ENVIRONMENTAL HEALTH SERIES
Air Pollution
Survey of Lead
in the Atmosphere
of Three Urban Communities
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
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Survey of Lead
in the Atmosphere
of Three Urban Communities
by
The Working Group on
Lead Contamination
American Petroleum Institute
Automobile Manufacturers Association
California State Department of Public Health
E. I. du Pont de Nemours and Company
Ethyl Corporation
Kettering Laboratory, University of Cincinnati
Public Health Service
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Division of Air Pollution
Cincinnati, Ohio 45226
January 1965
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The ENVIRONMENTAL HEALTH SERIES of reports was
established to report the results of scientific and engineering studies of
man's environment: The community, whether urban, suburban, or
rural, where he lives, works, and plays; the air, water, and earth he
uses and re-uses; and the wastes he produces and must dispose of in a
way that preserves these natural resources. This SERIES of reports
provides for professional users a central source of information on the
intramural research activities of Divisions and Centers within the
Public Health Service, and on their cooperative activities with State
and local agencies, research institutions, and industrial organizations.
The general subject area of each report is indicated by the two letters
that appear in the publication number; the indicators are
AP-Air Pollution
AH—Arctic Health
EE — Environmental Engineering
FP-Food Protection
OH — Occupational Health
RH — Radiological Health
WP-Water Supply and
Pollution Control
Triplicate tear-out abstract cards are provided with reports in the
SERIES to facilitate information retrieval. Space is provided on the
cards for the user's accession number and key words.
Public Health Service Publication No. 999-AP-12
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CONTENTS
Page
PREFACE 1
PURPOSE 2
PARTICIPATING ORGANIZATIONS AND ACKNOWLEDGMENTS 3
SUMMARY AND CONCLUSIONS 3
LEAD IN THE ENVIRONMENT 5
Sources of Lead in the Atmosphere 6
Industrial 6
Combustion of Fuel (Other than gasoline) 7
Motor Vehicles 7
Other Sources 10
Sources of Lead in Man 10
Ingestion 10
Inhalation 11
Smoking 12
Effect of Lead on Man 12
Intake of Lead 12
Output of Lead 12
Body Burden of Lead 13
Accumulation of Lead in Man 13
Lead Intoxication 14
INVESTIGATIONS IN CINCINNATI, Los ANGELES, AND PHILADELPHIA . 15
Atmospheric Sampling at Fixed Stations—Three-City Study ... 15
Aerometric Methods 16
Locations of Sampling Sites 16
Sampling Equipment 20
Sampling Methods 21
Analytical Methods 21
Intel-laboratory Comparisons 22
Data Handling 24
Concentrations of Air Pollutants 24
Suspended Particulates 24
Lead 29
Lead in Particulates 33
Diurnal Distribution of Lead ( 38
Relation Between Lead and Carbon Monoxide 45
Relationship of NASN Data to Three-City Study Data ... 45
Atmospheric Lead Trends 46
Meteorology 50
Meteorological Effects 50
Representativeness of Sample Year 50
Special Studies 54
Lead Concentrations in Heavy Traffic 54
Sumner Tunnel Study 57
Alkyl Lead Concentrations 57
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Biological Studies 58
Cincinnati 59
Populations Studied 59
Results 59
Los Angeles 67
Populations Studied 67
Pilot Studies 69
Data Collected 69
Results 69
Philadelphia 74
Populations Studied 74
Results 76
Discussion of Biological Investigations in the Three Cities ... 81
Relation of Biological Findings to Atmospheric Results 88
REFERENCES 90
APPENDIX 93
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PREFACE
In 1958, the Surgeon General of the Public Health Service was
asked by manufacturers of tetraethyl lead (TEL) for the advice and
guidance of the Public Health Service on the public health effects of
increasing the maximum concentration of tetraethyl lead in motor
gasoline from 3.0 to 4.0 milliliters per gallon. Although the Public
Health Service has no legal authority to control the amount of lead
antiknock in gasoline, the Surgeon General indicated that he would
appoint a committee to advise whether the proposed increase might
represent a hazard to public health. This committee (called the Advisory
Committee on Tetraethyl Lead to the Surgeon General) concluded that
such an increase in the TEL content of gasoline would not significantly
increase the hazard to public health from air pollution.1 It pointed out,
however, that a conclusive answer was not possible because of the lack
of sufficient relevant data.
The Advisory Committee on Tetraethyl Lead recommended to the
Surgeon General that "The Public Health Service, in collaboration
with manufacturers of tetraethyl lead, the petroleum industry, and
other appropriate organizations, conduct studies to provide more
definitive data on the levels and trends of atmospheric lead contamina-
tion in selected urban areas and of the body burden of lead of selected
population groups." The Surgeon General convened a meeting to de-
termine the interest of various groups in a cooperative study on
atmospheric lead contamination. As a result a Working Group was
formed to develop and execute a suitable program of studies.
The studies consisted of air sampling over a period of 1 year at a
number of locations in Cincinnati, Los Angeles, and Philadelphia, and
the gathering of blood and urine samples from selected population
groups in these cities. The details of this program and the results
obtained are the subject of this report.
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PURPOSE
The purpose of the program undertaken by the Working Group
on Lead Contamination was to:
1. Establish a baseline for the lead content of the atmosphere in urban
areas and in the blood and urine of selected population groups.
2. Ascertain whether differences exist in levels of lead in the blood and
urine of groups of individuals exposed to different amounts of lead
in a community atmosphere.
3. Obtain data that would permit review of the potential harmful
effects of existing lead concentrations in the atmosphere on the
general population or segments of the population.
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PARTICIPATING ORGANIZATIONS
AND ACKNOWLEDGMENTS
The Working Group responsible for coordinating the project consisted
of representatives of the following organizations: American Petroleum
Institute, Automobile Manufacturers Association, California State
Department of Public Health, E. I. du Pont de Nemours and Company,
Ethyl Corporation, Kettering Laboratory of the University of Cincin-
nati, and U. S. Public Health Service. The names of the individual
representatives are shown in the Appendix. The U. S. Public Health
Service provided financial support for the Philadelphia program. The
financial support for the Los Angeles study was provided jointly by
the California State Department of Public Health and the U. S. Public
Health Service. The Cincinnati survey was carried out by the Kettering
Laboratory, with financial support supplied by the American Petroleum
Institute, E. I. du Pont de Nemours and Company, and Ethyl Cor-
poration.
In the Philadelphia area, the U. S. Public Health Service was assisted
by the Philadelphia Health Department. In Los Angeles, assistance was
rendered in the operation of the atmospheric sampling stations by the
Los Angeles County Air Pollution Control District, California Insti-
tute of Technology, University of California at Los Angeles, Vernon
City Health Department, Los Angeles City Health Department, and
the Los Angeles County Arboretum.
Representatives of the agencies responsible for the day-to-day
operation of the project rendered invaluable service. The efforts of
these and many other individuals were essential to the completion of
the program. Their contributions are gratefully acknowledged.
SUMMARY AND CONCLUSIONS
The Surgeon General of the Public Health Service, in response to a
recommendation from an Advisory Committee on Tetraethyl Lead,
appointed a Working Group from industry, a university, and State and
Federal Governments, to investigate the problem of atmospheric lead
in selected urban areas. This investigation consisted' of a comprehensive
sampling program for lead in the atmosphere of Cincinnati, Los Angeles,
and Philadelphia, and for lead in the blood and urine of selected groups
of persons in the population of these cities. Limited investigations were
made of the concentration of atmospheric lead in heavy traffic and in
a vehicular tunnel.
From June 1961 through May 1962 approximately 3,400 samples of
particulate lead from the atmosphere were obtained at 20 sites in the
three cities. It was found that:
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1. The annual average concentration of lead in the atmosphere
ranged from about 2 micrograms per cubic meter of air in the
downtown and industrial area of Cincinnati, to about 1 in the
outlying areas of that city. The values in corresponding areas in
Philadelphia ranged from 3 to 1, and in Los Angeles from 3 to 2.
2. The average concentration of lead in all of the samples obtained
in each city was 1.4 micrograms per cubic meter in Cincinnati,
1.6 in Philadelphia, and 2.5 in Los Angeles.
3. The highest concentrations of lead were found in the air during
autumn and winter. The highest seasonal concentration of lead
at any station was 2.4 micrograms per cubic meter in Cincinnati,
3.8 in Philadelphia, and 4.1 in Los Angeles.
4. The highest monthly concentration at any site was 3.1 micrograms
per cubic meter in Cincinnati (October), 4.4 in Philadelphia
(October), and 6.4 in Los Angeles (December).
5. The highest concentration of lead in any one sample was 6.4
micrograms per cubic meter in Cincinnati, 7.6 in Philadelphia,
and 11.4 in Los Angeles.
6. The mean concentration of lead found in heavy traffic ranged
from about 14 micrograms per cubic meter on Cincinnati streets,
through approximately 25 on Los Angeles Freeways, to 44 in a
vehicular tunnel.
7. The average content of lead in particulate matter for all samples
was 1.7 percent in Cincinnati, 1.5 in Philadelphia, and 2.3 in
Los Angeles.
8. Atmospheric lead concentrations varied during the day; highest
concentrations occurred in the early morning.
The concentrations of lead found in the atmosphere in this study
were consistent with those obtained during the same period by the
National Air Sampling Network (NASN) of the Public Health Service.
Data from the NASN show no consistent trend in the concentrations
of lead in the atmospheres of the three cities during the past 5 years.
Data obtained by the Kettering Laboratory indicate that in Cincinnati
the trend has been downward since 1946.
The concentration of lead in the blood of approximately 2,300
individuals was determined, as was that in the urine of approximately
1,700 males within the same groups. Certain groups were selected
because of their apparent exposure to different amounts of lead in the
ambient air of the community in which they lived and worked. A few
groups were representative of occupations that provided an opportunity
for exposure to lead. Other groups were selected because they had
certain chronic diseases that might conceivably have some bearing on
ability to dispose of lead. Only 11 persons were found to have concen-
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trations of lead in their blood equal to or in excess of 0.06 milligram
per 100 grams of blood. A few values in excess of 0.06 are to be expected
in a large sample of individuals representing a variety of exposures
to lead.
Levels of lead concentration in the urine fell within the fairly nar-
row range that is presently denned as "normal."
The data on lead in the blood of the subjects were examined in rela-
tion to a number of variables. No relationship was found between
levels of lead in the blood and age. Levels in females were slightly
lower than those in males from comparable groups. In nearly all in-
stances, the mean concentration of lead in the blood of smokers was
slightly higher than that of non-smokers. There were no unusual findings
concerning persons who were investigated because of chronic diseases.
A general trend was noted toward an increase in the concentration
of lead in the blood of the groups of persons as they varied from rural
to central urban areas in their places of residence and work. For ex-
ample, those who lived and worked in rural or suburban areas had the
lowest concentrations of lead in their blood, and it was in these areas
that the lowest concentrations of lead were found in the atmosphere.
Highest mean levels of lead in the blood were noted for groups who
worked (and, in some cases lived) in areas characterized by higher
concentrations of lead. These relationships were not as well defined for
intermediate levels of lead in blood and in the atmosphere. Although
these trends are influenced by factors not dealt with in this study,
the correlation between the respective values at the extremes probably
has validity in the causal sense.
In general, the results of both the aerometric and biological phases
of the investigation confirm earlier findings based on more limited
observations. It is believed that these results have established a base-
line for future investigations of these types.
LEAD IN THE ENVIRONMENT
Lead occurs widely in the environment of man, both as a natural
constituent and as a contaminant. Lead is taken into the human body
in virtually all food and beverages and in respired air. It is a natural
constituent of soil, water, vegetation, and animal life, and many human
activities increase the lead in soil, in streams, and in the atmosphere.
As a result of its ubiquitous nature, lead is a regular component of the
minerals in living things generally and in man specifically. Further,
the metabolism of lead in man has been studied intensively and a great
deal has been learned about how the human body reacts to various
types of exposure to lead. The sources of lead in the environment of
man have been examined in detail in the past.
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SOURCES OF LEAD IN THE ATMOSPHERE
Industrial
Lead is used in practically every type of industry. In this country,
somewhat over 1,000,000 tons of lead are processed yearly.2'3 In addi-
tion to use in the production of lead alkyls, as in antiknock compounds,
large quantities are used in the manufacture of storage batteries, for
various construction purposes, in the production of paint pigments,
and in the covering of cable. During 1961, American industry consumed
lead as shown in Table I.2
TABLE 1
INDUSTRIAL CONSUMPTION OF LEAD IN THE
UNITED STATES DURING 1961
(In short tons)
Storage batteries 352,000
Oil refining and gasoline 166,000
Construction (caulking) 116,000
Pigments 83,200
Cable 58,000
Solder 55,000
Ammunition 46,000
Printing (type metal; 28,000
Unclassified 100,800
Total 1,005,000
The large tonnage listed as unclassified indicates many uses for lead
that are difficult to trace. While the consumption of lead has been very
stable during the last 10 years, there have been changes in the amounts
consumed by various industries; the amounts of lead for sheathing
cable and for production of white house paints, for example, have
decreased in the last decade because of the introduction of new materials.
Lead and its products are often processed from the molten state,
giving rise to fume. Many lead products may also be produced as
powders or involve products produced from powdered materials that
may be dispersed into the air. The in-plant hazard associated with the
processing of lead is often recognized, and most industries control this
hazard. Although some lead is removed from industrial discharges by
control devices, lead-bearing dusts and fumes escape to the outside air.
Such discharges may contain as much as several milligrams of lead per
cubic meter of air. Examples of concentrations of lead in in-plant air
that may be discharged to the outside are shown in Table 2. All cif
these discharges are not continuous, but may be produced intermittently.
6
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TABLE 2
CONCENTRATIONS OF LEAD IN THE IN-PLANT AIR
FROM A NUMBER OF OPERATIONS
Industry
Storage battery
manufacturing
Paint manufacturing
Insecticide manufacturing
Non-ferrous foundries
Painting & paint scraping
Riveting
Smelters
Glass manufacturing
Operation
Dumping & mixing
Pasting department
Drying
All
All
Blending room
Packaging room
Over cupolas
Tapping area
Furnace room
All
Hot riveting
Lead smelting
All
Pb range,
mg/m3
0.35-6.06
0.21-5.31
0.12-3.21
0.04-39.0
0.39-48.6
up to 8
1 to 11
4.46-12.0
2.0
0.51-0.75
0.6-32
6.4-8.2
0.01-2.45
up to 5.35
Reference
No.
32
32
32
33,34,35,36
31,37
38
38
39
39
39
40,41
42
43,44,6
45,46
Combustion of Fuel (Other than gasoline)
Air contaminated by fly ash or by soot derived from the combustion
of coal may contain appreciable quantities of lead. In 1958, Savul
reported finding from 0.005 to 1.67 ppm lead in coal and 25.5 ppm in the
ash." In 1933, Dunn reported finding 4, 25, and 358 ppm of lead in
soots from coal.6 Tomson found that fly ash from the combustion of
coal contained 100 to 150 ppm lead.6 In 1961, Cholak reported concen-
trations ranging from 2 to 40 ppm with an average of approximately
11 ppm for 23 samples of coal used in the Cincinnati area.7 Lead
emissions from dry-bottom power plants firing pulverized coal ranged
from 0.06 to 0.33 milligrams per cubic meter of standard flue gas for
three plants in Ohio and Pennsylvania.8 Although it is not known in
what form lead is present in coal, the low melting points of some of
the oxides and other lead compounds may result in the volatilization
of lead during combustion. The ash of coal burned at 1000°C contains
only 10 percent of the lead present when the combustion is carried out
at 500°C.»
Motor Vehicles
One of the sources of lead in the atmosphere is the exhaust from
gasoline-fueled vehicles. Essentially all of the motor gasoline sold in the
United States contains alkyl lead compounds added to improve the
antiknock quality of the fuel. During combustion, these lead compounds
undergo thermal and oxidative breakdown and are discharged in the
exhaust as inorganic salts.
The ability of alkyl lead compounds to increase the antiknock quality
of fuels used in spark-ignition engines was discovered in the early 1920's.
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Until 1959 the only alkyl lead compound used commercially was tetra-
ethyl lead, although the ability of other alkyl lead compounds to in-
crease antiknock quality was known. The relative effectiveness of the
various alkyl lead compounds in imparting antiknock quality to gasoline
depends on many factors including, to a large extent, the specific
hydrocarbons that comprise the finished gasoline blends. Developments
in the technology of petroleum processing in recent years have resulted
in significant changes in the number and types of hydrocarbons in
many of today's gasolines. Because of these changes and changes in
other vehicle factors that also influence the type of antiknock quality
required, certain refiners now find that alkyl lead compounds other than
tetraethyl lead are more effective in raising the antiknock quality of
their particular fuels. Antiknock compounds other than tetraethyl lead
currently being used are tetramethyl lead, physical mixtures of tetra-
ethyl lead and tetramethyl lead, and equilibrium mixtures of a catalyzed
redistribution reaction of tetraethyl lead and tetramethyl lead. The
amount of each of the alkyls in the latter mixture depends on the per-
centage of tetraethyl and tetramethyl lead used in the reaction. These
alkyl lead compounds are present in today's gasolines in widely varying
concentrations, the maximum in motor gasolines being 4.23 grams of
lead per gallon (equivalent to 4 milliliters of tetraethyl lead per gallon
of gasoline) in accordance with an agreement between the suppliers
and users that has the concurrence of the Office of the Surgeon General
of the U. S. Public Health Service. During the period of this investiga-
tion, the national use of antiknock compounds containing alkyl lead
averaged a little over 2.0 grams of lead per gallon of motor gasoline.
The total consumption of lead metal in antiknock compounds in
domestic motor gasolines for the past 10 years is shown in Table 3
with the average lead content per gallon during the same period.
TABLE 3
CONSUMPTION OF LEAD IN ANTIKNOCK COMPOUNDS
IN DOMESTIC MOTOR GASOLINEa
Total lead metal, Average lead content,
Year millions of pounds g/gal
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
234
248
276
288
282
253
258
263
256
280
2.28
2.34
2.37
2.44
2.38
2.12
2.06
2.04
1.98
2.08
aSource: Ethyl Corporation and E. I. du Pont de Nemours and Company.
8
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Commercial lead antiknock fluids of all types contain halogens
designated as scavengers that serve to reduce the accumulation of
decomposition products of the lead alkyls in certain critical areas of
the engine combustion chamber. Scavenger concentrations are ex-
pressed in terms of theories. One theory is defined as the amount of
the active halogen ingredient required to react chemically with all of
the lead present in the fluid. The most commonly used commercial
fluid contains 0.5 theory of ethylene dibromide and 1.0 theory of
ethylene dichloride.
When gasoline containing lead antiknock fluids is burned in an
engine, the alkyl lead compounds decompose at the high temperatures
and pressures developed by the combustion process and the decompo-
sition products, lead oxides, act to inhibit chain reactions that would
otherwise result in uncontrolled detonation or knock. The decomposi-
tion products then react with the scavengers present and these resultant
products are the materials that are carried into the exhaust system
along with the other combustion products. These inorganic lead com-
pounds are primarily PbCl • Br, alpha and beta forms of NH4C1 • 2PbCl •
Br, and 2NH4Cl'PbCl-Br with minor amounts of PbS04 and PbO
PbCl-Br-HjO. When phosphorous additives are present in the fuel,
up to one-fifth of the exhausted lead may be present as 3Pb3(P04)2'
PbCl-Br.
Studies of the lead particulates leaving the tailpipe have shown
that from 70 to 80 percent of the metallic lead used by a vehicle will
eventually be exhausted to the atmosphere over 20,000 to 30,000 miles
of city and country driving.10 The balance remains in the engine itself,
in the lubricating oil and oil filter, and in the vehicle exhaust system.
The amount and particle size of inorganic lead leaving the tailpipe of
a vehicle at any given time is dependent on many factors including the
operating mode at the instant, the short and long term type of preceding
operation, the age of the vehicle and its exhaust system, and engine
and exhaust system design features. These studies have also shown
that in city-type operation less lead is exhausted than in highway-type
service. In city operation from 20 to 60 percent of the lead burned in
the combustion chamber is exhausted from the tailpipe in inorganic
form depending upon the amount of lead particulates accumulated in
the exhaust system as the result of the preceding operating history. Of
this from one-half to three-fourths of the lead is in the particle size
range that might be expected to remain air-borne.
