U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
PUBLIC HEALTH SERVICE
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AIR POLLUTION IN THE
NATIONAL CAPITAL AREA
An appraisal made at the request of the
District of Columbia Department of Public Health
with the cooperation of the
Maryland State Department of Health and the
Virginia Department of Health
by
Gene B. Welsh
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Division of Air Pollution
Technical Assistance Branch
Washington 25, D. C.
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PHS Pub. No. 955
July 1962
For sale by the Superintendent of Documents, U. S. Government Printing Office,
Washington 25, D. C. Price 35 cents
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CONTENTS
Page
Summary and Recommendations v
Introduction 1
General Factors Affecting Air Pollution 3
Dispersion of Pollutants 7
Sources of Pollution 12
Indications of Air Pollution Levels 21
Status of Local Activity in Air Pollution 28
References 33
Appendix 35
LIST OF FIGURES
Figure Page
1 Washington Metropolitan Area Urbanized
Districts as of I960 Census 2
2 New Industrial Areas, Washington Metropolitan
Area 8
3 Washington Metropolitan Area Surface Wind
Roses by Months 11
111
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TABLES
Table Pa8e
1 Population Growth and Densities in the Washington
Metropolitan Area .................... 4
2 Washington Metropolitan Area Employment,
October, 1959 ........................ 5
3 Employment in Manufacturing Industries
Washington Metropolitan Area, October, 1958 .... 6
4 Seasonal Percent of Nighttime Cloud Cover and
Wind Speed, Washington, D. C., 1950-1954 ...... 12
5 Normal Monthly Degree Days for Washington
Metropolitan Area, 65° F Base (1921-1950) ..... 14
6 Summary of Refuse Disposal Practices, Washington
Metropolitan Area ..................... 19
7 Summary of Metropolitan Washington Major Manu-
facturing Industries and Their Contributions to
the Air Pollution Problem ................. 20
8 Concentrations of Oxidant and Sulfur Dioxide,
1953-1954 Study ...................... 23
9 Suspended Particulate Pollution in Washington, D. C.
as Measured in the National Air Sampling Net-
work 1953-1959 ........................ 24
10 Comparison of Suspended Particulate Pollutants for
Several Urban Stations 1957-1958 ............ 25
11 Seasonal Variation of Particulate Pollutants in
Washington, D. C., 1953-1959 ............... 27
12 Local Air Pollution Control Activities, Washington
Metropolitan Area ...................... 31
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SUMMARY AND RECOMMENDATIONS
Air pollution in the Washington Met-
ropolitan Area may be expected to increase
rapidly, unless adequate control measures
are taken. The Washington Metropolitan
Area anticipates rapid and continued pop-
ulation growth, particularly in the urban-
ized areas adjacent to the District of
Columbia, where sixty-two per cent of the
Area's 2 million people already live. This
growth rate - Area population more than
doubled since 1940 - favors higher pollu-
tion levels in the future because of in-
creasing pollutant emissions.
Despite topography and prevailing
wind conditions generally favorable to
dispersion of air pollutants, incidents of
eye-irritating smog, visibility reduction,
and plant damage have been experienced
in the Area evidence that photo-chemi-
cal air pollution is becoming a serious
problem. One or two prolonged periods
of stagnating air masses, usually during
late summer and fall, may be expected
each year, with a subsequent accumula-
tion of air pollutants.
Waste disposal operations such as
incinerators, backyard burning, open
burning dumps, the burning of leaves and
wastes of construction and demolition are
a significant contribution to the total air
pollution problem, as are motor vehicle
emissions, the combustion of coal and
oil for heating, power generation, and in-
dustrial processes. And the use of nat-
ural gas, although lesser in magnitude,
adds to emissions of certain gaseous
pollutants present at levels higher than in
some other cities of similar population.
Even though previous studies indicate
that the atmospheric particulate loading
in Washington is lower than in most
cities of comparable size, excessively
high loadings do occur. All the named
sources add to the total atmospheric
burden and may be expected to become
increasingly important as the Area con-
tinues to grow.
Enforcement of zoning laws in the
Washington Metropolitan Area has not
allowed the intermingling of residential,
commercial, and industrial land uses and
prevented some localized air pollution
problems which otherwise would have oc-
curred. This fact, along with the limited
extent of manufacturing operations, has
kept the industrial air pollution problem to
a minimum. Nevertheless, each govern-
mental jurisdiction has localized industrial
areas that are significant from an air pol-
lution standpoint. These small industrial
areas are responsible for a large portion
of the nuisance complaints made by the
public to the respective governmental agen-
cies, primarily concerning dusts, fumes,
smoke, and odors from specific sources.
Local interest in air pollution already
exists among officials and the general
populace and to judge by newspaper reports
is steadily increasing. Except for limited
smoke abatement activities, the air pol-
lution control program in the various local
governmental jurisdictions is directed
primarily toward investigation of nuisances
and complaints. At the request of the Dis-
trict of Columbia Department of Public
Health and with the cooperation of the Mary-
land State Department of Health and the
Virginia Department of Health, the Public
Health Service conducted an appraisal of
factors relating to air pollution in the Wash-
ington Metropolitan Area. This appraisal
was undertaken to determine the extent of
the existing and potential air pollution
problem and control activities, and to de-
velop general recommendations for activi-
ties to meet present and future air pollution
problems. This report is an analysis of in-
formation collected relating to sources of
pollutants, indications of pollution levels,
and status of local activities in the air
pollution field.
Recommendations
The following recommendations are
made on the basis of this appraisal and the
general available knowledge relating to
air pollution. A limited amount of data on
atmospheric pollution levels was available
from the National Air Sampling Network,
from some limited studies conducted sev-
eral years ago, and from a one-week pilot
study that was recently conducted by the
District of Columbia Department of Public
Health and the Public Health Service.
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The first section pertains to the Dis-
trict of Columbia and the second to the sub-
urban areas of Maryland and Virginia that
are adjacent to the District of Columbia.
The District of Columbia
1. Considering the nature and magni-
tude of the present and potential air pol-
lution problem -within the District of Co-
lumbia, it is recommended that a com-
prehensive air pollution control program
be established. Such a program should
provide not merely for smoke control,
as at present, but for comprehensive air
pollution control. The program should
include:
a. Routine air quality monitoring to
determine specifically the nature
and extent of air pollution within the
District.
b. An inventory of air pollution
sources to provide current data on
the quantity and types of air pollu-
tion emissions. Detailed sampling
and evaluation of certain sources
may be necessary to fully define
specific emissions.
c. A public education program to
disseminate complete and accurate
information about the nature, effects,
and costs of air pollution in the
District.
d. A permit or registration system
for the identification and control of
non-combustion sources of air pol-
lution. (Such a system exists for
combustion sources.)
e. Investigation of air pollution
complaints and, when indicated, in-
itiation of appropriate abatement
measures.
f. Implementation of additional air
pollution abatement programs when-
ever new information indicates a need
for them.
2. Necessary budget, personnel, and
laboratory facilities should be provided to
support the comprehensive air pollution
control program outlined above.
3. A study and review should be made
of existing regulations pertaining to air
pollution control so that necessary re-
visions can be made.
4. Appropriate consideration should
be given to planning and zoning activities
to minimize the intermingling of industrial
and residential areas.
5. An interdepartmental committee or
council should be organized to coordinate
the total air pollution program within the
District of Columbia. This group should
include representation from all of the Dis-
trict of Columbia governmental agencies
directly concerned with air pollution
control.
6. A Metropolitan Air Pollution Ad-
visory Board or Council should be organized
to provide leadership and cooperation for
the development of coordinated efforts
toward the study or control of air pollution
in the Washington Metropolitan Area. This
advisory group should include at least one
representative from the agency responsible
for air pollution control in the District of
Columbia, in each of Montgomery and Prince
Georges Counties in Maryland, and in Arling-
ton and Fairfax Counties and the city of
Alexandria in Virginia. Representatives of
interested Federal and State governmental
agencies should also be included.
The Suburban Areas
1. In view of the present and potential
air pollution problems in the suburban areas
of Maryland and Virginia that are adjacent
to the District of Columbia, it is recom-
mended that modest air pollution control
programs be developed within the local gov-
ernmental agencies. These programs should
initially consider the following:
a. Investigation of air pollution com-
plaints and initiation of abatement
measures when indicated.
b. Public education activities to dis-
seminate complete and accurate in-
formation about the nature, effects and
costs of air pollution in the Washington
suburbs.
c. Surveillance of air pollution problems
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by means of periodic air sampling
and identification of major air pol-
lution sources.
d. Implementation of additional air
pollution abatement programs when-
ever new information indicates a need
for them.
e. Collaboration with other local
governmental jurisdictions in the
organization of a Metropolitan Air
Pollution Advisory Board or Council
for the coordination of efforts toward
the study and control of air pollution
in the Washington Metropolitan Area.
2. It is recommended that the in-
dividual programs develop long-range
objectives for a comprehensive air pol-
lution control program that would expand
their activities to include:
a. Routine air quality monitoring.
b. Inventory and identification of air
pollution sources.
c. Ordinances or regulations spe-
cifically for air pollution control.
d. Adequate budget, personnel, and
laboratory facilities to support a com-
prehensive air pollution control program.
3. It is recommended that enabling leg-
islation be obtained in Maryland and Virginia
to allow the formation of interjurisdictional
air pollution control districts. This would
permit the establishment of a coordinated
and unified air pollution control program in
the Virginia portion of the Washington Metro-
politan Area and another in the Maryland
portion.
4. It is recommended that, contingent
on the enactment of such legislation, the
local governmental jurisdictions in Mary-
land and Virginia that are a part of the
Washington Metropolitan Area seriously
consider the formation of air pollution
control districts within their respective
States.
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INTRODUCTION
The Area
Washington, D. C., capital of the United
States and seat of the Federal Government,
is situated between Northern Virginia and
Southern Maryland on the east bank of the
Potomac River about 100 miles above its
mouth. The City of Washington is coexten-
sive with the District of Columbia and has
a total area of about 69 square miles, of
which approximately 8 square miles are
covered by water. (1) The altitude ranges
from about 10 to 500 feet above sea level.
As defined by the U.S. Bureau of the
Census, the Washington Standard Metropoli-
tan Area consists of Washington, D. C.,
Montgomery and Prince Georges Counties
in Maryland, Arlington and Fairfax Counties
in Virginia, and the independent Virginia
cities of Alexandria and Falls Church. (2)
The term Washington Metropolitan Area, as
used in this report, means the standard
metropolitan area as defined above. Wash-
ington, D. C., and the immediately adjacent
urbanized areas of Maryland and Virginia
(Figure 1) comprise the area of particular
interest because they contain practically all
of the metropolitan area population and in-
dustry. The outlying areas of Montgomery
and Prince Georges Counties in Maryland
and Fairfax County in Virginia are primarily
rural with a population density less than 1000
per square mile.
established to promote the control of
obnoxious noises, smoke, and fumes from
automotive equipment operated within the
Washington Metropolitan Area. As a result
of several committee meetings and other
activities, the District of Columbia Board
of Commissioners in July of I960 proposed
that the District of Columbia Fuel Burning
Equipment Regulations and the Traffic and
Motor Vehicle Regulations be amended to
require reduction of air pollution from
certain sources. Following public hear-
ings, the Traffic and Motor Vehicle Regu-
lations were amended in September I960
and the Fuel Burning Regulations were
amended in April 1961.
In July of I960 the District of Columbia
Department of Public Health requested that
the Public Health Service Regional Office
in Charlottesville, Virginia, conduct a study
of the total environmental health problems
and programs in the District of Columbia.
The Technical Assistance Branch of the
Division of Air Pollution completed that
portion of the environmental health study
pertaining to air pollution. It was later
agreed that in addition to complying with
the original request the air pollution study
should be expanded to provide a general
appraisal of the total air pollution problem
in the Washington Metropolitan Area and
general recommendations for the guidance
of local officials.
