NAA— Nonattainment Area
NAAEC— North American Agreement on Environmental
NAAQS— National Ambient Air Quality
NACA— National Agricultural Chemicals
NACEPT— National Advisory Council for
Environmental Policy and Technology
NADP/NTN— National Atmospheric Deposition
Program/National Trends Network
NAMS— National Air Monitoring Stations
NAPAP— National Acid Precipitation Assessment
NAPL— Non-Aqueous Phase Liquid
NAPS— National Air Pollution Surveillance
NARA— National Agrichemical Retailers
NARSTO— North American Research Strategy
for Tropospheric Ozone
NAS— National Academy of Sciences
NASDA— National Association of State
Departments of Agriculture
NCAMP— National Coalition Against the
Misuse of Pesticides
NCEPI— National Center for Environmental
Publications and Information
NCWS— Non-Community Water System
NEDS— National Emissions Data System
NEPI— National Environmental Policy
NEPPS— National Environmental Performance
NESHAP— National Emission Standard for
Hazardous Air Pollutants
NIEHS— National Institute for Environmental
NETA— National Environmental Training
NFRAP— No Further Remedial Action Planned
NICT— National Incident Coordination
NIOSH— National Institute of Occupational
Safety and Health
NIPDWR— National Interim Primary Drinking
NISAC— National Industrial Security
NMHC— Nonmethane Hydrocarbons
NMOC— Non-Methane Organic Component
NMVOC— Non-methane Volatile Organic
NO— Nitric Oxide
NOA— Notice of Arrival
NOAA— National Oceanographic and Atmospheric
NOAC— Nature of Action Code
NOAEL— No Observable Adverse Effect
NOEL— No Observable Effect Level
NOIC— Notice of Intent to Cancel
NOIS— Notice of Intent to Suspend
N2O— Nitrous Oxide
NOx— Nitrogen Oxides
NORM— Naturally Occurring Radioactive
NPCA— National Pest Control Association>
NPDES— National Pollutant Discharge
NPHAP— National Pesticide Hazard Assessment
NPIRS— National Pesticide Information
NPTN— National Pesticide Telecommunications
NRD— Natural Resource Damage
NRDC— Natural Resources Defense Council
NSDWR— National Secondary Drinking Water
NSEC— National System for Emergency
NSEP— National System for Emergency
NSPS— New Source Performance Standards
NSR— New Source Review
NTI— National Toxics Inventory
NTIS— National Technical Information
NTNCWS— Non-Transient Non-Community
NTP— National Toxicology Program
NTU— Nephlometric Turbidity Unit
National Ambient Air Quality
Standards (NAAQS)— Standards established
by EPA that apply for outdoor air throughout
National Emissions Standards
for Hazardous Air Pollutants (NESHAPS)—
Emissions standards set by EPA for an air
pollutant not covered by NAAQS that may cause
an increase in fatalities or in serious, irreversible,
or incapacitating illness. Primary standards
are designed to protect human health, secondary
standards to protect public welfare (e.g.
building facades, visibility, crops, and domestic
National Environmental Performance
Partnership Agreements— System that
allows states to assume greater responsibility
for environmental programs based on their
relative ability to execute them.
National Estuary Program—
A program established under the Clean Water
Act Amendments of 1987 to develop and implement
conservation and management plans for protecting
estuaries and restoring and maintaining their
chemical, physical, and biological integrity,
as well as controlling point and nonpoint
National Municipal Plan—
A policy created in 1984 by EPA and the states
in 1984 to bring all publicly owned treatment
works (POTWs) into compliance with Clean Water
National Oil and Hazardous Substances
Contingency Plan (NOHSCP/NCP)— The federal
regulation that guides determination of the
sites to be corrected under both the Superfund
program and the program to prevent or control
spills into surface waters or elsewhere.
National Pollutant Discharge
Elimination System (NPDES)— A provision
of the Clean Water Act which prohibits discharge
of pollutants into waters of the United States
unless a special permit is issued by EPA,
a state, or, where delegated, a tribal government
on an Indian reservation.
National Priorities List (NPL)—
EPA’s list of the most serious uncontrolled
or abandoned hazardous waste sites identified
for possible long-term remedial action under
Superfund. The list is based primarily on
the score a site receives from the Hazard
Ranking System. EPA is required to update
the NPL at least once a year. A site must
be on the NPL to receive money from the Trust
Fund for remedial action.