Although essentially all of the lead discharged by vehicles is exhausted
in the form of inorganic particles, small percentages of the alkyl lead
compounds blended in gasoline may reach the atmosphere through
escape of fuel vapors. Volatile fuel vapors can be lost from vents on
the carburetor and fuel system and are displaced from the tank during
refueling. The concentrations of alkyl lead compounds in the vapor
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are lower than those in the original gasoline since these compounds are
less volatile than gasoline and tend to remain behind in the unevaporated
portion. Some vaporized fuel containing alkyl lead compounds escapes
also in the blowby gases that are forced past the pistons and discharged
from the crankcase. (With the installation of positive crankcase ventila-
tion devices, this source will eventually be eliminated.) Moreover, in
the normal combustion process a very small percentage of the fuel
introduced is not completely burned. This unburned fuel contains some
alkyl lead compounds. This lead, however, is mixed with hot exhaust
gases and contacts components of the engine and exhaust system at
high temperature; considerable decomposition results, since the alkyl
lead compounds begin to decompose at temperatures as low as 400°F.
All organic lead compounds, even at low concentrations, are light-
sensitive and hence are subject to photochemical decomposition once
they reach the atmosphere.
Other Sources
Soils generally contain lead, and therefore particles of soil that be-
come airborne contribute small amounts of lead to the atmosphere.
The lead content of soils varies with the geology of the area. Gold-
schmidt reported that the average in the earth's crust is 16 ppm.11'12
Others have reported values ranging from 0.05 to several thousand parts
per million near smelters. Cholak and co-workers reported that the
lead content of soil in the Cincinnati area varied from 16.4 to 360 ppm.
The higher concentrations were found in soils of the older residential
areas with a longer history of repainting of dwellings.7 Prince, in 1957,
reported that the lead content of the loamy soil types in New Jersey
varied from 13.9 to 95.7 ppm.13
SOURCES OF LEAD IN MAN
Ingestion
It has been reported that the lead content of the composite food
of adult citizens of the United States ranges from under 0.1 milligram
to more than 4.0 milligrams per day, and averages approximately 0.3
milligram per day, dependent upon the amount and variety of food
consumed by the individual.14 The natural or treated water supplies
available for use in cities in the United States usually contain about
0.01 to 0.03 milligram per liter.16 For an average intake of water ranging
from 1 to 3 liters, this would amount to 0.01 to 0.09 milligram of lead
per day.
The absorption of lead from the alimentary tract is somewhat less
than 10 percent of that ingested. Even when a compound of lead has
been dissolved prior to its experimental ingestion, only 10 to 15 percent
of it is absorbed, when the dosage per day does not exceed 1 to 4 milli-
grams.16 A larger percentage may be absorbed when the dosage in the
10
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alimentary tract is considerably higher than that indicated above.
Acute poisoning may develop promptly following the ingestion of a
large dose of a soluble salt. Lead poisoning may also develop within
several weeks when the quantity of somewhat soluble lead ingested
per day by an adult is of the order of 6 to 10 milligrams.17
Inhalation
The monthly average concentration of lead in the atmospheres in
large U. S. cities varies from about 1 to 6 micrograms per cubic meter.
Since a person breathes approximately 15 cubic meters of air per day,
the lead inhaled from the general atmosphere of cities varies from
about 0.01 to 0.10 milligram per day.
It is not possible to describe the behavior of particulate compounds
of lead in the human respiratory tract in a precise manner. There is
sufficient evidence, however, to indicate the general pattern of pulmonary
retention of particulate matter by particle size.
Particles larger than 5 microns in diameter settle fairly rapidly and
do not usually constitute a large part of the suspended particulate
matter in the atmosphere. When such particles are inhaled they are
trapped in the nostrils or nasopharynx or are deposited upon the
tracheo-bronchial mucosa. Through the secretion of mucous and the
action of the cilia, they move to the pharynx, from which they are
evacuated in the mucous discharges of the nose and throat, or are
swallowed. Some portion of that which remains within the upper
respiratory tract for a time, or is swallowed, is absorbed.
Particles of lead compounds within the range of 2 to 5 microns in
diameter are deposited in various parts of the respiratory tree. Few, if
any, reach the alveoli. Particles less than 1 micron in diameter reach
the alveoli, and some are retained. Recent work by Robinson18 indicates
that "... a typical size distribution for lead aerosol would be one with
a mass median equivalent diameter of 0.2 micron with 25 percent of
the mass being accounted for by particles with an equivalent diameter
of less than 0.1 micron and another 25 percent of the mass being found
in particles larger than 0.5 micron."
The absorption of lead in the respiratory tract depends on a number
of factors, including the solubility of the compound in the epithelium
and endothelium of the respiratory tree, the dimensions of the dispersed
particles of the compound, and the surface relationships between the
particles and the respiratory membrane. Experimental evidence has
shown that the sesquioxide is rapidly absorbed l7-19 in the lung, and
certainly the chloride or bromide or the double halogen salt, as well
as many other compounds, would be absorbed readily.
Kehoe of the Kettering Laboratory reported in 1960 that 35 to 50
percent of finely divided, inhaled lead (particles of lead sesquioxide
under 0.2 micron in diameter at concentrations on the order of 150
11
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micrograms per cubic meter) is retained in the lungs, and that all of
this retained lead is eventually absorbed.17 More recent unpublished
data obtained by the Kettering Laboratory show that at concentrations
of 10 micrograms per cubic meter of air, somewhat less than 20 percent
of lead sesquioxide is retained.
Smoking
The quantity of lead in cigarettes and tobaccos has been the subject
of speculation as to the significance of the absorption of lead by smokers.
Because of the use of lead-bearing insecticides, it is not unusual to
find occasional samples of tobacco with a fairly high lead content. As
early as 1921, Cadenhead, investigating a possible source of lead poison-
ing, reported the finding of 0.2 gram of lead in a pipeful of tobacco;
at the same time he reported that only 76 micrograms (0.038 percent)
was in the smoke.20 In 1937, the lead concentration in Canadian cigar-
ettes was reported to average 22 ppm and to range from 7.5 to 27.5
ppm.21 In 1957, English tobaccos were found to contain lead concen-
trations of 4.8, 5.1, and 36 ppm respectively in pipe, cigarette, and
cigar tobaccos.22 These levels were considerably lower than those re-
ported in 1951 when the same materials averaged 96, 143, and 414
ppm, respectively.22 In 1961, Kehoe reported that lead in the ash of
smoked cigarettes averaged 14 micrograms per cigarette.17
Several reports indicate that tobacco smoke contains very little of
the lead originally present in the tobacco. In 1939, it was reported that
only one-fifteenth of the total lead in cigarettes was found in puffed
smoke.23 A more recent analysis of five different brands of cigarettes
indicated that the lead content per cigarette averaged 13 micrograms,
of which an average of only 0.6 microgram (4.9 percent) appeared in
the smoke.17'24 Cogbill and Hobbs, investigating the transfer of metallic
constituents of cigarettes to the smoke, also concluded that the metallic
constituents remain in the ash although small quantities may be
vaporized and appear in the smoke.26
EFFECT OF LEAD ON MAN
Intake of Lead
A normal adult may take into his body about 0.14 to 0.45 milligram
of lead per day. The largest portion of this lead is in food and beverages,
which may contribute, on the average, about 0.12 to 0.35 milligram
per day.17 The amount of lead taken in with the inspired air may range
from about 0.01 to 0.10 milligram per day.
Output of Lead
Roughly 90 percent of the ingested lead traverses the alimentary
tract unabsorbed and is discharged in the feces. To this unabsorbed
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lead in transit is added the unresorbed portion secreted into the alimen-
tary tract in the biliary, digestive and mucous secretions. The result
is that the amount of lead in the feces is practically equivalent to that
in food and beverages ingested.
As discussed earlier in this report, 20 to 50 percent of finely divided
inhaled lead particles is retained; consequently, 50 to 80 percent is
exhaled.
The amounts excreted in the urine over considerable periods of time
average from 0.02 to 0.04 milligram per day.17 Significant but ill-defined
quantities may be excreted in the sweat and in other aqueous, mucous,
and lipoid secretory discharges from the body. Further small quantities
of lead are shed regularly in falling hair, desquamating skin, and
clipped nails.
Body Burden of Lead
In persons of all ages (beyond early infancy, for which data are
scanty) in the United States, appreciable quantities of lead are widely
distributed throughout the body tissues. Concentrations in the soft
tissues are low, ranging from about 20 micrograms per 100 grams of
striated muscle to about 200 micrograms per 100 grams of liver; those
in the skeleton are relatively high, ranging from about 400 micrograms
to about 1200 micrograms per 100 grams in the ribs or vertebrae, to
two or three times these levels in the femur. (These concentrations are
expressed in terms of the fresh or formalin-fixed, rather than the dry
or ashed tissues) .l4 At first glance, lead in the body in such concentrations
suggests a progressive cumulative process whereby some of the lead
absorbed from the environment is retained in the body regularly. To a
limited extent this may be so, but present evidence indicates that an
approximate balance between intake and output is arrived at early in
life.
Equilibrium in a normal individual may be disturbed by an increase
or decrease in the intake of lead. Under such circumstances, the body
burden of lead may increase or decrease. Balance experiments have
shown that changes in the intake and output of lead occur from time
to time in response to changes in the environment of the individual.
The most obvious of such changes, aside from entering upon or ter-
minating employment in a lead-using industry, is altering the quality
or quantity of food. Anything that affects the appetite or promotes a
wider or narrower selection of food alters appreciably the intake of
lead in food or beverages, sometimes several fold. Another possible
change is that due to ^differing lead levels in the atmosphere to which
the subject is exposed.
Accumulation of Lead in Man
With a significant increase in the intake of lead, a response occurs
that is characterized by an increase in the absorption of lead, by in-
13
-------
creased concentrations in the various tissues and fluids of the body,
and by an increase in the excretion of lead from the body in the feces,
urine, and sweat.
If a sufficient increase in the intake of lead continues steadily for a
long time, the lead content of the body increases at a steady rate over
a corresponding period of time until equilibrium is reached. The ex-
cretion of lead also increases, but not, for at least several years, at a
rate equivalent to the increase in the rate of absorption; hence ac-
cumulation in the body occurs at a practically constant rate.16 In time,
the body burden may reach a threshold of danger; i.e., a level at which
intoxication may occur. It does not follow, necessarily, that when such
a level or one much higher has been reached, intoxication will occur
in an individual or in a large proportion of the individuals within a
group. An individual with a remarkably high body burden of lead may
remain in apparently excellent health. Cases of illness are noted only
when the concentration of lead in the blood reaches or exceeds the
danger threshold, generally considered to be about 0.08 milligram of
lead per 100 grams of blood. By comparison, investigations of large
numbers of persons who have not been subjected to discoverable ex-
posures to lead in industry or to other unusual conditions indicate
that the usual upper limit is about 0.06 milligram per 100 grams
of blood.
When the intake of lead is increased intermittently, the period of
relatively rapid absorption results in accumulation of lead in the
tissues, while the alternate period results in an overall loss of lead
from the body. If the overall severity of the exposure remains fairly
uniform, the quantities of lead lost from the body during the period
of freedom from exposure eventually come to be nearly equivalent to
the quantities of lead that accumulate during the periods of exposure.
This state of equilibrium is indicated by an essentially steady excretion
of lead in the urine and concentration of lead in the blood. Where the
exposure to lead is fairly constant, this steady state continues without
significant change for many years. The individuals so exposed continue
to excrete lead in the urine at a constant level, and maintain a cor-
respondingly constant concentration of lead in the blood. No evidence
of a progressive increase in the body burden of lead develops in per-
sons so exposed, even after many years. If the blood levels are below
the danger threshold, lead poisoning does not occur. Thus, in various
industrial operations, the severity of exposure to lead is indicated by
the concentrations of lead in the urine or blood.
Lead Intoxication
There are three forms of lead poisoning due to the absorption of
lead. The most common form of the disease manifests as a mild or
severe dysfunction of the alimentary tract, with loss of appetite, con-
14
-------
stipation, colic (as the dominant feature), and general weakness and
malaise.
Second, and much less frequent today, is the neuromuscular syn-
drome, characterized by weakness and a degree of atrophy of the ex-
tensor muscles of the forearms, or by paralysis of such muscles and
more striking atrophy.
The third is lead encephalopathy, which occurs frequently among
infants and young children but only rarely in industrial lead poisoning.
Associated with each of these three forms of lead intoxication, in
greater or lesser degree, are certain abnormalities of the blood that
arise from the effects of lead upon certain of the structural and chemi-
cal processes of hematopoiesis. Thus juvenile forms of erythrocytes,
reticulocytes, and erythrocytes containing excessive quantities of gran-
ular basophilic material appear in the peripheral blood, while in-
creased quantities of certain porphyrins appear in the blood and in
the urine as an expression of abnormalities in the synthesis of hemo-
globin.
INVESTIGATIONS IN CINCINNATI,
LOS ANGELES, AND PHILADELPHIA
The program to survey lead in urban communities included a sys-
tematic determination of lead concentrations in the air of Cincinnati,
Los Angeles, and Philadelphia and of lead concentrations in the urine
and blood of at least 500 selected residents of each of these communities.
Samples of atmospheric lead were collected continuously from June
1961 through May 1962. Biological samples were collected in Phila-
delphia during March and April, 1961; in Cincinnati during 1962-63,
and in Los Angeles during 1961-62.
ATMOSPHERIC SAMPLING AT FIXED STATIONS
THREE-CITY STUDY
The selection of cities for investigation involved a number of factors.
It was desirable to include cities for which available data indicated
that the atmospheric lead levels were among the highest in the country
and, therefore, the exposure of the population would be the greatest. A
range of geographical and climatological areas was also considered
desirable. The extensive nature of the atmospheric and biological sam-
pling, financial considerations and the availability of trained manpower
limited the choice and number of cities. It was believed that Cincinnati,
Philadelphia and Los Angeles best met the criteria. Also data from
earlier lead measurements in Cincinnati and Los Angeles would be
useful in the present study.
15
-------
Aerometric Methods
Locations of Sampling Sites: Sites were selected to represent four
geographical and land-use classifications: rural, residential, commer-
cial, and industrial. At least one air sampling station was established
to determine the atmospheric concentration of lead in each classification.
A total of four stations was used in Cincinnati, and a total of eight was
used in both Los Angeles and Philadelphia.
Uniform criteria for selection of individual sampling sites provided
that sites be representative of the surrounding area and near locations
from which biological samples were collected. Before final selection
was made, each site in the three cities was evaluated according to height
above ground surface, number of obstructions, and representativeness
of the site to the area.
The locations of sampling sites in the three cities are shown in
Figures 1, 2, and 3.
Site No. Classification
Height above
ground, ft.
Location
30* Commercial 70
31* Residential 40
32* Industrial 45
33* Rural 15
*Equipped with sequential tape sampler.
Cincinnati Main Library
Kettering Laboratory
Vine and Seymour Fire Station
French Park
FIGURE 1
.
LEAD SAMPLING SITES IN THE CINCINNATI AREA
16
-------
N
Site No. Classification Height above
ground, ft.
Location
1* Commercial
2* Commercial
3* Rural
4 Residential
5 Residential
6 Residential
7* Industrial
8 Commercial
80
5
5
10
60
40
5
95
Downtown Los Angeles —
County Air Pollution
Control District
West Los Angeles— County
Air Pollution Control District
Arcadia— County Aboretum
Pasadena — County Air
Pollution Control District
Pasadena — California
Institute of Technology
Inglewood— University of
California at Los Angeles
Vernon— Vernon City
Health Dept.
Downtown Los Angeles — Los
Angeles City Health Dept.
'Equipped with sequential tape sampler.
FIGURE 2
LEAD SAMPLING SITES IN THE LOS ANGELES AREA
17
-------
Site No.
10*
11*
12*
13*
14*
15*
16*
17
Classification Height above Location
ground, ft.
Commercial
Mixed
Commercial
Commercial
Industrial
Residential
Rural
Rural
70
5
50
5
25
12
10
10
International Airport, USWB
U. S. Naval Hospital
Philadelphia City Health Dept.
15th and Market
Air Pollution Control
Laboratory
Pennypack Home Owners Assn.
Private Residence
Eva and Dearnley
Water Treatment Plant
*Equipped with sequential tape sampler.
FIGURE 3
LEAD SAMPLING SITES IN THE PHILADELPHIA AREA
18
-------
,-- ORIFICE.
ORIFICE SECTION
CONNECTED FOR
FLOW MEASUREMENT
ONLY
77 \V
ORIFICE
MEMBRANE
FILTER 4W" D
BACKING SCREEN
BAFFLE
PLATE
AIR FLOW DIAGRAM DETAIL OF FILTER HOLDER WITH ORIFICE IN PLACE
FIGURE 4
SCHEMATIC OF EQUIPMENT FOR SAMPLING INORGANIC LEAD
-------
1KMK11T /\
SANITARY E
C, INC1NNATI, (IHII)
FIGURE 5
EQUIPMENT FOR SAMPLING INORGANIC LEAD
Sampling equipment: The atmospheric lead sampler included an
orifice-type metering device for determining initial and final air flows,
a stainless-steel filter holder to contain a 4J^-inch-diameter membrane
filter, a vane-type pump and motor capable of supplying a free flow of
5.9 cfm, a cooling blower, and auxiliary electrical equipment. An air-
flow diagram and a detailed drawing of the filter holder and orifice are
shown in Figure 4.
20
-------
At some of the installations, diurnal variations in lead concentrations
were determined by use of sequential tape samplers (Figure 5). These
instruments sampled at 0.25 cfm on either a 2- or 4-hour cycle with
Whatman No. 4 tape. Stations equipped with these tape samplers are
indicated in Figures 1, 2, and 3.
The pore diameter of the Millipore filter (Type WS) used in these
studies was 3.0 microns. To check its efficiency, an 8- by 10-inch WS
filter was backed by a Millipore WH filter (pore diameter 0.45 micron).
In one test, 1000 cubic meters of air was sampled over 4 days, and in
another test, 3500 cubic meters of air was sampled over 14 days. In
both tests, over 99 percent of the lead was collected on the first WS
filter and less than 1 percent was collected on the backup WH filter.
The collection efficiency of Whatman No. 4 filter tape used in the
sequential tape samplers is reported by Smith and Surprenant26 to be
esentially 100 percent for particles greater than 2 microns in diameter,
about 65 percent for particles 0.8 to 2 microns, and about 25 percent
for particles less than 0.8 micron in diameter. Samples were collected
on both Whatman No. 4 and Millipore WS filters. The Whatman No. 4
filters regularly gave lower values, which evidenced their lower collec-
tion efficiency. Consequently, samples collected on the Millipore filters
were used to determine absolute lead values, and the samples collected
on Whatman filter tapes were used to determine relative diurnal
variations.
Sampling methods: Samples of particulate matter were collected on
the Millipore WS filters during periods of 24,48, or 72 hours at a nominal
flow rate of 4 cfm. This sampling was continuous for the duration of
the investigation. As a rule, filters were changed on Mondays, Wednes-
days, and Fridays. No difficulties were experienced in Cincinnati or
Philadelphia with reduced flows caused by the plugging of the filter
within the 48- or 72-hour periods. In Los Angeles, however, the filter
became plugged and required more frequent changes, sometimes in less
than 24 hours. The problem was accentuated during periods of photo-
chemical air pollution.
The sequential samplers were operated on 2- or 4-hour cycles for the
duration of the investigation, the tapes being changed on Fridays.
Analytical methods: The Public Health Service acted as a clearing
house to coordinate the activities of the participating laboratories.
These were the Air and Industrial Hygiene Laboratory of the Calif orni a
State Department of Public Health, the Kettering Laboratory of the
University of Cincinnati, and laboratories of the Divisions of Air Pollu-
tion and Occupational Health of the Public Health Service.
Lead concentrations in particulate matter were determined by the
dithizone method,27 modified slightly to suit the experience of each
laboratory. To ensure uniformity of the 4-J^-inch membrane filters, all
21
-------
were procured by the Public Health Service clearing house. Out of each
package of 50 filters, one was analyzed for lead content to determine
the acceptability of the batch and to provide a blank value. The filters
were numbered serially, weighed after conditioning in a controlled
atmosphere, inserted in numbered plastic boxes, and shipped with
record forms to the individual laboratories.