Local Interest in Air Pollution
During June 1959 the Washington Metro-
politan Area experienced a four day episode
of eye irritating smog. The following Decem-
ber a local newspaper published a series of
five informative articles dealing with the air
pollution problem, especially that due to
automobile exhaust, in the Washington Metro-
politan Area.
In May of I960, the Engineer Commis-
sioner for the District of Columbia and the
Metropolitan Area Traffic Council organized
an Automotive Nuisance Abatement Com-
mittee of that Council. This Committee was
The Study
In accordance with the amended re-
quest, this appraisal of air pollution prob-
lems in the Metropolitan Washington Area
had three objectives:
1) To review and evaluate the existing
and potential air pollution problems of the
Metropolitan Area.
2) To review briefly air pollution con-
trol activities presently being conducted by
the respective local governmental agencies.
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WASHINGTON METROPOLITAN AREA
URBANIZED DISTRICTS AS OF
I960 CENSUS(2)
LEGEND
Districts with population
density of 1,000 persons or
more per square mile shaded.
Figure 1
- 2
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3) To develop recommendations for
the guidance of local officials in meeting
existing and future air pollution problems.
The scope of the study was limited to
consideration of available information re-
garding air pollution, including: activities
which cause pollution, evidence of pol-
lution levels, meteorological and topo-
graphical influences on dispersion of
pollutants, local air pollution control
activity, and other relevant community
characteristics. In view of these limita-
tions this report should be considered a
preliminary appraisal of air pollution
problems in the National Capital Area.
An engineer from the Technical As-
sistance Branch, Division of Air Pol-
lution, collected the data and prepared
this report. Valuable assistance was
given by personnel of various agencies
of the District of Columbia Government,
public health officials from suburban
Virginia and Maryland, trade associa-
tions, official and unofficial business and
industrial organizations, and interested
agencies of the Federal Government.
Specific acknowledgment is made to the
Environmental Meteorological. Research
Projects of the U. S. Weather Bureau
for their assistance in preparing the
meteorological and climatological data
for this report.
GENERAL FACTORS AFFECTING
AIR POLLUTION
Air pollution levels in any community
depend principally on the quantity, type,
and rate of discharge of pollutants to the
atmosphere and the ability of the atmos-
phere to disperse these pollutants. In
addition, some air pollutants are the re-
sult of reactions that occur between con-
taminants in the atmosphere.
Population, general character of in-
dustry and employment, and land use are
all general factors that are directly re-
lated to the discharge of pollutants to the
atmosphere. The ability of the atmosphere
to disperse the pollutants is directly re-
lated to certain meteorological and topo-
graphical factors.
Population
Daily activities of the general public
are responsible for the emission of certain
pollutants to the atmosphere. Activities
such as combustion of fuels for space and
water heating, cooking, transportation, and
the burning of rubbish and other waste ma-
terials contribute a significant amount of
pollution each day. The amount of air pol-
lution contributed by any one individual is
very small, but collectively, the total emis-
sions may reach enormous proportions. In
sparsely settled areas these emissions are
dispersed into the atmosphere and readily
assimilated, but as the population density
increases more pollutants are discharged
and it becomes increasingly difficult for the
atmosphere to disperse them. Population
estimates are an index of future pollution
levels, since a population increase is ac-
companied by an increase in pollution
emissions, both from the activities of the
general public and the accompanying in-
creased industrial-commercial activity.
The I960 census reported the popula-
tion of the Washington Standard Metropoli-
tan Area as 2,001,897, a net increase of
537,808 over the 1950 census even though
the population of the central city decreased
about 5 percent. (2) Approximately 62 per-
cent of the Metropolitan Area population
lives outside of Washington, D. C. Popula-
tion density for Washington, D. C., is high
in comparison to other cities in the United
States but the population densities for sub-
urban Maryland and Virginia are relatively
low. (Figure 1)
The Washington Metropolitan Area has
shown a consistent growth over the last
thirty years. Since 1930 population has
approximately tripled, a growth rate sur-
passing all other metropolitan areas among
the ten largest in the United States. (4) The
growth of the Washington Metropolitan Area
from 1940 to I960 is shown by Table 1.
The suburban areas of Maryland and
Virginia have shown tremendous growth in
recent years. The population of Fairfax
County, Virginia, has tripled in the last ten
years and in Montgomery and Prince Georges
Counties in Maryland the population has
doubled in the last ten years. It is anticipated
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TABLE 1
POPULATION GROWTH AND DENSITIES IN
THE WASHINGTON METROPOLITAN AREA
1940
1960
(2)
WASHINGTON SUBURBAN SUBURBAN
* AK D. C. MARYLAND VIRGINIA
1960A/ 763,956 698,323 539,618
1950JL/ 802,178 358,583 303,328
1940JL/ 663,091 173,402 131,492
TOTAL
2,001,897
1,464,089
967,985
POPULATION DENSITY I960
Land Area - 61 979 448
sq. miles
Population 12,525 715 1,205
density C/
1,488
1,345
A/ Final I960 Census Figures
B/ U.S. Bureau of the Census, Census of 1940 and 1950
C/ People per square mile
that practically all of the future growth in
the Washington Metropolitan Area will oc-
cur in the suburban areas of Maryland and
Virginia. Estimates indicate a continued
substantial growth for the Washington Met-
ropolitan Area, with a population of about
2,750,000 by 1970 and 3,500,000 by 1980.
(4) Air pollution levels will increase ac-
cordingly, unless steps are taken to con-
trol the emission of pollutants, because the
greater the population the greater the
activities that contribute to air pollution.
General Character of
Employment and Industry
The business life of the Washington
Area is determined largely by the fact
that it is the location of the nation's Capi-
tol. Also, the area is fast becoming one
of the world's leading science centers with a
larger portion of its population employed in
scientific and professional effort than any
other large metropolitan area in the United
States. The area has limited manufacturing
and other industry but does have a flourishing
retail trade and ranks high as a retail trading
center.
Table 2 shows the total employment in
the Washington Metropolitan Area as of
December I960. (4) The limited manufactur-
ing employment is offset by the high Federal
Government employment in the area. The
Federal, State, District of Columbia, and local
governments and the military services ac-
counted for approximately 40 percent of the
employment in the Washington Metropolitan
Area as of December I960. As may be ex-
pected, the second highest percentage of the
total employment is directed toward providing
necessary goods and services.
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TABLE 2
WASHINGTON METROPOLITAN AREA ESTIMATED EMPLOYMENT
DECEMBER I960 (4)
INDUSTRY
Federal Government (Civilian)
Wholesale and Retail Trade
Military Service
1 Construction
Ul
1 D. C., State, & Local Government
Professional Services & Organizations
Transportation, Communication, & Public Utilities
Personal Services & Domestics (Private Home)
Finance, Insurance, & Real Estate
Business, Repair, and Recreation Services
Manufacturing
Self -Employed
Mi s c ell ane ou s
WASHINGTON
174,400
' 83,697
23,800
21,149
25,100
42,500
28,400
28,300
25,632
17,200
20,684
33,000
8,500
SUBURBAN
MARYLAND
27,400
33,252
9,200
16,479
18,100
4,000
3,300
9,500
7,251
8,300
10,159
13,500
6,900
SUBURBAN
VIRGINIA
37,100
28,482
25,400
12,989
9,600
3,300
14,600
6,300
5,444
10,900
4,319
12,400
1,800
TOTAL
238,900
145,431
58,400
50,617
52,800
49,800
46,300
44,100
38,327
36,400
35,162
58,900
17,200
Totals 532,362 167,341 172,634 872,337
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TABLE 3
EMPLOYMENT IN MANUFACTURING INDUSTRIES
WASHINGTON METROPOLITAN AREA, OCTOBER 1958
INDUSTRY
Ordnance and accessories
Food and beverages
Apparel and other similar finished products
Lumber and products (except furniture)
Furniture and fixtures
Paper and allied products
i Printing and publishing
o- Chemicals and allied products
i Paving and roofing materials
Rubber and miscellaneous plastics products
Luggage
Stone, clay, and glass products
Primary metal industries
Fabricated metal products
Machinery (except electrical)
Electrical machinery
Transportation equipment
Scientific instruments
Miscellaneous
TOTAL NUMBER
PLANTS
1
107
23
62
46
9
339
32
11
6
1
81
4
78
28
43
6
29
38
~ ~
NUMBER OF
EMPLOYEES
125
7,826
"1 17 1
271
858
731
975
12,646
1,212
398
144
i a
ID
2,407
C O
58
2,715
347
8,285
214
1,037
387
.
Totals
944
40,651
Note: Total not comparable with data in Table 2 due to changes in the Standard Industrial Classification Code.
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In 1954 there were 854 manufacturing
establishments in the Washington Metro-
politan Area (5), and in October 1958 there
were 944, as shown by Table 3. (6) Princi-
pal industries are printing and publishing,
electrical machinery, and food and bever-
ages. Based on the 1958 data these three
industry classifications account for 52 per-
cent of the industrial plants and 71 percent
of the industrial employees in the Wash-
ington Metropolitan Area.
Land Use
Most of the land in the Washington
Metropolitan Area is useful. There is no
great expanse of swampland or other
waste-land. The land use pattern for the
metropolitan area shows that the District
of Columbia and the immediately adjacent
portions of suburban Maryland and Vir-
ginia are primarily concentrated residen-
tial areas, with relatively large areas
devoted to parks and governmental uses.
(7) In 1955 more than 42 percent of the
land area in the District of Columbia was
owned by the Federal Government. (8)
Although the exact proportion has not been
determined, it appears that the Federal
Government land ownership in suburban
areas of Maryland and Virginia that are
adjacent to Washington, D. C., may also
approach this magnitude. In addition to
the large areas of Federally owned land
that are devoted to parks and recreational
use, the State and local governments have
also provided large areas of land for these
purposes.
The industrial sections of the Wash-
ington Metropolitan Area are located
primarily along the Potomac and Ana-
costia River water fronts, along the rail-
road tracks, and along the main North -
South Highway. The main concentration
of industries is located in the Alexandria-
South Arlington area of Virginia and the
Northeast sector of the District of Colum-
bia. A wide variety of industries is present
in the Washington Metropolitan Area, but
in general they are classified as light
industries.
Several new industrial parks are being
developed in Suburban Maryland and Vir-
ginia as well as in the District of Colum-
bia. Figure 2 shows the general location
of the new industrial parks. They range in
size from several acres to several hundred
acres, and are generally located in outlying
suburban areas. (9) All of these sites are
generally protected by adequate zoning reg-
ulations as well as by restrictions and
performance standards regarding the types
of industries permitted.
In general, the land use pattern of the
Washington Metropolitan Area has not per-
mitted the intermingling of industrial and
residential areas. In some cases, the de-
velopment of industrial areas adjacent to
residential areas preceded the development
and enforcement of adequate zoning and
land use planning. This appears to be the
case in some of the older sections of the
metropolitan area such as Georgetown and
Alexandria. A land use pattern that permits
the intermingling of industrial and resi-
dential areas promotes the occurrence of
air pollution problems because it brings
major pollution sources into close proximity
with susceptible receptors.
DISPERSION OF POLLUTANTS
Topography
The Washington Metropolitan Area is
located at the western edge of the middle
Atlantic Coastal Plain, 35 miles west of the
Chesapeake Bay and far enough inland from
the ocean to escape the sea breeze effects
that normally occur along the coast during
the warmer months. The Blue Ridge
Mountains, rising to an elevation of 3,000
feet or more, are about 50 miles west of the
Washington Metropolitan Area, and the
orographic effects of these mountains is one
of warming and drying of westerly winds
reaching the area.
