EPA-450/3-74-085
EMISSIONS INVENTORY
OF AGRICULTURAL TILLING,
UNPAVED ROADS
AND AIRSTRIPS,
AND CONSTRUCTION SITES
by
Chattcn C. Cowherd, Jr. ,
Christine M. Guenther, and Dennis D. Wallace
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 64110
Contract No. 68-02-1437
EPA Project Officer: Charles O. Mann
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, N. C. 27711
November 1974
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This report is issued by the Environmental Protection Agency to
report technical data of interest to a limited number of readers.
Copies are available free of charge to Federal employees, current
contractors and grantees, and nonprofit organizations - as supplies
permit - from the Air Pollution Technical Information Center, Environmental
Protection Agency, Research Triangle Park, North Carolina 27711;
or, for a. fee, from the National Technical Information Service, 5285
Port Royal Road, Springfield, Virginia 22161.
This report was furnished to the Environmental Protection Agency
by Midwest Research Institute, Kansas City, Missouri 64110, in fulfillment
of Contract No. 68-02-1437. The contents of this report are reproduced
herein as received from Midwest Research Institute. The opinions,
findings, and conclusions expressed are those of the author and not
necessarily those of the Environmental Protection Agency, Mention
of company or product names is not to be considered as an endorsement
by the Environmental Protection Agency.
Publication No. EPA-450/3-74-085
11
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ACKNOWLEDGEMENTS
This report was prepared for the Environmental Protection Agency's
Office of Air Quality Planning and Standards under EPA Contract
No. 68-02-1437. Mr. Charles 0. Mann served as EPA Project Officer.
The program was conducted in MRl's Physical Sciences Division
under the supervision of Dr. Larry J. Shannon, Head, Environmental
Systems Section. Dr. Chatten Cowherd, Jr., was the Principal Investi-
gator for MRI. Dr. Cowherd was assisted by Ms. Christine Guenther and
Mr. Dennis Wallace.
Approved for:
i
TIJTE
H. M. Hubbard, Director
Physical Sciences Division
8 January 1975
ill
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CONTENTS
Page
List of Figures vii
List of Tables viii
Introduction. ........... ... 1
Unpaved Road Emissions 5
Source Extent 5
Correction Factors ... .... 7
Silt Content 7
Dry Days Per Year 9
Emission Factor. 9
Heavy Construction Emissions. .. 11
Source Extent. ...... 11
Emission Factor. .. ......... 11
Agricultural Tilling Emissions. .. 17
Source Extent. 17
Correction Factors 17
Silt Content 17
Precipitation-Evaporation Index ........... 22
Emission Factor. 24
Unpaved Airstrip Emissions 27
Source Extent 27
Correction Factors 29
Emission Factor. ............... 29
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CONTENTS (Concluded)
Page
Data Tabulations and Accuracies ..... ..... 31
References. .............. 39
VI
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LIST OF FIGURES
No. Page
1 Annual vehicle miles on unpaved roads 6
2 Unpaved roads silt content (percent) 8
3 Emission factors for unpaved roads (Ib/vehicle mile). . . 10
4 Annual acres of construction 12
5 Emission factors for construction (tons/acre) 14
6 Annual acres of land tilled 18
7 Agricultural silt content (percent) 20
8 Precipitation-Evaporation Index 23
9 Emission factors for agricultural tilling (Ib/acre) ... 25
10 Annual LTO cycles on dirt airstrips 28
11 Emission factors for dirt airstrips (Ib/LTO cycle). ... 30
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LIST OF TABLES
No. Page
1 Fugitive dust source parameters 2
2 Construction dollars-to-acres conversion factors 13
3 Estimated annual tillings by crop 19
4 Coded NEDS area source data for Alabama 32
5 Correction factors and corrected emission factors for
Alabama 34
6 Smallest geographical areas assigned single values. ... 36
7 Estimated error ranges for tabulated data 37
Vlll
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INTRODUCTION
Area dust emission sources contribute substantially to the
atmospheric particulate burden in many parts of the country. The
Environmental Protection Agency has identified several fugitive source
categories for inclusion in the National Emissions Data System (NEDS)
area source file. Among them are the following categories of fugitive
dust sources:
1. Unpaved Roads (dirt and gravel),
2. Heavy Construction Sites (such as road and building
construction),
3. Agricultural Land Tilling,
4. Unpaved Airstrips.
To determine the impact of these sources, it is necessary to
develop a national emissions inventory of these sources on a county-by-
county basis. Calculation of county emission totals for each source
category requires, in addition to the basic emission factor, (1) an
appropriate measure of the extent of the source type within the county
and (2) correction factors which adjust the emissions estimates for
local climatic conditions and properties of the emitting surface.
