A&I— Alternative and Innovative
(Wastewater Treatment System)
AA— Accountable Area; Adverse Action;
Advices of Allowance; Assistant Administrator;
Associate Administrator; Atomic Absorption
AAEE— American Academy of Environmental
AANWR— Alaskan Arctic National Wildlife
AAP— Asbestos Action Program
AAPCO— American Association of Pesticide
AARC— Alliance for Acid Rain Control
ABEL— EPA’s computer model for
analyzing a violator’s ability to pay
a civil penalty.
ABES— Alliance for Balanced Environmental
AC— Actual Commitment. Advisory Circular
A&C— Abatement and Control
ACA— American Conservation Association
ACBM— Asbestos-Containing Building Material
ACE— Alliance for Clean Energy
ACE— Any Credible Evidence
ACEEE— American Council for an Energy
ACFM— Actual Cubic Feet Per Minute
ACL— Alternate Concentration Limit.
Analytical Chemistry Laboratory
ACM— Asbestos-Containing Material
ACP— Agriculture Control Program (Water
Quality Management); ACP— Air Carcinogen
ACQUIRE— Aquatic Information Retrieval
ACQR— Air Quality Control Region
ACS— American Chemical Society
ACTS— Asbestos Contractor Tracking System
ACWA— American Clean Water Association
ACWM— Asbestos-Containing Waste Material
ADABA— Acceptable Data Base
ADB— Applications Data Base
ADI— Acceptable Daily Intake
ADP— AHERA Designated Person; Automated
ADQ— Audits of Data Quality
ADR— Alternate Dispute Resolution
ADSS— Air Data Screening System
ADT— Average Daily Traffic
AEA— Atomic Energy Act
AEC— Associate Enforcement Counsels
AEE— Alliance for Environmental Education
AEERL— Air and Energy Engineering Research
AEM— Acoustic Emission Monitoring
AERE— Association of Environmental and
AES— Auger Electron Spectrometry
AFA— American Forestry Association
AFCA— Area Fuel Consumption Allocation
AFCEE—Air Force Center for Environmental
AFS— AIRS Facility Subsystem
AFUG— AIRS Facility Users Group
AH— Allowance Holders
AHERA— Asbestos Hazard Emergency Response
AHU— Air Handling Unit
AI— Active Ingredient
AIC— Active to Inert Conversion
AICUZ— Air Installation Compatible Use
AID— Agency for International Development
AIHC— American Industrial Health Council
AIP— Auto Ignition Point
AIRMON— Atmospheric Integrated Research
AIRS— Aerometric Information Retrieval
AL— Acceptable Level
ALA— Delta-Aminolevulinic Acid
ALA-O— Delta-Aminolevulinic Acid Dehydrates
ALAPO— Association of Local Air Pollution
ALARA— As Low As Reasonably Achievable
ALC— Application Limiting Constituent
ALJ— Administrative Law Judge
ALMS— Atomic Line Molecular Spectroscopy
ALR— Action Leakage Rate
AMBIENS— Atmospheric Mass Balance of
Industrially Emitted and Natural Sulfur
AMOS— Air Management Oversight System
AMPS— Automatic Mapping and Planning
AMSA— Association of Metropolitan Sewer
ANC— Acid Neutralizing Capacity
ANPR— Advance Notice of Proposed Rulemaking
ANRHRD— Air, Noise, & Radiation
Health Research Division/ORD
ANSS— American Nature Study Society
AOAC— Association of Official Analytical
AOC— Abnormal Operating Conditions
AOD— Argon-Oxygen Decarbonization
AOML— Atlantic Oceanographic and Meteorological
AP— Accounting Point
APA— Administrative Procedures Act
APCA— Air Pollution Control Association
APCD— Air Pollution Control District
APDS— Automated Procurement Documentation
APHA— American Public Health Association
APRAC— Urban Diffusion Model for Carbon
Monoxide from Motor Vehicle Traffic
APTI— Air Pollution Training Institute
APWA— American Public Works Association
AQ-7— Non-reactive Pollutant Modelling
AQCCT— Air-Quality Criteria and Control
AQCP— Air Quality Control Program
AQCR— Air-Quality Control Region
AQD— Air-Quality Digest
AQDHS— Air-Quality Data Handling System
AQDM— Air-Quality Display Model
AQMA— Air-Quality Maintenance Area
AQMD— Air Quality Management District