The terrain to the east of the Washington
area is generally flat, with elevations being
less than 100 feet above sea level. To the
west, gently rolling hills, with elevations of
200 to 500 feet above sea level, extend to the
Blue Ridge Mountains. Consequently, the
topography in the vicinity of the Washington
area generally allows free air movement
with little channeling effects.
Meteorological Factors in Air Pollution
Air pollution generally decreases with
increasing wind speed, i.e., the volume of air
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NEW INDUSTRIAL AREAS
WASHINGTON METROPOLITAN AREA
MARYLAND
COUNTY
Va.U Md.
LEGEND
.State Boundary Lines
, County Boundary Lines
Railroads
Highways
New Industrial Areas
- 8 -
Figure 2
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into which pollutants are emitted is directly
proportional to wind speed and the concentra-
tion of airborne pollutants is inversely pro-
portional to wind speed. However, high winds
are not always beneficial, since local inci-
dences of high pollution can result from aero-
dynamic downwash of stack effluents. In es-
sence, wind speed and direction data yield
an index to horizontal transport and diffusion
of airbonre material, and thus indicate a
rate of ventilation.
Of equal importance is the extent of
vertical mixing in the atmosphere, implied
by the temperature distribution with height.
When there exists a large decrease of tem-
perature with an increase in height, the air
is unstable, and turbulence and vertical ex-
change of material occur readily; however,
when there is a small decrease or increase
(inversion) of temperature with an increase
in height, the air is stable with little or no
turbulence. The effect at the ground surface
usually depends on whether the stable layer
is at the surface or aloft. If aloft, pollutants
may rise and accumulate under the temper-
ature "lid," only to be brought to the ground
surface in high concentrations when convec-
tive heating processes occur in a vigorous
mixing of the air between the surface and
the elevated stable layer. Such "fumigation"
processes usually occur shortly after sun-
rise. If the stable layer extends from the
ground surface upward, which is the usual
situation for nocturnal inversions, diffusion
of pollutants is restricted in the vertical
so that they tend to spread horizontally.
Such low-level stabilization is usually ac-
companied by calm or light winds, thereby
giving rise to a condition of poor ventilation
and limited vertical mixing and thus to a
limited volume of air for pollutant dispersion.
In urban areas there are parameters to be
considered which may promote some dilution.
Heat sources such as buildings, automobiles,
etc., can provide energy for convective mix-
ing, and a light wind flow over the irregular
surface of a metropolitan area can enhance
vertical mixing. Hence, marked vertical
stratification of polluted layers is probably
more frequent in suburban and nearby rural
areas than "downtown." Topographic fea-
tures may influence diffusion processes; how-
ever, such influences are not necessary in
order for stagnant weather conditions to
occur. This can be exemplified by the
Greater London smog episode of December
5-9, 1952. Because of their combined ef-
fect on temperature profile, air drainage,
and radiation, valleys may influence the
diffusion processes. Some of the river
valleys in the Washington area may have
local effects on atmospheric diffusion.
The effects of moisture content of the
air and condensation processes on atmos-
pheric pollution are not so direct. Since
precipitation is usually associated with
unstable weather regimes, and thus with
good diffusion, the potential washout
process is usually of no concern. The
role of fog in air pollution is also indirect,
since the meteorological circumstances
which favor poor diffusion also favor the
formation of radiation fog. To the extent
that fog may attenuate solar radiation reach-
ing the surface during daytime hours and
thus restrict convective mixing processes,
its presence may enhance poor diffusion.
Stagnant Weather Conditions
While short-duration diffusion anomalies
are common to most areas and can cause
pollution problems, the most dramatic and
by far the most insidious community prob-
lems involving atmospheric pollution are
those resulting from prolonged stagnant
weather regimes, which are usually en-
hanced by topographic influences. Large
scale atmospheric stagnation was respon-
sible for most of the well-known disastrous
episodes, such as those of the Meuse Valley,
Donora, and Greater London. Although the
simultaneous occurrence of light and vari-
able winds, great stability in the lower at-
mosphere, and often fog, causing a build-up
of high pollutant concentrations, is not un-
usual, the persistence of such weather con-
ditions for several consecutive days rarely
occurs in most areas, other than those
dominated by semi-permanent high pres-
sure systems, such as the Pacific High off
the California coast.
In the United States, east of the Rocky
Mountains, stagnation periods lasting for
several consecutive days are generally as-
sociated with slowly moving or quasi-sta-
tionary high pressure systems. Subsiding
air from aloft, associated with these high
pressure systems, causes a warming of the
air in its descent and an inversion is estab-
lished at levels from about 800 to 3,000 feet
- 9 -
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above the surface. This "subsidence inver-
sion" persists throughout the day and night
and acts as a lid to vertical mixing during
daylight hours. The combination of light
wind speeds at the ground and aloft gives
rise to a low rate of ventilation and restric-
ted vertical mixing. This results in a
greatly reduced volume of air into which
pollutants are emitted, causing pollution
concentrations higher than usual.
Recent studies (10,11) of these stag-
nant episodes show that over a 21-year
period the Washington area experienced 144
days of stagnation and 30 stagnation epi-
sodes with at least 4 consecutive days of
stagnation. This averages about 7 stagna-
tion days and 1.5 stagnation episodes per
year. Such stagnation periods usually oc-
cur during the summer or fall months, with
August, September, and October the months
having the highest frequency in the Washing-
ton area.
General Climatology
The Washington area climate has the
seasonal and daily variations characteristic
of the eastern seaboard, with moderate
winters and frequent intervals of high hu-
midity and oppressive heat in the summer.
The winter season is generally shorter and
milder than in cities located to the north and
west. This affords reduced heating require-
ment during the winter. During the summer,
high temperatures may average in the upper
eighties, but temperatures of 90° F to 100°
F are not uncommon. (12,13)
The average annual precipitation is
about 41 inches, with no pronounced wet or
dry season. While the annual snowfall aver-
ages about 20 inches, greater amounts can
be expected in nearby western and northern
suburban areas.
Surface wind roses by months are shown
in Figure 3. During the colder months of
the year, winds from the northwest quadrant
are most frequent, while winds from the
south and southwest prevail during the sum-
mer season.
The frequent movement of cold polar
and Arctic air masses into the Middle At-
lantic States from Canada result in a pre-
vailing northwest flow of unstable air in
Washington from late November through
April. The unstableness and relatively
high wind speeds attending these air
masses result in good atmospheric dilution
conditions. These good diffusion regimes
are interrupted for only brief periods, oc-
casioned by nocturnal radiation inversions
when skies are clear and winds subside, or
by light southerly flow which brings warm
moist air into the region preceding cold
frontal passages. In general, the winter
and spring months constitute the period
of most frequent unstable weather in
Washington, i.e., storminess and high
winds, and thus result in good atmospheric
dilution and good ventilation in the lower
atmosphere.
The summer and fall months are
characterized by a reduction of wind
speed and the prevalance of southerly
winds. These months also have a higher
frequency of cloudless and light wind con-
ditions during nocturnal hours, permitting
a higher frequency of radiational surface-
based inversions to form. This is shown
by the cloudcover and wind speed data for
nighttime hours in Table 4. Consequently,
the summer and fall seasons constitute the
periods of lowest ventilation and highest
potential for atmospheric stagnation for
the Washington area.
As pointed out previously, atmospheric
stability is an important aspect of air pol-
lution. Vertical temperature gradient data,
obtained from upper air soundings made
twice daily at nearby Silver Hill, Mary-
land, give percent frequency values of in-
versions based below 500 feet above ground
that are compatible with other stations in
the Middle Atlantic Coastal Plain. In gen-
eral, the Washington area has low-level
stability on about 40-60 percent of the
nights in any season, a frequency similar
to most inland areas of the eastern United
States.
The potential for atmospheric disper-
sion of pollutants can be generalized as
follows: 1) The Washington area topography
does not restrict the dispersion of airborne
pollutants; 2) The area is too far inland to
be directly influenced by the sea breeze
effect; 3) The Washington area may exper-
ience several stagnant weather episodes a
year, which may contribute to the buildup
of airborne pollutants; 4) Stagnant weather
10
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WASHINGTON METROPOLITAN AREA
SURFACE WIND ROSES BY MONTHS
JAN
FEB
APR
AUG.
DEC.
LEGEND
The solid radial bars: show the average percentage of time the wind
blows from each direction; the figure in the center shows the average per-
cent of the time the wind is calm. The hatched radial bars: \\\\\ show the
average wind speed from each direction, in miles per hour.
Figure 3
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TABLE 4
SEASONAL PERCENT OF NIGHTTIME CLOUD COVER
AND WIND SPEED <13)
WASHINGTON, D. C. 1950-1954
WINTER
SPRING
SUMMER
FALL
LOCAL STANDARD TIME
Cloud Cover
(0.3 or less of sky
covered by clouds)
1600-0600 1800-0500 2000-0400
42.7
37.7
48.7
1800-0500
53.3
Wind Speed
0 3 mph
0-7 mph
14.0
37.3
13.3
37.3
21.7
58.3
21.3
54.0
conditions, persisting 3 to 5 consecutive
days, are most likely to occur during the
summer and fall; 5) Unstable weather, and
thus good atmospheric dispersion condi-
tions, prevails much of the time during
winter and spring; 6) Low-level nocturnal
inversions occur on most nights having rela-
tively clear skies and light winds, with higher
frequency in the suburban and rural areas
than over the central city. In general there
is nothing particularly adverse about the
diffusion climate of the Washington Metro-
politan Area.
SOURCES OF POLLUTION
Pollution From Fuel Usage
Pollutants in the form of gases, solid
particulates, and liquid droplets are released
to the atmosphere by the combustion of fuel
for heating, power generation, transportation,
and industrial process needs. The type and
quantity of pollutants are related to the type
of fuels used, condition of the firing equip-
ment, firing practices, load demands, and
the use of pollution control measures.
Typical pollution rates from various
fuel uses are given in the Appendix.
Coal During I960, about 2,800,000
tons of coal were consumed in the Washing-
ton Metropolitan Area, broken down as fol-
lows: 1) about 2,190,000 tons for steam-
electric generation; 2) about 360,000 tons
used by the Federal Government primarily
at central plants for space heating of Fed-
eral Buildings; and 3) about 250,000 tons
for residential space heating and other com-
mercial and industrial uses. (14)
Practically all of the coal is obtained
from the bituminous coal regions of West
Virginia, Pennsylvania, and Virginia. This
coal generally contains about 20 to 40 per-
cent volatile matter, 5 to 10 percent ash and
0.9 to 3 percent sulfur. (15,16) The two
central heating plants operated by the Fed-
eral Government are equipped with under-
feed stokers. Electrostatic precipitators
and mechanical collectors are used to pre-
vent dust emission. The Capitol Power
Plant is equipped with spreader stokers
and electrostatic precipitators for dust col-
lection. The Naval Weapons Plant has both
underfeed and spreader stokers with elec-
trostatic precipitators provided on the
spreader stoker units. (16)
The four steam-electric plants oper-
ated by the local utility company all feed
pulverized coal. (15) Three of the plants
are equipped with electrostatic precipita-
tors and mechanical collectors. The fourth
plant has only mechanical collectors.
The total coal consumption in the Wash-
ington Metropolitan Area should remain at
about the same level in the future. The
amount of coal used for space heating and
12 -
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for commercial and industrial purposes is
decreasing but this is offset by increases
in the amount used for steam-electric
generation.
Discharge of particulate matter from
the combustion of coal may be reduced by
using low volatile coal, changing combus-
tion equipment and firing practices, or by
installing high efficiency collection systems.
Sulfur dioxide, a major gaseous pollutant
from the combustion of coal, can be effec-
tively reduced by using low sulfur content
coal. Because most of the coal is consumed
at several large installations, control of
emissions should be easier than if there
were a multitude of smaller plants.