The basic emission factors with associated correction terms were
developed by MRI^/ under EPA Contract No. 68-02-0619. Table 1 lists
the measures of source extent and the correction parameters which are
required for the calculation of corrected emission estimates.
The objective of the program reported herein was (1) the calcula-
tion of source extent and emission factor correction terms on a county-
by-county basis for the source categories designated above, and
(2) the documentation of the methodology used in these calculations,
including procedures used to estimate missing data.
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The following sections of this report present, for each source
category, a comprehensive description of the calculation methodology.
The final data tabulations including the coded NEDS area source data
forms, have been submitted as a separately bound attachment to this
report.
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UNPAVED ROAD EMISSIONS
SOURCE EXTENT
The basic equation for the calculation of annual traffic flow on
unpaved roads in a specified county is given by:
v = 365 (ADT) m (1)
where v is the vehicle miles traveled per year; ADT is average daily
traffic on unpaved roads in the county; and m is mileage of unpaved
roads in the county. The procedure used to determine ADT and m for
each county is depicted in Figure 1.
Regression analysis of statewide traffic counts for unpaved roads
in Kansas yielded the following equation:
ADT = 15 + 2.8 I Z ) (2)
where p is the county rural population?.' and a is the county
area (sq mile).^-/ Kansas was the only state which was found to have
actual ADT data for unpaved roads. For this reason and because Kansas
is thought to be fairly representative of areas of the country with
substantial mileage of unpaved roads, the above ADT correlation was
applied to all of the other states.
Tabulations of the mileage of unpaved roads (surface types A
through E) in each state are prepared annually by the Department of
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Transportation.' However, the county statistics must be obtained
individually from each state.
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Unpaved road mileage data by county for five states (Kansas,'
Nebraska,' Arkansas,' North Dakota,U and South Dakota^/) were
analyzed by plotting mileage density (m/a) versus rural population
density (p/a) for each state. It was observed that for p/a > 8 persons
per square mile, the mileage density becomes essentially independent of
rural population density. For the counties with p/a < 8, further
analysis leads to the conclusion that the dependence of mileage density
on population density was too small to justify development of complex
correlations to be applied to the relatively few sparsely populated
counties. Therefore, for all states (other than the five mentioned
above) the state unpaved road mileage totals were apportioned among
the respective counties on the basis of county area.
CORRECTION FACTORS
The emission factor for dust emissions from unpaved roads-i' con-
tains three correction factors: (1) average vehicle speed; (2) sur-
face silt content; and (3) rainfree days per year.
Based on previous field testing experience,' the average vehicle
speed on unpaved roads was taken to be 40 mph.
Silt Content
The average surface silt content of unpaved roads for each state
was calculated using the following equation (see Figure 2):
s = 3 (DE)(15) + (NS)s
r 3(DE) + NS
where sr is the weighted surface silt content; DE are miles of roads
with surface types D (soil-surfaced) and E (slag, gravel, or stone-
surfaced); NS are the miles of nonsurfaced* roads in the state; and
s~ is the average soil silt content for the state. The value for s~ ,
which represents the silt content for vehicles traveling on dirt roads,
was determined by averaging the county soil silt contents determined
for calculation of agricultural tilling emissions (see Agricultural
Tilling Correction Factors). The constant 15 represents the percent
silt for D- and E-surfaced roads.' The factor 3 is an estimate of
the ratio of vehicle miles traveled on D- and E-surfaced roads compared
to that on nonsurfaced roads.
* Nonsurfaced roads include primitive (type A), unimproved (type B),
and graded and drained (type C) roads.
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Dry Days per Year
The starting point for the determination of the number of dry days
per year for each county was a national map of average annual frequency
of measurable precipitation.&/ If the number of dry days in a given
state varied by less than 20, an average was taken for the state;
otherwise, the state was divided into regions for which the difference
was less than 20, and an average for each region was estimated. Finally,
the dry days for each county were taken to be the average value for the
region or the state in which that county is located.
