United States
Environmental Protection
Agency
March 1979
Office of
Public Awaseness
Washington DC 20460
OPA 54/8
Air
Pollution
and
Your Health
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The air you breathe can sometimes
make you sick, even kill you.
People have known for centuries
that air could carry poisons. Metal
workers succumbed to smelter fumes.
Hatmakers often became irrational
from breathing the mercury they used
in making felt (hence the phrase "mad
as a hatter"). Miners took caged birds
into the coal pits; if the/birds died the
men knew the air contained deadly
gases they could not smell.
These are examples of bad air in a
particular workplace or occupation.
The general poisoning of the arnbient,
or surrounding, air did not occur until
after the industrial revolution, when
concentrations of factories and
chimneys began pouring vast quan-
tities of smoke, soot, and combustion
gases into the air of certain cities.
When windless, stagnant weather
allowed these pollutants to accumulate
in one area for several days in succes-
sion, the damage could be disastrous,
with thousands of persons made sick
and scores or even hundreds of
deaths.
Such acute episodes of air pollution
were at first blamed on "smog," a
word coined from smoke and fog. We
now know that fog — visible water
vapor — had little to do with wide-
spread sickness. Fog just coincided
with the weather conditions that
trapped the pollution from smoke-
stacks and chimneys.
'In recent years most air pollution
episodes have been associated with
automobiles as well as industry. Smog
has come to mean the thick haze that
often blankets big cities and is clearly
visible from a distance. This smog is
made up mainly of photochemical ox-
idants, a kind of pollution that is
formed in air from auto exhausts and
industrial emissions by chemical reac-
tions spurred by sunlight. Acute cases
of this kind of smog have occurred in
urban areas throughout the country —
Los Angeles, Denver, Chicago, Bir-
mingham, Pittsburgh, New York, and
St. Louis — where both autos and in-
dustry are concentrated. Episodes can
also occur in areas like Washington,
D.C.; St. Petersburg, Fla.; and
Phoenix, Ariz.; where there is little in-
dustry and autos are mainly respon-
sible for the pollution.
If a Lot Can Hurt, a Little Won't Help
If high levels of air pollution can cause
marked increases in sickness and
deaths, it is reasonable to think that
lower, less acute pollution can also be
harmful to health. Thousands of scien-
tific and medical studies in recent years
have shown positive relations .bettveen
air pollution and increases in respira-
tory ailments, heart disease, and
cancer. Just what rgljjTpollutants play
in making people sick is not yet fully
understood; no single disease but a
mixture of ailments is involved, and
pollutants usually occur in varying
combinations, rather than one at a
time.
The human body is a complicated
organism. Individuals vary widely in
their reactions to bodily stress. They
also vary widely in occupations and
habits that help determine the amounts
of pollution they are exposed to. Many
people breathe extra pollution at their
jobs, and many breathe the polluting
smoke of ciaarettes, their own or
Despfi& these handicaps, scientists
have established that air pollution does
harm hum40;health. They have done
this by mean's of three kinds of
studies:
Epidemiological research. This com-
pares pollution levels with health statis-
tics: hospital admissions, the number
and severity of illnesses, and death
rates. Many strong correlations have
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been found, that is, effects increase
when pollution increases, decrease
when pollution levels go down.
Animal experiments. In the labora-
tory, controlled amounts of air pollu-
tion have been found to harm
monkeys, dogs, rats, and other experi-
mental animals. There is a strong pre-
sumption that whatever make rats and
monkeys sick will do the same for
people.
Human experiments. Studies with
human volunteers also show adverse
effects from breathing polluted air in
Who Gets Sick and How
controlled situations, as in the U.S.
Environmental Protection Agency's
Health Effects Research Laboratory in
North Carolina. However, such tests
are comparatively rare and are usually
limited to young, healthy subjects and
to exposures involving no risks known
to be serious.
Clinical experience with persons ac-
cidentally exposed to high levels of air
pollution has added a lot to our knowl-
edge of pollution's health effects, but
such cases are not, strictly speaking,
scientific experiments.
The gist of the scientific studies and
the clinical evidence can be summed
up briefly. Air pollution is related to
human sickness and sometimes to
premature death. People of both sexes
and all ages can be affected, but the
danger is greatest for the very old and
the very young and people already sick
with certain chronic ailments.
Air pollution probably causes and
certainly aggravates:
• Disease of the respiratory (breath-
ing) system: nose, sinuses, throat,
bronchial tubes, and lungs. All these
organs have direct contact with
breathed-in air.