Oil Consumption of fuel oil in the
District of Columbia has been reported as
207,100,000 gallons for I960, about evenly
divided between distillate fuel oil and resi-
dual fuel oil. (17) It has been estimated
that the suburban areas consumed about
100,000,000 gallons of fuel oil during I960.
(18) This would indicate a total fuel oil
consumption of about 307,100,000 gallons
in I960 for the Washington Metropolitan
Area.
The combustion of fuel oil releases
aldehydes, oxides of nitrogen, sulfur ox-
ides, organic acids, other organic mate-
rials, and ash. For the practically smoke-
less operation of oil burning equipment it
is essential that the equipment be properly
designed, adjusted, maintained, and oper-
ated.
The use of fuel oil in the Washington
Metropolitan Area is gradually increasing,
primarily in the residual fuel oils that are
used for space heating in the larger office
buildings, hotels, and apartments. (18)
Fuel oil consumption in this area is not
considered a major smoke problem, but it
must be considered as a source of air pol-
lution in the form of organic substances
and sulfur and nitrogen oxides.
Gas Gas usage during I960 amounted
to 46"7Mb,000 thousand cubic feet (MCF) (19)
divided by general usage as follows:
Residential &; Commercial
with Heating 38,400,000 MCF
Residential &: Commercial
without Heating 7,150,000 MCF
Public Authorities
1,250,000 MCF
Industry uses practically no gas except
for certain limited space heating require-
ments. About 55 percent of the total volume
of gas used during I960 was used solely for
residential and commercial space heating
purposes. (19) Nearly all new homes being
built in the Washington Metropolitan Area
are equipped for both gas space and gas hot
water heating. In addition, gas cooking
equipment is predominant in newly con-
structed homes and apartments. Since 1950
the total gas consumption in the Washington
Metropolitan Area has increased by almost
250 percent. (19) It is anticipated that with
the continued population increase and the
availability of gas in the growing suburban
areas the total gas consumption will continue
to increase at the rate of about 20 percent
per year.
The combustion of gas does not produce
visible smoke, but it does produce pollutants
such as aldehydes, nitrogen oxides, organic
acids, and other organics which add to the
total atmospheric pollution.
Residential Use of Fuel In 1950 the
predominant fuels for residential heating in
the Washington Metropolitan Area were oil
37.8 percent, coal 30.8 percent, and natural
gas 25.5 percent. (20) Since 1950 the use
of coal has declined and the use of gas has
greatly increased until present estimates
indicate that fuel usage, excluding coal for
steam-electric generation and that used by
the Federal Government principally for
central heating plant operation, may be sum-
marized as approximately 59 percent natural
gas, 39 percent oil, and 2 percent coal (on a
potential BTU basis). The general trend has
been toward the use of fuel oil for heating
the larger apartment buildings and gas for
the individual residences, along with the
conversion in older buildings from coal to
either fuel oil or natural gas.
It is not expected that the increased
use of gas and oil for residential fuel will
create a major smoke problem. It should
be realized that the use of fuel oil at the
larger apartments, office, and hotel buildings
may create a smoke problem unless the firing
equipment is properly maintained and operated.
The principal air pollution contribution from
gas and oil is in the form of organic sub-
stances and oxides of sulfur and nitrogen.
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Seasonal Variation in Fuel Consump-
tion The use of fuel for space heating
purposes is related to the heating degree
days (Table 5). Approximately 73 percent
of the space heating contribution to air pol-
lution occurs during a four month period,
December through March.
Because a large percentage of the gas
is used for heating purposes the monthly
consumption varies markedly. During
August I960, 1,510,000 MCF of gas were
used, primarily for cooking, hot water
heating, air conditioning, and commercial
uses. (21) During December I960, 8,700,000
MCF of gas were used, largely for heating
purposes. (21)
Because of its fuel use pattern, the
Washington Metropolitan Area does not
have a great problem of smoke and fly ash
such as is normally associated with the
widespread use of coal for heat and power.
This does not mean that the combustion of
oil and gas for heating purposes is not a
part of the community air pollution prob-
lem, on the contrary, it must be considered
a significant part of the total air pollution
problem.
Pollution from Transportation
Motor Vehicles Motor vehicles are
considered a very significant source of air
pollution in large communities throughout
the country. Motor vehicles discharge
significant quantities of hydrocarbons,
carbon monoxide, and nitrogen oxides and
relatively smaller quantities of aerosols,
oxides of sulfur, aldehydes, ammonia, or-
ganic acids, and other organic compounds.
Gasoline additives such as tetraethyl lead,
boron, and phosphorous compounds as well
as motor oil and their additives also cause
specific air pollutants. (See Appendix.)
In I960 there were about 185,000 auto-
mobiles, 19,000 trucks, and 1,800 buses
registered in the District of Columbia. In
addition, it is estimated that about 24,000
automobiles, owned by military personnel
and other Federal employees, are located
and operated in the District of Columbia
but are registered in other States. This
indicates a total of about 230,000 motor
vehicles owned and operated by people liv-
ing in the District of Columbia. (24)
In I960 there were about 280,000 motor
TABLE 5
NORMAL MONTHLY AND ANNUAL DEGREE DAYS FOR
WASHINGTON METROPOLITAN AREA, 65° F BASE
(1921-1950) (22)
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
Degree Days
871
762
626
288
74
0
0
0
33
271
519
834
4,224
Percent of
Heating Load
20.6
18.0
14.8
6.8
1.8
0
0
0
0.8
5.2
12.2
19.8
100.0
14 -
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vehicles owned and operated in suburban
Maryland and about 175,000 in suburban
Virginia. (25) This indicates that a total
of about 685,000 motor vehicles are owned
and operated in the Washington Metropolitan
area.
A 1959 traffic survey indicated that
about 667,000 motor vehicles entered or
left the District of Columbia during an
average 24-hour period, 263,000 going to
or from Virginia and 404,000 going to or
from Maryland. It has been estimated that
the number of motor vehicles entering or
leaving the District of Columbia has more
than doubled in the last 10 years. A certain
percentage of the motor vehicles entering
or leaving the area is due to through traffic
on U.S. Highways 1, 29, 50 and 240, especially
on U.S. Highway 1, a main north-south truck
route, passing directly through the District
of Columbia. Of the motor vehicles oper-
ating in the District of Columbia on an
average day, about 49 percent are regis-
tered in the District of Columbia, 24 per-
cent are registered in Maryland, 19 percent
registered in Virginia and 8 percent regis-
tered in other States, including through truck
and tourist travel. (25)
The movement of more than half a mil-
lion motor vehicles per day into and out of
the District of Columbia emphasizes the
need for a metropolitan area approach for
the reduction of emissions from motor
vehicles. Improvement of highways and
bridges, along with continual population
growth, will certainly increase the volume
of motor vehicle movements in the Washing-
ton Metropolitan Area. Because of the many
governmental jurisdictions involved, how-
ever, reduction of motor vehicle emissions
may prove difficult.
In the District of Columbia, motor ve-
hicle registrations have shown an increase
from 195,000 in 1950 to 206,000 in I960. (26)
During the same period of time motor
vehicle registrations in suburban Virginia
have increased from 100,000 to 175,000 and
in suburban Maryland motor vehicle regis-
trations have increased from 190,000 in
1955 to 280,000 in I960. (24) It is antici-
pated that the number of motor vehicle
registrations in the Washington Metropolitan
Area will continue to increase, probably at
a relatively slow rate in the District of
Columbia and at a rapid rate in the suburban
areas of Maryland and Virginia. This of
course will increase air pollution in the
Washington Metropolitan Area. It is cer-
tainly possible that the number of motor
vehicles operated in the Washington Metro-
politan Area will approach 1,000,000 by
1970.
Approximately 195,307,000 gallons of
gasoline were sold in the District of Colum-
bia and about 295,500,000 gallons were sold
in suburban Maryland and Virginia during
I960. (23) This indicates that a total of
about 490,807,000 gallons of gasoline were
sold in the Washington Metropolitan Area
during I960.
About 15,500,000 gallons of diesel fuel
were sold in the District of Columbia during
I960, about 6,200,000 gallons were for on
highway use and the remainder for railroads
vessels, military and other miscellaneous
uses. (17) Actual figures for diesel fuel
sales in suburban Maryland and Virginia
were not readily obtainable but it has been
estimated that they are at least equal to
those reported for the District of Columbia.
This would indicate that approximately
30,000,000 gallons of diesel fuel were sold
in the Washington Metropolitan Area during
I960.
Internal combustion engines make a
significant contribution to the overall air
pollution problem in the Washington Metro-
politan Area. While emissions from motor
vehicles and other pollution sources may
not create a condition as severe as exists
in Los Angeles, it should be recognized
that the potential for a problem of that
type but of lesser intensity does exist in
the Washington Metropolitan Area. In fact,
past episodes of eye irritation and photo-
chemical smog in the Washington Metro-
politan Area have shown that the problem
may already exist to a limited degree.
Based on limited observations and
spot checks, about 5 to 15 percent of the
motor vehicles operated within the District
of Columbia emit excessive visible exhaust
smoke. (23) This is evidence that the
engines are in bad adjustment or a poor
state of repair. In either case, these
engines emit more unburned hydrocarbons,
carbon monoxide, and visible smoke than
engines that are properly adjusted and
maintained.
- 15
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Odorous materials emitted from diesel
powered trucks and buses are a cause of
public complaints. The increasing use of
diesel fuel will lead to more complaints
regarding the odors created. This will be
especially true at bus terminals and along
heavily used bus and truck routes.
Shipping The port of Washington, D. C.
handles about 2,000,000 tons of freight per
year and the port of Alexandria, Virginia,
handles about 330,000 tons per year. (27)
In addition, a number of U. S. Navy ships
ply the waters adjacent to the Washington
Metropolitan Area. Most of these ships
are oil fired and, considering the overall
air pollution picture, the total contribution
from shipping is believed to be relatively
Rail Seven railroads serve the Wash-
ington Metropolitan Area. About 145 daily
passenger trains carry an estimated 35,000
passengers per day to and from the Nation's
Capital. (3) In addition a great number of
freight trains operate through Washington,
which is a strategic rail crossing of the
Potomac, to provide direct service between
the Northeast and Southeast. Most of the
trains are diesel powered, although some
are electric powered. A diesel unit (usually
3 or 4 units are used per train) burns about
2 gallons of fuel per mile, while diesel
switch units burn about 8 gallons of fuel
per hour of operation. While diesel loco-
motives do not contribute significantly to
the dust fall problem, the combustion of
diesel fuel does release pollutants to the
atmosphere (Appendix). Proper operation,
maintenance, and adjustment of diesel units
is essential to prevent smoke. The contri-
bution of diesel locomotives to the overall
air pollution loading in the Washington Metro-
politan Area is considered to be minor.
Airlines Washington, D. C. ranks
third among United States cities in the
number of air passengers. National Air-
port, which is located across the Potomac
River, about four miles from the heart of
the city, handles over 20,000 passengers
per day, with an average of about 800 ar-
riving and departing flights per day. (3)
One of the world's largest and finest air-
ports is scheduled to open in late 1962, 20
miles west of Washington. It is anticipated
that this new airport will be handling 4 mil-
lion passengers per year by 1965 and 7 million
by 1970. There are also three military air
fields; Andrews Air Force Base, Boiling
Air Force Base, and Anacostia Naval Air
Station. Emissions from all of these sources
are considered a minor portion of the total
air pollution problem of the Washington
Metropolitan Area.
Pollution From Waste Disposal Operations
Refuse Disposal The method used for
refuse disposal is an important factor in
controlling air pollution. The burning of
refuse on open dumps or on private premises
is the poorest method of disposal. Incom-
plete combustion of refuse results in pro-
duction of a wide variety of gaseous and
particulate matter including odors, smoke,
aerosols, aldehydes, organic acids and
other pollutants (Appendix).