National Response Center—
The federal operations center that receives
notifications of all releases of oil and hazardous
substances into the environment; open 24 hours
a day, is operated by the U.S. Coast Guard,
which evaluates all reports and notifies the
National Response Team (NRT)—
Representatives of 13 federal agencies that,
as a team, coordinate federal responses to
nationally significant incidents of pollution—an
oil spill, a major chemical release, or a
- superfund response action—and provide
advice and technical assistance to the responding
agency(ies) before and during a response action.
National Secondary Drinking
Water Regulations— Commonly referred
to as NSDWRs.
Navigable Waters— Traditionally,
waters sufficiently deep and wide for navigation
by all, or specified vessels; such waters
in the United States come under federal jurisdiction
and are protected by certain provisions of
the Clean Water Act.
Necrosis— Death of plant
or animal cells or tissues. In plants, necrosis
can discolor stems or leaves or kill a plant
Negotiations (Under Superfund)—
After potentially responsible parties are
identified for a site, EPA coordinates with
them to reach a settlement that will result
in the PRP paying for or conducting the cleanup
under EPA supervision. If negotiations fail,
EPA can order the PRP to conduct the cleanup
or EPA can pay for the cleanup using Superfund
monies and then sue to recover the costs.
Nematocide— A chemical
agent which is destructive to nematodes.
of of measuring turbidity in a water sample
by passing light through the sample and measuring
the amount of the light that is deflected.
Netting— A concept in
which all emissions sources in the same area
that owned or controlled by a single company
are treated as one large source, thereby allowing
flexibility in controlling individual sources
in order to meet a single emissions standard.
the acidity or alkalinity of a substance by
adding alkaline or acidic materials, respectively.
New Source— Any stationary
source built or modified after publication
of final or proposed regulations that prescribe
a given standard of performance.
New Source Performance Standards
(NSPS)— Uniform national EPA air emission
and water effluent standards which limit the
amount of pollution allowed from new sources
or from modified existing sources.
New Source Review (NSR)—
A Clean Air Act requirement that State Implementation
Plans must include a permit review that applies
to the construction and operation of new and
modified stationary sources in nonattainment
areas to ensure attainment of national ambient
air quality standards.
Nitrate— A compound containing
nitrogen that can exist in the atmosphere
or as a dissolved gas in water and which can
have harmful effects on humans and animals.
Nitrates in water can cause severe illness
in infants and domestic animals. A plant nutrient
and inorganic fertilizer, nitrate is found
in septic systems, animal feed lots, agricultural
fertilizers, manure, industrial waste waters,
sanitary landfills, and garbage dumps.
Nitric Oxide (NO)— A gas
formed by combustion under high temperature
and high pressure in an internal combustion
engine; it is converted by sunlight and photochemical
processes in ambient air to nitrogen oxide.
NO is a precursor of ground-level ozone pollution,
Nitrification— The process
whereby ammonia in wastewater is oxidized
to nitrite and then to nitrate by bacterial
or chemical reactions.
Nitrilotriacetic Acid (NTA)—
A compound now replacing phosphates in detergents.
Nitrite— 1. An intermediate
in the process of nitrification. 2. Nitrous
oxide salts used in food preservation.
Nitrogen Dioxide (NO2)—
The result of nitric oxide combining with
oxygen in the atmosphere; major component
of photochemical smog.
Nitrogen Oxide (NOx)—
The result of photochemical reactions of nitric
oxide in ambient air; major component of photochemical
smog. Product of combustion from transportation
and stationary sources and a major contributor
to the formation of ozone in the troposphere
and to acid deposition.
Nitrogenous Wastes— Animal
or vegetable residues that contain significant
amounts of nitrogen.
organopesticides containing carbon, hydrogen,
nitrogen, and oxygen.
No Further Remedial Action Planned—
Determination made by EPA following a preliminary
assessment that a site does not pose a significant
risk and so requires no further activity under
No Observable Adverse Effect
Level (NOAEL)— An exposure level at
which there are no statistically or biologically
significant increases in the frequency or
severity of adverse effects between the exposed
population and its appropriate control; some
effects may be produced at this level, but
they are not considered as adverse, or as
precurors to adverse effects. In an experiment
with several NOAELs, the regulatory focus
is primarily on the highest one, leading to
the common usage of the term NOAEL as the
highest exposure without adverse effects.
No Till— Planting crops
without prior seedbed preparation, into an
existing cover crop, sod, or crop residues,
and eliminating subsequent tillage operations.
Exposure level at which there are no statistically
or biological significant differences in the
frequency or severity of any effect in the
exposed or control populations.
Noble Metal— Chemically
inactive metal such as gold; does not corrode
Noise— Product-level or
product-volume changes occurring during a
test that are not related to a leak but may
be mistaken for one.