In the three cities, the filters were loaded by use of plastic-tipped
tweezers into the special filter holders, which were placed in plastic
bags with the appropriate record for transportation to the sampling
site. At the sampler, the filter holder was exchanged for the used filter
and holder. Final air flow values for the used filter and initial flow values
for the new filter were obtained at that time. The used filters were
transferred from the plastic bags to a plastic petri dish for shipment to
the clearing house.
The membrane filters were returned to the clearing house, and again
weighed after conditioning to determine total particulate matter de-
posited thereon. A special template was used to divide the filter into
10 equal wedges. Five wedges were returned to the respective lab-
oratories, and the other five were retained by the clearing house. The
participating laboratories than analyzed one or more wedges of the
filter and reported results to the clearing house on the record form in
micrograms of lead per cubic meter of air. The remaining wedges were
retained for possible future studies involving other atmospheric con-
stituents.
Whatman No. 4 tapes from the sequential tape samplers were processed
by the participating laboratories. The tapes were divided to provide
six 4-hour or twelve 2-hour samples per day on a seasonal basis (Decem-
ber through February, March through May, June through August,
and September through November). At least 1 inch of each strip of
tape between the deposited spots was retained as a blank.
Interlaboratory comparisons: Each participating laboratory performed
the chemical analyses of the samples from a particular city; i.e., Los
Angeles samples were analyzed by the California laboratory, Cincinnati
samples by the Kettering Laboratory, and Philadelphia samples by
the Public Health Service laboratory.
Although the determinations were made in essentially the same man-
ner by all three laboratories, minor differences in techniques suggested
the possibility that results might not be comparable. To determine the
extent of variability, if any, the clearing house set up a program in
which each laboratory performed lead determinations on (1) synthetic
samples, (2) sections of membrane filters on which atmospheric particu-
lates had been collected, (3) about 5 percent of all the atmospheric
samples collected during this investigation.
Prior to field sampling, each laboratory performed lead determina-
22
-------
tions on synthetic samples spiked with a known amount of lead (5.0
micrograms). Although the results for individual samples ranged from
4.6, to 5.5 micrograms, the means of the values reported by the three
laboratories varied only from 4.8 to 5.1 micrograms. The differences
were not statistically significant. The standard deviation for an in-
dividual lead value was the same for all laboratories—0.15 microgram.
When sections of membrane filters on which particulate matter had
been collected were analyzed, agreement among laboratories was not
as good as with the synthetic sample. Investigations established that
this difference was not due to differences in the digestion procedures
used by the three laboratories. Special care was taken to ensure that
wedges cut from a given filter were of equal size. It was also found
that the lead on a given filter was uniformly distributed so that a given
wedge would not show more than its proportionate share of lead. In spite
of these checks and precautions, the differences in analytical results re-
mained greater with particulate samples than with synthetic samples.
The reasons for this are not known, but may arise from a lack of discrim-
ination of the method in analyzing the complex particulate sample as
compared to a soluble, essentially pure lead compound in the syn-
thetic sample.
When atmospheric samples from the three-city survey were used in
the comparison program, each laboratory was asked to analyze three
wedges from each filter. The analytical variability in terms of standard
deviations, which was about the same for the three laboratories, was
not related to the amount of lead on the filter. The pooled estimate of
the standard deviation of an individual lead determination was about
60 micrograms of lead per filter. On the basis of the pooled estimate,
the standard deviation varied from about 30 percent for a sample con-
taining 200 micrograms of lead to only 3 percent for a sample containing
2000 micrograms of lead.
As a continuing check on the interlaboratory comparability of lead
determinations, about 5 percent of the group of particulate samples
collected during the year-long investigation were reanalyzed. Each lab-
oratory was asked to analyze a single wedge from each filter in the 5-
percent group of samples. Of course one of the three laboratories had
already performed a lead determination on each filter. The 5-percent
group of samples involved a total of 186 particulate (filters.
Results of analysis of the 5-percent group of samples are summarized
in Table 4. Throughout this period the results reported by the California
laboratory tended to be below the average for all three laboratories
by about 9 percent. Determinations reported by the Public Health
Service laboratory were about 9 percent above the average, and values
reported by the Kettering Laboratory were the same as the average for
all three laboratories.
The differences were not large enough to affect the comparability of
23
-------
the results. They can, if desired, be taken into account when assessing
the data from the various laboratories.
Only limited comparisons were made for lead in biological samples.
In the analyses of blood and urine, there was generally good agreement
among the laboratories.
Data handling: The clearing house transferred all aerometric data to
punch cards, which were processed by the Division of Air Pollution.
An electronic computer was used to prepare the data tabulations for
analysis and inclusion in this report.
TABLE 4
INTERLABORATORY COMPARISON OF SAMPLES
Month Average percent difference from the mean
Laboratory
California PHS Kettering
June-1961
July
September
October
December
February-1962
April
- 3
— 3
—14
—21
—12
— 3
4
+10
+ 9
+17
+17
+ 7
+ 1
0
— 7
— 6
— 3
+ 4
+ 5
+ 2
+ 4
All months — 9 +9
Concentrations of Air Pollutants
Suspended particulates: Concentrations of suspended particulates
obtained as part of the atmospheric lead sampling program are given
in Tables 5, 6, and 7 and Figure 6.
Mean concentrations of suspended particulates for all samples in
each city were 81 micrograms per cubic meter in Cincinnati, 117 in
Los Angeles, and 105 in Philadelphia (Table 5).
The average monthly concentrations obtained from samples from all
sites in Philadelphia and Los Angeles were highest in October and in
Cincinnati in May (Table 5 and Figure 6). The value for Cincinnati was
98 micrograms per cubic meter, for Los Angeles, 144, and Philadelphia,
125; Figure 6 shows that lesser peaks of average monthly-concentrations
occurred in Los Angeles in January and April. Philadelphia had sec-
ondary monthly peaks in February and May, and Cincinnati showed
a secondary peak in October.
The highest single concentration of suspended particulates was 237
micrograms per cubic meter in Cincinnati, 306 in Philadelphia, £,nd
509 in Los Angeles. (Not shown in any Tables included in this report.)
24
-------
TABLE 5
ANNUAL, SEASONAL, AND MONTHLY MEAN SUSPENDED PARTICULATE CONCENTRATIONS IN
CINCINNATI, LOS ANGELES, AND PHILADELPHIA-JUNE 1961 THROUGH MAY 1962
(IN MICROGRAMS PER CUBIC METER OF AIR)
CITY
Cincinnati
Los Angeles
Philadelphia
Site
All
30
31
32
33
All
1
2
3
4
5
6
7
8
All
10
11
12
13
14
15
16
17
Annual
81
98
77
95
54
117
124
108
115
110
106
98
142
135
105
'94
122
118
146
125
85
69
79
Sumr
87
106
79
100
61
121
126
100
131
133
127
95
127
130
103
95
119
112
134
126
85
73
78
SEASON
Fall Wntr
81
100
79
98
48
128
145
130
125
105
112
98
156
152
106
93
127
117
146
128
83
71
87
74
93
70
84
51
116
118
110
111
101
86
101
168
130
111
103
128
135
164
132
81
64
78
Sprng
82
96
79
98
57
105
109
90
91
101
99
100
119
128
100
85
115
109
141
115
93
68
74
Jun
90
111
81
104
63
129
133
104
150
143
136
103
125
136
99
88
113
105
129
125
84
71
81
Jul
82
97
76
94
61
118
123
98
126
128
125
87
135
125
111
110
134
125
144
132
89
77
79
Aug
88
109
80
103
59
116
121
98
118
128
119
95
121
130
97
88
111
106
129
120
81
72
74
Sep
79
94
79
95
47
101
115
104
106
88
96
76
111
110
104
99
130
109
137
115
87
74
81
Oct
95
118
93
118
52
144
159
150
144
118
123
115
173
171
125
106
142
138
181
152
101
82
98
MONTH
Nov Dec
70
89
65
81
46
139
161
137
125
110
118
105
183
174
90
74
108
104
122
118
60
56
82
70
87
64
81
48
115
129
130
105
82
89
87
155
138
97
82
116
119
134
122
68
58
76
Jan
76
93
72
88
52
134
143
108
125
105
95
102
240
156
111
110
128
132
166
131
86
63
75
Feb
77
98
75
83
52
98
81
93
104
115
75
114
110
94
123
117
139
152
192
144
88
71
83
Mar
74
88
74
83
51
84
93
77
78
75
80
59
115
92
86
79
110
94
130
98
61
51
65
Apr
74
89
69
92
48
135
143
119
114
141
131
126
147
155
105
82
105
118
142
121
124
69
80
May
98
111
94
117
72
96
91
75
81
87
87
113
97
138
109
95
131
115
152
126
94
84
77
to All Cities
101 103 105 100 96 106 104 100 94 121 100 94 107 100 81 105 101
-------
TABLE 6
ANNUAL, SEASONAL, AND MONTHLY MEAN SUSPENDED PARTICULATE CONCENTRATIONS ON
WEEKENDS IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA-JUNE 1961 THROUGH MAY 1962
(IN MICROGRAMS PER CUBIC METER OF AIR)
CITY
Cincinnati
Los Angeles
Philadelphia
All Cities
Site Annual
Mean
30
31
32
33
Mean
1
2
3
4
5
6
7
8
Mean
10
11
12
13
14
15
16
17
75
93
72
85
49
100
109
92
96
95
92
86
114
116
100
94
118
114
138
115
77
64
81
92
Sumr
81
104
76
91
55
111
118
93
121
119
118
84
118
120
91
89
105
100
115
109
70
65
73
94
SEASON
Fall Wntr
74
92
73
88
41
113
137
115
117
94
101
81
128
131
101
89
118
111
142
116
79
66
80
96
72
92
69
79
47
80
85
70
72
78
58
78
104
98
114
114
133
138
163
134
81
67
86
89
Sprng
73
85
72
84
53
95
96
91
75
90
92
100
105
116
94
86
116
105
132
100
79
60
73
88
Jun
83
115
77
93
48
114
124
88
134
130
121
89
109
117
82
75
96
89
103
99
65-
58
68
93
Jul
76
89
69
87
60
115
120
99
122
119
122
85
130
125
107
109
125
118
132
126
85
76
82
99
Aug
85
109
81
93
56
105
109
91
108
107
111
78
115
119
84
82
94
94
109
102
61
62
69
91
Sep
78
97
79
99
38
73
89
85
77
60
68
44
81
82
102
94
128
113
136
110
82
70
80
84
Oct
75
94
76
88
44
119
139
127
115
100
98
94
132
150
111
99
123
123
170
123
87
71
94
102
MONTH
Nov Dec
67
84
65
79
42
146
183
134
158
123
136
104
171
160
91
72
102
97
121
115
68
57
97
101
64
83
61
71
43
80
107
61
60
55
73
63
109
110
108
97
135
129
138
130
78
68
87
84
Jan
72
90
71
80
48
84
76
62
86
69
70
104
101
106
115
122
129
137
167
135
83
67
84
91
Feb
78
102
75
84
50
77
73
86
70
109
32
66
101
78
120
122
134
149
186
138
82
66
86
92
Mar
70
83
73
75
51
70
78
72
60
55
65
50
100
83
81
82
113
90
132
84
47
43
60
74
Apr
59
73
57
64
41
133
132
128
88
132
124
143
139
175
91
77
90
103
118
105
96
60
77
94
May
90
99
85
112
65
83
76
-73
78
82
87
108
76
89
110
100
143
121
148
112
95
77
82
94
-------
TABLE 7
ANNUAL, SEASONAL, AND MONTHLY MEAN SUSPENDED PARTICULATE CONCENTRATIONS ON
WEEKDAYS IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA-JUNE 1961 THROUGH MAY 1962
(IN MICROGRAMS PER CUBIC METER OF AIR)
CITY Site
Cincinnati All
30
31
32
33
Los Angeles Ail
1
2
3
4
5
6
7
8
Philadelphia All
10
11
12
13
14
15
16
17
to All Cities
-a
Annual Sumr
86
103
81
104
58
131
137
120
129
122
119
106
159
152
J09
94
126
122
153
134
92
73
78
109
91
107
82
108
66
128
131
105
140
143
134
103
134
138
112
100
130
121
148
137
95
79
81
110
SEASON
Fall Wntr
88
107
85
106
53
145
161
146
138
116
131
110
180
176
111
97
134
122
150
139
86
76
84
114
77
93
71
90
54
138
139
138
135
120
108
114
194
157
108
95
124
132
165
131
81
63
72
108
Sprng
90
104
85
112
60
111
118
90
104
109
105
97
130
137
106
85
117
114
150
127
106
74
75
102
Jun
95
107
85
113
75
140
139
117
162
154
149
113
137
151
112
97
126
117
148
142
97
81
91
116
Jul
88
105
83
101
61
121
126
96
130
133
128
89
140
124
116
111
143
133
156
137
93
78
76
108
Aug
90
109
79
110
61
124
128
101
127
144
125
105
127
138
106
92
123
114
142
132
94
78
77
107
Sep
78
91
79
93
50
120
135
117
129
105
116
89
130
136
106
102
132
106
137
119
90
78
81
101
Oct
113
140
110
143
60
178
197
183
178
138
169
137
217
210
138
113
159
151
191
179
114
94
101
143
MONTH
Nov Dec
72
91
65
82
48
136
151
138
108
105
107
105
193
183
90
75
112
109
123
120
55
55
71
99
75
90
68
90
53
141
154
178
128
113
102
103
186
167
89
73
103
112
132
116
61
50
69
102
Jan
80
94
72
96
56
161
179
139
147
129
120
99
278
197
108
100
128
129
165
128
89
59
67
116
Feb
76
96
74
83
53
112
85
97
129
118
102
139
117
108
126
113
143
155
198
149
94
78
80
105
Mar
76
91
75
89
51
93
103
80
92
90
90
65
124
99
89
76
107
98
129
108
73
57
68
86
Apr
90
103
80
125
54
136
152
113
136
145
138
109
115
138
119
88
120
131
165
136
150
77
82
115
May
104
119
100
121
76
105
100
76
84
91
87
117
111
174
109
92
122
112
155
136
94
90
74
106
-------
Particulate levels at rural sites in Cincinnati and Philadelphia were
lower than at other sites. This was not true in Los Angeles, probably
because its rural, industrial, and downtown areas are less well defined
(Figures 1, 2, and 3, and Table 5).
The average concentration of particulates in all weekday samples
was 15 percent higher than that in all weekend samples in Cincinnati,
30 percent higher in Los Angeles, and 10 percent higher in Philadelphia
(Tables 6 and 7). The greatest weekday-weekend difference over one
season occurred in winter in Los Angeles where the average of all
weekday samples was about 75 percent above that for weekends. In
that same season, the average value of all weekday samples was 7
percent higher than the weekend average in Cincinnati, and 5 percent
lower in Philadelphia.
I
£
FIGURE 6
MONTHLY MEAN PARTICULATE CONCENTRATIONS
AT ALL STATIONS IN
CINCINNATI, LOS ANGELES, AND PHILADELPHIA
28
-------
Very often, mean monthly concentrations for weekend samples were
higher than those for weekdays. For example, in Philadelphia during
December and January and in Los Angeles in November, mean monthly
concentrations on weekdays were lower than on weekends at most of
the sampling sites.
Lead: Data on atmospheric lead are presented in Tables 8 through
18 and Figures 7 through 16.
The distributions of lead concentration by sites for each city are
shown in Figures 7 through 9. The annual average concentration of
lead at downtown and industrial sites in Cincinnati was about 2 micro-
grams per cubic meter. At the suburban Cincinnati site the value was
approximately 1 microgram per cubic meter. The corresponding values
in downtown and suburban Philadelphia were 3 and 1. In Los Angeles
the values were 3 and 2, and at no sites did values average as low as 1
microgram per cubic meter. This again was probably due to the absence
of well-defined suburban, downtown, and industrial areas in this city.
N
KEY:
(30)—Station No.
1.7 —Lead Concentration
FIGURE 7
MEAN ANNUAL CONCENTRATIONS OF LEAD
IN CINCINNATI AREA BY SITE
(In micrograms per cubic meter of air)
-------
KEY:
(1)—Station No.
2.3—Lead Concentration
FIGURE 8
MEAN ANNUAL CONCENTRATIONS OF LEAD
IN LOS ANGELES AREA BY SITE
(In micrograms per cubic meter of air)
The average concentration of lead for all samples collected over the
year was 1.4 micrograms per cubic meter in Cincinnati, 2.5 in Los
Angeles, and 1.6 in Philadelphia (Table 8).
Fall and winter were the seasons of highest lead concentrations in all
three cities. The highest seasonal concentration at any station was 2.4
micrograms per cubic meter in Cincinnati, 4.1 in Los Angeles, and 3.8
in Philadelphia (Table 8). The highest concentration for all samples
during the fall season in Cincinnati was 30 percent greater than that
for summer. In Los Angeles, the average for all winter samples was
63 percent higher than for summer. In Philadelphia, the average value
for both the fall and winter seasons was 35 percent greater than the
summer seasonal average.
The highest monthly concentrations for all samples in each city were
2.1 micrograms per cubic meter in Cincinnati (October), 3.9 in Los
Angeles (December), and 2.3 in Philadelphia (October) (Table 8 and
30
-------
KEY:
(10)—Station No.
1.5 —Lead Concentration
FIGURE 9
MEAN ANNUAL CONCENTRATIONS OF LEAD
IN PHILADELPHIA AREA BY SITE
(In micrograms per cubic meter of air)
Figure 10). Highest monthly concentration for any one site was 3.1
micrograms per cubic meter in Cincinnati, 6.4 in Los Angeles, and 4.4
in Philadelphia (Table 8).
The highest concentrations of lead in individual samples were 6.4
micrograms per cubic meter in Cincinnati, 11.4 in Los Angeles, and 7.6
in Philadelphia. The frequency distribution of individual airborne lead
samples is shown in Table 9.
In Los Angeles, the average of all weekday samples was 23 percent
higher than the average of all weekend samples (Tables 10 and 11). In
Philadelphia and Cincinnati, annual weekday values were similar to
weekend values. At individual sites in all three cities, however, the
monthly lead concentrations were often lower on weekdays than on
weekends.
31
-------
-------
MONTH
FIGURE 10
j
1962
MEAN MONTHLY CONCENTRATIONS OF LEAD
AT ALL SITES IN
CINCINNATI, LOS ANGELES, AND PHILADELPHIA
Lead in participates: Correlations between lead and suspended par-
ticulates at the sites in Cincinnati and Philadelphia for the study year
were about 0.7; variance in concentrations of suspended particulates
thus explains about half of the variation in lead concentrations. In
Los Angeles, the correlation was about 0.6, which explains about
one-third of the variance.
The average content of lead in particulate matter for all samples
was 1.7 percent in Cincinnati, 2.3 in Los Angeles, and 1.5 in Phila-
delphia (Table 12). The mean percentage of lead was the same on week-
ends and weekdays in the three cities. (Not shown in any Tables in-
cluded in this report.) The percentage of lead averaged for individual
sites by month ranged from 0.9 to 2.5 in Cincinnati, 0.9 to 5.3 in Los
Angeles, and 0.9 to 3.1 in Philadelphia (Table 12).
33
-------
05
TABLE 9
FREQUENCY DISTRIBUTIONS OF AIRBORNE LEAD CONCENTRATIONS
(IN MICROGRAMS PER CUBIC METER OF AIR)
CITY
Cincinnati
Los Angeles
Philadelphia
SEASON*
WINTER
SPRING
SUMMER
AUTUMN
ANNUAL
WINTER
SPRING
SUMMER
AUTUMN
ANNUAL
WINTER
SPRING
SUMMER
AUTUMN
ANNUAL
CNT
149
153
160
154
616
275
299
409
264
1247
309
299
350
310
1268
MIN
.3
.3
.3
.4
.3
.4
.2
.1
.4
.1
.2
.2
.1
.3
.1
10
.6
.5
.6
.6
.5
1.1
.9
1.0
1.0
1.0
.6
.5
.6
.7
.6
20
.7
.6
.7
.8
.7
1.6
1.2
1.3
1.5
1.3
.9
.6
.8
.9
.8
30
.9
.7
.8
.9
.8
1.9
1.3
1.5
1.9
1.6
1.1
.8
.9
1.2
1.0
PERCENTILES
40 50 60
1.0
.9
1.0
1.2
1.0
2.3
1.6
1.7
2.1
1.8
1.3
1.0
1.1
1.3
1.2
1.1
1.1
1.2
1.3
1.2
2.7
1.9
1.9
2.5
2.1
1.5
1.2
1.2
1.6
1.3
1.2
1.2
1.4
1.6
1.3
3.3
2.2
2.1
2.9
2.4
1.8
1.4
1.4
1.8
1.6
70
1.4
1.5
1.5
2.0
1.6
4.2
2.6
2.4
3.4
2.8
2.3
1.6
1.6
2.2
1.9
80
1.7
1.8
1.8
2.5
1.9
5.5
2.9
2.7
4.1
3.4
2.9
2.0
2.0
2.8
2.4
90
2.1
2.5
2.3
3.3
2.6
7.3
3.5
3.1
5.3
4.5
3.6
2.8
2.5
3.5
3.1
Max.