The District of Columbia Division of
Sanitation burns about 1600 tons of rubbish
each day, about 1200 tons at three incinera-
tors and about 400 tons at an open dump. (28)
The open dump burning operation has been
used for quite a few years, due to inadequate
incinerator capacity. It is anticipated that
a new 500 ton per day incinerator will be
operated during 1962; this -will provide
adequate capacity so that operation of the
open burning dump may not be necessary.
Some problems were encountered
several years ago with the Georgetown
incinerator, due to fly ash and other emis-
sions. This particular incinerator is
located lower than, but very near to, resi-
dential areas so that the top of the stack is
at about the same elevation as the surround-
ing residential areas. Through a very care-
fully controlled operating procedure the fly
ash and other emissions have been reduced
until practically no complaints are received.
Most of the garbage from within the
District of Columbia is used for hog feed-
ing. Some of the garbage, which is not suit-
able for hog feeding, along with incinerator
residue, street sweepings, ashes, and other
non-combustibles is hauled to a transfer
station, located a few thousand feet from
the Capitol Building, where it is loaded in
large tractor-trailer units and gondola
railroad cars for transport to sanitary
landfills. In passing enabling legislation
authorizing this installation, Congress wrote
16
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a proviso into the law that the structure be
equipped for odor and dust control because
of its proximity to the Capitol. This resulted
in a system of cyclones, fiberglass filters,
and carbon absorption canisters which has
been reported as 95 percent efficient in re-
moving odors and very effective in control-
ling the dust problem. (29)
In the suburban areas of Maryland that
are a part of the Washington Metropolitan
Area approximately 100 tons of refuse are
incinerated per day. The only incinerator
in this area is operated by the Washington
Suburban Sanitary Commission and serves
about 60,000 people. (30) Most of the other
residential, commercial, and industrial re-
fuse is disposed of at sanitary landfills
located at various sites in Montgomery and
Prince Georges Counties and operated by
respective towns, cities, special taxing
districts and the county. (31) These oper-
ations are periodically inspected by the
county health agencies to enforce the re-
spective county regulations that prohibit
burning at open dumps or landfills.
In the suburban areas of Virginia that
are a part of the Washington Metropolitan
Area approximately 400 tons of refuse are
incinerated each day (300 in Arlington
County and 100 in the City of Alexandria).
(32) In addition, some refuse from Arling-
ton County and the City of Alexandria, as
well as all of the refuse from Fairfax
County and the independent City of Falls
Church, is disposed of at sanitary landfills
located within their respective areas. (32,
33) In all of these areas, close supervision
has minimized the amount of burning-at the
landfill sites.
Burning of combustible refuse in indi-
vidual backyard trash burners has been
prohibited in the District of Columbia for
years. This practice, which results in the
discharge of large quantities of gaseous
and particulate pollutants to the atmosphere,
is permitted in the suburban areas of Mary-
land and Virginia. Backyard burning is
restricted to after 4 p.m. in Prince Georges
and Fairfax Counties during the spring
months and in Montgomery and Prince
Georges Counties during the fall months.
Except as indicated above, open burning in
the suburban areas of Maryland and Virginia
is permitted during the daylight hours. Al-
though restriction of backyard burning to
the hours after 4 p.m. may be desirable for
fire prevention, this is the normal period of
light wind speed and poor ventilation during
the fall months, hence the least desirable
period for burning from an air pollution
standpoint.
The many trees in the Washington Metro-
politan Area produce great quantities of
leaves that are usually disposed of by open
burning. This results in the discharge of
large quantities of gaseous and particulate
pollutants to the atmosphere during the
season of the year in which most air stag-
nation episodes are experienced. The open
burning of a single pile of leaves is, not of
course, a major source of air pollution.
However, this practice should be seriously
questioned when it is conducted on a large
scale. Even though the burning of leaves
is prohibited in the District of Columbia
and restricted to certain daylight or even-
ing hours in other areas, dense smoke from
burning leaves may be experienced through-
out the entire Washington Metropolitan Area
during the fall months.
Practically all new apartment houses
in the Washington Metropolitan Area are
equipped with single- or multi-chamber
incinerators for the disposal of combus-
tible rubbish. In addition, many of the
newer commercial and industrial establish-
ments are also equipped with single- or
multi-chamber incinerators. Recent amend-
ments to the District of Columbia Fuel Burn-
ing Regulations require that multi-chamber
incinerators be installed in the District of
Columbia after October 1961. Single-chamber
incinerators, which produce greater quantities
of air pollutants per pound of material burned
than multi-chamber units, are still permitted
in other portions of the Washington Metro-
politan Area.
Because of the many construction proj-
ects for new buildings, highways, and resi-
dential areas the quantity of waste materials
from construction and demolition activities
in the Washington Metropolitan Area has
reached enormous proportions. Most of
these waste materials are disposed of by
opening burning. This produces significant
quantities of gaseous and particulate air
pollutants. Open burning of construction
and demolition wastes in Alexandria is done
under a permit system; however, this does
not prevent the open burning of these
- 17 -
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materials. Recent amendments to the Dis-
trict of Columbia Fuel Burning Regulations
prohibit open burning unless a very definite
need can be established and there is no other
practical method of disposal available. In
such cases a permit may be issued. These
new restrictions should greatly reduce, if
not eliminate, open burning of construction
and demolition wastes in the District of
Columbia.
The District of Columbia Department of
Highways burns dead, diseased trees, and
trimmings from its own activities and for
the National Capital Parks at the Poplar
Point Nursery grounds. Even though dis-
eased elm trees must be burned as a part of
the disease eradication program this activity
must be considered as contributing to the
total air pollution problem.
In summary, the Washington Metropoli-
tan Area disposes of about 1700 tons of
refuse per day at municipal incinerators and
about 400 tons per day at an open burning
dump. The remainder of the Metropolitan
Area refuse, consisting of several hundred
tons per day, is disposed of by back-yard
burning, apartment house incineration, and
sanitary landfills. In addition, quantities of
leaves, trees and waste materials from con-
struction and demolition activities are dis-
posed of by open burning in the Washington
Metropolitan Area. These activities result
in the discharge of a considerable amount of
atmospheric pollutants each day and are con-
sidered a significant contribution to air
pollution in this area. Table 6 shows a
general summary of the waste disposal
practices.
Sewage Disposal Complaints of odors
have come from the immediate vicinity of
some sewage treatment plants, especially
during the summer months when the day-
time temperatures and relative humidity are
quite high and there is little or no air move-
ment. In most cases, these odor problems
are experienced only in areas immediately
adjacent to the sewage treatment plants.
About 1,000,000 cubic feet of sewage
sludge gas is produced each day by the va-
rious sewage treatment plants in the Wash-
ington Metropolitan Area. (34) This gas is
used as fuel for certain types of engines or
for heating purposes, or is wasted by flaring.
The combustion or burning of the sludge gas
produces aldehydes, oxides of nitrogen,
oxides of sulfur, and other gaseous pollu-
tants that contribute to the total community
air pollution problem.
Sewage disposal operations in the
Washington Metropolitan Area are con-
sidered a contributor to the total air pollu-
tion problem, but they are not considered
of major importance.
Industrial and Commercial Emissions
Emissions to the Washington Metro-
politan Area atmosphere from industrial
processes contribute to the total air pollu-
tion situation. Metropolitan Washington is
not a heavy industrial area and the emis-
sions from industrial operations are of the
type and quantity generally associated with
light industry and manufacturing and serv-
ice operations. Because exhaust stack
sampling and plant inspections were not
undertaken as a part of this evaluation, the
following discussion and Table 7 are of a
general nature. However, air pollution
problems normally associated with specific
types of industry are indicated.
Table 7 gives a summary of the major
industries and their contributions to the
community air pollution problem. Some
are of minor significance, some are of a
localized nature, and others are considered
significant contributors. This indicates
that industries in the Metropolitan Wash-
ington Area are an important part of the
total air pollution problem even though they
are not the most significant group of pollu-
tion sources.
Dust arising from construction opera-
tions, particularly highway construction, is
a frequent source of public complaint.
Complaints about commercial operations
are usually associated with emissions such
as hydrocarbons from petroleum bulk stor-
age and retail filling stations, smoke and
odors from scrap or salvage yards, odors
from restaurants and markets, and smoke
and odors due to laundries and dry clean-
ing establishments. The last are especially
important in the Washington area because
of the great number of small laundry and
dry cleaning plants. Hydrocarbon losses
from petroleum handling and storage also
contribute to the overall pollution load on
18
-------
TABLE 6
SUMMARY OF REFUSE DISPOSAL PRACTICES
WASHINGTON METROPOLITAN AREA
Area
District of Columbia
Montgomery County
Maryland
Prince Georges County
Maryland
Arlington County
Virginia
Fairfax County & City of
Falls Church, Va.
City of Alexandria,
Virginia
Amount
Incinerated
Tons /Day*
1200
100
None
300
None
100
Open
Burning
Dump
Tons /Day
400
None
None
None
None
None
Sanitary
Landfill
Yes
Yes
Yes
Yes
Yes
Yes
Backyard
Residential
Area
Incinerators
No
Yes
Yes
No
Yes
Yes
Other
Residential
Area
Burning
Prohibited
Limited
(Leaves)
Leaves
Limited
(Leaves)
Leaves
Leaves
Construction
&
Demolition
Waste
Burning
(Permit)
Burning
Burning
Burning
(Limited)
Burning
Burning
(Permit)
*Does not include quantities incinerated at apartment houses or commercial or industrial installations.
-------
TABLE 7
SUMMARY OF METROPOLITAN WASHINGTON MAJOR MANUFACTURING
INDUSTRIES AND THEIR CONTRIBUTIONS
TO THE AIR POLLUTION PROBLEM
Industry
Food & Kindred Products
Lumber & Wood Products
Printing fk Publishing
Chemical & Allied Products
Petroleum & Coal Products
Stone, Clay fe Glass Products
Fabricated Metal Products
Electrical Machinery
Primary Metals
Total
Plants
107
62
339
32
11
81
78
43
4
Contributions to Air Pollution Problem
Odors coffee roasting and animal
rendering plants - localized com-
plaints minor contribution
Burning wood wastes, saw dust, spray
paint mist, and creosote odors - mill-
work, prefabrication, and container
manufacturing localized complaints -
minor contribution
Solvent odors printing processes -
localized complaints minor
contribution
Dusts, sulfuric acid mists, fluorides
and odors - fertilizer, insecticide, and
paint manufacturing - localized com-
plaints significant contribution
Dust and oil fumes - asphalt paving
plants - many localized complaints -
significant contribution
Dusts ready-mixed concrete and
concrete or allied products - localized
complaints significant contribution
Gases and dusts - spray painting,
de greasing, and grinding aluminum
doors & windows, structural and
ornamental steel products - no com-
plaints minor contribution
Gases and dusts - spray painting,
degreasing and grinding no complaints
minor contribution
Gases and particulates steel tube
production and gray iron castings -
localized complaints minor con-
tribution
- 20
-------
the atmosphere. Factors for estimating
losses from gasoline handling operations
are given in the Appendix.
Certain Federal Government operations
such as the Naval Weapons Plant, Govern-
ment Printing Office, and the Bureau of
Printing and Engraving are considered as
industrial operations. Several years ago
there were emissions from the Naval Weap-
ons Plant due to metal plating and forging.
Present emissions from the plant are due to
steam electric generation, incineration of
combustible wastes and occasional open
burning of certain scrap products. The Gov-
ernment Printing Office and the Bureau of
Printing and Engraving are basically print-
ing, engraving and publishing operations.
These activities generally do not produce
significant quantities of air pollutants, other
than some solvent odors. Altogether, the
industrial type activities conducted by the
Federal Government in the Washington
Metropolitan Area contribute to the total air
pollution problem, but they are considered
of minor significance.