• Diseases of the heart and blood
vessels. Pollutants can pass through
the lung membranes into the blood.
• Cancer, especially of the lungs.
Airborne cancer-causing agents can
enter the body through the skin as well
as the lungs and be carried by the
blood to any organ. '...••"
• Skin diseases, allergies, eye irrita-
tion.
No one is free from air pollutants.
Since we all must breathe the ambient
air, everyone is exposed to some
degree. Those who live in or near big
cities are likely to have more exposure,
because heavy automobile traffic and
polluting industrial plants tend to be
concentrated in these areas. Those
who can least afford to move away
from urban areas to avoid dirty air are
the urban poor and old people living
on fixed incomes.
But pollution can affect the middle
classes and the well-to-do as well as
the poor, the young and healthy as
well as the old and sick, residents of
suburbs and rural areas as well as
cities.
Large masses of polluted air can drift
with prevailing winds from the cities
where they were formed to cause dis-
comfort and health risks to people far
away. Connecticut is frequently
polluted by air drifting from New York
City and northern New Jersey. Los
Angeles smog regularly moves east-
ward to affect people in Riverside, 50
miles away, and to damage trees in the
San Bernardino Mountains. EPA scien-
tists have traced "plumes" of air pollu-
tion from St. Louis that are still intact
and measurable 100 miles away over
southern Illinois.
Controlling or reducing air pollution
is obviously a problem that cannot be
solved by State or local action alone.
Pollution is no respecter of political
boundaries.
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**
Chest X-ray shows how lung damaged by emphysema is much larger than normal lung
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What Is Being Done?
By Federal law, Congress has charged
the U.S. Environmental Protection
Agency (EPA) with responsibility for:
• Determining what kinds of air
pollutants are hazardous to public health
and welfare,
• Setting standards for each, and
• In cooperation with the States,
enforcing adherence to these stan-
dards.
The law is called the Clean Air Act.
It was passed by Congress in 1970 as
amendments to previous legislation
that had provided assistance to States
and research funding in air pollution
abatement. It was amended again and
strengthened in 1977.
Under the law, EPA in 1971 desig-
nated six kinds of air pollutants to be
controlled and set limits for each type
in the ambient air. The six were judged
to be the most pervasive and the most
in need of immediate reduction and
control. A seventh standard — for air-
borne lead — was adopted in 1978. All
of them, with their principal sources
and their effects on human health, are
described in the final section of this
pamphlet, starting on page 7.
The law provides for two kinds of
standards: "primary," to protect
human health, and "secondary," to
protect welfare and property. Only two
of the seven pollutants, sulfur oxides
and particulates, have secondary stan-
dards that are different from the
primary ones. For all other pollutants
EPA has set identical primary and
secondary standards.
Each air quality standard is based on
a careful survey of the scientific and
medical studies that have been made
of that pollutant's effects. Summaries
of these surveys, called "criteria docu-
ments," are published by EPA so that
the public may know the basis for the
standard.
In addition, the law provides for
special curbs on the emission into the
air of hazardous substances that are
associated with disease risks at rela-
tively low concentrations. Hazardous
substances designated so far are
asbestos, mercury, beryllium, vinyl
chloride, and benzene.
The 1977 Amendments to the Clean Air Act
The 1970 Act set as a goal the general
attainment of the health-protecting
primary standards by July 1975. That
date came and went without the goal
being universally reached. At many
monitoring sites the standards were
being exceeded with considerable
regularity, though less often than they
had in the past. This did not come as a
surprise to EPA and State officials.
Soon after the Act's enforcement ef-
forts got under way, officials realized
that it was not possible to meet the
Act's goal in every area that soon.
In the Clean Air Act Amendments of
1977 Congress set new deadlines: as
expeditiously as possible but not later
than 1982, for general attainment of
the primary standards. This provided a
more realistic target.
A further extension of the deadline,
to 1987, was provided for two pollu-
tants most closely related to transpor-
tation systems, carbon monoxide and
ozone (photochemical oxidants).
States are required to inventory all
sources of air pollution in "nonattain-
ment" areas, those that exceed the
standards. And States must draft and
carry out abatement plans in a more
methodical manner, making full use of
past experience and the management
methods that have proved to be effec-
tive.
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Keeping Track of Air Pollution
A nationwide network of monitoring
stations, established by EPA and the
States, measures pollution levels
regularly and feeds the information to
official centers for tabulation and
analysis. Under certain conditions,
readings may be taken several times a
day, or even hourly.