6.4
5.0
3.8
5.9
6.4
9.6
6.7
5.8
11.4
11.4
7.6
5.2
4.7
6.9
7.6
Arith.
Mean
1.3
1.3
1.4
1.7
1.4
3.6
2.1
2.0
2.9
2.6
1.9
1.4
1.5
1.9
1.7
Geom.
Mean
1.2
1.1
1.2
1.4
1.2
2.8
1.9
1.8
2.5
2.2
1.6
1.2
1.3
1.6
1.4
Std.
Dev.
1.66
1.83
1.65
1.87
1.77
1.99
1.75
1.67
1.85
1.87
1.92
1.87
1.68
1.83
1.87
aWINTER: December 1, 1961 thru February 28, 1962
SPRING: March 1, 1962 thru May 31, 1962
SUMMER: June 1, 1961 thru August 31, 1961
AUTUMN: September 1, 1961 thru November 30, 1961
-------
TABLE 10
ANNUAL, SEASONAL, AND MONTHLY MEAN CONCENTRATIONS OF LEAD ON WEEKENDS
IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA-JUNE 1961 THROUGH MAY 1962
(IN MICROGRAMS PER CUBIC METER OF AIR)
CO
UT
CITY
Cincinnati
Los Angeles
Philadelphia
All Cities
Site
All
30
31
32
33
All
1
2
3
4
5
6
7
8
All
10
11
12
13
14
15
16
17
Annual Sumr
1.3
1.7
1.2
1.7
0.7
2.2
2.5
2.5
2.4
2.0
1.9
1.4
2.0
2.7
1.6
1.5
174
1.7
3.1
2.1
1.1
0.8
0.9
1.7
1.3
1.8
1.2
1.4
0.9
1.8
2.0
1.9
2.3
2.2
1.9
1.2
1.3
2.0
1.2
1.3
1.1
1.2
2.3
1.5
0.9
0.8
0.8
1.5
SEASON
Fall Wntr
1.6
1.8
1.6
2.5
0.7
2.5
3.1
3.7
2.9
1.7
1.7
1.3
2.4
3.0
1.8
1.6
1.5
1.8
3.5
2.2
1.4
1.0
1.1
2.0
1.3
1.7
1.1
1.5
0.7
2.4
3.0
2.7
2.9
2.2
1.7
1.7
2.4
2.8
2.0
2.0
1.9
2.3
3.8
2.9
1.3
1.0
1.0
1.9
Sprng
1.1
1.4
0.9
1.5
0.6
2.0
2.0
2.0
1.6
2.0
2.2
1.4
1.8
3.0
1.3
1.1
1.1
1.5
2.8
1.7
0.8
0.6
0.5
1.5
Jun
1.5
2.2
1.4
1.4
0.9
1.5
2.1
1.1
2.2
1.7
1.6
0.8
0.9
1.5
1.0
0.9
1.0
1.0
1.7
1.3
0.8
0.7
0.8
1.3
Jul
0.9
1.0
0.7
1.1
0.7
1.7
1.7
1.8
2.0
2.1
1.7
1.1
1.7
1.7
1.3
1.4
1.2
1.2
2.7
1.6
0.8
0.8
0.7
1.3
Aug
1.6
2.3
1.5
1.7
1.0
2.3
2.3
2.7
2.7
2.7
2.4
1.7
1.4
2.7
1.4
1.6
1.2
1.4
2.5
1.6
1.0
0.8
0.9
1.8
Sep
1.7
2.0
1.5
2.4
0.8
2.0
2.2
2.9
2.5
1.5
1.4
0.9
1.9
2.5
1.6
1.6
1.4
1.6
3.2
1.7
1.0
1.0
0.9
1.7
Oct
1.7
1.8
1.8
2.6
0.7
2.2
2.9
3.2
2.8
1.4
1.6
1.4
2.1
2.5
2.1
2.0
1.9
2.0
4.0
2.5
1.8
1.1
1.3
2.0
MONTH
Nov Dec
1.5
1.7
1.4
2.4
0.6
3.2
4.2
4.9
3.5
2.2
2.0
1.7
3.1
4.1
1.6
1.3
1.3
1.7
3.2
2.3
1.3
0.8
1.1
2.1
1.3
1.6
1.0
1.7
0.7
3.0
4.7
3.7
3.5
2.0
1.9
1.6
3.4
3.0
2.3
2.3
2.2
2.6
4.2
3.4
1.5
1.3
1.1
2.2
Jan
1.1
1.4
1.0
1.3
0.8
2.3
2.5
1.8
3.2
1.9
2.3
2.1
1.6
3.0
2.0
1.9
1.9
2.3
3.9
2.7
1.5
1.1
0.9
1.8
Peb
1.4
2.2
1.2
1.5
0.7
2.1
1.7
2.5
2.1
2.8
1.0
1.5
2.3
2.5
1.8
1.8
1.6
2.1
3.4
2.5
1.0
0.7
1.0
1.7
Mar
0.9
1.1
0.7
1.2
0.5
1.9
2.5
1.0
1.9
1.4
2.1
0.9
2.4
3.3
1.2
0.9
1.0
1.5
2.8
1.6
0.6
0.5
0.4
1.3
Apr
0.8
1.3
0.6
1.0
0.4
2.6
2.5
3.2
1.6
2.5
2.3
1.9
2.2
4.2
1.1
0.9
0.8
1.2
2.2
1.6
0.9
0.6
0.5
1.5
May
1.7
1.9
1.3
2.4
1.0
1.5
0.9
1.8
1.4
2.0
2.1
1.3
0.9
1.4
1.5
1.6
1.4
1.8
3.3
1.9
0.9
0.7
0.7
1.6
-------
O5
TABLE 11
ANNUAL, SEASONAL, AND MONTHLY MEAN CONCENTRATIONS OF LEAD ON WEEKDAYS
IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA-JUNE 1961 THROUGH MAY 1962
(IN MICROGRAMS PER CUBIC METER OF AIR)
CITY
Cincinnati
Los Angeles
Philadelphia
All Cities
Site Annual
All
30
31
32
33
All
1
2
3
4
5
6
7
8
All
10
11
12
13
14
15
16
17
1.4
1.8
1.1
1.8
1.1
2.7
2.8
3.4
3.0
2.7
2.3
1.6
2.5
3.1
1.7
1.5
1.4
1.9
3.5
2.3
1.2
0.9
0.9
1.9
Sumr
1.4
1.5
1.1
1.6
1.3
2.0
2.0
2.1
2.3
2.5
2.1
1.1
1.4
2.3
1.5
1.5
1.3
1.4
3.1
2.1
1.1
0.9
1.0
1.6
SEASON
Fall Wntr
1.7
2.1
1.4
2.4
0.8
3.1
3.0
4.5
3.9
2.8
2.4
1.8
2.7
3.4
1.9
1.8
1.7
2.1
4.0
2.3
1.4
1.1
1.0
2.2
1.3
1.6
1.0
1.5
1.2
3.5
3.9
4.9
4.1
2.9
2.4
2.0
3.6
4.2
1.9
1.7
1.6
2.3
3.9
2.4
1.3
0.9
0.8
2.2
Sprng
1.4
1.8
1.0
1.8
0.9
2.1
2.2
2.1
1.6
2.5
2.2
1.5
2.1
2.4
1.5
1.1
1.2
1.6
3.1
2.3
1.0
0.9
0.7
1.6
Jun
1.3
1.1
1.0
1.4
1.8
1.9
2.0
1.7
2.2
2.3
1.8
1.1
1.4
2.5
1.5
1.3
1.2
1.3
2.9
2.0
1.0
0.8
1.4
1.6
Jul
1.2
1.4
1.0
1.4
1.1
2.0
2.0
2.4
2.1
2.4
2.1
1.0
1.4
2.2
1.6
1.6
1.4
1.6
3.1
2.0
1.1
0.8
0.8
1.6
Aug
1.5
1.9
1.2
1.9
1.0
2.2
2.0
2.3
2.7
2.9
2.4
1.3
1.5
2.3
1.6
1.5
1.3
1.4
3.2
2.2
1.2
1.0
0.9
1.8
Sep
1.4
1.8
1.2
1.8
0.6
2.4
2.3
3.1
3.4
2.2
1.8
1.6
1.9
3.1
1.6
1.6
1.5
1.5
3.5
1.8
1.1
0.9
0.9
1.8
Oct
2.4
2.6
2.2
3.5
1.1
3.2
3.1
4.4
4.8
3.2
3.1
2.2
3.0
1.8
2.5
2.3
2.1
2.5
4.8
3.0
2.2
1.6
1.3
2.7
MONTH
Nov Dec
1.4
2.0
0.9
1.8
0.8
3.5
3.6
6.0
3.6
2,9
2.2
1.6
3.1
5.3
1.7
1.4
1.4
2.2
3.6
2.2
0.9
0.8
0.9
2.2
1.6
1.9
1.1
2.0
1.5
4.6
4.9
8.4
5.1
3.6
3.1
2.6
4.2
4.9
1.9
1.6
1.6
2.4
4.2
2.4
1.2
0.9
0.8
2.7
Jan
1.3
1.6
1.0
1.4
1.2
3.6
4.6
3.9
4.5
2.5
2.1
1.8
4.3
5.3
1.6
1.4
1.3
1.9
3.4
2.0
1.5
0.7
0.7
2.2
Feb
1.1
1.4
0.8
1.1
1.0
2.3
2.1
2.5
2.8
2.6
1.9
1.8
2.4
2.4
2.1
2.0
2.0
2.6
4.0
2.7
1.2
1.0
0.9
1.8
Mar
1.0
1.4
0.7
1.2
0.5
2.0
2.3
1.4
1.7
2.2
2.1
0.9
2.3
2.9
1.3
1.0
1.1
1.5
2.7
1.9
0.6
0.7
0.6
1.4
Apr
1.6
2.0
1.1
2.3
0.9
2.3
2.7
2.3
1.7
2.8
2.7
2.0
2.1
2.2
1.7
1.3
1.3
1.9
3.2
2.6
1.4
1.0
0.8
1.9
May
1.6
2.0
1.3
2.0
1.2
1.9
1.5
2.5
1.5
2.6
1.9
1.6
1.9
2.0
1.5
1.1
1.1
1.5
3.4
2.3
0.9
0.9
0.7
1.7
-------
TABLE 12
ANNUAL, SEASONAL, AND MONTHLY PERCENTAGE OF LEAD IN PARTICULATE MATTER
IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA-JUNE 1961 THROUGH MAY 1962
CITY
Cincinnati
Los Angeles
Philadelphia
All Cities
Site
All
30
31
32
33
All
1
2
3
4
5
6
7
8
All
10
11
12
13
14
15
16
17
Annual Sumr
1.7
1.7
1.4
1.8
1.7
2.3
2.2
2.9
2.8
2.4
2.1
1.8
1.7
2.5
1.5
1.6
1.2
1.5
2.3
1.7
1.4
1.3
1.2
1.8
1.5
1.4
1.4
1.5
1.9
1.6
1.6
2.0
1.8
1.8
1.6
1.2
1.1
1.7
1.4
1.5
1.1
1.2
2.1
1.4
1.2
1.1
1.2
1.5
SEASON
Fall Wntr
2.0
2.0
1.8
2.4
1.7
2.3
2.2
3.3
2.9
2.1
1.9
1.8
1.7
2.4
1.7
1.9
1.2
1.7
2.7
1.8
1.7
1.5
1.3
2.0
1.7
1.8
1.4
1.7
2.0
3.2
3.1
4.1
4.3
3.2
2.8
2.4
2.3
3.2
1.7
1.8
1.4
1.7
2.4
1.9
1.7
1.5
1.2
2.2
Sprng
1.5
1.7
1.2
1.7
1.3
2.2
2.0
2.3
2.1
2.4
2.4
1.8
1.8
2.6
1.4
1.4
1.0
1.5
2.1
1.7
1.1
1.1
0.9
1.7
Jun
1.6
1.3
1.4
1.3
2.3
1.3
1.6
1.4
1.5
1.4
1.3
1.0
0.9
1.5
1.3
1.4
1.0
1.2
1.9
1.4
1.2
1.1
1.5
1.4
Jul
1.3
1.2
1.1
1.3
1.5
1.6
1.5
2.2
1.6
1.8
1.5
1.1
1.1
1.6
1.2
1.4
1.0
1.1
2.0
1.3
1.1
1.0
1.0
1.4
Aug
1.8
1.8
1.6
1.8
1.8
1.9
1.7
2.5
2.3
2.3
2.0
1.6
1.2
1.9
1.5
1.8
1.2
1.4
2.3
1.6
1.4
1.3
1.2
1.7
Sep
1.9
2.0
1.7
2.2
1.6
2.3
2.1
3.0
2.9
2.2
1.8
2.0
1.8
2.7
1.6
1.7
1.1
1.5
2.6
1.6
1.4
1.4
1.2
1.9
Oct
2.0
1.8
2.0
2.5
1.7
1.9
1.9
2.5
2.5
1.9
1.7
1.6
1.5
1.4
1.8
2.0
1.4
1.7
2.6
1.9
2.0
1.6
1.4
1.9
MONTH
Nov Dec
2.0
2.1
1.7
2.5
1.7
2.6
2.5
4.3
3.3
2.1
2.1
1.8
1.9
3.1
1.8
1.9
1.2
2.0
2.8
1.9
1.7
1.5
1.2
2.1
2.0
2.0
1.5
2.1
2.4
3.7
3.9
5.3
5.1
3.6
3.1
2.6
2.7
3.2
2.0
2.2
1.6
2.1
3.1
2.2
2.0
1.8
1.3
2.6
Jan
1.7
1.7
1.4
1.5
2.0
2.9
2.8
3.5
3.9
2.9
2.6
2.3
1.8
3.2
1.6
1.5
1.2
1.5
2.2
1.8
1.7
1.4
1.2
2.0
Feb
1.5
1.7
1.2
1.4
1.7
3.0
2.7
3.5
3.9
3.0
2.6
2.2
2.5
3.3
1.5
1.6
1.3
1.5
1.9
1.7
1.3
1.2
1.2
2.0
Mar
1.2
1.5
0.9
1.5
1.0
2.6
2.6
1.8
2.7
2.6
2.9
1.7
2.2
4.0
1.4
1.2
1.0
1.6
2.1
1.8
1.1
1.2
0.9
1.7
Apr
1.5
1.8
1.2
1.7
1.4
1.9
1.7
2.3
1.6
1.9
1.9
1.9
1.5
2.0
1.3
1.4
1.0
1.4
1.9
1.7
1.1
1.2
0.9
1.6
May
1.7
1.8
1.4
1.9
1.6
2.1
1.6
2.9
1.9
2.7
2.3
1.7
1.6
1.7
1.4
1.5
1.0
1.4
2.3
1.7
1.0
1.0
1.0
1.7
-------
In the fall, the percentage of lead in samples in Cincinnati was one-
third higher than in summer, and in Philadelphia it was one-fourth
higher (Table 12 and Figure 11). The greatest seasonal difference
occurred in Los Angeles, where the winter percentage of all samples
was one-half higher than the summer value. The factors responsible for
these seasonal differences are not clear. The average summer values for
suspended particulates differ very little from the fall and winter values.
Lead values, however, are considerably lower in summer than in fall
and winter in all three cities.
Diurnal distribution of lead: Lead concentrations in all three cities
peaked in the morning around 7 A.M. (Tables 13, 14, and 15, and Fig-
ures 12, 13, and 14). Secondary peaks occurred in the afternoon in
Philadelphia and Los Angeles. In Cincinnati, the secondary peak was
not as pronounced and occurred in the early evening. These diurnal
variations reflect variations in both source strength and meteorological
conditions.