AQMP— Air-Quality Maintenance Plan;
Air-Quality Management Plan
AQSM— Air-Quality Simulation Model
AQTAD— Air-Quality Technical Assistance
AR— Administrative Record
A&R— Air and Radiation
ARA— Assistant Regional Administrator;
Associate Regional Administrator
ARAC— Acid Rain Advisory Committee
ARAR— Applicable or Relevant and Appropriate
Standards, Limitations, Criteria, and Requirements
ARB— Air Resources Board
ARC— Agency Ranking Committee
ARCC— American Rivers Conservation Council
ARCS— Alternative Remedial Contract
ARG— American Resources Group
ARIP— Accidental Release Information
ARL— Air Resources Laboratory
ARM— Air Resources Management
ARNEWS— Acid Rain National Early Warning
ARO— Alternate Regulatory Option
ARRP— Acid Rain Research Program
ARRPA— Air Resources Regional Pollution
ARS— Agricultural Research Service
ARZ— Auto Restricted Zone
AS— Area Source
ASC— Area Source Category
ASDWA— Association of State Drinking
ASHAA— Asbestos in Schools Hazard Abatement
ASHRAE— American Society of Heating,
Refrigerating, and Air-Conditioning Engineers
ASIWCPA— Association of State and Interstate
Water Pollution Control Administrators
ASMDHS— Airshed Model Data Handling
ASRL— Atmospheric Sciences Research
AST— Advanced Secondary (Wastewater)
ASTHO— Association of State and Territorial
ASTM— American Society for Testing and
ASTSWMO— Association of State and Territorial
Solid Waste Management Officials
AT— Advanced Treatment. Alpha Track
ATERIS— Air Toxics Exposure and Risk
ATS— Action Tracking System; Allowance
ATSDR— Agency for Toxic Substances and
ATTF— Air Toxics Task Force
AUSM— Advanced Utility Simulation Model
A/WPR— Air/Water Pollution Report
AWRA— American Water Resources Association
AWT— Advanced Wastewater Treatment
AWWA— American Water Works Association
AWWARF— American Water Works Association
Abandoned Well— A well whose use has
been permanently discontinued or which is in
a state of such disrepair that it cannot be
used for its intended purpose.
Abatement— Reducing the degree or intensity
of, or eliminating, pollution.
Abatement Debris— Waste from remediation
Absorbed Dose— In exposure assessment,
the amount of a substance that penetrates an
exposed organism’s absorption barriers
(e.g. skin, lung tissue, gastrointestinal tract)
through physical or biological processes. The
term is synonymous with internal dose.
Absorption— The uptake of water , other
fluids, or dissolved chemicals by a cell or
an organism (as tree roots absorb dissolved
nutrients in soil.)
Absorption Barrier— Any of the exchange sites
of the body that permit uptake of various substances at different
rates (e.g. skin, lung tissue, and gastrointestinal-tract wall)
Accident Site— The location of an unexpected
occurrence, failure or loss, either at a plant
or along a transportation route, resulting in
a release of hazardous materials.
Acclimatization— The physiological and
behavioral adjustments of an organism to changes
in its environment.
Acid Aerosol— Acidic liquid or solid
particles small enough to become airborne. High
concentrations can irritate the lungs and have
been associated with respiratory diseases like
Acid Deposition— A complex chemical and
atmospheric phenomenon that occurs when emissions
of sulfur and nitrogen compounds and other substances
are transformed by chemical processes in the
atmosphere, often far from the original sources,
and then deposited on earth in either wet or
dry form. The wet forms, popularly called “acid
rain,” can fall to earth as rain, snow,
or fog. The dry forms are acidic gases or particulates.
Acid Mine Drainage— Drainage of water
from areas that have been mined for coal or
other mineral ores. The water has a low pH because
of its contact with sulfur-bearing material
and is harmful to aquatic organisms.