There are two purposes for such
reporting:
• For research on air pollution
trends, to determine if we are reducing
pollution of a certain kind, and if so
how much.
• To warn people whenever pollu-
tion in any locality is reaching
dangerous levels.
It is now common practice to in-
clude air pollution conditions in the
weather reports given several times
each day on radio and television broad-
casts and in newspapers. EPA scien-
tists have devised a pollution standards
index (PSD that indicates the degree of
health hazard from any one pollutant
or from any combination of two or
more. This is expressed by a single
number that is keyed to the actions
recommended for people to take to
minimize their exposure to the hazard.
The PSI rating has been adopted by
about half the States and is soon ex-
pected to become a nationwide,
uniform, warning system.
Physician attends a patient hospitalized with lung disease ascribed to inhaling iron mine dust
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Summing Up
The adverse health effects of air pollu-
tion are widespread and costly even
though they cannot be measured
precisely and recorded in a ledger.
Sickness means increased costs for
medical care, hospitalization, and
drugs. Time lost by wage earners is a
debit to the persons involved and to
the national economy. Dollar values
can be estimated for the loss of clean
air's amenities, unobscured views,
more enjoyable surroundings.
All these costs add up to a substan-
tial, though imprecise, sum. The Amer-
ican Lung Association, after surveying
23 studies made in a ten-year period by
government, industry, and university
scientists and economists, concluded
that a reasonable estimate of the
health cost of polluted air in the United
States is more than $10 billion per
year.
The air quality standards are still be-
ing exceeded in many parts of the
country, but the number of violations
is steadily going down. There is still a
long way to go before we succeed, but
improvements are already apparent.
This is due to emission controls on
autos, stack gas controls and process
improvements by industry, and an in-
creased awareness by everyone that
people have a right to breathe clean
air.
Cities bring polluting vehicles and people together; this is mid-town Manhattan
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Principal Kinds of Air Pollution, Their Sources and Effects
Here are brief descriptions of the air
pollutants for which EPA standards
have been set, their principal sources,
and summaries of the adverse effects
of each on human health.
Sulfur oxides are gases that come
from the burning of sulfur-containing
fuel, mainly coal and oil, and also from
the smelting of metals and from certain
industrial processes. They have a dis-
tinctive odor. Sulfur dioxide (S02)
comprises about 95 percent of these
gases, so scientists use a test for S02
alone as a measure of all sulfur oxides.
As the level of sulfur oxides in air in-
creases, there is an obstruction of
breathing, a choking effect that doc-
tors call "pulmonary flow resistance."
The amount of breathing obstruction
has a direct relation to the amount of
sulfur compounds in the air. The effect
of sulfur pollution is enhanced by the
presence of other pollutants, especially
particulates and oxidants. That is, the
harm from two or more pollutants is
more than additive. Each augments the
other, and the combined effect is
greater than the sum of the parts
would be.
Many types of respiratory disease
are associated with sulfur oxides:
coughs and colds, asthma, bronchitis,
and emphysema. Some researchers
believe that the harm is mainly due not
to the sulfur oxide gases but to other
sulfur compounds that accompany the
oxides: sulfur acids and sulfate salts.
Particulates are solid particles or li-
quid droplets small enough to remain
suspended in air. They include dust,
soot, and smoke — particles that may
be irritating but are usually not
poisonous — and bits of solid or liquid
substances that may be highly toxic.
Particulates are measured all
together by filtering all the particles
from a known amount of air and
weighing them. The EPA standard for
particulates gives only a rough indica-
tion of the health hazard, since it does
not separate toxic particles from those
that are merely annoying. Research is
under way to find quick, economical
methods of measuring various kinds of
particles and also their sizes. The
smaller the particles, the more likely
they are to reach the innermost parts
of the lungs and work their damage.
The harm may be physical: clogging
the lung sacs, as in anthracosis, or
coal miners' "black lung" from inhaling
coal dust; asbestosis or silicosis in peo-
ple exposed to asbestos fibers or dusts
from silicate rocks; and byssinosis, or
textile workers' "brown lung" from in-
haling cotton fibers.
The harm may also be chemical:
changes in the human body caused by
chemical reactions with pollution par-
ticles that pass through the lung mem-
branes to poison the blood or be car-
ried by the blood to other organs. This
can happen with inhaled lead, cad-
mium, beryllium, and other metals, and
with certain complex organic com-
pounds that can cause cancer.
Many studies indicate that par-
ticulates and sulfur oxides (they often
occur together) increase the incidence
and severity of respiratory disease.