FIGURE 11
MONTHLY MEAN PERCENT OF LEAD IN PARTICULATE
MATTER AT ALL STATIONS IN
CINCINNATI, LOS ANGELES, AND PHILADELPHIA
38
-------
TABLE 13
DIURNAL VARIATIONS OF ATMOSPHERIC LEAD IN
CINCINNATI EXPRESSED AS THE RATIO OF DIURNAL
VALUES TO THE YEARLY MEAN SAMPLING INTERVAL
Site
All
30
31
32
33
Season
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Mean
1.0
1.1
1.3
0.9
0.9
1.4
1.5
1.5
1.3
1.4
1.1
1.3
1.3
1.0
0.9
1.2
1.2
1.6
0.8
0.9
0.5
0.5
0.5
0.6
0.5
23:00
to
03:00
1.3
1.4
1.3
0.9
1.3
1.6
1.9
1.6
1.0
1.9
1.5
1.8
1.9
1.1
1.3
1.4
1.5
2.3
0.8
1.1
0.5
0.5
0.5
0.5
0.6
03:00
to
07:00
1.1
1.4
1.3
0.8
1.0
1.5
2.0
1.5
1.0
1.4
1.3
1.8
1.6
0.9
0.9
1.0
1.3
1.5
0.5
0.9
0.5
0.5
0.4
0.5
0.6
07:00
to
11:00
1.4
1.4
1.8
1.1
1.1
\
2.0
2.0
2.8
1.5
1.9
1.4
1.5
1.8
1.1
1.1
1.3
1.3
1.9
0.9
0.9
0.8
0.8
0.6
1.0
0.6
11:00
to
15:00
0.8
0.6
0.8
1.0
0.6
1.1
0.9
0.9
1.5
1.0
0.6
0.5
0.6
1.0
0.5
0.8
0.6
0.9
0.6
0.6
0.5
0.3
0.5
0.6
0.4
15:00
to
19:00
0.9
0.8
1.0
1.0
0.6
1.3
1.1
1.1
1.5
1.0
0.8
0.5
0.8
0.9
0.6
1.0
1.1
1.3
1.0
0.6
0.5
0.4
0.6
0.6
0.3
19:00
to
23:00
1.0
1.0
1.4
1.0
0.9
1.3
1.3
1.4
1.3
1.3
1.0
1.1
1.1
1.0
0.9
1.4
1.3
2.3
0.9
1.0
0.5
0.4
0.6
0.6
0.4
39
-------
TABLE 14
DIURNAL VARIATIONS OF ATMOSPHERIC LEAD IN
LOS ANGELES EXPRESSED AS THE RATIO OF DIURNAL
VALUES TO THE YEARLY MEAN SAMPLING INTERVAL
Site Season
All Annual
Summer
Fall
Winter
Spring
1 Annual
Summer
Fall
Winter
Spring
2 Annual
Summer
Fall
Winter
Spring
3 Annual
Summer
Fall
Winter
Spring
7 Annual
Summer
Fall
Winter
Spring
Mean
1.0
0.7
1.2
1.4
0.7
0.9
0.7
1.2
1.2
0.5
1.3
1.0
1.2
2.0
0.9
0.8
0.4
1.0
0.9
0.8
1.0
0.6
1.2
1.4
0.7
23:00
to
03:00
1.0
0.6
1.2
1.4
0.8
1.0
0.7
1.3
1.4
0.7
1.3
0.8
1.1
2.0
1.2
0.8
0.6
1.0
0.8
0.7
1.0
0.5
1.3
1.6
0.8
03:00
to
07:00
1.1
0.6
1.4
1.5
0.8
1.0
0.8
1.4
1.3
0.5
1.2
0.7
1.2
2.0
1.0
0.9
0.4
1.2
1.0
0.8
1.2
0.7
1.7
1.7
1.0
07:00
to
11:00
1.2
1.1
1.3
1.4
0.8
1.1
1.0
1.5
1.2
0.6
1.6
1.6
1.6
2.1
1.1
0.7
0.8
0.7
0.6
0.5
1.3
1.0
1.5
1.7
0.9
11:00
to
15:00
0.7
0.7
0.7
0.9
0.5
0.6
0.5
0.8
0.6
0.4
1.1
1.0
1.1
1.7
0.7
0.5
0.6
0.5
0.4
0.5
0.6
0.5
0.5
0.7
0.4
15:00
to
19:00
0.8
0.5
1.0
1.3
0.5
0.7
0.5
0.9
0.8
0.5
1.1
0.9
1.0
2.1
0.5
0.9
0.3
1.0
1.3
0.7
0.7
0.4
0.9
1.0
0.4
19:00
to
23:00
1.1
0.5
1.5
1.8
0.8
1.2
0.5
1.7
2.1
0.5
1.2
0.7
1.2
2.2
0.8
1.1
0.4
1.4
1.3
1.2
1.1
0.4
1.7
1.7
0.7
40
-------
TABLE 15
DIURNAL VARIATIONS OF ATMOSPHERIC LEAD IN
PHILADELPHIA EXPRESSED AS THE RATIO OF DIURNAL
VALUES TO THE YEARLY MEAN SAMPLING INTERVAL
Site
All
10
11
12
13
14
15
16
Season
Annual
Summer
Pall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Annual
Summer
Fall
Winter
Spring
Mean
1.0
0.9
1.2
1.2
0.8
0.7
0.8
0.7
0.5
0.7
0.7
0.7
0.8
0.8
0.5
1.1
0.7
1.4
1.3
0.9
2.0
1.7
2.5
2.2
1.4
1.4
1.2
1.5
1.4
1.3
0.7
0.6
0.9
0.7
0.5
0.5
0.5
0.5
0.6
0.5
23:00
to
03:00
0.9
0.8
1.1
0.9
0.9
0.8
0.8
0.8
0.5
1.1
0.6
0.7
0.8
0.6
0.4
0.8
0.6
0.9
0.8
0.8
1.4
1.2
1.5
1.5
1.0
1.1
0.9
1.5
1.0
1.1
1.0
1.0
1.2
0.8
1.1
0.6
0.6
0.5
0.5
0.6
03:00
to
07:00
0.8
0.9
0.9
0.8
0.7
0.6
0.8
0.6
0.4
0.7
0.5
0.5
0.7
0.6
0.3
1.0
0.9
1.0
1.2
0.7
1.3
1.1
1.5
1.5
0.8
1.4
1.7
1.4
1.0
1.2
0.7
0.6
1.0
0.6
0.5
0.5
0.4
0.4
0.5
0.5
07:00
to
11:00
1.4
1.2
1.7
1.4
1.3
0.8
0.9
0.8
•0.6
0.9
1.2
1.2
1.2
1.1
1.4
1.5
1.1
1.9
1.7
1.2
2.6
2.4
3.5
2.7
1.8
2.1
1.5
2.5
2.0
2.4
0.8
0.8
1.1
0.7
0.5
0.6
0.5
0.8
0.5
0.5
11:00
to
15:00
0.8
0.8
0.9
1.0
0.5
0.5
0.6
0.5
0.4
0.3
0.6
0.6
0.7
0.9
0.4
0.9
0.6
1.0
1.1
0.7
2.2
2.1
2.7
2.4
1.5
1.0
1.2
0.9
0.9
0.9
|0.5
0.4
0.5
0.5
0.3
0.5
0.3
0.5
0.5
0.4
15:00
to
19:00
1.1
0.7
1.2
1.5
0.9
0.6
0.7
0.6
0.6
0.5
0.6
0.6
0.7
0.8
0.5
1.2
0.5
1.5
1.6
0.8
2.4
2.0
3.0
2.8
1.5
1.2
0.9
1.2
1.6
1.0
0.5
0.3
0.5
0.7
0.3
0.5
0.3
0.4
0.8
0.4
19:00
to
23:00
1.1
0.9
1.3
1.3
0.9
0.8
0.9
0.8
0.8
0.7
0.7
0.8
0.8
0.6
0.5
1.2
0.7
1.6
1.2
1.0
2.1
1.7
2.6
2.2
1.6
1.4
1.0
1.5
1.5
1.4
0.9
0.9
0.8
1.1
0.7
0.6
0.5
0.6
0.8
0.5
41
-------
to
LU
<.
•z.
oc
=
Q
£
O
1
FIGURE 12
DIURNAL VARIATIONS OF ATMOSPHERIC LEAD IN CINCINNATI
-------
FIGURE 13
DIURNAL VARIATIONS OF ATMOSPHERIC LEAD IN LOS ANGELES
-------
o
o
1?
FIGURE 14
DIURNAL VARIATIONS OF ATMOSPHERIC LEAD IN PHILADELPHIA
-------
Relation between Lead and Carbon Monoxide ••
The California Department of Public Health and the Los Angeles
County Air Pollution Control District have estimated that motor
vehicles are the source of over 90 percent of the carbon monoxide in
Los Angeles County. At three of the sampling sites in Los Angeles
carbon monoxide was measured as part of the Air Pollution Control
District's air monitoring program; Because motor vehicles are also a
source of lead, it was decided to correlate lead concentrations against
carbon monoxide concentrations at the three sites during months when
highest levels of these pollutants were found. The correlation coefficients
between these measures were high and approximately the same at all
three locations (Table 16). Data on carbon monoxide were not available
for any of the lead-sampling sites in Cincinnati and Philadelphia.
TABLE 16
CORRELATIONS BETWEEN LEAD CONCENTRATIONS
AND CARBON MONOXIDE CONCENTRATIONS AT
THREE LOS ANGELES STATIONS2
Sampling
site
Downtown
Los Angeles
West Los
Angeles
Pasadena
Correlation
coefficient
0.79
0.81
0.81
Significant
atl%
level
Yes
Yes
Yes
Percent
variance
explained
62
66
66
Regression line
Intercept,
jig Pb/m3
-9.84
-5.97
-6.99
Slope
[ig Pb/m3
vs.
ppm CO
1.12
0.82
0.82
aCorrelations are between individual lead samples and average
carbon monoxide concentrations for the corresponding time periods,
for the months of November, December and January, 1961-1962.
Relationship of National Air Sampling Network data to three-city
study data: One of the sites in each of the cities in the three-city study
was selected to correspond to the National Air Sampling Network
(NASN) station of the Public Health Service. Approximately 25 NASN
samples were taken at each of these sites during the present study.
These samples were analyzed for lead by both emission spectrometry,
the usual NASN method, and the dithizone method used for the present
investigations. Appropriate Millipore samples of 2- and 3-day duration
were matched with the 25 NASN samples collected at each site at
the same time.
Mean lead concentrations determined by NASN methods (emission
spectrometry) are about the same as those determined by lead-study
45
-------
methods (dithizone analysis). In Cincinnati and Philadelphia, the mean
concentrations -measured by NASNi methods were about 10 percent
higher than those measured by lead-study methods at the same location;
in Los Angeles they were about 10 percent lower (Table 17).
Atmospheric lead trends: NASN stations have been in operation at
one of the lead study sites in Philadelphia since 1957 and in Cincinnati
and Los Angeles since 1959. Unanalyzed portions of filters used in
regularly scheduled sampling have been retained by the NASN. Com-
posites of these unused portions at each of these three sites were pre-
pared and analyzed by the dithizone method. This method was selected
because of its specificity for lead in contrast to the spectrographic
method, which involves the determination of a number of metals and
utilizes a single photographic plate at some sacrifice of accuracy in the
determination of any one metal.
TABLE 17
COMPARISON OF ATMOSPHERIC LEAD CONCENTRATIONS
IN NATIONAL AIR SAMPLING NETWORK (NASN) AND
LEAD STUDY SAMPLES AT SAME SITES
Mean concentrations,
CITY Site [Ag/m3
number Lead NASN
study
Cincinnati
Los Angeles
Philadelphia
30
1
14
1.5
2.7
1.8
NASN
1.7
2.5
2.0
Lead study
1.13
0.93
1.11
Correlation
Coeffi- Percent
cient variance
0.82
0.66
0.60
67
44
36
The results of these analyses indicate that the annual average lead
concentration at the Philadelphia site decreased from 2.3 micrograms
per cubic meter to 1.3 during the period 1957-62 (Table 18 and Figure
15). Concentrations at Cincinnati decreased from 1.9 micrograms per
cubic meter in 1959 to 0.8 in 1961, but increased to 2.1 in 1962. The
reason for these fluctuations is not apparent. Lead concentrations at
Los Angeles increased from 3.6 micrograms per cubic meter to 4.4 over
the period 1959-62. Since air pollutant concentrations may vary sig-
nificantly from year to year because of meteorological and source
factors, it is not possible to establish trends on the basis of the limited
period for which data are available. The data for the cities as a whole
suggest that there has been little change in atmospheric lead concen-
trations over the past 3 years.
Kettering Laboratory has been measuring concentrations of lead in
the atmosphere in Cincinnati since 1946. Data for areas corresponding
46
-------
o
SE
f- n
S 3
z
o
o
1961
1962
YEAR
FIGURE 15
TRENDS IN THE CONCENTRATION OF ATMOSPHERIC
LEAD IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA
(NASN DATA)
to those included in the lead study are shown in Figure 16. The figure
shows a downward trend in the central residential and basin areas from
1946 to 1954, and in the commercial areas from 1955 to 1961. No trend
is apparent for the peripheral residential area. Data reported for the
commercial area in Figure 16 differ from the NASN data for site No. 30
(commercial) shown in Figure 15.
The reasons for the general decline in Cincinnati since 1946 include
the diminishing use of solid fuels, better collection and removal of
47
-------
particulates from industrial operations, an increasingly effective en-
forcement of the ordinance relating to abatement of smoke, and changes
in traffic flow and land use in the metropolitan area.7
300*-
280
260
o
z
o
o
ce.
UJ
ca
220
200
180
160
140
* 4
O
§ 3
| 2
HOUSING UNITS
• COMMERCIAL
°-^
BASIN "'"o^ INDUSTRIAL
V"«"«•... CENTRAL RESIDENTIAL
1-
100
90
80
70
60
50
40
30
20
10
0
4
3
2
1946
'50
'52
'54
YEAR
'56
'58
'60
'62
FIGURE 16
TRENDS IN THE CONCENTRATION OF ATMOSPHERIC
LEAD COMPARED WITH NUMBERS OF PASSENGER CARS
AND NEW HOUSING UNITS IN CINCINNATI
48
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TABLE 18
ANNUAL MEAN CONCENTRATIONS OF ATMOSPHERIC
LEAD IN CINCINNATI, LOS ANGELES, AND PHILADELPHIA,
1957 through 1962 (NASN Data)
CITY
Site No.
Concentration,
1957 1958 1959 1960 1961 1962 Mean
Cincinnati
Los Angeles
Philadelphia
30
1
14
1.9
3.6
2.3 2.4 2.1
1.4
3.8
1.7
0.8
4.2
1.8
2.1
4.4
1.3
1.6
4.0
1.9
I
20 30
PERCENT OF HOURS WITH WIND SPEED LESS THAN 4 mph
40
FIGURE 17
RELATIONSHIP BETWEEN ATMOSPHERIC LEAD AND
WIND SPEED IN LOS ANGELES
49
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Meteorology
The meteorological conditions that1 prevailed during this investiga-
tion were examined to determine possible effects of meteorology on the
atmospheric concentrations of lead and to determine the representa-
tiveness of the survey year.
Meteorological effects: Storm situations with strong winds were as-
sociated with low concentrations of lead; precipitation alone produced
no significant effect, nor did flooding or snow cover. Also, increased
space heating on days with record low temperatures produced no ap-
parent effect.
High concentrations of airborne lead were associated with very low
wind speeds in Los Angeles as shown by Figure 17. A similar relation-
ship was also shown for Philadelphia and Cincinnati. Highest lead
concentrations would be expected when low wind speeds are combined
with a temperature inversion based at or near the surface. Inversion
data for Cincinnati and Philadelphia were too meager to permit general-
ization. In Los Angeles, however, the period of high lead concen-
tration did not coincide with the photochemical smog season from June
to November, but occurred in December during periods of surface
inversions associated with low temperatures. This is also shown by the
peaking of carbon monoxide concentrations during the same period.
This indicates that different meteorological factors predominate in
determining lead concentrations and photochemical smog.
Representativeness of sample year: Meteorological data obtained at the
Greater Cincinnati Airport are summarized in Figure 18. Precipitation
during the sample year was somewhat above normal. Twice the normal
amount was recorded in February; April was extremely dry. The per-
centage of possible sunshine was below normal much of the year.
Heating requirements were slightly above normal. January was much
colder than normal. Average wind speeds were near normal and were
relatively constant during the sampling year. One advisory of high air
pollution potential including the Cincinnati area was in effect from 3:00
p.m. August 30 to 10:00 a.m. September 1. No increase in atmospheric
lead concentrations was observed, however.
Meteorological data obtained at the Los Angeles International Air-
port are summarized in Figure 19. Precipitation amounts were signifi-
cantly large only during February, when 11 inches of rain fell. No
measurable precipitation occurred in June, July, and October 1961 or
in April and June 1962. Sunshine for the year was near normal except
during February. Heating requirements have less meaning for the Los
Angeles area than for the Philadelphia and Cincinnati areas, where( the(
burning of coal might add lead to the atmosphere. A record high
perature of 106° occurred in Los Angeles in mid-October.
50
-------
I I I I I I
I I I I
^ 10
*
8 6
4
2
J J A S 0 N 0 J F M A M J
n i i \ i | i i i i r
PERCENT OF POSSIBLE SUNSHINE
' 1961-1962
JJASONDJFMAMJ
\ r
SCO
400
300
200
100
JJASONDJFMAMJ
1IIt \I1^ [ I I
AVERAGE WIND SPEED
I I I I I I I I I I I
JJASOHO 1FMAMJ
5-y£AR AVERAGE
1961-19S2 AVERAGE
FIGURE 18
METEOROLOGICAL DATA OBTAINED AT
GREATER CINCINNATI AIRPORT
51
-------
5
£ 3
30-YEAR AVERAGE
s
I 5
I I I I I i i I I I T
AVERAGE WIND SPEED
-1961-19(2
*— 10-YEAR AVERAGE
JJASONDJFMAMJ JJASONDIFMAMJ
I I I I I I I
21-YEAR AVERAGE
PERCENT OF POSSIBLE SUNSHINE
I I I I I I I I I I I
JJASONDJFMAMJ
I I I I I i I
I I I I I I I
JJASOND JFMAMJ
1961-1962 AVERAGE
FIGURE 19
METEOROLOGICAL DATA OBTAINED AT
LOS ANGELES INTERNATIONAL AIRPORT
52
-------
— PRECIPITATION
i — i — i — i — i — i — i — i — r
I I 1 I I I I
I I
T—I—I I"
— AVERAGE WIND SPEED
i I
i i I i I i
i i i i \ i r
PERCENT OF POSSIBLE SUNSHINE
. 196H962
J F M
10-YEAR AVERAGE
1961-1962 AVERAGE
FIGURE 20
METEOROLOGICAL DATA OBTAINED AT
PHILADELPHIA INTERNATIONAL AIRPORT
53
-------
Wind speeds were higher than normal at the Los Angeles Interna-
tional Airport during all months except December and January; in
downtown Los Angeles, however, they were near normal for all months.
Monthly wind directions during the study did not differ significantly
from the long-term directions. In contrast to Philadelphia and Cincin-
nati, winds in Los Angeles were lower in December and January than
during the remainder of the year. These low wind speeds probably were
important factors in the relatively high concentrations of lead in the
fall and winter in Los Angeles as compared to summer and spring.
Meteorological data obtained at the Philadelphia International Air-
port are summarized in Figure 20. Precipitation was relatively high in
July 1961 and in June 1962. The percent of possible sunshine was greater
than normal in all months except February. Heating requirements were
above normal throughout the winter. Average monthly wind speeds
were about normal throughout the year, but in March were somewhat
higher. Wind direction frequencies were near normal for the period
as a whole.
An advisory of high air pollution potential including the Philadel-
phia area began at 2:00 p.m., October 10, and ended at 3:00 p.m.,
October 13, 1961. During the alert, 24-hour average wind speeds mea-
sured at the Philadelphia International Airport were 4.5 mph on the
10th; 4.6 mph on the llth; 6.3 mph on the 12th; and 7.1 mph on the
13th; the mean monthly speed is 8.9 mph. From the llth through the
13th, surface visibility was restricted by smoke and haze to less than
7 miles. The particulate sample taken during this period at the Philadel-
phia NASN station was the second highest loading of the year. The
highest lead concentrations for the month occurred during this period
and were 1.5 to 2.0 times the monthly mean at each site.
SPECIAL STUDIES
Lead Concentrations in Heavy Traffic
Samples were obtained in Cincinnati and Los Angeles by means of
mobile samplers to determine atmospheric levels of lead in or near heavy
traffic streams. The samples were collected during the morning and
afternoon traffic rush and during midday on representative traffic
arteries. In addition, samples were taken while the test vehicles were
parked at the curb at various downtown locations.
Two station wagons were used for this work; Kettering Laboratory
operated the one in Cincinnati, and the Public Health Service operated
the one in Los Angeles. Both were equipped with gasoline-powered
generators, pumps, and air filters. Samples were taken from the,left,
and right rear windows and from positions within the station wstgon'
near the driver's head. Similar values were obtained for all of these
54
-------
positions. Samples were collected with the same equipment and analyzed
in the same manner as were those collected at the fixed stations.
In the Cincinnati area, 140 samples were taken; in Los Angeles, 191.
Results are summarized in Tables 19 and 20.
In Los Angeles traffic, atmospheric lead levels were about 25 micro-
grams per cubic meter, whereas in Cincinnati the values were about
14. Successively lower values were found at greater distances from the
traffic; e.g., values obtained at curbside along a busy residential street
in Cincinnati with 503 cars per hour averaged 4.6, and those on a country
road averaged about 3.
Other studies have illustrated the variability of lead concentrations
and their relationship to automobile sources.28
TABLE 19
ATMOSPHERIC CONCENTRATIONS O^ LEAD IN TRAFFIC
CINCINNATI AREA
(IN MICROGRAMS PER CUBIC METER)
Description of Route No. of Samples Mean Range
I Mobile sampling in traffic
7 Commuter Routes, Morning Rush
7 Commuter Routes, Afternoon Rush
7 Commuter Routes, Midday
Streets Loaded Heavily, 2150 Cars/Hr.
Downtown during Afternoon Rush
20
8
8
35
3
14.2
15.2
9.1
14.3
11.5
7.2-19.5
9.3-21.1
7.0-12.3
9.0-26.7
8.6-15.8
II Fixed Position Sampling
Parked at Curb, Downtown,
Christmas Rush 4 21.4 17.7-24.4
Parked at Curb, 2150 Cars/Hr. 12 7.6 3 -15
Parked at Curb, 820 Cars/Hr. 13 i 4.8 1 -11
Parked at Curb, 500 Cars/Hr. 15 4.6 1-9
Parked at Curb, 220 Cars/Hr. 5 1.9 1 - 3
III Mobile Sampling—Rural
Cruise at 30-40 Mph. 13 3.1 0.6- 6.6
Stop and Go behind Another Car 4 4.3 1.7- 6.5
TOTAL 140
55
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TABLE 20
ATMOSPHERIC CONCENTRATIONS OF LEAD IN TRAFFIC-LOS ANGELES AREA
(IN MICROGRAMS PER CUBIC METER)
Route
Parked Along Freeway*
Parked Along Freeway
Parked Along Freeway
Parked Along Freeway
Freeway Traffic
Freeway Traffic
Freeway Traffic
Freeway Traffic
Los Angeles Downtown Traffic
Los Angeles Downtown Traffic
Los Angeles Downtown Traffic
Los Angeles Downtown Traffic
Pasadena Downtown Traffic
Pasadena Downtown Traffic
Pasadena Downtown Traffic
Pasadena Downtown Traffic
Sampling
Time
0600-0900
0900-1600
1600-1800
0600-0900
0900-1600
1600-1800
0600-0900
0900-1600
1600-1800
0600-0900
0900-1600
1600-1800
Day of
Week
Weekdays
Weekdays
Weekdays
Saturday
Weekdays
Weekdays
Weekdays
Saturday
Weekdays
Weekdays
Weekdays
Saturday
Weekdays
Weekdays
Weekdays
Saturday
Description
Morning Rush
Midday
Afternoon Rush
Morning Rush
Midday
Afternoon Rush
Morning Rush
Midday
Afternoon Rush
Morning Rush
Midday
Afternoon Rush
TOTAL
Mean
38.0
24.1
18.4
19.9
29.3
21.5
22.2
25.3
23.6
10.5
15.3
9.4
11.9
12.4
Range
26.9-54.3
16.6-31.1
8.7-25.4
17.7-22.2
10.9-41.3
4.5-39.2
10.5-43.1
10.0-71.3
19.1-29.9
8.4-12.2
12.4-18.6
8.6-10.3
8.6-14.6
12.3-12.4
No. of
Samples
7
7
7
4
35
39
34
32
6
4
4
4
6
2
191
^Parked on shoulders of major freeway in downtown Los Angeles.