Acid Neutralizing Capacity— Measure
of ability of a base (e.g. water or soil) to
resist changes in pH.
Acidic— The condition of water or soil
that contains a sufficient amount of acid substances
to lower the pH below 7.0.
Action Levels— 1. Regulatory levels recommended
by EPA for enforcement by FDA and USDA when pesticide residues
occur in food or feed commodities for reasons other than the
direct application of the pesticide. As opposed to “tolerances” which
are established for residues occurring as a direct result of
proper usage, action levels are set for inadvertent residues
resulting from previous legal use or accidental contamination.
2. In the Superfund program, the existence of a contaminant concentration
in the environment high enough to warrant action or trigger a
response under SARA and the National Oil and Hazardous Substances
Contingency Plan. The term is also used in other regulatory programs.
Activated Carbon— A highly adsorbent form of carbon
used to remove odors and toxic substances from liquid or gaseous
emissions. In waste treatment, it is used to remove dissolved
organic matter from waste drinking water. It is also used in
motor vehicle evaporative control systems.
Activated Sludge— Product that results
when primary effluent is mixed with bacteria-laden
sludge and then agitated and aerated to promote
biological treatment, speeding the breakdown
of organic matter in raw sewage undergoing secondary
Activator— A chemical added to a pesticide
to increase its activity.
Active Ingredient— In any pesticide product,
the component that kills, or otherwise controls,
target pests. Pesticides are regulated primarily
on the basis of active ingredients.
Activity Plans— Written procedures in
a school’s asbestos-management plan that
detail the steps a Local Education Agency (LEA)
will follow in performing the initial and additional
cleaning, operation and maintenance-program
tasks; periodic surveillance; and reinspection
required by the Asbestos Hazard Emergency Response
Acute Exposure— A single exposure to
a toxic substance which may result in severe
biological harm or death. Acute exposures are
usually characterized as lasting no longer than
a day, as compared to longer, continuing exposure
over a period of time.
Acute Toxicity— The ability of a substance
to cause severe biological harm or death soon
after a single exposure or dose. Also, any poisonous
effect resulting from a single short-term exposure
to a toxic substance.
Adaptation— Changes in an organism’s
physiological structure or function or habits
that allow it to survive in new surroundings.
Add-on Control Device— An air pollution
control device such as carbon absorber or incinerator
that reduces the pollution in an exhaust gas.
The control device usually does not affect the
process being controlled and thus is “add-on”
technology, as opposed to a scheme to control
pollution through altering the basic process
Adequately Wet— Asbestos containing material
that is sufficiently mixed or penetrated with
liquid to prevent the release of particulates.
Administered Dose— In exposure assessment,
the amount of a substance given to a test subject
(human or animal) to determine dose-response
relationships. Since exposure to chemicals is
usually inadvertent, this quantity is often
called potential dose.
Administrative Order— A legal document
signed by EPA directing an individual, business,
or other entity to take corrective action or
refrain from an activity. It describes the violations
and actions to be taken, and can be enforced
in court. Such orders may be issued, for example,
as a result of an administrative complaint whereby
the respondent is ordered to pay a penalty for
violations of a statute.
Administrative Order On Consent— A legal
agreement signed by EPA and an individual, business,
or other entity through which the violator agrees
to pay for correction of violations, take the
required corrective or cleanup actions, or refrain
from an activity. It describes the actions to
be taken, may be subject to a comment period,
applies to civil actions, and can be enforced
Administrative Procedures Act— A law
that spells out procedures and requirements
related to the promulgation of regulations.
Administrative Record— All documents
which EPA considered or relied on in selecting
the response action at a Superfund site, culminating
in the record of decision for remedial action
or, an action memorandum for removal actions.
Adsorption— Removal of a pollutant from
air or water by collecting the pollutant on
the surface of a solid material; e.g., an advanced
method of treating waste in which activated
carbon removes organic matter from waste-water.
Adulterants— Chemical impurities or substances
that by law do not belong in a food, or pesticide.