Non-Aqueous Phase Liquid (NAPL)—
Contaminants that remain undiluted as the
original bulk liquid in the subsurface, e.g.
Non-Attainment Area— Area
that does not meet one or more of the National
Ambient Air Quality Standards for the criteria
pollutants designated in the Clean Air Act.
Non-Binding Allocations of Responsibility
(NBAR)— A process for EPA to propose
a way for potentially responsible parties
to allocate costs among themselves.
Non-Community Water System—
A public water system that is not a community
water system; e.g. the water supply at a camp
site or national park.
Non-Compliance Coal— Any
coal that emits greater than 3.0 pounds of
sulfur dioxide per million BTU when burned.
Also known as high-sulfur coal.
Non-Contact Cooling Water—
Water used for cooling which does not come
into direct contact with any raw material,
product, byproduct, or waste.
Any pollutant not statutorily listed or which
is poorly understood by the scientific community.
Non-Degradation— An environmental
policy which disallows any lowering of naturally
occurring quality regardless of preestablished
Non-Ferrous Metals— Nonmagnetic
metals such as aluminum, lead, and copper.
Products made all or in part from such metals
include containers, packaging, appliances,
furniture, electronic equipment and aluminum
Radiation— 1. Radiation that does not
change the structure of atoms but does heat
tissue and may cause harmful biological effects.
2. Microwaves, radio waves, and low-frequency
electromagnetic fields from high-voltage transmission
Non-Methane Hydrocarbon (NMHC)—
The sum of all hydrocarbon air pollutants
except methane; significant precursors to
Non-Methane Organic Gases (NMOG)—
The sum of all organic air pollutants. Excluding
methane; they account for aldehydes, ketones,
alcohols, and other pollutants that are not
hydrocarbons but are precursors of ozone.
Non-Point Sources— Diffuse
pollution sources (i.e. without a single point
of origin or not introduced into a receiving
stream from a specific outlet). The pollutants
are generally carried off the land by storm
water. Common non-point sources are agriculture,
forestry, urban, mining, construction, dams,
channels, land disposal, saltwater intrusion,
and city streets.
Non-potable— Water that
is unsafe or unpalatable to drink because
it contains pollutants, contaminants, minerals,
or infective agents.
Non-Road Emissions— Pollutants
emitted by combustion engines on farm and
construction equipment, gasoline-powered lawn
and garden equipment, and power boats and
Water System— A public water system
that regularly serves at least 25 of the same
non-resident persons per day for more than
six months per year.
Nondischarging Treatment Plant—
A treatment plant that does not discharge
treated wastewater into any stream or river.
Most are pond systems that dispose of the
total flow they receive by means of evaporation
or percolation to groundwater, or facilities
that dispose of their effluent by recycling
or reuse (e.g. spray irrigation or groundwater
Materials— Any material containing more
than one percent asbestos (as determined by
Polarized Light Microscopy) that, when dry,
cannot be crumbled, pulverized, or reduced
to powder by hand pressure.
Nonhazardous Industrial Waste—
Industrial process waste in wastewater not
considered municipal solid waste or hazardous
waste under RARA.
Notice of Deficiency—
An EPA request to a facility owner or operator
requesting additional information before a
preliminary decision on a permit application
can be made.
Notice of Intent to Cancel—
Notification sent to registrants when EPA
decides to cancel registration of a product
containing a pesticide.
Notice of Intent to Deny—
Notification by EPA of its preliminary intent
to deny a permit application.
Notice of Intent to Suspend—
Notification sent to a pesticide registrant
when EPA decides to suspend product sale and
distribution because of failure to submit
requested data in a timely and/or acceptable
manner, or because of imminent hazard.
Nuclear Reactors and Support
Facilities— Uranium mills, commercial
power reactors, fuel reprocessing plants,
and uranium enrichment facilities.
Nuclear Winter— Prediction
by some scientists that smoke and debris rising
from massive fires of a nuclear war could
block sunlight for weeks or months, cooling
the earth’s surface and producing climate
changes that could, for example, negatively
affect world agricultural and weather patterns.
Nuclide— An atom characterized
by the number of protons, neturons, and energy
in the nucleus.
Nutrient— Any substance
assimilated by living things that promotes
growth. The term is generally applied to nitrogen
and phosphorus in wastewater, but is also
applied to other essential and trace elements.
Nutrient Pollution— Contamination
of water resources by excessive inputs of
nutrients. In surface waters, excess algal
production is a major concern.