EMISSION FACTOR
The emission factor for dust emissions from unpaved roadsi' is
given by (see Figure 3):
EFr = 0.49(sr) I < (4)
The factor gives the pounds of dust particles smaller than 30 urn in
diameter* (based on a particle density of 2 to 2.5 g/cnr) emitted by a
vehicle traveling at a speed of 40 mph over a distance of 1 mile.
* The approximate effective cutoff diameter of a standard high-volume
particulate sampler.!/
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HEAVY CONSTRUCTION EMISSIONS
SOURCE EXTENT
The most comprehensive available data on the extent of heavy
construction* in the United States are state construction receipts
as derived from the 1972 Census of Construction.2/ Values are broken
down by SIC subcategory. Figure 4 diagrams the procedure which was
used to go from state construction receipts to acres of construction
by county.
After consultation with construction statistics experts, it
was decided that the most reasonable technique for estimation of
county acres would consist of:
(1) conversion of state construction receipts to equivalent
acres of construction,
(2) apportionment of state construction acreage to counties
on the basis of the fraction of the state construction employment
assigned to each county.2J
The conversion factors for step 1, as presented in Table 2, were
developed by MRI for each SIC subcategory. These were applied
separately to the state construction dollars in each SIC code to
determine the acreage of active construction during the base year
(1972). It should be noted that construction dollars for certain
SIC categories were missing for a few states, and therefore were not
included in the computation of total construction acreage.
EMISSION FACTOR
To determine a state-wide emission factor for dust emissions from
construction activities, it was necessary to multiply the previously
Although heavy construction normally is defined as nonbuilding
construction, both building (SIC Code 15) and nonbuilding (SIC
Code 16) construction were included in this section.
11
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Table 2. CONSTRUCTION DOLLARS-TO-ACRES CONVERSION FACTORS
Factor
SIC code (acres/$106)
1521 5
1522 5
1531 5
1541 5
1542 5
1611 25
1622 25
1623 5
1629 150
determined emission rate factor (1 ton/acre/month)'by an average dura-
tion of construction projects within each state. As indicated in
Figure 5, the average duration was determined from the relative propor-
tions of acreage differentiated by project type and the average duration
of construction for each project type. MRI economists estimated the
average duration of construction to be:
6 months for residential buildings,
11 months for nonresidential buildings,
18 months for nonbuilding construction.
Therefore, the emission factor for heavy construction can be
written as follows:
EFC = D ton/acre (5)
where D is the weighted average duration of construction within a
given state. Note that this factor describes emissions of particles
13
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smaller than 30 urn in diameter* (based on a particle density of 2 to
2.5 g/cm3).
The approximate effective cutoff diameter for a standard high-
volume particulate sampler.'
15
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AGRICULTURAL TILLING EMISSIONS
SOURCE EXTENT
The annual acres of land tilled is the designated measure of
source extent for fugitive emissions from agricultural tilling. Data
used for this determination were (see Figure 6):
(1) harvested cropland by county, in acres; and
(2) an estimation of the number of annual tillings, by crop.
The acres of harvested cropland for all farms on a county basis
was obtained from the 1969 Census of Agriculture.A2/ The number of
annual tillings for major crops was estimated by knowledgeable MRI
personnel (see Table 3). An overall value of three tillings per year
was determined to be representative for all cropland. Therefore,
the acres of land tilled in each county was calculated to be three
times the annual harvested cropland.
CORRECTION FACTORS
Two correction factors were calculated for agricultural tilling:
(1) agricultural soil silt content; and (2) Precipitation-Evaporation
Index (a measure of average surface soil moisture content).
Silt Content
Three soils maps were used in determining agricultural silt
content by county. Figure 7 shows the procedure for this calculation.
A map of the soils of the North Central United States-^!/ was
used as the main source of data for the agricultural belt. This map
classifies soils according to their soil series (the most specific
soil classification unit). Map numbers indicate a predominant soil
series and one or two secondary soil series for each respective
geographical area.
17
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Table 3. ESTIMATED ANNUAL TILLINGS BY CROP
Crop
Barley
Corn
Cotton
Oats
Sorghum
Soybeans
Wheat
Number of tillings
per year
3
3
4, 3 (East, West)
3
2, 3 (East, West)
3
3, 2 (East, West)
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The following steps were taken to convert soil series information
to silt content values:
i 2 /
(1) The soil series were redefined into soil families ' (the
second most specific classification of soils, indicating the texture
of the soil);
(2) The soil texture triangle' was used to estimate silt
content for each family classification;
(3) A representative value of percent silt content was
determined for each map number by weighting the silt content of each of
the one to three soil series silt content values.