Adulterated— 1. Any pesticide whose strength
or purity falls below the quality stated on
its label. 2. A food, feed, or product that
contains illegal pesticide residues.
Advanced Treatment— A level of wastewater
treatment more stringent than secondary treatment;
requires an 85-percent reduction in conventional
pollutant concentration or a significant reduction
in non-conventional pollutants. Sometimes called
Advanced Wastewater Treatment— Any treatment
of sewage that goes beyond the secondary or
biological water treatment stage and includes
the removal of nutrients such as phosphorus
and nitrogen and a high percentage of suspended
Adverse Effects Data— FIFRA requires
a pesticide registrant to submit data to EPA
on any studies or other information regarding
unreasonable adverse effects of a pesticide
at any time after its registration.
Advisory— A non-regulatory document that communicates
risk information to those who may have to make risk management
Aerated Lagoon— A holding and/or treatment
pond that speeds up the natural process of biological
decomposition of organic waste by stimulating
the growth and activity of bacteria that degrade
Aeration— A process which promotes biological
degradation of organic matter in water. The process may be passive
(as when waste is exposed to air), or active (as when a mixing
or bubbling device introduces the air).
Aeration Tank— A chamber used to inject
air into water.
Aerobic— Life or processes that require,
or are not destroyed by, the presence of oxygen.
Aerobic Treatment— Process by which microbes
decompose complex organic compounds in the presence
of oxygen and use the liberated energy for reproduction
and growth. (Such processes include extended
aeration, trickling filtration, and rotating
Aerosol— 1. Small droplets or particles
suspended in the atmosphere, typically containing
sulfur. They are usually emitted naturally (e.g.
in volcanic eruptions) and as the result of
anthropogenic (human) activities such as burning
fossil fuels. 2. The pressurized gas used to
propel substances out of a container.
Aerosol— A finely divided material suspended
in air or other gaseous environment.
Affected Landfill— Under the Clean Air
Act, landfills that meet criteria for capacity,
age, and emissions rates set by the EPA. They
are required to collect and combust their gas
Affected Public— 1.The people who live and/or
work near a hazardous waste site. 2. The human population adversely
impacted following exposure to a toxic pollutant in food, water,
air, or soil.
Afterburner— In incinerator technology,
a burner located so that the combustion gases
are made to pass through its flame in order
to remove smoke and odors. It may be attached
to or be separated from the incinerator proper.
Age Tank— A tank used to store a chemical
solution of known concentration for feed to
a chemical feeder. Also called a day tank.
Agent— Any physical, chemical, or biological
entity that can be harmful to an organism (synonymous
Agent Orange— A toxic herbicide and defoliant
used in the Vietnam conflict, containing 2,4,5-trichlorophen-oxyacetic
acid (2,4,5-T) and 2-4 dichlorophenoxyacetic
acid (2,4-D) with trace amounts of dioxin.
Agricultural Pollution— Farming wastes,
including runoff and leaching of pesticides
and fertilizers; erosion and dust from plowing;
improper disposal of animal manure and carcasses;
crop residues, and debris.
Agroecosystem— Land used for crops, pasture,
and livestock; the adjacent uncultivated land
that supports other vegetation and wildlife;
and the associated atmosphere, the underlying
soils, groundwater, and drainage networks.
AHERA Designated Person (ADP)— A person
designated by a Local Education Agency to ensure
that the AHERA requirements for asbestos management
and abatement are properly implemented.
Air Binding— Situation where air enters
the filter media and harms both the filtration
and backwash processes.
Air Changes Per Hour (ACH)— The movement
of a volume of air in a given period of time;
if a house has one air change per hour, it means
that the air in the house will be replaced in
a one-hour period.
Air Cleaning— Indoor-air quality-control
strategy to remove various airborne particulates
and/or gases from the air. Most common methods
are particulate filtration, electrostatic precipitation,
and gas sorption.
Air Contaminant— Any particulate matter,
gas, or combination thereof, other than water
Air Curtain— A method of containing oil
spills. Air bubbling through a perforated pipe
causes an upward water flow that slows the spread
of oil. It can also be used to stop fish from
entering polluted water.