Miscellaneous sources of air pollution
are common to most metropolitan areas
and no attempt was made to evaluate their
individual contributions to the Washington
area air pollution problem. Their total
contribution is considered of minor sig-
nificance in the total air pollution problem.
Geographic Distribution of Industrial Sources
The Metropolitan Washington Area is
relatively free of major industrial air pollu-
tion sources. The problems encountered
are usually due to nuisances from specific
odors or dusts in limited areas. Most of the
industries are located along the Potomac and
Anacostia Rivers, and along the railroad
tracks and major highways. The industrial
areas are dispersed and generally separated
from residential sections. These factors,
along with the nature and limited extent of
the industries help to minimize the effect of
industrial pollutants on the total air pollu-
tion problem.
INDICATIONS OF AIR
POLLUTION LEVELS
Past Investigations
In 1931-1933, atmospheric pollution
was studied in 14 of the largest cities of
the United States, including Washington,
D. C. (35) This study reported dustfall
rates for Washington, D. C. as 26 tons per
square mile per month during the winter,
24 tons per square mile per month during
the summer, and 24 tons per square mile
per month for the entire year. The study
also reported that the average amount of
suspended matter in the air during the
winter months in the 14 cities was 510
micrograms per cubic meter of air. The
Group III cities, which included Washington,
D. C., averaged 350 micrograms per cubic
meter. The study indicated that if the de-
gree of atmospheric pollution during the
winter months for all of the cities com-
bined was taken as 100, the Group III
cities would have a value of 56. Thus it
would appear that in 1931-1933 the air
pollution situation in Washington, D. C.,
was better than that in many other large
cities in the United States.
During 1953-54, oxidant and sulfur
dioxide were measured in 10 cities, in-
cluding Washington, D. C. (36) Sampling
was done for only a few days in each city,
but a variety of weather conditions oc-
curred, including a few days of smog. The
Washington, D. C. oxidant level, as mea-
sured by the potassium iodide method,
ranged from a high of 0.078 ppm (parts per
million parts of air) to a low of 0.003 ppm,
with an average of 0.039 ppm. Although
atmospheric oxidant measurements usually
include all oxidizing substances, ozone is
one of the most important oxidants found in
the air. Ozone is a highly reactive, unique
form of oxygen that may be produced in the
atmosphere by the action of sunlight on
organic material in the presence of nitro-
gen dioxide. Sulfur dioxide concentrations
ranged from a high of 0.12 ppm to a low of
less than 0.01 ppm, with an average of 0.04
ppm as measured using the alkaline iodine
- 21 -
-------
method. Total sulfate concentrations ranged
from a high of 0.35 ppm to a low of less than
0.01 ppm, with an average of 0.09 ppm.
Table 8 shows the values for Washington,
D. C. and the maximum and minimum values
for all 10 cities included in the study. The
results indicate that oxidant concentrations
in Washington were higher than the average
for the 10 cities, in fact Washington was
third highest in this respect, and the sulfur
dioxide values were about average.
Plant Damage
As is true with many large metropolitan
areas, symptoms of smog injury to vegeta-
tion have been found in the Metropolitan
Washington Area. Such occurrences indicate
the existence of an air pollution problem.
Although estimates of economic losses in the
Washington area due to plant damage by
smog have not been made, it is known that
economic losses in tens of millions of dollars
have been experienced in other areas . No
attempt has been made to complete a fre-
quency-severity survey of plant damage in
the Washington area.
The occurrence of plant damage in the
Washington Metropolitan Area has received
considerable attention in the last few years.
It has been shown that the "weather fleck"
injury to tobacco plants at the U. S. Depart-
ment of Agriculture Plant Industry Station,
Beltsville, Maryland, -was probably the re-
sult of atmospheric ozone, which is one of
the most important atmospheric oxidants.
(37) It has also been postulated that the high
ozone levels (peak values of 0.31 to 0.50 ppm
as measured by the buffered potassium io-
dide method) observed at Beltsville, which
may have caused the plant damage, were the
result of air pollution from the Washington
Metropolitan Area. (38) Studies of the ozone
injury problem are continuing and the sever-
ity of fleck in the tobacco at Beltsville con-
tinues to correlate -with atmospheric ozone
levels. Studies done in fumigation chambers
at Beltsville using known ozone concentra-
tions have confirmed the idea that fleck can
be caused by ozone. Ozone levels required
to produce the injury correlate with the at-
mospheric ozone concentrations found on
days when flecking of tobacco occurs in
plants exposed to ambient air.
The general symptoms of ozone injury
on other crops has been reported. (39)
Studies at Beltsville indicate that ozone
injury symptoms on grape, spinach, tomato,
and other crops correlate with tobacco
fleck occurrences and atmospheric ozone
levels.
There is little doubt that the Washing-
ton Metropolitan Area is the source of at
least one phytotoxicant with a potential for
inducing serious economic loss in vegeta-
tion. While a complete assessment has not
been made, it is evident that vegetation
damage does occur and deserves serious
attention.
The National Air Sampling Network
Washington, D. C. has participated in
the National Air Sampling Network of the
Public Health Service since 1953. Samples
of air are collected for a 24 hour period,
using a high-volume sampler, on a prede-
termined schedule, by representatives of
the District of Columbia Department of
Public Health. The samples are sent to the
Public Health Service's Sanitary Engineer-
ing Center in Cincinnati, Ohio, where they
are analyzed. Data are available from 1953
through 1959 for suspended particulate
matter, organic pollutants, reflectance, beta
radio activity, and certain inorganic pollu-
tants. (40,41)
Since 1953 four separate sampling lo-
cations have been used, including areas
classified as commercial, residential, and
a combination of commercial-residential
(Table 9). The results reflect conditions
in the different areas.
Particulate Matter Washington, D. C.
had an average particulate pollution loading
of 132 micrograms per cubic meter of air
during the period of 1953-1959. Table 9
shows the results for the four separate
sampling sites that have been used during
the six-year period and the total results
for this period. The values obtained dur-
ing 1955-1956, which are higher than for
other years, were probably influenced by
dusty play fields and other activities at the
high school, public recreation center, uni-
versity, and large stadium that are all lo-
cated nearby. Table 10 shows a comparison
of suspended particulate matter concentra-
tions results for Washington, D. C. and
several other large cities. These results
indicate that Washington's particulate pol-
lution levels are less than the national
average but higher than some other large
cities; however, it also shows that the
22 -
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TABLE 8
CONCENTRATION OF OXIDANT AND SULFUR DIOXIDE,
1953-1954 STUDY
Washington, D. C.
Maximum
Minimum
Average
10 Cities Studied
Maximum
Minimum
Average
Oxidants
by Potassium
Iodide Method
ppm
0.078
0.003
0.039
1.180
0.000
0.026
Sulfur Dioxide
by Alkaline
Iodine Method
ppm
0.12
< 0.01
0.04
0.38
< 0.01
0.06
Sulfur Dioxide Calculated
from Total Sulfate
after trapping in
Alkali ppm
0.35
< 0.01
0.09
1.22
<0.01
0.10
-------
TABLE 9
SUSPENDED PARTICULATE POLLUTION IN WASHINGTON, D. C.
AS MEASURED IN THE NATIONAL AIR SAMPLING NETWORK, 1953-1959 (40-41)
Site
No. 1
HEW -North
No. 2
Cardoza High
School
No. 3
Health Center
No. 4
District Bldg.
TOTAL
Type Area
C-R
C-R
R
C
Years
19
53-54
19
55-56
19
56-57
19
58-59
1953-59
No. of
Samples
44
70
40
51
205
Micrograms Per Cubic Meter
Min.
66
70
41
38
38
Max.
276
459
258
231
459
Ave.
129
171
97
107
132
C - Commercial Area
R - Residential Area
-------
TABLE 10
COMPARISON OF SUSPENDED PARTICULATE POLLUTANTS
FOR SEVERAL URBAN STATIONS, - 1957 - 58 (40,41)
I960
Area & Population
Washington, D. C.
2,001,897
Baltimore, Md.
1,727,023
Los Angeles, Calif.
6,742,696
San Francisco, Calif.
2,783,359
St. Louis, Mo.
2,060,103
Cleveland, Ohio
1,796,595
Pittsburgh, Pa.
2,405,435
Portland, Ore.
821,897
Total NASN Stations
No. of
Samples
50
51
45
51
49
51
49
50
5340
Micrograms Per Cubic Meter
Min.
61
65
89
22
89
69
78
26
11
Max.
258
301
361
253
332
314
534
334
978
Ave.
102
138
138
80
177
175
184
99
131
tv
I
-------
maximum concentrations in Washington are
lower than in most of the cities listed.
Reflectance The average light re-
flectance value of the Washington, B.C. high
volume filter samples is 16 percent. Re-
flectance is used as a measure of the soiling
properties of the collected pollutants. The
lower the reflectance value the dirtier or
grimier is the particulate matter in the air.
Variation in reflectance readings can occur
due to variations in composition of the par-
ticulate matter collected on the sample as
well as variations in the amount of material.
Inorganic Pollutants - The National Air
Sampling Network samples have been ana-
lyzed for a wide variety of inorganic solids.
Many of these inorganic materials can be
related to specific industrial processes and
operations and they can sometimes be used
to determine sources of pollution. The re-
sults of these analyses pertaining to Wash-
ington, D. C. for 1953-1957 have been pub-
lished and, therefore, a detailed review will
not be undertaken in this report. (40) Aver-
age values for specific inorganic solids found
in the Washington air samples are about the
same as the national average values.
Seasonal Variation If the year is
divided into a "heating season" (November
through April) and a "non-heating season"
(May through October) a significant differ-
ence is noted in the atmospheric pollutants
measured at the network station (Table 12).
The primary reason for this difference is
ascribed to the increased use of fuel for
space heating. Pollution levels are higher
in winter even though, as previously pointed
out, the meteorological conditions are gen-
erally more favorable for atmospheric dis-
persion of pollutants during the November-
April period.
Pilot Sampling Project
In December I960 a seven day pilot air
sampling project was completed by the Dis-
trict of Columbia Department of Public Health
and the Public Health Service. The maximum
values obtained during this period were: 0.25
ppm oxidant (which includes ozone), 0.40 ppm
nitrogen dioxide, 0.70 ppm nitric oxide, 6.7
ppm carbon monoxide, 5.5 Cohs per 1000
linear feet for "smoke" (small sized par-
ticles, largely from combustion operations),
and 445 micrograms per cubic meter for
suspended particulate material. (42) The
significant values obtained for oxidant,
nitrogen dioxide, and nitric oxide indicate
that photochemical smog is a problem in
Washington. The values obtained for
"smoke" and suspended particulate mate-
rial were also significant. The maximum
oxidant level of 0.25 ppm equalled the level
at which some people experience eye irri-
tation; in fact, several cases of eye irrita-
tion were reported during the study. This
study indicates that among others, "smoke"
and motor vehicle emissions are two major
factors in the Washington air pollution
problem.
Past Episodes
Photochemical air pollution is char-
acterized by eye irritation, visibility re-
duction, cracking of rubber products, and
results from the oxidation of hydrocarbons
(primarily gasoline vapors) in the presence
of nitrogen dioxide and sunlight.
The Washington Metropolitan Area has
recently experienced three separate epi-
sodes of eye-irritating smog, June 8-11,
1959, September 23-27, I960, and Decem-
ber 5-6, I960. The 1959 episode occurred
when a high pressure air mass existed
and the I960 episodes during atmospheric
temperature inversions. A portion of the
population experienced eye-irritation and
other discomforts during these episodes,
visibility was noticeably reduced, and nu-
merous complaints were made to local
governmental agencies. These recorded
eye-irritating, visibility reducing, smog
episodes are a definite manifestation of
the photochemical air pollution problem of
the Washington Metropolitan Area and warn
of more serious future problems.