-------
Surnner Tunnel Study
The atmosphere in Boston's Sumner Tunnel was studied in July and
September 1961. The 35,000 vehicles per day that traversed the then
two-way tunnel produced an average carbon monoxide concentration of
70 parts per million in the tunnel. Inlet air contained an average of 1.1
micrograms of lead per cubic meter, and outlet air contained 44.5.
Similar increases were noted for other pollutants measured.29
In Miranda's study of the lead concentrations in the blood of 47 of
these tunnel employees, the overall mean concentration was 0.03 milli-
gram per 100 grams of blood. He also observed that concentrations of
lead in the blood of long-term employees who smoked were higher than
those of all other employees combined.30
Alkyl Lead Concentrations
The values of lead reported for the three-city study are for the in-
organic lead content of the atmosphere. Although this form of lead
predominates in the atmosphere, some alkyl lead in the form of vapor
is present. The primary source of this alkyl lead is the alkyl lead vapors
associated with unburned gasoline, as discussed earlier. Small quantities
of these alkyl lead compounds escape to the atmosphere from several
points on a motor vehicle. In addition, these compounds are introduced
into the atmosphere whenever leaded gasoline is spilled or evaporated.
Because alkyl lead vapors are present in very small concentrations,
large samples of air must be collected for their measurement. Three
sampling systems were tried: (1) A total volume of 0.23 cubic meter of
air was first passed through a membrane filter to remove particulate
lead and then drawn through a scrubber containing 1 gram of crystalline
iodine. (2) A total volume of 1.2 cubic meters of air was first passed
through a membrane filter and then drawn through two scrubbers,
in series, containing 1 N solution of iodine. (3) A total volume of 2 cubic
meters of air was first passed through a membrane filter and then drawn
through a scrubber containing 20 grams of crystalline iodine. In each
sampling system, the membrane filter and the contents of the scrubber
system were analyzed separately.
Alkyl lead samples were collected in heavy traffic in the Cincinnati
area by use of the mobile sampler. Data are summarized in Table 21.
Results were inconsistent in that alkyl lead concentrations varied in-
versely with the volume of air sampled. This indicates that the sampling
and analytical procedures are not adequate to quantitate the low con-
centrations of alkyl lead compounds that may be present in the at-
mosphere. Similar inconsistent results were obtained for sampling in
heavy traffic in the Los Angeles area. Evaluation of the levels of these
compounds in the atmosphere requires the development of improved
sampling and analytical procedures. Although it is not possible to
assign any degree of reliability to the values shown in Table 21, the
57
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TABLE 21
CONCENTRATIONS OF ALKYL LEAD VAPORS
IN THE ATMOSPHERE IN HEAVY TRAFFIC
IN THE CINCINNATI AREA
Air
sampled,
Sampling procedure m3
Iodine crystal (1 g)
Iodine solution
Iodine crystal (20 g)
0.23
1.2
2.1
No.
of
Samples
8
15
3
Concentration of lead, (J.g/m3
Alkyl lead
Mean
2.1
1.1
0.2
Range
0.9-3.5
0.4-2.4
0.1-0.2
Inorganic
Mean
16.0
11.1
15.5
Range
8.4-28
2.5-19.5
1.3-23.5
results do indicate that at most the alkyl lead concentrations did not
reach 10 percent of the inorganic lead values, and probably were
considerably less.
BIOLOGICAL STUDIES
In conjunction with the atmospheric studies, investigations were
conducted to determine the lead content of the blood and urine of
selected population groups in the three cities. In general, the subjects
were selected on the following bases:
1. Most of the individuals had no known industrial exposure to lead.
A few groups were selected who had some opportunity for occu-
pational exposure.
2. The range of ages was as wide as possible.
3. Within specific groups, an equal number of males and females
was selected wherever possible.
4. All subjects lived in the survey areas for at least 5 years.
The general procedure employed in Philadelphia and Los Angeles
was to draw from each subject one sample of blood of from 10 to 20
milliliters through a lead-free stainless-steel needle into a lead-free
Vacutainer. A single specimen of urine was taken from each male sub-
ject at the time the blood sample was drawn. After digestion of the
blood and urine samples, a dithizone analysis similar to that previously
described was performed to determine the total lead content.27 The
procedure in Cincinnati differed somewhat in that duplicate samples of
blood were obtained for analysis by spectrography in addition to anal-,
ysis by the dithizone method. A social and medical history, including
smoking habits, was obtained from each individual.
58
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Because there were some differences in the detailed procedures of
the biological phase of the program in the three cities, each study is
discussed individually.
Cincinnati
Populations Studied: In Cincinnati, the procedures for investigating
biological effects of general environmental exposure to lead differed
somewhat from those employed in Philadelphia or Los Angeles. Many
persons in Cincinnati had been investigated in this manner previously,
most recently in the winter of 1955-56. In that survey of approximately
500 persons, f eces as well as blood and urine had been sampled and sub-
jected to analysis for lead. Very little more was learned concerning the
contribution made by atmospheric contamination to the absorption
and excretion of lead than had been learned in previous investigations
of this type. It was hoped, therefore, that in the three-city survey, by
judicious selection of groups of persons in the population, it might be
possible to determine the relative importance of the atmospheric source.
For these and other reasons, subjects were sought who had expe-
rienced more than the usual opportunities for respiratory exposure
to the principal sources of lead in the atmosphere of Cincinnati. The
most promising groups were those who spent most of their working hours
regularly in the streets and on the sidewalks of the city close to its
motor traffic. In this category are city police (traffic officers in partic-
ular) ; postal employees, especially letter carriers on foot and in motor
cars; city firemen; and certain peripatetic, technical employees of the
City Health Department (housing inspectors and air pollution inspec-
tors). Professional drivers of motor vehicles, such as taxicab and
delivery truck drivers, were regarded as desirable subjects, but were
not readily available. Only 14 taxicab drivers were examined; results
of these analyses are given in this report but are not considered rep-
resentative of this occupational group because of the small sample size.
To encompass other segments of the Cincinnati population, results
of observations made in the winter of 1955-56 on 478 persons in Cin-
cinnati and vicinity are recorded. The analytical data were obtained by
the same methods of analysis and are comparable in every respect to
those obtained in this survey. Not only is this additional number of
persons important, but their locations and types of employment in
relation to combustion products of automotive engines broaden the
scope of the investigation significantly.
Results: The principal analytical data of the two surveys have been
assembled in Tables 22 and 23, according to the frequencies of occur-
rence of various ranges of the concentration of lead in the blood and
urine.
Table 22 gives the blood analyses. The outstanding example, on the
high side, is garage mechanics. A small group of men employed in
59
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TABLE 22
DISTRIBUTION OF PERSONS IN VARIOUS OCCUPATIONAL GROUPS ACCORDING TO
CONCENTRATIONS OF LEAD IN BLOOD-CINCINNATI
Lead in blood,
mg/lOOg
0-0.009
0.010-0.019
0.020-0.029
0.030-0.039
0.040-0.049
0.050-0.059
0.060-0.069
Totals
Mean
Std.-Dev.
Service Refinery
station handlers
attend- of
ants gasoline
1956 1956
1 2
42 30
71 46
14 8
2
130 86
0.028 0.027
0.007 0.006
Park-
ing
attend-
ants
1956
1
26
20
1
48
0.034
0.006
Garage
Me-
chanics
1956
8
43
72
25
4
152
0.038
0.009
Drivers of
cars
1956
17
19
9
45
0.033
0.006
1963
1
4
9
14
0.031
0.006
Police
Traffic
officers
1956 1963
7
9
1
17
0.031
0.006
3
23
9
4
1
40
0.030
0.009
All
police8
1963
12
78
27
5
1
123
0.025
0.007
Fire-
men
1963
18
123
44
6
191
0.025
0.006
Post-
Office
Emp.
1963
22
90
24
2
1
1
140
0.023
0.007
City
Health
Dept.
Emp.
1963
10
24
2
36
0.021
0.005
alncludes traffic officers for 1963.
-------
TABLE 23
DISTRIBUTION OF PERSONS IN VARIOUS OCCUPATIONAL GROUPS ACCORDING TO
CONCENTRATIONS OF LEAD IN URINE-CINCINNATI
Lead in urine,
mg/1
0-0.009
0.010-0.019
0.020-0.029
0.030-0.039
0.040-0.049
0.050-0.059
0.060-0.069
0.070-0.079
0.08-0.12
Totals
Mean
Std. Dev.
Service
station
attend-
ants
1956
1
74
33
13
5
3
1
130
0.027
0.010
Refinery
L> A« Jl AW
handlers
of
gasoline
1956
1
1
49
22
9
4
86
0.028
0.013
Park-
ing
attend-
ants
1956
1
4
21
12
7
2
1
48
0.028
0.011
Garage
Me-
chanics
1956
4
2
39
33
30
21
16
4
3
152
0.040
0.020
Drivers
cars
of
1956 1963
1
28
11
2
2
1
45
0.020 0
0.011 0
5
4
4
1
14
.036
.010
Police
Traffic
officers
1956 1963
2
9
5 13
7
3 8
2
1
1
3
17 37
0.023 0.039
0.011 0.020
All
police3
1963
2
6
29
21
30
12
7
3
6
116
0.038
0.018
Fire-
men
1963
47
71
36
19
9
2
1
185
0.027
0.011
Tl _ «4-
Post-
Office
Emp.
1963
49
52
19
9
1
130
0.022
0.009
City
TT _ _ 14.1-
Health
Dept.
Emp.
1963
12
18
6
1
37
0.022
0.007
2 "Includes traffic officers for 1963.
-------
several parking garages and parking lots (investigated in 1955-56) is
next in order on the high side, and a correspondingly small group of
regular drivers of motor cars (also investigated in 1955-56) comes next
and is almost paralleled by the small group of taxicab drivers included
in the present survey. Next in descending order come the traffic officers,
and with insignificant difference, the larger group of policemen of which
they are a part. From here on down from the mid-point in the sequence
of mean values come firemen, post-office personnel, and the peripatetic
technical personnel of the City Health Department. Despite the small
ranges of the individual findings and of the mean concentrations of
lead in the blood of several groups, the differences between the groups
reach statistical significance at several intervals from the lowest to
the highest.
The degree of variability of the concentrations of lead in the spec-
imens of the urine (Table 23) of nearly 1000 persons in these divergent
walks of life is remarkably small, the total range extending from 0.005
to 0.12 milligram per liter. This indicates that quantities of lead ab-
sorbed by the individuals in these groups from day to day, while highly
variable, are uniformly small. There are significant differences in the
groups, however; the outstanding example is that of the garage me-
chanics. Other groups, notably the police officers as an entire group,
and a fairly sizable subgroup of traffic officers, are in the relatively high
zone of the total spectrum of mean values.
One may postulate under these conditions that such a variable as
the atmospheric lead content, if distributed in sufficiently distinctive
orders of magnitude in well-defined areas of a city, would reveal its
effects in a distinctly variable manner through the responses of the
residents of these areas. Accordingly, to determine the significance of
one factor that might contribute to the differentiation of the exposure
to airborne lead of individuals within the several groups, the subjects
were classified according to four general areas in which their homes
were situated: industrial, commercial, residential, or rural. The results
of the examination of the analytical data arranged in this manner are
shown in Tables 24 and 25. No valid or consistent relationship between
these areas and the lead content of the blood and urine was established.
Another variable in the experience of the subjects—their habits of
smoking—was examined in considerable detail because of its possible
effect in masking or distorting the physiological response to lead in the
general atmosphere. For reasons set forth earlier, it was not anticipated
that this effect would be striking or even certainly discernible. The
data that are available in sufficient numbers to be worthy of statistical
examination are assembled in Table 26.
It is evident that the differences between smokers and nonsmokers
of cigarettes in the several groups of subjects, while very small and
statistically not significant, are with one exception (concentration of
62
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TABLE 24
CONCENTRATIONS OF LEAD IN BLOOD FOR FOUR VOCATIONAL GROUPS
DISTRIBUTED ACCORDING TO HOME ADDRESSES-CINCINNATI
Industrial
Commercial
Residential
Rural
Mean, Mean, Mean, Mean,
Vocational mg/ Std. mg/ Std. mg/ Std. mg/ Std.
Group Number lOOg dev. Number lOOg dev. Number lOOg dev. Number lOOg dev.
Policemen
Firemen
Post-Office
Employees
Health
Department
Employees
10
5
20
1
0.026 0.007
0.026 0.004
0.022 0.005
0.025
12
22
14
6
0.029
0.026
0.026
0.021
0.011
0.007
0.011
0.005
85
148
68
24
0.024
0.025
0.024
0.021
0.006
0.006
0.007
0.005
10
16
17
3
0.029
0.022
0.023
0.025
0.005
0.004
0.005
0.005
All Groups
36 0.023
54 0.025
325 0.024
46 0.023
CO
-------
05
Groups
TABLE 25
CONCENTRATIONS OF LEAD IN URINE FOR FOUR VOCATIONAL GROUPS
DISTRIBUTED ACCORDING TO HOME ADDRESSES-CINCINNATI
Industrial Commercial
Vocational
Group
Policemen
Firemen
Post-Office
Employees
Health
Department
Employees
Mean,
Number mg/1
9 0.048
5 0.027
18 0.020
1 0.020
Std. Mean,
dev. Number mg/1
0.019 12 0.037
0.008 21 0.026
0.005 14 0.020
6 0.020
Std.
dev.
0.024
0.011
0.010
0.004
Residential
Mean,
Number mg/1
80 0.037
143 0.027
63 0.023
23 0.022
Std.
dev.
0.017
0.011
0.009
0.008
Rural
Mean,
Number mg/1
10 0.040
16 0.025
15 0.020
3 0.030
Std.
dev.
0.016
0.012
0.006
0.009
33 0.028
53 0.026
309 0.028
44 0.027
-------
TABLE 26
CONCENTRATIONS OF LEAD IN BLOOD AND URINE FOR FOUR VOCATIONAL GROUPS
DISTRIBUTED AS SMOKERS AND NONSMOKERS-CINCINNATI
Subjects
Policemen
Firemen
Post-Office Employees
Health Department
Employees
All Subjects
1963
All Smokers
All Smokers of
Cigarettes
Subgroup
Smokers
Nonsmokers
Smokers
Nonsmokers
Smokers
Nonsmokers
Smokers
Nonsmokers
Smokers
Nonsmokers
Inhale
Do Not Inhale
Unfiltered
Filtered
Lead in blood, mg/lOOg
Number Mean Std. dev.
107
11
163
27
118
20
30
5
418
63
294
46
173
131
0.025
0.023
0.025
0.024
0.024
0.022
0.022
0.016
0.024
0.022
0.024
0.022
0.022
0.024
0.007
0.006
0.006
0.006
0.006
0.010
0.005 ' '
0.002
0.006
0.007
0.006
0.005
0.005
0.006
Lead in urine,
Number Mean
104
8
158
26
109
19
29
5
400
58
282
43
168
123
0.038
0.039
0.027
0.026
0.023
0.019
0.023
0.018
0.028
0.025
0.029
0.025
0.037
0.023
mg/1
Std. dev.
0.019
0.013
0.012
0.008
0.009
0.007
0.007
0.004
0.014
0.010
0.012
0.010
0.017
0.010
-------
lead in the urine of policemen) in the same direction; i.e., they show a
trend toward the occurrence of larger quantities of lead in the blood
and urine of smokers than of nonsmokers. This trend, in view of its
essential uniformity within the group, is sustained in the comparison
of all of the smokers with all of the nonsmokers. It is important to
recognize, however, that the differences between the vocational groups
are influenced either slightly or not at all by the factor of smoking.
Obviously, therefore, the factor that differentiates policemen from post-
office employees, whatever it may be, is much more potent than the
factor of smoking. The differences between smokers with respect to
whether or not they inhale are favorable to the hypothesis that more
lead is absorbed by those who inhale. Just what can be made, other than
as the intervention of chance, of the contradictory findings yielded by
the urine and blood of men who smoke unfiltered as compared to filtered
cigarettes is not apparent.
Additional relationships between the levels of lead in the urine and
blood of the subjects in vocational and combined groupings were inves-
tigated statistically. Included in these were such factors as the age of
the subjects, the duration of their employment in their specific voca-
tional categories, the source of their water supply, the type of heating
and cooking devices in their homes or quarters, certain physical ail-
ments (specifically, pulmonary, renal, and hepatic diseases), and the
frequency and severity of effects suggestive of exposure to significant
concentrations of carbon monoxide, such as headaches, dizziness, and
feelings of undue tiredness, singly and in combination. No correlations
between these factors and the data indicative of variable levels of
absorption of lead were discovered. Tables 27 and 28, which present
data with respect to the age of members of two of the groups versus the
.concentrations of lead in the blood and urine, illustrate the procedure
as well as the lack of relationship that characterized this group of
variables.
TABLE 27
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
POLICEMEN BY AGE GROUPS-CINCINNATI
Age, Lead in blood, mg/lOOg Lead in urine, mg/1
Years Number Mean Std. dev. Number Mean Std. dev.
20-29
30-39
40-49
50-59
15
42
46
18
0.028
0.027
0.028
0.026
0.005
0.005
0.008
0.007
17
38
41
17
0.053
0.046
0.041
0.053
0.017
0.025
0.019
0.01^
66
-------
TABLE 28
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
FIREMEN BY AGE GROUPS-CINCINNATI
Age,
Years
20-29
30-39
40-49
50-59
60-69
Lead
Number
25
103
35
25
3
in blood,
Mean
0.026
0.027
0.028
0.026
0.030
mg/lOOg
Std. dev.
0.008
0.005
0.005
0.006
—
Lead
Number
28
97
33
24
3
in urine,
Mean
0.028
0.031
0.025
0.029
0.035
mg/1
Std. dev.
0.014
0.011
0.009
0.009
—
Los Angeles
Populations studied: The Los Angeles study was designed to compare
the levels of lead in the blood and urine of groups exposed to different
degrees of air pollution during their normal daily activities. In the
selection of subjects, the fact that people often work and live in widely
different areas was considered, and exposure to air pollution in both
places was taken into account. Another factor considered was the daily
exposure during time spent commuting to and from work and the types
of traffic encountered.
The choice of participants was governed by the availability of groups
from which volunteers could be obtained. Interest in the project and a
guarantee of cooperation were obtained from the Los Angeles Police
Department, a group of municipal employees in Pasadena, and em-
ployees in an aircraft plant. Specifically, the following groups were
selected for study on the basis of responses to a questionnaire.
1. Individuals who worked and lived in the coastal portion of the
Los Angeles Basin in which levels of atmospheric lead were assumed
to be lower than in areas farther inland (aircraft employees).
2. Individuals who worked in the coastal area and lived in one of
two inland areas (aircraft employees).
3. Individuals who were exposed to heavy pollution from motor
vehicle exhaust because of their occupation (policemen working
in Los Angeles downtown traffic).
4. Individuals who worked and lived in an inland area (municipal
employees).
For each group information was obtained on amount and type of
commuting.
Involved in this program were 141 Los Angeles policemen, 291 male
aircraft-plant employees, 87 female aircraft-plant employees, and 150
Pasadena municipal employees. In addition, several groups of chron-
ically ill individuals were studied.