Air Exchange Rate— The rate at which
outside air replaces indoor air in a given space.
Air Gap— Open vertical gap or empty space
that separates drinking water supply to be protected
from another water system in a treatment plant
or other location. The open gap protects the
drinking water from contamination by backflow
or back siphonage.
Air Handling Unit— Equipment that includes
a fan or blower, heating and/or cooling coils,
regulator controls, condensate drain pans, and
Air Mass— A large volume of air with
certain meteorological or polluted characteristics—e.g.,
a heat inversion or smogginess—while in
one location. The characteristics can change
as the air mass moves away.
Air/Oil Table— The surface between the
vadose zone and ambient oil; the pressure of
oil in the porous medium is equal to atmospheric
Air Padding— Pumping dry air into a container
to assist with the withdrawal of liquid or to
force a liquefied gas such as chlorine out of
Air Permeability— Permeability of soil
with respect to air. Important to the design
of soil-gas surveys. Measured in darcys or centimeters-per-second.
Air Plenum— Any space used to convey
air in a building, furnace, or structure. The
space above a suspended ceiling is often used
as an air plenum.
Air Pollutant— Any substance in air that
could, in high enough concentration, harm man,
other animals, vegetation, or material. Pollutants
may include almost any natural or artificial
composition of airborne matter capable of being
airborne. They may be in the form of solid particles,
liquid droplets, gases, or in combination thereof.
Generally, they fall into two main groups—
(1) those emitted directly from identifiable
sources and (2) those produced in the air by
interaction between two or more primary pollutants,
or by reaction with normal atmospheric constituents,
with or without photoactivation. Exclusive of
pollen, fog, and dust, which are of natural
origin, about 100 contaminants have been identified.
Air pollutants are often grouped in categories
for ease in classification; some of he categories
are— solids, sulfur compounds, volatile
organic chemicals, particulate matter, nitrogen
compounds, oxygen compounds, halogen compounds,
radioactive compound, and odors.
Air Pollution— The presence of contaminants
or pollutant substances in the air that interfere
with human health or welfare, or produce other
harmful environmental effects.
Air Pollution Control Device— Mechanism
or equipment that cleans emissions generated
by a source (e.g. an incinerator, industrial
smokestack, or an automobile exhaust system)
by removing pollutants that would otherwise
be released to the atmosphere.
Air Pollution Episode— A period of abnormally
high concentration of air pollutants, often
due to low winds and temperature inversion,
that can cause illness and death.
Air Quality Criteria— The levels of pollution
and lengths of exposure above which adverse
health and welfare effects may occur.
Air Quality Standards— The level of pollutants
prescribed by regulations that are not be exceeded
during a given time in a defined area.
Air Sparging— Injecting air or oxygen
into an aquifer to strip or flush volatile contaminants
as air bubbles up through The ground water and
is captured by a vapor extraction system.
Air Stripping— A treatment system that
removes volatile organic compounds (VOCs) from
contaminated ground water or surface water by
forcing an airstream through the water and causing
the compounds to evaporate.
Air Toxics— Any air pollutant for which
a national ambient air quality standard (NAAQS)
does not exist (i.e. excluding ozone, carbon
monoxide, PM-10, sulfur dioxide, nitrogen oxide)
that may reasonably be anticipated to cause
cancer; respiratory, cardiovascular, or developmental
effects; reproductive dysfunctions, neurological
disorders, heritable gene mutations, or other
serious or irreversible chronic or acute health
effects in humans.
Airborne Particulates— Total suspended
particulate matter found in the atmosphere as
solid particles or liquid droplets. Chemical
composition of particulates varies widely, depending
on location and time of year. Sources of airborne
particulates include— dust, emissions
from industrial processes, combustion products
from the burning of wood and coal, combustion
products associated with motor vehicle or non-road
engine exhausts, and reactions to gases in the
Airborne Release— Release of any pollutant
into the air.
Alachlor— A herbicide, marketed under
the trade name Lasso, used mainly to control
weeds in corn and soybean fields.