The silt content for each county in the 12-state North Central
region was then determined by the following procedure:
(1) The one or two soil map numbers covering the largest
areas within the county were identified and the fraction of the county
that each covered was estimated.
(2) If the map numbers identified in step 1 covered more
than two-thirds of the area, step 3 was skipped.
(3) The soil map number covering the third largest area
within the county was identified and the fraction of the county that
it covered was estimated.
(4) From the fractions of county area determined above,
and the silt content for each soil map number, a weighted value for
soil silt content was calculated.
The second map encompassed the Great Plains region of the United
States-"' and contained several states not included in the first map.
In this case, map numbers specified the soil family classification.
This information was used along with the soil texture triangle I^/
to assign an estimated silt content to each map number. The silt
content for each county was then determined in the manner described
above for the North Central states.
The third map was a soils map of the entire United States. i'
This map indicated only broad soil classifications: orders, suborders,
and great groups. No general procedure was available to determine
family (or texture) classifications from either suborders or great
groups; for this reason, it was not possible to use the soil texture
21
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triangle to estimate silt content. The methods detailed in the para-
graphs below were used to estimate silt content for each great group
(where possible) or suborder indicated on the national soils map.
First, for each soils area outside the states covered by the
first two maps, an attempt was made to locate the designated great
group (or suborder) in one of the previously defined soils areas. If
the desired great group (or suborder) was located, the soils area in
question was assigned the corresponding silt content.
If it was not possible to locate a similar soil for which the
silt content had been previously estimated, a set of scattered soil
texture profiles^-/ was searched. Each of these measured profiles
characterizes a soil suborder, i.e., the dominant soil suborder at the
location where that soil sample was obtained. If a profile for the
corresponding suborder was located, the soil in question was assigned
the silt content from the profile.
Finally, if neither of these procedures was possible, an
estimate of the silt content was made for the suborder based upon the
silt content of the surrounding area and the silt content of other
suborders within the same order.
After each of the suborders was assigned a silt content, the
silt content for each county was determined using the method described
previously for the North Central states.
It should be noted that the method for estimation of silt content
from the national soils map is less accurate than the methods which
utilized the first two maps. Thus, the confidence level of estimates
of silt content for areas not covered by the North Central states
map and Great Plains map is lower. However, agricultural tilling in
areas outside those maps is also less significant.
Precipitation-Evaporation Index
Thornthwaite's Precipitation-Evaporation index' is used to
correct emissions for geographical differences in soil mixture. A
map of PE-index by state climatic division was generated from an
earlier MRI study.!/ A value of the PE-index for each county was
determined by assigning all counties in each state climatic division
the value assigned to that state climatic division. Weighted values
of the PE-index were determined for those counties which were part of
more than one state climatic division. State maps -Is/ indicating both
the state climatic division and the counties were used for assigning
values and weighting functions. This procedure is outlined in Figure 8,
22
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EMISSION FACTOR
The emission factor for dust emissions from agricultural tilling
is given by the following equation:
EFt = iS (6)
t (PE/50)2
where the symbols are defined in Figure 9 and a value of 5.5 mph has
been substituted for average implement speed.
Equation (6) estimates the total emissions of dust particles
smaller than 30 urn in diameter"" (based on a particle density of 2 to
2.5 g/cm3).
* The approximate effective cutoff value for a standard high-volume
particulate sampler.
24
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UNPAVED AIRSTRIP EMISSIONS
SOURCE EXTENT
The measure of source extent for fugitive emissions from un-
paved* airstrips is annual LTO (landing/take-off) cycles. Figure 10
illustrates the procedure used to determine LTO cycles on unpaved
airstrips by county.
Contacts were made with the Federal Aviation Administration to
determine availability and accessibility of data on:
(1) the number of LTO cycles at small airport facilities,
in relation to the number of based aircraft: and
(2) the number of aircraft based at unpaved airstrips
in the United States, by county.
A computer tape with data on each airporti^-' was obtained from
the Washington offices of FAA. Data on this tape included the follow-
ing information for each airport in the United States: site number,
city, state, airport name, county code, latitude, longitude, airport
type, number of total based aircraft, number of multi-engine based
aircraft, runway pavement, runway length, population served, ownership
type and usage type.