67
-------
TABLE 29
CONCENTRATIONS OF LEAD IN BLOOD BY SEX AND BY SMOKING HABITS
PILOT STUDY-OAKLAND AND LOS ANGELES-1960
(IN MILLIGRAMS OF LEAD PER 100 GRAMS OF BLOOD)
Sample, by smoking habit
TOTAL
Oakland:
Total
Nonsmokers
Cigarette Smokers:
Less than 10 cigarettes/day
10 or more cigarettes/day
Other Smokers
Los Angeles:
Total
Nonsmokers
Cigarette Smokers:
Less than 10 cigarettes/day
10 or more cigarettes/day
Other Smokers
Number
81
36
19
9
8
45
25
3
16
1
Males
Mean
0.021
0.022
0.019
0.029
0.023
0.020
0.020
0.020
Std. dev.
0.008
0.009
0.007
0.012
0.007
0.008
0.010
0.006
Number
93
53
32
9
12
40
20
11
9
Females
Mean
0.017
0.018
0.015
0.025
0.022
0.016
0.016
0.011
0.021
Std. dev.
0.008
0.009
0.007
0.013
0.008
0.006
0.006
0.004
0.005
-------
Pilot Studies: In the summer of 1960, a pilot study was conducted
in Oakland and Los Angeles to devise techniques and to test the inter-
view schedule for use in the larger study described in this report. The
sample was drawn from persons receiving routine examinations at the
Northern California Kaiser Foundation Clinic (Oakland) and the
Southern California Kaiser Foundation Clinic (Los Angeles). Each
volunteer was interviewed and a blood specimen was drawn. The
results of this study are shown in Table 29.
Other data were collected as part of a multiphase examination of
residents of Alpine County, a rural area in the Sierra Nevada. Most of
these persons are of American Indian ancestry. The results are pre-
sented in Table 30.
TABLE 30
CONCENTRATIONS OF LEAD IN BLOOD OF RESIDENTS
OF A RURAL CALIFORNIA COUNTY
Mean concentration,
Number mg/lOOg
Total
Male
Female
Sex Not Stated
37
16
11
10
0.011
0.012
0.009
0.013
Data, Collected: In order to attribute observed differences in lead con-
centrations to differences in exposure to air pollution, it is necessary
to control, either in selection of the sample or in analysis, the other
variables that might be expected to affect the concentration of lead.
Therefore, individuals participating in the study were asked questions
concerning occupational and residence history, smoking, chronic con-
ditions involving the liver, kidney, and lung, occupational illness, and
time taken for commuting. The usual identifying information was
asked permitting use of age and sex as variables. Basically, the ana-
lytical problem was one of comparing the mean lead values obtained
in the different groups classified according to their presumptive ex-
posure and other pertinent characteristics.
Results: Table 31 shows the distribution of lead values in blood
(milligrams of lead per 100 grams of blood) by sex and employment
group. Table 32 shows comparable data for lead values in urine (mil-
ligrams per liter). No urine specimens were obtained from female sub-
jects. The differences between the means of the groups are in all cases
small; the ranges are not large, and nearly all individual measurements
are well below 0.05. The highest mean levels for both urine and blood
69
-------
TABLE 31
DISTRIBUTION OF SUBJECTS IN VARIOUS OCCUPATIONAL
GROUPS ACCORDING TO CONCENTRATION
OF LEAD IN BLOOD-LOS ANGELES
Lead in blood,
mg/lOOg
0 -0.009
0.010-0.019
0.020-0.029
0.030-0.039
0.040-0.049
0.050-0.059
0.060-0.069
0.070-0.079
Totals
Mean
Std. dev.
Aircraft
employees
Male
25
148
86
17
10
1
3
1
291
0.019
0.010
Female
12
53
16
3
2
1
87
0.017
0.009
Los Angeles
policemen
3
57
83
11
1
155
0.021
0.006
Pasadena City
employees
Male
16
31
25
13
3
88
0.019
0.011
Female
19
23
9
1
52
0.012
0.009
TABLE 32
DISTRIBUTION OF MALES IN VARIOUS OCCUPATIONAL
GROUPS ACCORDING TO CONCENTRATION
OF LEAD IN URINE-LOS ANGELES
Lead in urine,
mg/1
0 -0.009
0.010-0.019
0.020-0.029
0.030-0.039
0.040-0.049
0.050-0.059
0.060-0.069
0.070-0.079
Totals
Mean
Std. dev.
Aircraft
employees
112
85
54
13
4
3
0
1
272
0.014
0.011
Los Angeles
policemen
18
54
37
13
7
3
1
133
0.021
0.013
Pasadena
City
employees
27
29
14
4
2
2
0
1
79
0.017
0.013
70
-------
TABLE 33
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
SUBJECTS BY AREA OF RESIDENCE-LOS ANGELES
Lead in blood
Lead in urine
Area of residence
No. of
sub-
jects
Mean,
mg/
lOOg
Std.
dev.
No. of
sub- Mean, Std.
jects mg/1 dev.
0.014
0.013
0.017
0.015
0.021
0.025
0.022
0.019
0.011
0.011
0.011
0.015
Aircraft employees:
Male total: 291 0.019 0.010 272
Coastal area 197 0.019 0.011 185
Central area 57 0.020 0.007 54
Inland area 37 0.020 0.010 33
Female total: 87 0.017 0.009
Coastal area 67 0.017 0.009
Central area 17 0.015 0.007 '
Inland area 3 0.020 0.019
Los Angeles
policemen:
Male total: 155 0.021 0.006 133
Coastal area 30 0.022 0.007 26
Central area 22 0.020 0.006 19
Inland area 103 0.021 0.006 88
Pasadena City
employees:
Male total: 88 0.019 0.011 79
Coastal area 1 0.000 — 0
Central area 0 — — 0
Inland area 87 0.019 0.011 79
Female total: 52 0.012 0.009
Coastal area 0 — —
Central area 1 0.002 —
Inland area 51 0.012 0.009
0.013
0.013
0.017
0.011
0.017 0.013
0.017 0.013
are found in the police group. The highest values of lead in the blood for
females in both groups are lower than the comparable values for the
males.
Table 33 gives results of subdividing the basic groups in terms of
their residence in the coastal, central, or inland areas of greater Los
Angeles. Individuals were classified in the residential area in which they
lived for the longest period of time between 1956 and 1961. No significant
differences in lead levels were observed in these subgroups.
71
-------
TABLE 34
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
SUBJECTS BY SMOKING HABITS-LOS ANGELES
Classification of
subjects
Lead in blood
No. of Mean,
sub- mg/ Std.
jects lOOg dev.
Lead in urine
No. of
sub- Mean, Std.
jects mg/1 dev.
Aircraft employees:
Male total: 291 0.019 0.010
Smokers:
Cigarettes 137 0.022 0.010
Other 33 0.017 0.007
Nonsmokers 121 0.018 0.011
Female total: 87 0.017 0.009
Smokers:
Cigarettes 55 0.019 0.009
Other 0 — —
Nonsmokers 32 0.014 0.007
Los Angeles
policemen:
Male total: 155 0.021 0.006
Smokers:
Cigarettes 85 0.022 0.006
Other 15 0.016 0.009
Nonsmokers 55 0.020 0.005
272
129
31
112
0.014
0.015
0.015
0.013
133
76
13
44
0.022
0.017
0.020
0.011
0.013
0.014
0.009
0.021 0.013
0.012
0.008
0.014
Pasadena City
employees:
Male total:
Smokers:
Cigarettes
Other
Nonsmokers
Female total:
Smokers:
Cigarettes
Other
Nonsmokers
88
45
6
- 37
52
9
0
43
0.019
0.020
0.021
0.018
0.012
0.012
—
0.012
0.011
0.011
0.014
0.010
0.009
0.007
—
0.009
79
39
5
35
0.017
0.020
0.026
0.012
0.013
0.014
0.027
0.007
The effects of smoking on lead levels were examined in the five
employee groups; the results are presented in Table 34. The group
labeled "smokes cigarettes" included all respondents who currently
smoked cigarettes. The smokers labeled "other" included current
smokers of pipes or cigars who did not smoke cigarettes at the time
of the study. The "nonsmokers" included individuals who had never
72
-------
smoked or who were currently nonsmokers. Again, although the dif-
ferences are small, lead levels are generally somewhat higher in smokers
of cigarettes than in nonsmokers or those who smoke pipes or cigars.
The only exceptions are the Pasadena female group, in which mean
TABLE 35
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
SUBJECTS BY COMMUTING TIME-LOS ANGELES
Lead in blood
Commuting time,
minutes
Aircraft employees:
Male total:
0- 9
10-29
30-59
60+
Not Stated
Female total:
0- 9
10-29
30-59
60+
Not Stated
Los Angeles
policemen :
Male total:
0- 9
10-29
30-59
60+
Not Stated
Pasadena City
employees:
Male total:
0- 9
10-29
30-59
60+
Female total:
0- 9
10-29
30-59
60+
No. of
sub-
jects
291
37
130
99
24
1
87
12
46
25
2
2
155
5
85
59
3
3
88
10
61
16
1
52
12
36
3
1
Mean,
mg/
lOOg
0.019
0.019
0.019
0.020
0.018
0.017
0.014
0.017
0.017
0.026
0.021
0.021
0.021
0.021
0.020
0.019
0.024
0.019
0.019
0.000
0.012
0.012
0.012
0.012
0.019
Std.
dev.
0.010
0.012
0.011
0.009
0.008
0.009
0.006
0.009
0.008
0.023
0.006
0.002
0.006
0.007
0.004
0.011
0.009
0.011
0.011
0.009
0.009
0.009
0.010
Lead in urine
No. of
sub-
jects
272
33
125
94
19
1
133
5
69
53
3
3
79 •
9
56
14
0
Mean,
mg/1
0.014
0.014
0.014
0.014
0.011
0.021
0.017
0.020
0.023
0.026
0.017
0.014
0.017
0.017
Std.
dev.
0.011
0.011
0.011
0.012
0.009
0.013
0.011
0.012
0.014
0.003
0.013
0.017
0.013
0.011
73
-------
lead levels in the blood of smokers and nonsmokers are the same, and
the Pasadena male group, in which levels are higher for pipe and cigar
smokers than for the cigarette smoking group. Here again, lead levels
in the blood of females are consistently somewhat lower than those of
their male counterparts, by smoking groups.
Table 35 shows the mean lead values in blood and urine according
to sex, employment group, and commuting time. There is no progres-
sion of values with increasing commuting time in any employment group.
For policemen, the mean and standard deviations of lead values in
blood and urine are shown in Table 36, by type of duty. The subgroup
assigned to parking and intersection work shows slightly higher mean
lead values for both blood and urine than the motorcycle subgroup.
The possible relationships of the lead levels in blood and urine to
occupation and to medical history were explored. No significant cor-
relations were found.
TABLE 36
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
POLICEMEN BY TYPE OF DUTY-LOS ANGELES
Lead in blood
Duty classification
TOTAL
Motorcycle
Parking and
Intersection
No. of
sub-
jects
155
62
93
Mean,
mg/
lOOg
0.021
0.020
0.022
Std.
dev.
0.006
0.006
0.006
Lead in urine
No. of
sub-
jects
133
55
78
Mean,
mg/1
0.021
0.019
0.022
Std.
dev.
0.013
0.009
0.015
Chronic disease patients: Table 37 shows the individual lead values
for the blood and urine of a number of patients with chronic medical
conditions studied at a hospital for treatment of chronic diseases and
at an outpatient clinic in Los Angeles. In some cases, as indicated,
more than one condition was present and for this reason the classification
is to some extent an arbitrary one. Neither the ranges of individual
values nor the means of lead concentrations in the blood in the grouped
cases are remarkable. These limited and exploratory data yield no
suggestion that illnesses of these types result in any special abnormal-
ities in the metabolism of lead.
Philadelphia
Populations Studied: In Philadelphia, a volunteer group of 113 indi-
viduals exposed to community atmospheric lead in normal working
74
-------
TABLE 37
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
SELECTED CHRONIC-DISEASE PATIENTS-LOS ANGELES
Sex
M
F
M
F
M
F
M
M
M
M
M
F
M
M
M
F
M
M
F
F
M
M
M
M
M
M
M
M
F
F
M
F
M
M
M
M
F
F
F
M
M
M
F
F
F
F
F
F
F
M
Mean:
Age,
years
15
26
29
33
33
34
35
36
40
43
44
45
46
48
48
51
53
56
56
56
56
57
57
59
59
59
59
62
64
64
65
65
65
65
66
67
67
69
74
74
75
76
80
83
87
88
89
91
98
—
Respiratory conditions
Lead
in Lead Addi-
blood, in tional
mg/ urine, condi-
lOOg mg/I tions
0.004 Kidney
0.007
0.025 0.019
0.034 0.041
0.018 0.018
0.012
0.022
0.050 Kidney
0.046
0.041 Kidney
0.038 0.006
0.023
0.012
0.010
0.028 0.019
0.000
0.025
0.023
Kidney conditions
Lead
in Lead Addi-
blood, in tional
mg/ urine, condi-
lOOg mg/1 tions
0.022
0.028
0.014
0.013
0.010
0.028
0.009 Bone
0.023
0.024
0.013
0.054 0.027
0.022
0.025
0.011 Bone,
resp.
0.007 0.044
0.006
0.003
0.004
0.024
0.006
0.000 Heart,
bone
0.018
Bone
conditions
Lead
in Lead Addi-
blood, in tional
mg/ urine, condi-
lOOg mg/I tions
0.019
0.008
0.020
0.019
0.022
0.010
0.006
0.024
0.017
0.033
0.019
0.004
0.014
Liver
Heart,
resp.
Heart
Resp.
Heart,
resp.
75
-------
environment was obtained from the Philadelphia Police Department.
About 60 percent of these men were members of the foot traffic division,
who served on duty at busy intersections for not less than 5 years and
in many instances much longer. The remaining 40 percent were officers
engaged in patrol-car duty in the downtown section of the city. The
residences of the individual officers were situated in all areas of the city.
A second group consisted of 106 individuals who had lived and worked
within a 25-block radius of the Philadelphia City Hall for a minimum
of 5 years. A third group comprised 50 suburban commuters who had
lived in an outlying section of the city for at least 5 years and commuted
daily to work in the downtown Philadelphia area. Another group of 81
suburban subjects was made up of persons who had lived in the same
section of the city as the suburban commuters for at least 5 years,
but who normally spent their entire time in that neighborhood. A final
group of 75 consisted of subjects known to have chronic diseases of the
liver, kidney, bone, and lung, which might affect lead levels in blood
and urine. These individuals were outpatients at the Pennsylvania,
Philadelphia General, and Jefferson hospitals.
Results: Tables 38 and 39 show the frequency distributions of the
concentrations of lead in the blood and urine of the various groups.
As the area of residence shifts from the core of the city toward the
suburbs, concentrations of lead in the blood tend consistently downward.
TABLE 38
DISTRIBUTION OF SUBJECTS ACCORDING TO THE
CONCENTRATION OF LEAD IN BLOOD -PHILADELPHIA
Suburban Commuter Downtown
mg/lOOg Male Female Male Female Male Female Police
0 -0.009
0.010-0.019
0.020-0.029
0.030-0.039
0.040-0.049
6
14
3
14
39
2
3
5
17
16
4
1
1
5
1
2
12
37
12
3
4
24
9
3
0
17
70
22
4
Totals 23 58 43 7 66 40 113
Mean
Std. dev.
0.013
0.005
0.013
0.007
0.019
0.009
0.015
0.004
0.024
0.008
0.018
0.007
0.026
0.006
Levels for the downtown police group were slightly higher than for the
downtown males. With the exception of the suburban area, males show
higher levels of lead in their blood than comparable females.
76
-------
TABLE 39
DISTRIBUTION OF MALES ACCORDING TO
CONCENTRATION OF LEAD IN URINE-PHILADELPHIA
Lead in
urine,
mg/1
0 -0.009
0.010-0.019
0.020-0.029
0.030-0.039
0.040-0.049
0.050-0.059
0.060-0.069
0.070-0.079
0.080-0.089
Totals
Mean
Std. dev.
Suburban
5
4
7
1
1
1
19
0.020
0.014
Commuter
5
6
11
6
1
2
2
0
1
34
0.028
0.019
Downtown
3
12
12
13
8
4
> 0
1
53
0.030
0.015
Police
2
18
28
26
24
8
7
113
0.033
0.014
Table 40 presents the lead levels in the blood and urine of smokers
and nonsmokers in the population groups. In all groups except the
downtown females, mean values are slightly higher for smokers than
for nonsmokers. In all groups except suburban, levels are lower for
females than for male counterparts.
Lead levels in the blood and urine of the police group classified by
age are tabulated in Table 41. The lead levels in blood showed no trend
with age. Lead levels in urine decreased irregularly with age.
To quantitate the relationships among the various factors and the
concentrations of lead in the blood, an exact "weighted" analysis of
variance was performed on the cells of a four-factor cross-classification
based upon age, sex, smoking, and group. Before the analysis, data
obtained for downtown males and police were pooled, and all analytical
findings were transformed to logarithms to the base 10. The log-
transformation was performed because the frequency histograms were
more normally distributed when plotted on a logarithmic scale. A report
by Horiuchi and Takada supports the appropriateness of such a trans-
formation when dealing with probability statements about mean lead
concentrations in blood.31
77
-------
TABLE 40
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
SUBJECTS CLASSIFIED BY SMOKING HABITS-PHILADELPHIA
Lead in blood
Classification
Suburban
Males
Smokers
Nonsmokers
Females
Smokers
Nonsmokers
Commuter
Males
Smokers
Nonsmokers
Females
Smokers
Nonsmokers
Downtown
Males
Smokers
Nonsmokers
Females
Smokers
Nonsmokers
Police
Smokers
Nonsmokers
No. of
sub-
jects
23
14
9
58
22
36
43
33
10
7
4
3
66
55
11
40
29
11
113
83
30
Mean,
mg/
lOOg
0.013
0.015
0.011
0.013
0.016
0.011
0.019
0.021
0.013
0.015
0.018
0.012
0.024
0.025
0.022
0.018
0.018
0.018
0.026
0.026
0.024
Std.
dev.
0.005
0.005
0.006
0.007
0.008
0.006
0.009
0.008
0.006
0.004
0.004
0.003
0.008
0.008
0.008
0.007
0.007
0.006
0.006
0.007
0.005
Lead in urine
No. of
sub-
jects
19
12
7
34
26
8
53
43
10
113
83
30
Mean,
mg/1
0.020
0.026
0.009
0.028
0.029
0.027
0.030
0.030
0.029
0.033
0.034
0.028
Std.
dev.
0.014
0.014
0.005
0.019
0.021
0.016
0.015
0.015
0.012
0.014
0.015
0.013
TABLE 41
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF
POLICE CLASSIFIED BY AGE-PHILADELPHIA
Lead in blood
Age, years
20-29
30-39
40-49
50-59
60+
No. of
sub-
jects
17
56
29
10
1
Mean,
mg/
lOOg
0.027
0.027
0.024
0.027
0.021
Std.
dev.
0.006
0.006
0.006
0.008
Lead in urine
No. of
sub-
jects
17
57
29
9
1
Mean,
mg/1
0.039
0.032
0.034
0.030
0.025
Std.
dev.
0.013
0.014
0.015
0.011
78
-------
The results of this analysis are given in Table 42. The relationships
between the mean concentrations of lead in blood and both smoking
and composition of group were statistically significant, the relationship
between lead in blood and sex was of questionable significance; and that
with age, of no significance.
A more detailed comparison of males and females with respect to
lead concentrations was made with the Student's "t-test" in each group.
The tests were made separately for smokers and nonsmokers, after the
pooling of data pertinent to the various age groups. Several of the more
important tests are shown in Table 43. Only in the downtown groups
did the mean concentrations of lead in the blood of comparable groups
of males and females differ significantly.
The presence of an interaction effect for smoking and group as shown
in Table 42 reflects the overall pattern of results with regard to these
variables. In the male downtown groups, area of activity is associated
with higher concentrations of lead in the blood, and there is no detect-
able association with smoking. Among the suburban groups, smoking
is associated with higher concentrations of lead in the blood. Smoking
affects both suburban commuters and suburban noncommuters.
Commuting has no effect on nonsmokers, but a combination of com-
muting and smoking has a greater effect than smoking alone.
This pattern can be explained by the assumption that the smoking-
associated effect is, on the average, of equal magnitude among the
groups, and therefore of decreasing relative significance as the concen-
tration of lead in the blood increases. The urban-associated effect,
however, increases in magnitude and in relative significance as one
progresses toward the core of the city, where the average concentration
of lead in the blood is highest.