Carbon monoxide (CO) is a colorless,
odorless, poison gas formed when
carbon-containing fuel is not burned
completely. It is by far the most plenti-
ful air pollutant. EPA estimates that
more than 102 million metric tons of
CO are spewed into the air each year
in the United States. (A metric ton is
1,000 kilograms, or about 2,200
pounds.)
Fortunately this deadly gas does not
persist in the atmosphere. It is ap-
parently converted by natural pro-
cesses to harmless carbon dioxide, in
ways not yet understood, fast enough
to prevent any general buildup. But it
can reach dangerous levels in local
areas, as in city-street canyons with
heavy auto traffic and little wind. More
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than 75 percent of the CO emitted
comes from road vehicles.
Clinical experience with accidental
CO poisoning has shown clearly how it
affects the body. When the gas is
breathed, CO replaces oxygen in the
red blood cells, reducing the amount
of oxygen that can reach the body
cells and maintain life. Lack of oxygen
affects the brain, and the first symp-
toms are impaired perception and
thinking. Reflexes are slowed, judgment
weakened, and a person becomes
drowsy. An auto driver breathing high
levels of CO is more likely to have an
accident; an athlete's performance and
skill drop suddenly. Lack of oxygen
then affects the heart. Death can come
from heart failure or general asphyxia-
tion, if a person is exposed to very
high levels of CO.
Ozone is a poisonous form of pure ox-
ygen and the principal component of
modern smog. Until recently EPA
called this type of pollution "photo-
chemical oxidants." The name was
changed because ozone was the only
oxidant actually measured and by far
the most plentiful.
Ozone and other oxidants — includ-
ing peroxyacetal nitrates (PAN), for-
maldehydes, and peroxides — are not
emitted into the air directly. They are
formed by chemical reactions in the air
from two other pollutants, hydrocar-
bons and nitrogen oxides. Energy from
sunlight is needed for these chemical
reactions, hence the term photochemi-
cal smog, and the daily variation in
ozone levels, increasing during the day
and decreasing at night.
Ozone is a pungent-smelling, faintly
bluish gas. It irritates the mucous
membranes of the respiratory system,
causing coughing, choking, and im-
Steel plant pollution along the Monongo-
hela River spreads over downtown Pitts-
burgh, Pa.
paired lung function. It aggravates
chronic respiratory diseases like
asthma and bronchitis and is believed
capable of hastening the death, by
pneumonia, of persons in already
weakened health. PAN and the other
oxidants that accompany ozone are
powerful eye irritants.
It is an irony of nature that a form of
pure oxygen can be so harmful.
Regular oxygen (02, two atoms to the
molecule) gives life to all animals and
most plants; ozone (03, three atoms) is
poisonous.
Note: Ozone in the air we breathe
should not be confused with the so-
called "ozone layer" in the strato-
sphere. The stratosphere begins at an
altitude of seven to ten miles, depend-
ing on the latitude and the season of
the year. Ozone in this thin air absorbs
a large part of the sun's ultraviolet
radiation. Scientists believe that some
human actions — for instance, super-
sonic aircraft flights and the release of
fluorocarbon gases from spray cans —
could cause a permanent reduction in
stratospheric ozone. This could in-
crease the ultraviolet radiation reaching
the earth, raising the incidence of
human skin cancer and probably af-
fecting the earth's climate and
ecological systems in unpredictable
ways. The high ozone layer seems to
be maintained by natural processes,
mainly the sun's radiation. Lightning
discharges are the principal natural
source of ozone in the lower atmo-
sphere.
Nitrogen oxides. When any fuel is
burned at a high enough temperature
- above 650 °C (1,200°F) - some of
the abundant nitrogen in the air will
react too, forming poisonous, highly
reactive gases called nitrogen oxides.
Nitrogen dioxide (N02) is the most
plentiful of these and the one
measured to indicate all. It is a suf-
focating, brownish-colored gas and a
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strong oxidizing agent, quick to react
with water vapor to form corrosive
nitric acid.
Principal sources of nitrogen oxide
emissions are electric utility and in-
dustrial boilers (56%) and auto and
truck engines (40%.) •
Occupational health studies have
shown that nitrogen oxides can be
fatal at high concentrations. At lower
levels, they can irritate the lungs,
cause bronchitis and pneumonia, and
lower resistance to respiratory infec-
tions like influenza. However, the prin-
cipal harm to people seems to come
not from nitrogen oxides directly but
from the oxidants they help to form by
uniting in sunlit air with hydrocarbons
to make ozone and other ingredients of
photochemical smog.