The computer tape was processed and punched cards were generated
containing the pertinent information for those airports listed as
pavement type 5. (This pavement type includes dirt, water, sand, and
gravel pavement.) The punched cards were then sorted to eliminate air-
ports with no based aircraft, airports no longer in operation, and
heliport or seaplane bases. Data for over 1,000 airports remained, and
these cards were sorted by county and state codes. It was necessary to
convert the state and county codes from the FAA system to the SAROAD
coding system. This was manually accomplished by code comparison using
an IBM manual2.0-/ and the SAROAD Station Coding Manual./
* Excluding grass (turf) airstrips.
27
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Local FAA officials estimated the number of operations per based
aircraft at small airport facilities to be in the range of 400 to 800
operations per year with a typical value being 500, i.e., 250 LTO
cycles. Thus, the total number of LTO cycles on unpaved airstrips in
each county was calculated by multiplying the total number of aircraft
based at unpaved airstrips by 250.
CORRECTION FACTORS
The emission factor for dust emissions from unpaved airstrips
contains five correction parameters (see Figure 11):
(1) the surface texture, measured as percent silt content;
(2) the average LTO speed, estimated to be 40 mph;
(3) the surface soil moisture as determined by annual
number of dry days;
(4) the length of runway used for one complete LTO cycle,
estimated to 1 mile; and
(5) a wind-erosion multiplier, estimated to be equal to 2.
The silt content on a state basis and the annual number of dry
days on a county basis were assumed to be the same as those developed
as correction factors for unpaved roads. The estimates for average
LTO speed and length of runway used" in one LTO cycle were derived
from conversations with local FAA officials. The wind-erosion multi-
plier is an estimated value which accounts for the emissions generated
by the propeller wash.
EMISSION FACTOR
The emission factor for unpaved airstrips (Ib/LTO cycle) was
derived by analogy to the equation for unpaved roads. The equation for
unpaved airstrips is given by:
EFa = 2
0.49 si.
(7)
Predominate use of unpaved airstrips is limited to single-engine
aircraft.
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DATA TABULATIONS AND ACCURACIES
Two types of data tabulations were prepared as part of this
study:
(1) coded NEDS area source data forms, listing source
extent for each designated source category, on a county-by-county basis,
(2) tabulations of the correction factors and the corrected
emission factors for each source category, on a county-by-county basis.
Example completed forms (for Alabama) are shown in Tables 4 and 5.
A listing of data specificity of the submitted tabulation is pre-
sented in Table 6. As indicated, for some correction factors, single
values were assigned to multi-county regions or to states as a whole
rather than to individual counties.
The annual number of dry days and silt content for unpaved roads
and airstrips (mostly D- and E-surfaced) do not vary sharply enough
to justify calculation of separate values for each state. In the
case of duration of construction activity, county construction data
were not available.
Table 7 presents estimates for possible error in the calculated
data. These values correspond to a 90% confidence level. They were
determined by a progressive analysis of the errors associated with each
calculation step. Separate values are presented for the source
extent and the corrected emission factor for each source category.
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-------
Table 7. ESTIMATED ERROR RANGES FOR TABULATED DATA
Estimated relative error
Source category Extent of source Corrected emission factor
±
Unpaved roads
Heavy construction ± 40% ± 50%
Agricultural tilling ± 15% ± 30%
Dirt airstrips ± 25% ± 30%
37
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REFERENCES
1. Cowherd, C., Jr., K. Axetell, Jr., C. M. Guenther, and G. A.
Jutze, Development of Emission Factors for Fugitive Dust
Sources, prepared for the U.S. Environmental Protection
Agency, Office of Air and Waste Management, Office of Air
Quality Planning and Standards, Contract No. 68-02-0619,
Publication No. EPA-450/3-74-037, June 1974.
2. County and City Data Book 1972, a Statistical Abstract Supplement,
U.S. Department of Commerce, Bureau of the Census, U.S. Govern-
ment Printing Office, Washington, D.C. (1973).
3. Highway Statistics 1972, U.S. Department of Transportation, Fed-
eral Highway Administration, Washington, D.C., Table M-3,
October 1973.