In addition to samples from the population groups already discussed,
blood (and some urine) specimens from several groups of patients from
a dispensary in Philadelphia were analyzed. These patients were
selected because they suffered from certain types of chronic illnesses.
The results are presented in Table 44. Neither the ranges nor mean
levels of lead in the blood from the four disease groups are remarkably
high or low.
Discussion of Biological Investigations in the Three Cities
In the combined data here reported, concentrations of lead in the
blood were determined for a total of 2,342 individuals. Of these, 2,216
were normal individuals, and 126 were selected patients with various
chronic diseases. Of the normal population group, 478 had been studied
in a previous survey in Cincinnati in 1956, and 211 had been examined
during pilot studies in California. Of this number, only 11 persons were
found to have concentrations of lead in the blood equal to or in excess
of 0.06 milligrams per 100 grams of blood. Five of these results were
79
-------
TABLE 42
ANALYSIS OF VARIANCE TO DETERMINE WHETHER SIGNIFICANT DIFFERENCES OCCUR
IN THE MEAN LEVELS OF LEAD IN BLOOD OF SELECTED GROUPS IN PHILADELPHIA
Effects
Main effects:
H = Smokers vs nonsmokers
A = Between age groups
G = Between groups
S = Males vs females
Two-factor interaction effects:6
H,A
H,G
H,S
A,G
A,S
G,S
Sum of
squares
0.437396
0.016660
1.560629
0.118630
0.001708
0.294352
0.019714
0.105994
0.106398
0.045606
Degrees of
freedom
1
2
2
1
2
2
1
4
2
2
Variance
0.437396
0.008330
0.780315
0.118630
0.000854
0.147176
0.019714
0.026476
0.053199
0.022803
F-ratio
14.02
0.27
25.01
3.80
0.03
4.72
0.63
0.85
1.70
0.73
Significance
level
1% 10%
yes yes
yes yes
yes
yes yes
aAn interaction between two factors measures the variability of the effect of the first factor among levels of the other factor.
-------
TABLE 43
COMPARISON OF MEAN CONCENTRATIONS OF LEAD IN BLOOD
BY USE OF STUDENTS' "t-TEST"-PHILADELPHIA
(IN MILLIGRAMS OF LEAD PER 100 GRAMS OF BLOOD)
Police downtown
(Male)
Female
Average
Suburban commuter
(Male and female)
Suburban
(Male and female)
Average
Smokers
(1) 0.0245*
(4) 0.0167
["t" (1, 4) = 5.53=
(1), (4) are not
averageable]
(7) 0.0186
(9) 0.0141
["t" (7, 9) = 2.28=
(7), (9) are not
averageable]
Nonsmokers
(2) 0.0226
(5) 0.0182
["t" (2, 5) = 1.83=
(2), (5) are not
averageable]
(8) 0.0117
(10) 0.0101
["t" (8, 10) = 0.91b
(8), (10) are
averageable]
Average = 0.0105
Average
(3) 0.0240
["t" (1, 2) = 1.34b
(1), (2) are averageable]
(6) 0.0171
["t" (4, 5) = 0.64b
(4), (5) are averageable]
["t" (7, 8) = 2.80=
(7), (8) are not
averageable]
["t" (9, 10) = 2.80=
(9), (10) are not averageable]
oo
^Concentrations indicated are geometric means.
b"t-Test" does not show a difference between (x) and (y) at the 10% level of significance.
="t-Test" does show a difference between (x) and (y) at the 10% level.
-------
00
to
TABLE 44
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF SELECTED
CHRONIC-DISEASE PATIENTS-PHILADELPHIA
Sex
M
F
F
F
F
M
F
F
F
M
M
M
M
F
F
M
M
M
F
Age,
yr
14
18
20
23
28
29
34
35
36
36
37
38
41
42
42
42
42
43
49
Respiratory conditions
Lead Lead
in blood, in urine,
mg/lOOg mg/1
0.014
0.011
0.016
0.052
0.034 0.031
Kidney conditions
Lead Lead
in blood, in urine,
mg/lOOg mg/1
0.022
0.027
0.021
0.009
0.019 0.049
0.019
0.012
0.021 0.053
0.011
Bone conditions Liver conditions
Lead Lead Lead Lead
in blood, in urine, in blood, in urine,
mg/lOOg mg/1 mg/lOOg mg/1
0.017
0.043 0.014
0.021 0.031
0.025
0.020
-------
TABLE 44 Continued
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF SELECTED
CHRONIC-DISEASE PATIENTS-PHILADELPHIA
Sex
M
M
M
M
F
M
M
F
M
M
M
F
M
M
M
F
M
M
M
Age,
yr
50
50
50
51
52
54
55
55
55
56
57
57
58
58
59
59
60
60
61
Respiratory conditions
Lead Lead
in blood, in urine,
mg/lOOg mg/1
0.020 0.022
0.040
0.017
0.056
0.015 0.014
0.037 0.004
0.036
0.037
Kidney conditions Bone conditions Liver conditions
Lead Lead Lead Lead Lead
in blood, in urine, in blood, in urine, in blood,
mg/lOOg mg/1 mg/lOOg mg/1 mg/lOOg
0.029
0.049
0.026
0.010
0.013 0.015
0.018
0.016
0.020a
0.015
0.022
0.015
Lead
in urine,
mg/1
0.012
0.046
0.025
0.011
0.020
0.010
-------
00
TABLE 44 Continued
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF SELECTED
CHRONIC-DISEASE PATIENTS-PHILADELPHIA
Sex
M
M
F
F
F
F
M
M
M
M
M
M
F
F
M
F
M
M
M
Age,
yr
61
62
62
63
63
64
64
66
66
67
68
68
68
68
68
69
69
71
72
Respiratory conditions
Lead Lead
in blood, in urine,
mg/lOOg mg/1
0.029
0.016 0.003
0.021
0.019 0.031
0.020
0.012
0.018 0.020
0.018 0.023
0.012b 0.006b
Kidney conditions Bone conditions Liver conditions
Lead Lead Lead Lead Lead Lead
in blood, in urine, in blood, in urine, in blood, in urine,
mg/lOOg mg/1 mg/lOOg mg/1 mg/lOOg mg/1
0.014 0.013
0.018
0.010
0.023
0.021
0.027
0.027
0.030
0.020
0.016
-------
TABLE 44 Continued
CONCENTRATIONS OF LEAD IN BLOOD AND URINE OF SELECTED
CHRONIC-DISEASE PATIENTS-PHILADELPHIA
Sex
M
F
M
M
M
M
M
M
F
F
F
M
F
F
M
M
M
M
F
Mean
Age,
yr
72
72
72
72
72
73
73
75
77
78
78
78
79
79
80
80
80
81
87
Respiratory conditions
Lead Lead
in blood, in urine,
mg/lOOg rng/1
0.014
0.014
0.042
0.022 0.041
0.027
0.024
Kidney conditions
Lead Lead
in blood, in urine,
mg/lOOg mg/1
0.031
0.012
0.019
0.018
Bone conditions Liver conditions
Lead Lead Lead Lead
in blood, in urine, in blood, in urine,
mg/lOOg mg/1 mg/lOOg mg/1
0.018 0.007
0.017
0.023
0.022
0.012
0.022 0.005
0.014
0.010
0.016
0.022
0.023
0.019 0.023
00
en
aPatient also suffering from lung condition.
bPatient also suffering from kidney condition.
-------
obtained in Cincinnati in the survey of 1956 (four garage mechanics
and one parking attendant), two in Cincinnati in the present survey
(one traffic policeman and one post-office employee), and four in Los
Angeles (male employees of an aircraft manufacturer). These 11 persons
were from groups which had an opportunity for occupational exposure
to lead. A small percentage of values equal to or in excess of 0.006 is
to be expected in such groups. An additional 30 persons (25 garage
mechanics, 1 post office employee, 2 service station attendants, and 2
employees of an aircraft manufacturer) had concentrations of lead in
the blood between 0.05 and 0.06. Again most of these individuals were
from groups with potential occupational exposure to lead.
Levels of lead were determined in the urine of 1,663 males in the
group of 2,342 individuals. These urine values fall within the fairly
narrow range that is defined presently as "normal." Of the highest
values, 11 were equal to or in excess of 0.08 milligram per liter and
23 were equal to or in excess of 0.07.
Levels of lead in the blood were analyzed in relation to a number of
variables. In relation to the geographic location of residence and place
of work, the Philadelphia data show an increasing gradation of the levels
of lead in the blood from the suburban through the commuter to the
urban group. The rural group examined in the California pilot study
shows the lowest levels. In the Cincinnati and Los Angeles groups, no
notable gradation in relation to geographic location is apparent. In
addition, the Los Angeles data show no relation between lead levels
and commuting time. This aspect was not examined in the other two
cities.
Within the study groups selected, particularly in Cincinnati, several
occupational groups are included that were selected because of their
probable exposure at work to high levels of automobile exhaust.
Policemen were examined in all three cities, and commercial drivers
and parking attendants were included in the Cincinnati study. In ad-
dition, garage mechanics, who as a group are exposed to lead in a variety
of ways other than that derived from automobile exhaust, were in-
vestigated again as they had been in previous surveys in Cincinnati.
All of these groups showed levels of lead in blood and urine that were
higher than those found in the blood and urine of persons in ordinary
occupations. This was evident in the garage mechanics in particular, and
in a small group of parking attendants. In Los Angeles and Cincinnati,
policemen concerned with traffic direction at busy intersections showed
somewhat higher levels of lead than other police. Aside from the specific
occupational categories given above, the mean concentrations of lead
showed no correlation with occupational histories obtained from all
individuals in Los Angeles and Cincinnati. There was also no evidence
of a relationship between the lead levels and specific items in'the
medical histories.
86
-------
The possibility of a relationship between the lead levels and age
was examined in two groups in Cincinnati and one in Philadelphia. No
relationship was found. The levels of lead in the urine of Philadelphia
police show some tendency to decline in the older age groups. The values
here are small, and the trend is opposite to that which would be expected
if any accumulation were occuring with age.
With one exception (suburban Philadelphia), the levels of lead in the
blood of females are slightly lower than those found in comparable
males. Nothing in these data, e.g., smoking or work, suggests an ex-
planation for this observation. The differences are not great, but are
remarkably consistent. These studies were not designed to investigate
this particular problem. Special studies to determine whether such dif-
ferences are due to intrinsic or extrinsic factors would be desirable.
These studies provide some information about the variable of smok-
ing, although again, they were not designed to examine this factor
specifically. The limited material available indicates that further exam-
ination of this problem must be designed especially for this purpose.
In nearly all instances smokers showed slightly higher lead levels than
nonsmokers. The small amount of information obtained on type and
amount of smoking was insufficient to yield conclusions.
These observations show several interesting gradations, even though
the values are well within the presently accepted normal range of lead
levels in humans. The levels of lead in blood tend to increase gradually
as the place of residence and work varies from rural to central urban
areas. A second gradation is found in relation to increasing opportunity
for occupational exposure to exhausts of automobiles. All of these varia-
bles — sex, smoking habits, and exposure to automobile exhaust, appear
to be independent of each other.
In Philadelphia and Los Angeles selected groups of patients ill with
chronic disease of the lungs, bones, kidneys and liver, were examined
to determine the level of lead in the blood. This was done to ascertain
whether there was evidence of unusually high or low levels in any of
these diseased groups that would indicate the need, for further study.
No unusual findings were obtained.
In the course of these investigations, some actually or potentially
pertinent factors were not examined in detail. The most important, as
discussed previously in this report, are lead intakes in food and in
water. These could logically influence the minor differences observed
in the levels of lead in the blood and urine.
In addition, the size of the particle of airborne lead and the seasonal
variations in the metabolism of lead were not examined.
87
-------
RELATION OF BIOLOGICAL FINDINGS TO
ATMOSPHERIC RESULTS
One of the objectives of this study was to ascertain whether detectable
differences exist in the lead content of blood and urine of people who
are subject to exposure of different concentrations of lead in the. atmo-
sphere.
The difficulties in assessing a relationship of this nature were described
in earlier portions of this report. In its simplest form the problem is to
determine: (1) whether variations such as were found in the lead con-
tent of the blood and urine are due to variations in the concentration
of lead in the atmosphere or to variations in the quantities ingested in
food and beverages or a combination of these two variables, and (2)
how the composite respiratory exposure to lead for a mobile population
can be determined. If only random population groups were considered,
differences in the mean concentrations of lead in blood and urine could
not be ascribed either to ingestion or inhalation. In this investigation,
however, random selections were not made. Some 25 male population
groups were selected with respect to their supposed exposure to varying
concentrations of atmospheric lead.
Table 45 shows the male groups for which values of lead in the blood
were obtained. The groups are arranged in order of their mean values of
lead in blood. There is about a four-fold difference (0.009 to 0.038 mg
Pb/lOOg blood) in these values, and there appears to be an orderly
progression in values according to the most likely concentration of lead
in the atmosphere to which these groups were exposed. For example,
the lowest concentrations were found in the suburban and rural groups;
intermediate concentrations, in the downtown employees; and the high-
est concentrations were found among drivers of cars and parking
attendants.
Although some of these groups, such as garage mechanics, service
station attendants, and refinery handlers of gasoline, are exposed to
lead in their occupations as well as to lead in the atmosphere, they are
listed in Table 45 to show comparative levels of lead in the blood. Also
the possibility that the variability of the amounts of lead ingested with
food and beverages accounts for some of the differences cannot be
ignored. It is important to recognize that the differences between the
lowest and the highest of the groups, while relatively large, are well
within the presently accepted range of lead levels for humans and are not
significant in terms of a threat of the occurrence of lead intoxication
within the groups.
88
-------
TABLE 45
SUMMARY OF CONCENTRATIONS OF LEAD IN BLOOD
OF SELECTED GROUPS OF MALES3
Mean, No. of
mg/lOOg Subjects Identity of Group
0.011 9 Suburban nonsmokers, Philadelphia
0.012 16 Residents of rural California county
0.013 10 Commuter nonsmokers, Philadelphia
0.015 14 Suburban smokers, Philadelphia
0.019 291 Aircraft employees, Los Angeles
0.019 88 City employees, Pasadena
0.021 33 Commuter smokers, Philadelphia
0.021 36 City Health Dept. employees, Cincinnati
0.021 155 Policemen, Los Angeles
0.022 11 Live and work downtown, nonsmokers, Philadelphia
0.023 140 Post-office employees, Cincinnati
0.024 30 Policemen, nonsmokers, Philadelphia
0.025 191 Firemen, Cincinnati
0.025 123 All policemen, Cincinnati
0.025 55 Live and work downtown, smokers, Philadelphia
0.026 83 Police, smokers, Philadelphia
0.027 86 Refinery handlers of gasoline, Cincinnati (1956)
0.028 130 Service station attendants, Cincinnati (1956)
0.030 40 Traffic police, Cincinnati
0.030 60 Tunnel employees, Boston
0.031 17 Traffic police, Cincinnati (1956)
0.031 14 Drivers of cars, Cincinnati
0.033 45 Drivers of cars, Cincinnati (1956)
0.034 48 Parking lot attendants, Cincinnati (1956)
0.038 152 Garage mechanics, Cincinnati (1956)
1877 Total
"Values are those determined in the present study, except where otherwise indicated.
89
-------
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91
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92
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APPENDIX
WORKING GROUP ON LEAD CONTAMINATION
W. A. Burhouse, American Petroleum Institute (1964-65)
L. C. Burroughs, American Petroleum Institute (1961-64)
V. J. Castrop, Automobile Manufacturers Association (1960-65)
D. R. Diggs, Ph.D., E. I. du Pont de Nemours and Company (1962-65)
N. V. Hendricks, Esso Research and Engineering Co. (1960-61)
Donald Hofreuter, M.D., Public Health Service (1960-61)
H. E. Hesselberg, Ethyl Corporation (1960-65)
R. A. Kehoe, M.D., Kettering Laboratory (1960-65)
J. H. Ludwig, Sc.D., Chairman, Public Health Service (1960-65)
J. A. Maga, California State Dept. of Public Health (1960-65)
R. 0. McCaldin, Ph.D., Public Health Service (1961-65)
M. R. Plancey, M.D., American Petroleum Institute (1963-65)
C. L. Samuelson, M.D., American Petroleum Institute (1961-63)
B. M. Sturgis, Ph.D., E. I. du Pont de Nemours and Company (1960-62)
TASK GROUPS
TASK GROUP ON SAMPLING, ANALYTICAL
METHODS AND REFERENCING SERVICE
Jacob Cholak, Kettering Laboratory (1960-65)
R. G. Keenan, Public Health Service (1960-65)
J. B. Pate, Chairman, Public Health Service (1960-61)
E. C. Tabor, Chairman, Public Health Service (1961-65)
G. J. Taylor, California State Dept. of Public Health (1960-65)
H. L. Helwig, Ph.D., California State Dept. of Public Health (1961-1963)
TASK GROUP ON COMPREHENSIVE URBAN STUDIES
Jacob Cholak, Chairman, Kettering Laboratory (1960-65)
N. V. Hendricks, Esso Research and Engineering Co. (1960-61)
R. O. McCaldin, Ph.D., Public Health Service (1960-65)
G. J. Taylor, California State Dept. of Public Health (1960-65)
Charles Xintaras, Public Health Service (1960-62)
TASK GROUP ON MEDICAL STUDIES
J. R. Goldsmith, M.D., California State Dept. of Public Health (1960-65)
Donald Hofreuter, M.D., Public Health Service (1960-61)
R. Ji. M. Horton, M.D., Public Health Service (1962-65)
R. A. Kehoe, M.D., Kettering Laboratory (1960-65)
J. N. Miranda, M.D., Public Health Service (1961-63)
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EDITORIAL TASK GROUP
D. R. Diggs, Ph.D., E. I. du Pont de Nemours and Company (1962-65)
J. A. Maga, California State Dept. of Public Health (1962-65)
R. O. McCaldin, Ph.D., Chairman, Public Health Service (1962-65)
TASK GROUP ON DATA ANALYSIS
R. I. Larsen, Ph.D., Public Health Service (1960-65)
Theodore Sterling, Ph.D., Kettering Laboratory (1960-65)
C. E. Zimmer, Public Health Service (1960-65)
K. A. Busch, Public Health Service (1962-65)
94
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BIBLIOGRAPHIC: Survey of Lead in the Atmosphere of
Three Urban Communities. PHS Publ. No. 999-AP-12.
Jan. 1965. 94 pp.
ABSTRACT: A study of the concentrations of lead in
the atmospheres of Cincinnati, Los Angeles, and
Philadelphia was conducted jointly by industrial,
State, Federal, and university groups during the period
June 1961 through May 1962. In each city, from four
to eight sampling stations, representing four geograph-
ical and land-use classifications (rural, residential, com-
mercial, and industrial) were operated continuously
with membrane filter samplers. In addition, at one
station of each classification in each city, diurnal varia-
tions were investigated by use of sequential tape sam-
plers. In each city samples of blood and urine were
obtained from selected groups of residents and exam-
ined for concentrations of lead. All samples were ana-
lyzed by the dithizone method. Approximately 3,400
samples of particulate lead from the atmosphere were
obtained, and the concentrations of lead in blood of
approximately 2,300 individuals and of lead in urine
of 1,700 males were determined. Details of the study
and the results obtained are reported.
ACCESSION NO.
KEY WORDS:
BIBLIOGRAPHIC: Survey of Lead in the Atmosphere of
Three Urban Communities. PHS Publ. No. 999-AP-12.
Jan. 1965. 94 pp.
ABSTRACT: A study of the concentrations of lead in
the atmospheres of Cincinnati, Los Angeles, and
Philadelphia was conducted jointly by industrial,
State, Federal, and university groups during the period
June 1961 through May 1962. In each city, from four
to eight sampling stations, representing four geograph-
ical and land-use classifications (rural, residential, com-
mercial, and industrial) were operated continuously
with membrane filter samplers. In addition, at one
station of each classification in each city, diurnal varia-
tions were investigated by use of sequential tape sam-
plers. In each city samples of blood and urine were
obtained from selected groups of residents and exam-
ined for concentrations of lead. All samples were ana-
lyzed by the dithizone method. Approximately 3,400
samples of particulate lead from the atmosphere were
obtained, and the concentrations of lead in blood of
approximately 2,300 individuals and of lead in urine
of 1,700 males were determined. Details of the study
and the results obtained are reported.
ACCESSION NO.
KEY WORDS:
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