Complaints
The public certainly is not without
cause for complaints concerning odors,
smoke, and dusts from certain industrial
operations which cause nuisance condi-
tions. Some complaints regarding vegeta-
tion damage and glass etching have been
received in certain areas of the Washington
Metropolitan Area. To a great extent the
complaints involve air pollution due to
odors, dust, fumes, or smoke in the area
immediately adjacent to a specific source
of the air pollutant.
- 26
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TABLE 11
SEASONAL VARIATION OF PARTICULATE POLLUTANTS
IN WASHINGTON, D. C. 1953 - 1959 (40-41)
Season
Heating
Non -heating
Months
Nov. -Apr.
May -Oct.
Percent of
Degree Days
92.2
7.8
Total
Participates
(1)
147
107
Acetone
Soluble
Organics
(1) *
32.1
21.5
Benzene
Soluble
Organics
(1) **
15.1
9.3
Percent
Reflectance
***
11
21
(1) Micrograms per cubic meter.
* Prior to July 1, 1955, results reported as Acetone soluble organics.
** After July 1, 1955, results reported as Benzene organics.
### The lower the reflectance value the dirtier the air.
-------
Potential Health Effects
Apart from the specific findings of this
survey, continuing research conducted or
sponsored by the Public Health Service is
adding steadily to the body of circumstantial
evidence which links air pollution to certain
cardio-respiratory diseases such as chronic
bronchitis, asthma, emphysema, and lung
cancer. For example, close correlations
have been found very recently between at-
mospheric levels of sulfur dioxide and the
frequency and severity of asthmatic attacks.
Of course, the avoidance of needless risks
to human health adds a most cogent reason
to those developed in this report for a more
efficient and more comprehensive air pollu-
tion control program in the Washington
Metropolitan Area.
STATUS OF LOCAL ACTIVITY
IN AIR POLLUTION
District of Columbia
In 1935 Congress enacted Public Law
279, District of Columbia Smoke Law, which
prohibits the discharge of dense smoke from
any building, stationary or locomotive en-
gine, or motor vehicle, place or premises
within the District of Columbia. This law
also requires that all ashes, cinders, rub-
bish, dirt, and refuse be removed to a proper
place and that cinders, dust, gas, steam, or
offensive or noisome odors shall not be dis-
charged from any building or place to the
detriment or annoyance of other persons.
The law further authorized the Commis-
sioners of the District of Columbia to prom-
ulgate, alter, amend, or rescind regulations
as they deem necessary. Enforcement of
the law was made the responsibility of the
Commissioners of the District of Columbia.
They may direct the police department,
health department, or any other officer or
employee of the government of the District
of Columbia to perform such services as
necessary for enforcement of the smoke
law. Limited modifications and revisions
have been made to the smoke law, but for
the most part it is basically the same as it
was when originally enacted.
The Department of Licenses and In-
spections is responsible for administration
of the Smoke Law. This responsibility
includes: (1) Examination of building plans
for the construction, installation, recon-
struction, alteration or repair of stacks,
incinerators, boilers or furnaces; (2) is-
suance of permits and certificates for in-
stallations; (3) maintenance of records
regarding applications, permits, plans,
violations and complaints; and (4) investi-
gation of complaints, observation of smoke
conditions, and inspection of all equipment
for which a permit has been issued. In
general, single family homes are about the
only installations that are not covered by the
regulations.
The smoke abatement activities of this
department are conducted by two different
sections. The plan review portion is han-
dled by the Engineering Branch of the de-
partment and all of the field inspections
are handled by the Smoke and Boiler Sec-
tion. Only three smoke inspectors are
presently employed although authority exists
for five smoke inspectors. Because of bud-
get limitations, the low starting salary, and
the lack of available candidates, difficulties
have been experienced in hiring and retain-
ing competent smoke inspectors. This has
resulted in fewer smoke observations and
inspections being made, thus reducing the
effectiveness of the smoke abatement
program.
During 1959 three smoke inspectors
made 6,379 smoke inspections and 771 ob-
servations of smoke, and handled 237 com-
plaints and 322 smoke violations. Insofar
as possible, complaints are given priority
and are followed up, by the smoke inspector
who personally contacts the individual who
made the complaint. Most of the smoke
violations are due to improper operating
procedures. Necessary corrections are
usually brought about by a discussion be-
tween the smoke inspector and the equip-
ment owner or operator of the reasons for
the violation.
Since 1936, this program, through its
inspection of plans and issuance of permits
for fuel burning equipment, has had a great
influence on the abatement of smoke and
improvement of conditions which might
cause nuisances. Through its adherence
to proper engineering design and installa-
tion practices, the smoke abatement pro-
gram has assured that, with proper opera-
tion, fuel burning equipment installations
would not create nuisances or violate the
smoke law. This has been very important
during the past 25 years, when thousands
of new or modified installations have been
completed.
- 28 -
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The Police Department recently entered
the field of air pollution control through en-
forcement of amendments to the Traffic and
Motor Vehicle Regulations. These regula-
tions prohibit motor vehicle exhaust emis-
sions darker than Ringelmann No. 2. Opera-
tors of motor vehicles producing excessive
smoke are given a police notice to appear at
one of the Department of Motor Vehicle In-
spection Stations for further observation.
Those found in violation of the regulation
are given 10 days to obtain necessary repairs
or face court action. In addition, the Depart-
ment of Motor Vehicle Inspection Stations
check for excessive exhaust smoke as a part
of the required annual inspection of all motor
vehicles registered in the District of Colum-
bia. These combined activities should tend
to reduce the number of motor vehicles that
emit excessive exhaust smoke and thus con-
tribute more than their proportionate share
of the total air pollution load.
Under Reorganization Plan No. 5 of
1952, as amended, the District Department
of Public Health was given responsibility
for supervising adherence to proper stand-
ards of hygiene for occupations, work places,
work material, work conditions, and related
matters concerning city planning; heating,
lighting, ventilation, aerial pollution, noise,
and public health nuisances related to vacant
land, occupations, and work places; and
health hazards associated with work mate-
rial and conditions. In addition, under vari-
ous sections of the amended Health Ordi-
nances, the District Department of Public
Health has authority to investigate and have
corrected nuisances due to noisome odors
or noxious gases.
The District Health Department is re-
sponsible for (1) the investigation of air
pollution complaints of a non-combustion
nature; (2) operation of the Public Health
Service National Air Sampling Station; and
(3) the issuance of permits for the fumiga-
tion of buildings and facilities. This pro-
gram is handled on a part-time basis by
regular employees who are primarily re-
sponsible for other activities. The National
Air Sampling Network Station activity con-
sists of periodically collecting samples of
particulate and gaseous materials and for-
warding them to the PHS Sanitary Engineer-
ing Center at Cincinnati for analysis and
tabulation. Complaint investigations are
primarily concerned with localized situations
that involve odors or dusts from a specific
source and in past years have numbered
about 5 to 10 per year. The fumigation
permit issuance activity requires periodic
inspections but does not require any ap-
preciable professional time.
The District of Columbia Commis-
sioners recently delegated authority to the
Department of Public Health for developing
an air survey and monitoring program to
determine the extent and causes of air
pollution. The D. C. Health Department
was also directed to work with other de-
partments in preparing specific proposals
that will provide the necessary organiza-
tion and budgetary arrangements to effect
a sound air survey and monitoring program
that would lead to an air pollution control
program for the District of Columbia.
Suburban Maryland
In Montgomery County, air pollution
control activity is handled by the health
department and primarily consists of in-
vestigation of complaints. If possible, the
complaints are handled by the health de-
partment staff but, if complex problems
are encountered, assistance may be ob-
tained from the Maryland State Department
of Health. It was reported that about 20 air
pollution complaints are investigated each
year. The County does not have a smoke
abatement program but the County ordi-
nances and regulations establish perform-
ance standards for all incinerators and
prohibit open burning of leaves and other
combustibles during certain hours of the
day.
In Prince Georges County a very
limited air pollution control program is
conducted by the health department. This
program primarily consists of investigat-
ing complaints. It was reported that about
20 complaints are investigated each year,
excluding numerous complaints pertaining
to the open burning of leaves and rubbish.
The health department normally handles
the air pollution complaint investigations
but may obtain assistance from the Mary-
land State Department of Health on special
studies or complex complaints. The County
does not have a smoke abatement program
but county regulations establish perform-
ance standards for all incinerators and
prohibit open burning at dumps and sani-
tary landfills.
- 29 -
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Suburban Virginia
In Arlington County the limited air pol-
lution activities are handled by the Depart-
ment of Inspections. These activities are
primarily directed toward the inspection and
licensing of boilers and incinerators. It was
reported that one or two air pollution com-
plaints are received each year and they are
referred to the Virginia Department of
Health for investigation. Reports are sent
back to the local department. County regu-
lations limit the times when leaves and other
combustibles may be burned in the open.
In Fairfax County and the City of Falls
Church all the air pollution control activities
are under the supervision of the Virginia
Department of Health. It has been reported
that no complaints regarding air pollution
have been received in years. The County
recently passed a zoning ordinance which
established performance standards for the
emission of smoke and other air pollutants.
In Alexandria, the local health depart-
ment investigates complaints and makes
some limited investigations of specific
problems, with assistance from the Virginia
Department of Health. It was reported that
about 5 air pollution complaints are investi-
gated each year. The smoke abatement
activities are handled by the smoke and
boiler inspector. Activities include plan
review and inspection of boilers, stokers,
and incinerators. Individual backyard in-
cinerators are permitted and private open
burning of leaves and other combustibles is
allowed. Disposal methods for construction
and demolition wastes is controlled by a
permit system.
Table No. 12 gives a summary of local
air pollution control activities in the Wash-
ington Metropolitan Area. The lack of air
pollution control programs in this area is
evident.
Zoning Regulations
Zoning provisions are often used as a
means of controlling air pollution, either
by establishing performance standards or
by separation of industrial and residential
areas. In general, the respective zoning
ordinances in the Washington Metropolitan
Area have prevented many major air pol-
lution problems. In some of the older areas
of Washington, and to some extent Alexan-
dria and Arlington, the industrial areas
were developed adjacent to residential
areas prior to the establishment of effective
zoning requirements. These situations ac-
count for a large proportion of the air
pollution complaints received in the spe-
cific areas. The zoning regulations in ef-
fect in the various local governmental
areas, through the use of performance
standards and the separation of major air
pollution sources and residential areas,
have minimized the extension of air pollu-
tion problems into rural areas and pre-
vented the intermingling of industrial and
residential properties.
The District of Columbia Zoning Regu-
lations prohibit the discharge of objection-
able amounts of cinders, dust, fly ash, or
noxious, toxic, or corrosive fumes or
gases from buildings or structures located
in manufacturing districts. Periodic sur-
veys of commercial and industrial areas
are conducted by the Department of Licenses
and Inspections to determine compliance
with provisions of the zoning regulations
that pertain to external effects and the dis-
charge of objectionable materials. This
has tended to eliminate some potential air
pollution problems.
- 30 -
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TABLE 12
LOCAL AIR POLLUTION CONTROL ACTIVITIES
WASHINGTON METROPOLITAN AREA
Area
Washington, D. C.
Montgomery County, Maryland
Prince Georges County, Maryland
Arlington County, Virginia
Alexandria (City), Virginia
Fairfax County, Virginia
Smoke
Control
Yes
No
No
Limited
Limited
No
Other Air Pollution Control
Complaint
Investigation
Yes
Yes
Yes
No
Yes
No
Comprehensive
Program
No
No
No
No
No
No
10
I'
I
-------
REFERENCES
(1) Encyclopedia Americana, Vol. 29, 1958.