Alar— Trade name for daminozide, a pesticide
that makes apples redder, firmer, and less likely
to drop off trees before growers are ready to
pick them. It is also used to a lesser extent
on peanuts, tart cherries, concord grapes, and
Aldicarb— An insecticide sold under the
trade name Temik. It is made from ethyl isocyanate.
Algae— Simple rootless plants that grow
in sunlit waters in proportion to the amount
of available nutrients. They can affect water
quality adversely by lowering the dissolved
oxygen in the water. They are food for fish
and small aquatic animals.
Algal Blooms— Sudden spurts of algal
growth, which can affect water quality adversely
and indicate potentially hazardous changes in
local water chemistry.
Algicide— Substance or chemical used
specifically to kill or control algae.
Aliquot— A measured portion of a sample
taken for analysis. One or more aliquots make
up a sample.
Alkaline— The condition of water or soil
which contains a sufficient amount of alkali
substance to raise the pH above 7.0.
Alkalinity— The capacity of bases to
neutralize acids. An example is lime added to
lakes to decrease acidity.
Allergen— A substance that causes an
allergic reaction in individuals sensitive to
Alluvial— Relating to and/or sand deposited
by flowing water.
Alternate Method— Any method of sampling
and analyzing for an air or water pollutant
that is not a reference or equivalent method
but that has been demonstrated in specific cases-to
EPA’s satisfaction-to produce results
adequate for compliance monitoring.
Alternative Compliance— A policy that
allows facilities to choose among methods for
achieving emission-reduction or risk-reduction
instead of command-and control regulations that
specify standards and how to meet them. Use
of a theoretical emissions bubble over a facility
to cap the amount of pollution emitted while
allowing the company to choose where and how
(within the facility) it complies.
Alternative Fuels— Substitutes for traditional
liquid, oil-derived motor vehicle fuels like
gasoline and diesel. Includes mixtures of alcohol-based
fuels with gasoline, methanol, ethanol, compressed
natural gas, and others.
Alternative Remedial Contract Strategy Contractors—
Government contractors who provide project management
and technical services to support remedial response
activities at National Priorities List sites.
Ambient Air— Any unconfined portion of
the atmosphere— open air, surrounding
Ambient Measurement— A measurement of
the concentration of a substance or pollutant
within the immediate environs of an organism;
taken to relate it to the amount of possible
Ambient Medium— Material surrounding
or contacting an organism (e.g. outdoor air,
indoor air, water, or soil, through which chemicals
or pollutants can reach the organism.
Ambient Temperature— Temperature of the
surrounding air or other medium.
Amprometric Titration— A way of measuring
concentrations of certain substances in water
using an electric current that flows during
a chemical reaction.
Anaerobic— A life or process that occurs
in, or is not destroyed by, the absence of oxygen.
Anaerobic Decomposition— Reduction of
the net energy level and change in chemical
composition of organic matter caused by microorganisms
in an oxygen-free environment.
Animal Dander— Tiny scales of animal
skin, a common indoor air pollutant.
Animal Studies— Investigations using
animals as surrogates for humans with the expectation
that the results are pertinent to humans.
Anisotropy— In hydrology, the conditions
under which one or more hydraulic properties
of an aquifer vary from a reference point.
Annular Space, Annulus— The space between
two concentric tubes or casings, or between
the casing and the borehole wall.
Antagonism— Interference or inhibition
of the effect of one chemical by the action
Antarctic “Ozone Hole”—
Refers to the seasonal depletion of ozone in
the upper atmosphere above a large area of Antarctica.
Anti-Degradation Clause— Part of federal
air quality and water quality requirements prohibiting
deterioration where pollution levels are above
the legal limit.
Anti-Microbial— An agent that kills microbes.
Applicable or Relevant and Appropriate Requirements
(ARARs)— Any state or federal statute
that pertains to protection of human life and
the environment in addressing specific conditions
or use of a particular cleanup technology at
a Superfund site.
Applied Dose— In exposure assessment,
the amount of a substance in contact with the
primary absorption boundaries of an organism
(e.g. skin, lung tissue, gastrointestinal track)
and available for absorption.
Aqueous— Something made up of water.