N02 has been difficult to measure in
the ambient air. The first sampling and
analysis methods turned out to be
unreliable and were withdrawn as of-
ficial methods in 1973. After extensive
testing a reliable monitoring technique
was approved in 1976.
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Hydrocarbons are unburned fuels in
gaseous or vapor form. Gasoline, for
example, is a mixture of many kinds of
hydrocarbons, each containing more
than twice as many hydrogen atoms as
carbon atoms linked together in
molecules of many different sizes and
patterns.
Unlike sulfur and nitrogen oxides,
the vast family of hydrocarbons is not
measured by testing for a single com-
pound. Indeed, the simplest hydrocar-
bon, methane (CH4), that occurs in
swamps, coal mines, and natural gas,
Children play on street in North Birming-
ham, A/8., near pollution from industrial
plants
is excluded by the official testing
method; only more complex hydrocar-
bons that are highly reactive are
measured.
Most of the estimated 28 million
metric tons of hydrocarbons emitted
each year in the United States come
from gasoline vapors that escape burn-
ing in auto engines, either evaporating
from the tank or fuel lines or going out
the tail pipe. Other large sources are
gasoline stations, handlers, and trans-
porters; industries that use solvents;
and users of paint and drycleaning
fluids.
At the levels usually found in am-
bient air, hydrocarbons, as a class of
compounds, may have no direct effect
on human health. In a confined space,
of course, they could cause asphyxia-
tion by displacing the air, and some,
like benzene, can be hazardous in
themselves. A major problem with
hydrocarbons stems from the oxidants
they help to form by reacting with
nitrogen oxides in sunlight.
Lead. Particles of this metal or its
compounds enter the air from auto ex-
haust (tetraethyl lead, an anti-knock
agent in gasoline) and from industries
that smelt or process the metal. About
90% of all airborne lead is from autos.
Lead is absorbed into the body and
accumulates in bone and soft tissues.
Its most pronounced effects are on the
blood-forming, nervous, and kidney
systems, though it may also affect
other body functions. Young children
are especially susceptible to lead
poisoning.
The ambient air standard for lead
was adopted by EPA in 1978, seven
years after the other six standards.
11
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EPA Region 1 • JFK
Federal Bldg. • Boston
MA 02203 • Connec-
ticut, Maine, Massachu-
setts, New Hampshire,
Rhode Island, Vermont •
617-223-7210
EPA Region 2 • 26
Federal Plaza • New
York NY 10007 • New
Jersey. New York, Puer-
to Rico, Virgin Islands •
212-264-2525
EPA Region 3 • 6th
and Walnut Streets •
Philadelphia PA 19106
« Delaware, Maryland,
Pennsylvania, Virginia,
West Virginia, District of
Columbia • 215-597 9814
If you have suggestions, questions,
or requests for further information, they
may be directed to your nearest
EPA Regional public information office.
EPA Region 4 • 345
Courtland Street NE •
Atlanta GA 30308 •
Alabama, Georgia,
Florida, Mississippi,
North Carolina, South
Carolina, Tennessee,
Kentucky • 404-881-4727
EPA Region 5 • 230 S.
Dearborn • Chicago IL
60604 • Illinois, Indiana,
Ohio, Michigan, Wiscon-
sin, Minnesota •
312-353-2000
EPA Region 6 • 1201
Elm Street • Dallas TX
75270 • Arkansas, Loui-
siana, Oklahoma, Texas,
New Mexico •
214-7672600
EPA Region 7 • 324
East 11th Street •
Kansas City MO 64106
• Iowa, Kansas,
Missouri, Nebraska •
816-374-5493
EPA Region 8 • 1860
Lincoln Street •
Denver CO 80295 • Col-
orado, Utah, Wyoming,
Montana, North Dakota,
South Dakota •
303-837-3895
EPA Region 9 • 215
Fremont Street • San
Francisco CA 94105 •
Arizona, California,
Nevada, Hawaii, Guam,
American Samoa, Trust
Territories of the Pacific
• 415-556-2320
EPA Region 10 • 1200
Sixth Avenue • Seattle
WA 98101 • Alaska,
Idaho, Oregon, Washing-
ton • 206-442-1220
12
EPA is charged by Congress to protect the Nation's land, air and water
systems. Under a mandate of national environmental laws focused on air
and water quality, solid waste management and the control of toxic
substances, pesticides, noise and radiation, the Agency strives to formulate
and implement actions which lead to a compatible balance between human
activities and the ability of natural systems to support and nurture life.
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