERITY - An indication of the hazard potential of
an emission source.
THRESHOLD LIMIT VALUE (TLV) - Refers to airborne concentra-
tions of substances and represents conditions under which it
is believed that nearly all workers may be repeatedly exposed
day after day without adverse effect.
59
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SECTION IX
CONVERSION FACTORS AND METRIC PREFIXES51
Conversion Factors
To convert from
joule (J)
joule (J)
kilogram (kg)
kilogram (kg)
kilometer2 (kn2)
meter
meter
meter
meter2 (m2)
meter2 (m2)
meter3 (m3)
metric ton
metric ton
to
British thermal unit
(Btu)
cal
pound-mass (Ib mass
avoirdupois)
ton (short, 2,000 Ib
mass)
mile2
feet
inch
mile
acre
hectare
feet3
pound-mass
ton
Multiply by
9.479 x 10"1*
2.388 x 10-1
2.205
1.102 x 10~3
3.861 x ID"1
3.281
3.937 x 101
6.215 x ID'4
2.470 x ID"4
1.000 x 104
3.531 x 101
2.205 x 103
1.103
51 Standard for Metric Practice.
and Materials. Philadelphia.
February 1976. 37 p.
American Society for Testing
ASTM Designation: E-380-76.
60
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Metric Prefixes
Prefix Symbol Multiplication factor Example
mega M 106 1 MJ = 1 x 106 joules
kilo k 103 1 kg = 1 x 103 grams
milli m 10~3 1 mg = 1 x 10~3 gram
micro y 10~6 1 ym = 1 x 10~6 meter
61
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SECTION X
REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
Walton, J. W. Disposal of Agricultural Waste by
Controlled Burning - A Regulatory Viewpoint. (Presented
at Special Conference, Air Pollution Control Association,
Proc. Control Technology for Agricultural Air Pollutants.
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Johnson, A. J., and G. H. Auth. Fuels and Combustion
Handbook. McGraw-Hill, New York, 1951.
Shum, Y. S., and W. D. Loveland. Atmospheric Trace
Element Concentrations Associated with Agricultural
Field Burning in the Willamette Valley of Oregon.
Atmospheric Environment, 8:645, December 1974.
Edwards, J. B.
Trace Species.
1974.
Combustion - Formation and Emission of
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Orning, A. A. The Principles of Combustion. In:
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Yamate, G. Development of Emission Factors for Estimating
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62
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9. Sandburg, D. V., S. G. Pickford, and E. F. Darley.
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16. Personal communication. Charles Mann. OAQPS, EPA,
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63
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23. Compilation of Air Pollutant Emission Factors (Revised).
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24-25, 1972.)
30. Darley, E. F., and S. L. Lerman. Air Pollutant Emissions
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33. Shendrikar, A. D., and P. W. West. Determination of
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64
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34. Moore, J., and C. D. Wolbach. Source Sampling of Sugar-
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35. Thershold Limit Values for Chemical Substances and
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65
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46. Sherman, C. J. Is the Industry Going Up in Smoke?
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Water Poll. 1:473, July 1963.
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66
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