Aqueous Solubility— The maximum concentration
of a chemical that will dissolve in pure water
at a reference temperature.
Aquifer— An underground geological formation,
or group of formations, containing water. Are
sources of groundwater for wells and springs.
Aquifer Test— A test to determine hydraulic
properties of an aquifer.
Aquitard— Geological formation that may
contain groundwater but is not capable of transmitting
significant quantities of it under normal hydraulic
gradients. May function as confining bed.
Architectural Coatings— Coverings such
as paint and roof tar that are used on exteriors
Area of Review— In the UIC program, the
area surrounding an injection well that is reviewed
during the permitting process to determine if
flow between aquifers will be induced by the
Area Source— Any source of air pollution
that is released over a relatively small area
but which cannot be classified as a point source.
Such sources may include vehicles and other
small engines, small businesses and household
activities, or biogenic sources such as a forest
that releases hydrocarbons.
Aromatics— A type of hydrocarbon, such
as benzene or toluene, with a specific type
of ring structure. Aromatics are sometimes added
to gasoline in order to increase octane. Some
aromatics are toxic.
Arsenicals— Pesticides containing arsenic.
Artesian (Aquifer or Well)— Water held
under pressure in porous rock or soil confined
by impermeable geological formations.
Asbestos— A mineral fiber that can pollute
air or water and cause cancer or asbestosis
when inhaled. EPA has banned or severely restricted
its use in manufacturing and construction.
Asbestos Abatement— Procedures to control
fiber release from asbestos-containing materials
in a building or to remove them entirely, including
removal, encapsulation, repair, enclosure, encasement,
and operations and maintenance programs.
Asbestos Assessment— In the asbestos-in-schools
program, the evaluation of the physical condition
and potential for damage of all friable asbestos
containing materials and thermal insulation
Asbestos Program Manager— A building
owner or designated representative who supervises
all aspects of the facility asbestos management
and control program.
Asbestos-Containing Waste Materials (ACWM)—
Mill tailings or any waste that contains commercial
asbestos and is generated by a source covered
by the Clean Air Act Asbestos NESHAPS.
Asbestosis— A disease associated with
inhalation of asbestos fibers. The disease makes
breathing progressively more difficult and can
Ash— The mineral content of a product
remaining after complete combustion.
Assay— A test for a specific chemical,
microbe, or effect.
Assessment Endpoint— In ecological risk
assessment, an explicit expression of the environmental
value to be protected; includes both an ecological
entity and specific attributed thereof. entity
(e.g. salmon are a valued ecological entity;
reproduction and population maintenance—the
attribute—form an assessment endpoint.)
Assimilation— The ability of a body of
water to purify itself of pollutants.
Assimilative Capacity— The capacity of
a natural body of water to receive wastewaters
or toxic materials without deleterious effects
and without damage to aquatic life or humans
who consume the water.
Association of Boards of Certification—
An international organization representing boards which
certify the operators of waterworks and wastewater facilities.
Attainment Area— An area considered to
have air quality as good as or better than the
national ambient air quality standards as defined
in the Clean Air Act. An area may be an attainment
area for one pollutant and a non-attainment
area for others.
Attenuation— The process by which a compound
is reduced in concentration over time, through
absorption, adsorption, degradation, dilution,
and/or transformation. an also be the decrease
with distance of sight caused by attenuation
of light by particulate pollution.
Attractant— A chemical or agent that
lures insects or other pests by stimulating
their sense of smell.
Attrition— Wearing or grinding down of
a substance by friction. Dust from such processes
contributes to air pollution.
Availability Session— Informal meeting
at a public location where interested citizens
can talk with EPA and state officials on a one-to-one
Available Chlorine— A measure of the
amount of chlorine available in chlorinated
lime, hypochlorite compounds, and other materials
used as a source of chlorine when compared with
that of liquid or gaseous chlorines.
Avoided Cost— The cost a utility would
incur to generate the next increment of electric
capacity using its own resources; many landfill
gas projects’ buy back rates are based
on avoided costs.
A-Scale Sound Level— A measurement of
sound approximating the sensitivity of the human
ear, used to note the intensity or annoyance
level of sounds.