(2) U. S. Bureau of the Census, "Final
I960 Census Figures".
(3) Washington Board of Trade, "It's a
Capital Idea", Sixth Edition, March
1961.
(4) Personal correspondence with the Eco-
nomic Development Committee, Wash-
ington Board of Trade, June I960.
(5) U. S. Bureau of the Census: "1954
Census of Manufacturers" Volume II.
(6) Industrial Directory of Washington
Metropolitan Area, Washington Board
of Trade, February 1959.
(7) National Capital Planning Commission,
Land Use, 1955.
(8) Encyclopedia Americana, Vol. 9, 1958.
(9) Potomac Electric Power Company,
"Profit by the Prestige of a Capital
Plant Location".
(10) Korshover, Julius, "Synoptic Climatol-
ogy of Stagnating Anticyclones East of
the Rocky Mountains in the United
States for the Period 1936-1956".
Tech. Rep. A 60-7, Public Health Serv-
ice, Sanitary Eng. Cen., Cincinnati,
Ohio.
(11) Niemeyer, L. E., "Forecasting Air
Pollution Potential," Monthly Weather
Review, 88, No. 3, U. S. Weather Bu-
reau, March I960.
(12) U. S. Weather Bureau, "The Climatic
Handbook for Washington, D. C.,"
Weather Bureau Technical Paper No.
8, Washington, D. C., 1949.
(13) U. S. Weather Bureau, "Local Clima-
tological Data with Comparative Date
for Washington, D. C.," National Air-
port, 1953.
(14) Personal correspondence with Potomac
Electric Power Company, U. S. Gov-
ernment General Services Adminis-
tration, and the Merchants and Manu-
facturers Association.
(15) Personal correspondence with Po-
tomac Electric Power Company.
(16) Personal correspondence with Gov-
ernment Fuel Yard, General Services
Administration.
(17) Personal correspondence with Min-
eral Industry Surveys, Bureau of
Mines, U.S. Department of the
Interior.
(18) Personal correspondence with the
Oil Heat Institute and the American
Petroleum Institute.
(19) Washington Gas Light Company, An-
nual Operating Report, I960.
(20) U. S. Bureau of the Census: "1950
Census of Housing," Vol. 1, Part 2.
(21) Personal correspondence with Wash-
ington Gas Light Company.
(22) Personal correspondence with the
Office of Climatology, U. S. Weather
Bureau, Washington, D. C.
(23) Personal correspondence with Dis-
trict of Columbia Department of
Motor Vehicles.
(24) Personal correspondence with Mary-
land Department of Motor Vehicles
and Virginia Division of Motor
Vehicles.
(25) Personal correspondence with Dis-
trict of Columbia Department of
Highways and Traffic.
(26) U. S. Bureau of the Census: "Statis-
tical Abstract of the United States,
I960."
(27) The World Almanac, I960, New York
World-Telegram.
(28) Personal correspondence with Dis-
trict of Columbia Department of
Sanitation.
33 -
-------
(29) Xanten, W. A., Superintendent, Division
of Sanitation, Washington, D. C., "D.C.
Refuse Transfer Station A New De-
velopment in Large-Scale Odor and
Dust Control Produces Nuisance -
Free Refuse Handling Station." (41)
(30) Personal correspondence with Wash-
ington Suburban Sanitary Commission.
(31) Personal correspondence with Mont- (42)
gomery County and Prince Georges
County Health Departments.
(32) Personal correspondence with Alex-
andria City Health Department and
Arlington County Health Department.
(33) Personal correspondence with Fairfax
County Health Department.
(34) District of Columbia Department of
Sanitary Engineering, Report of Sew-
age Treatment Plant Operation, Fiscal
Year I960.
(35) Ives, J. E., et aL: "Atmospheric Pol-
lution of American Cities for Years
1931 to 1933," U. S. Public Health Bul-
letin No. 224, 1936.
(43)
(44)
(45)
(36) Cholak, J., et aL: "Air Pollution in a
Number of American Cities", Archives
of Industrial Health LI, 280, (1955). (46)
(37) Heggestad, H. E., and Middleton, J. T.,:
"Ozone in High Concentrations as
Cause of Tobacco Leaf Injury," Sci-
ence, 129, 208, (1959).
(47)
(38) Wanta, R. C., and Heggestad, H. E.,:
"Occurrence of High Ozone Concentra-
tions in the Air Near Metropolitan
Washington," Science, 130, 103 (1959).
(39) Ledbetler, M. C., Zimmerman, P. W., (48)
and Hitchcock, A. E., Contributions of
Boyce Thompson Institute, 20, 275,
(1959).
(40) "Air Pollution Measurements of the
National Air Sampling Network, 1953-
57." Public Health Service Publication
No. 637, United States Government
Printing Office, Nov. 1958; 259 pp.
Supt. of Documents, Washington 25,
D. C., $2.00.
Unpublished Data, National Air Sam-
pling Network, U.S. Department of
Health, Education, and Welfare, Pub-
lic Health Service.
Department of Public Health, District
of Columbia and U.S. Department of
Health, Education, and Welfare, Pub-
lic Health Service,: "A Pilot Study
of Air Pollution in Washington, D. C.,
December 2-8, I960."
U.S. Department of Health, Education,
and Welfare, Public Health Service,:
"The Louisville Air Pollution Study,
I960." (unpublished as of this date)
Chass, R. L., _et aL: "Total Air Pol-
lution Emissions in Los Angeles
County." J. Air Pollution Control
Association, Vol. 10, No. 5,Oct. I960.
Wohlers, H. C. and Bell, G. B.,:
"Literature Review of Metropolitan
Air Pollutant Concentrations", Stan-
ford Research Inst., Menlo Park,
Calif., Nov. 1956.
Yocum, J. E., Gein, G. M. and Nelson,
H. W.,: "A Study of Effluents From
Backyard Incinerators," J. Air Pol-
lution Control Association, Vol. 6,
No. 2, Aug. 1956.
Williamson, J. E. and Twiss, H. M.,:
"Multiple Incinerator Design Stand-
ards for Los Angeles County," Los
Angeles County Air Pollution Control
District, Los Angeles, Calif., c. 1954.
Eliassen, R.: "Domestic and Munici-
pal Sources of Air Pollution", from
Proceedings - National Conference
on Air Pollution, Nov. 18-20, 1958.
Public Health Service Publication No.
654, United States Government
Printing Office, Washington 25, D. C.,
1959.
- 34
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APPENDIX
Examples of Pollution Emission Rates
The data presented in this appendix are of value only as general information on the
composition and magnitude of pollution from several activities. They should not be applied
to any specific situation without due consideration of the many factors which affect pollution
emissions.
- 35 -
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Estimates of Products of Combustion from Fuel Burning Operations
(Emissions in Lbs./Lb. of Fuel Fired) (43)
Pollutant
Sulfur Dioxide
Sulfur Trioxide
Hydrogen Sulfide
Oxides of Nitrogen (as NO2)
Total Hydrocarbons
Inorganic Chlorides (as HC1)
Fluorides (as HF)
Organic Acids (as CHaCOOH)
Aldehydes (as CHsCHO)
Ammonia
Particulates
Fuel
Coal
1.7 x S*
0.2 x S
0.004 x S
0.010
0.010
0.002
0.002
n.a.
n.a.
n.a.
See Tables A-2 & A-3
Fuel Oil (a)
1.8x S
0.2 x S
n.a. **
0.013
0.005
n.a.
n.a.
0.015
0.0018
0.000006
0.00025
Natural Gas (b)
1.8 x S
0.2 x S
n.a.
0.005
0.0015
(c)
(c)
0.0012
0.0004
0.000006
(c)
UJ
I
* S = Ibs. sulfur/lb. fuel
** Not available
(a) Weight of No. 2 fuel oil may be taken as 7.16 Ib./gal.
(b) Weight of natural gas may be taken as 0.04575 Ib./cu. ft.
(c) Negligible
-------
Estimates of Particulates from Industrial Coal Burning;
According to Firing Method (43)
(Emissions in Libs, per Lb. of Fuel Fired)
Firing Method Solids*
Underfeed Stoker 0.15 A**
Travelling Grate 0.15 A
Cyclone Furnace 0.15 A
Spreader Stoker - Dust Reinjection 1.00 A
Spreader Stoker - No Dust Reinjection 0.60 A
Pulverized Coal 0.75 A
* Ash and unburned fuel.
** A = Lbs. ash per Ib. of fuel
-------
Estimates of Particulates from Domestic and Commercial Coal Burning;
According to Firing Method (43)
(Emissions in Libs, per Lib. of Fuel Fired)
OJ
00
Firing Method
Hand Fired Furnaces
Stoker Fired Furnaces and Stoves
Hand Fired Stoves
Carbon and Tars
< IP *
0.006
0.0025
0.014
> I,/**
0.004
0.0015
0.010
Ash
( > 1/0
0.002
0.0015
0.003
*Less than 1 micron in size.
**Greater than 1 micron in size.
-------
vO
I
Pollution Emissions from Gasoline and Diesel Engines
(highly variable)
Pollutant
Hydrocarbons
Aldehydes ketones
Other organic gases
Carbon monoxide
Oxides of nitrogen
Sulfur dioxide
Aerosols
Emissions
Gasoline
engines(44) (
0.332
0.004
0.005
2.91
0.113
0.009
0.011
in pounds per gallon
of fuel used
a) engine s^^'
0.18
0.01
n.a.
0.06 (b)
0.10
0.04
0.11
(a) Includes blowby emissions but not evaporation losses.
(b) Reference 44 used.
-------
Pollution Emissions from Single and Multiple
Chamber Incinerators
Gaseous compound
or group
Methanol
Ethylene
Acetone
Methane
Acetylene
Alpha olefins (as propylene)
Carbonyl sulfide
Benezene
Acids (as acetic)
Phenols (as phenols)
Aldehydes (as formaldehydes)
Ammonia
Oxides of nitrogen (as NC>2)
Carbon monoxide
Solid and liquid
emissions
Solids, gr./SCF, @ 12% COz
Volatiles, gr./SCF, @ 12% COz
Total, gr./SCF, @ 12% COz
Total, Ibs./ton of refuse burned
Pollution emission in pounds
per ton of refuse burned
Single
chamber
incinerator^4"'
9-23
8-61
>8
23-150
< 4-73
<6
>3
>3
>4
>8
5-64
0.9-4
<0.1
197-990
Single
chamber
incinerator''*''
0.9
0.5
1.4
23.8
Multiple
chamber
incinerator'4''*
<0.05
<0.05
<0.05
< 0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
^.0.3
< 0.05
^> 2.1
<0.05
Multiple
chamber
incinerator'4 ')
0.11
0.07
0.19
3.5
*Losses listed as < 0.05 Ibs./ton were below the detectable limit.
- 40 -
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Estimated Contaminants Discharged from Burning Dumps (48)
Pollutants
Sulfur Oxides
Nitrogen Oxides
Ammonia
Aldehydes
Organics
Organic Acids
Solids
Total
Pounds per day per
persons using refuse
100,000
disposal
180
90
345
600
42,000
225
7,000
50,400
-------
Estimated Hydrocarbon Losses from Gasoline Handling Operations V4-3'
(Emission in Lb./10,000 gal. of Gasoline Handled) (a'
Operation
Marketing (b>
Filling Service Station
Tanks
Filling Auto Tanks
Evaporation from Auto
Tanks and Carburetors
Totals
Temperature
40°F
28
18
21
124
191
50°F
37
24
28
163
252
60°F
50
32
38
222
342
70°F
67
43
51
297
458
80°F
89
57
68
393
607
90°F
120
77
91
530
818
100°F
152
98
116
674
1040
(a) As an approximation of the vapor pressures of gasoline, the vapor pressures of
n - heptane were used.
(b) Marketing is the handling of gasoline at the bulk plants.
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