Glossary
Air Toxics:
Synonym for "hazardous air pollutants." (See
below).
Ambient Air:
Any unconfined portion of the atmosphere: open
air,
surrounding air.
Benzene:
A colorless, volatile, flammable, toxic liquid
aromatic
hydrocarbon (C6H6) used in organic synthesis, as
a
solvent, and as a component of motor fuel.
Biomonitoring:
Analysis of blood, urine, tissues, etc., to
measure
chemical exposure in humans.
Carcinoma:
Cancer that begins in the tissues lining or
covering an
organ.
Carbon Monoxide (CO):
A colorless, odorless, poisonous gas
produced
by incomplete fossil fuel combustion.
Chromium:
A heavy metal that is an important hazardous air
pollutant. (See "heavy metals.")
Contaminant:
Any physical, chemical, biological, or
radiological
substance or matter in air, water, or soil that can have adverse
health
effects.
Criteria Pollutants:
The 1970 amendments to the Clean Air
Act
required EPA to set National Ambient Air Quality
Standards for certain pollutants known to be hazardous to human
health. EPA
has set standards to protect human health and welfare for six
pollutants: ozone,
carbon monoxide, total suspended particulates, sulfur dioxide, lead,
and
nitrogen oxides. The term "criteria pollutants" derives from the
requirement
that
EPA must describe the criteria-characteristics and potential health
and
welfare effects of these pollutants-for setting or revising
standards.
Deciliter:
One-tenth of a liter (0.1 liter).
Exposure:
Human contact with environmental contaminants or
concentrations of contaminants in media.
Media:
Specific environments-air, water, soil-that are the
subject
of regulatory concern and activities because of potential for human
exposure.
Environmental Tobacco Smoke:
Mixture of smoke exhaled by a
smoker
and the smoke from the burning end of the smoker's cigarette, pipe,
or
cigar.
Germ Cell Tumor:
A type of tumor found in the ovaries or
testicles.
Gonadal Tumor:
Tumor specific to the gonads.
Hazardous Air Pollutants:
Air pollutants that are not
covered by
ambient air quality standards but which, as defined in the Clean
Air Act, may
reasonably be expected to cause or contribute to irreversible
illness or
death. Such pollutants include asbestos, beryllium, mercury, benzene,
coke
oven emissions, radionuclides, and vinyl chloride. A total of 188
hazardous
air pollutants are listed in section 112(b) of the Clean Air Act,
as amended in
1990.
Heavy Metals:
Metallic elements with high atomic weights,
e.g.,
mercury, chromium, cadmium, arsenic, and lead; can damage living
things at low
concentrations.
Immunodeficiency:
Inability to produce a normal complement
of
antibodies or immunologically sensitized T cells, especially in
response to
specific antigens.
Ionizing Radiation:
Radiation that can strip electrons from
atoms,
i.e., alpha, beta, and gamma radiation.
Lymphoma:
Lymphomas are tumors in the lymph system, which
is
responsible for fighting diseases in the body and is part of the
immune system.
Lymphomas are the
third most common form of cancer in children.
Mercury:
A heavy metal that can bioaccumulate in the
environment and
is highly toxic if breathed or swallowed.
Methemoglobinemia:
The presence of excess methemoglobin in
the
blood, which replaces hemoglobin and results in loss of the ability
to
transport oxygen in the
blood. A small amount of methemoglobin is present in the blood
normally, but
injury or toxic agents, such as nitrites, convert a larger
proportion of
hemoglobin into methemoglobin.
Microgram (µg):
One-millionth of a gram.
Microorganisms:
Tiny living organisms that can be seen only
with the
aid of a microscope. Some microorganisms can cause acute health
problems when
consumed in drinking water.
Also known as microbes.
Mortality:
Death rate.
National Ambient Air Quality Standards (NAAQS):
Standards
established by EPA to protect human health
and the environment from criteria
pollutants, which apply for outside air throughout the nation.
Nitrogen Dioxide (NO2):
A chemical that results
from
nitric oxide combining with oxygen in the atmosphere; a major
component of
photochemical smog.
Ozone:
A gas that results from complex chemical reactions
between
nitrogen dioxide and volatile organic compounds; the major component
of smog.
Particulate Matter:
Particles in the air, such as dust,
dirt, soot,
smoke, and liquid droplets; may have significant effects on human
health.
Polychlorinated Biphenyls (PCBs):
A group of toxic,
persistent
chemicals used in electrical transformers and capacitors for
insulating
purposes, and in gas pipeline systems
as a lubricant. The sale and new use of PCBs were banned by law
in 1979.
Prenatal:
Occurring, existing, or performed before birth.
Radionuclides:
Radioactive isotopes or unstable forms of
elements.
Retinoblastomas:
Tumors of the eye.
Sulfur Dioxide (SO2):
A pungent, colorless, gaseous
pollutant formed
primarily by the combustion of fossil fuels.
Superfund:
The program operated under the legislative
authority of
the Comprehensive Environmental Response, Compensation and Liability
Act of
1980 (CERCLA)
that funds and carries out EPA solid waste emergency and long-term
removal and
remedial activities. These activities include establishing the National
Priorities
List, investigating sites for inclusion on the list, determining
their
priority, and conducting and/or supervising cleanup and other remedial
actions.
Trichloroethylene (TCE):
A stable, low boiling-point
colorless
liquid, toxic if inhaled. Used as a solvent or metal decreasing
agent, and in
other industrial applications.