4. "Number of Miles and Annual Average Daily Vehicle Miles of Travel
on Local Rural Roads in Kansas by County for the Year Ending
December 31, 1972," State Highway Commission of Kansas Planning
and Development Department, August 10, 1973.
5. Nebraska Highway Statistics State and Local Construction Mileage
for 1972, Nebraska Department of Roads, Office of Engineering
Services, Planning Division, Highway Statistics Unit, September
1973.
6. Arkansas Road and Street Mileages, Arkansas State Highway Depart-
ment, Division of Planning and Research, in cooperation with
the Federal Highway Administration, U.S. Department of Trans-
portation, January 1, 1973.
7. "Miles of Unpaved Roads by County," estimated for North Dakota
and South Dakota, personal communication from Charles Mann,
U.S. Environmental Protection Agency, National Air Data Branch,
July 23, 1974.
39
-------
8. Climatic Atlas of the United States, U.S. Department of Commerce,
Environmental Science Services Administration, Environmental
Data Service, U.S. Government Printing Office, Washington, D.C.,
June 1968.
9. 1972 Census of Construction Industries, Preliminary Report, U.S.
Department of Commerce, Bureau of the Census.
10. 1969 Census of Agriculture, County Summary, Table 2, U.S. Depart-
ment of Commerce, U.S. Government Printing Office, Washington,
B.C.
11. "Major Soils of the North Central Region, U.S.A.," a map from
Soils of the North Central Region of the United States,
North Central Regional Publication No. 76, Bulletin 544,
published by the Agricultural Experimental Station, University
of Wisconsin, in cooperation with the U.S. Department of
Agriculture, June 1960.
12. Soil Series of the United States, Puerto Rico, and Virgin Islands:
Their Taxonomic Classification, Soil Conservation Service,
U.S. Department of Agriculture, pp. 1-1 through 1-228, April
1972.
13. "Guide for Textural Classification in Soil Families," supplement
to Soil Classification: A Comprehensive System, Seventh Approxi-
mation, Soil Survey Staff, Soil Conservation Service, U.S.
Department of Agriculture, p. 40, March 1967.
14. "Soils of the Great Plains," soil map, copyright A.R. Aandahl, 1972,
P. 0. Box 81242, Lincoln, Nebraska.
15. "Distribution of Principal Kinds of Soils: Orders, Suborders, and
Great Groups," a map from the National Atlas, Sheet No. 85/86,
U. S. Geological Survey, Soil Conservation Service, Washington,
D.C. (1967).
16. Soil Classification: A Comprehensive System, Seventh Approximation,
Soil Conservation Service, U. S. Department of Agriculture,
August 1960.
17. Thornthwaite, C. W., "Climates of North America According to a New
Classification," Geograph. Rev., 21:633-655 (1931).
40
-------
18. State maps, National Climatic Center, Asheville, North Carolina.
19. "Airport Services Tape," Federal Aviation Administration, Public
Information Center, AIS 230, Washington, D.C. 20591.
20. Numerical Code for States, Counties, and Cities of the United
States, IBM Manual C20-8073-0.
21. Fair, Don H., SAROAD Station Coding Manual for Aerometric Sampling
Networks, U.S. Environmental Protection Agency, Office of Air
Programs, Research Triangle Park, North Carolina, Publication
No. APTD-0907, February 1972.
41
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO.
EPA-450/3-74-085
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Emissions Inventory of Agricultural Tilling,
Unpaved Roads and Airstrips, and Construction Sites
5. REPORT DATE
November 1974
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Chatten C. Cowherd, Jr., Christine M. -luenther, and
Dennis D. Wallace
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 64110
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-1437
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
To determine the air pollution impact of selected fugitive dust sources, a
national emission inventory on a county-by-county basis was developed. Source
categories included were unpaved roads, unpaved airstrips, heavy construction
sites (road and building construction), and agricultural land tilling. Emission
factors, which include correction factors to adjust for local climatic conditions
and properties of emitting surfaces were calculated for each county based m
the results from EPA Contract No. 68-02-0619. Measures of the extent of activity
for each category were derived from available data. The methodology including
procedures used to estimate missing data, is documented in the report. The surce
data were coded on National Emission Data System (NEDS) area source forms.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Emission Factors
Correction Factors
NEDS
13. DISTRIBUTION STATEMEN1
Release Unlimited
21. NO. OF PAGES
41
20. SECURITY qLA.SS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
42
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