Cubic Meters
NA
Non-Attainment (CAA)
NA
North American (DOT). When NA precedes a four-digit number, it indicates that the identification number is used in the United States and Canada to identify a hazardous material (HM) in transportation.
NAAQS
National Ambient Air Quality Standards (Clean Air Act) (40 CFR, Part 50).
NACA
National Agricultural Chemicals Association
NACE
National Association of Corrosion Engineers
NAFTA
North American Free Trade Agreement
NAICS
North American Industry Classification System: A method of classifying various facilities. Replaced the 1987 Standard Industrial Classification (SIC) code system for the collection of statistical economic data.
Narcosis
Stupor or unconsciousness produced by chemical substances.
Natural Attenuation
The result of several processes, such as biodegradation, abiotic transformation, mechanical dispersion, sorption and dilution that reduces the contaminant concentration in the Environment
NCP
National Contingency Plan (40 CFR 300); Superfund procedures and standards for clean up of hazardous waste sites
NDC
National Defense Council
NEC
National Electrical Code
Necrosis
Destruction of body tissue
NEPA
National Environment Policy Act
NESHAP
National Emission Standards for Hazardous Air Pollutants (CAA: 40 CFR, PART 60); a set of national emission standards for a list of hazardous pollutants emitted from specific classes or categories of new and existing sources. These include and were introduced in the Clean Air Act Amendments of 1997. Under Title III of the 1990 CAAA, hazardous air pollutants are by definition included in the NESHAP’s program.
Neutralization
The process by which acid or alkaline properties of a solution are altered by the addition of reagents to bring the hydrogen and hydroxide concentrations to equal value or to a neutral pH of 7.
Neutron
A small particle, typically found within an atom’s nucleus, that possesses no electrical charge.
NFA
National Fire Academy
NFPA
National Fired Protection Association; an international voluntary membership organization to promote and improved fire protection
NFPA Fire Diamond
The NFPA Fire Diamond is divided into four parts listing the health hazards, flammability concerns and reactivity of a compound, along with recommended protective equipment. Each section is rated on a scale of 0 (minimal hazard) to 4 (extreme).
ng
Nanogram
ng/m3
Nonogram Per Cubic Meter
NHSTA
National Highway Traffic Safety Administration
NH3-N
Ammonia Nitrogen
NIH
National Institute of Health
NIMBY
Not In My Back Yard
NIOSH
National Institute for Occupational Safety and Health; independent federal agency charged with performing research on occupational disease and injury. NIOSH tests and certifies respiratory protective devices and air-sampling detector tubes, recommends occupational exposure limits for various substances and assists OSHA and MSHA in occupational safety and health investigation and research
NIST
National Institutes for Standards & Testing
NMHC
Non-methane hydrocarbon
NO
Nitric Oxide
NO2
Nitrogen Dioxide
NOx
A criteria air pollutant. Nitrogen oxides are produced from burning fuels, including gasoline and coal. Nitrogen oxides are smog-formers, which react with volatile organic compounds to form smog. Nitrogen oxides are also major components of acid rain. Nitrogen Oxides are a mixture of Nitric Oxide (NO) and Nitrogen Dioxide (NO2); gases released primarily from the burning of fossil fuels.
NOAA
National Oceanic and Atmospheric Administration. Scientific support organization serving regulatory agencies charged with enforcing environmental laws affecting oceans and the atmosphere.
NOAEL
No Observed Adverse Effect Level
NOC
Notification of Compliance
NOD
Notice of Deficiency
NOI
Notice of Intent
Nonattainment area
(CAA) A geographic area in which the level of a criteria air pollutant is higher than the level allowed by the federal standards. A single geographic area may have acceptable levels of one criteria air pollutant but unacceptable levels of one or more other criteria air pollutants; thus, an area can be both attainment and nonattainment at the same time.
Nonpoint
sources
(CWA); Sources associated with widespread activities such as agriculture, atmospheric deposition or erosion and runoff. Generally, ill-defined runoff that enters a waterway.
Non-Wastewater
A waste containing greater than 1% (10,000 PPM) by weight TOC or greater than 1% (10,000 PPM) Total Suspended Solids (TSS)
NORM
Naturally Occurring Radioactive Material
n.o.s. or NOS
Not Otherwise Specified
NOT
Notice of Termination
NOV
Notice of Violation
nm
nanometer (1E-9 meters; 1 billionth of a meter)
NPDES
National Pollutant Discharge Elimination System: CWA, (40 CFRM Part 106). NPDES requires permits for discharge of pollutants from any point source into waters of the United States.
NPL
National Priorities List; a list of hazardous sites ranked under CERCLA to be remediated.
NPRM
Notice of Proposed Rulemaking (regulatory proposal)
NPTN
National Pesticide Telecommunications Network
NQT
Nonquenched and Tempered
NRDC
National Resource Defense Council
NRC
National Response Center
NRC
Nuclear Regulatory Commission; federal body overseeing the operation of consumer nuclear power plants and other installations
NRRPC
National Railroad Passenger Corporation
NSC
National Safety Council
NSPS
New Source Performance Standards (CAA or CWA). New Source Performance Standards applies only to stationary sources that are constructed or modified after an ambient standard has been proposed.
NSR
New Source Review (CAA)
NTIS
National Technical Information Service
NTP
Normal Temperature and Pressure (77E F = 298.15E K, 1 ATM)
NTSB
National Transportation Safety Board
Nucleus
The central part of an atom that contains protons and neutrons.
Nuclide
A general term applicable to all atomic forms of an element. Nuclides are characterized by the number of protons and neutrons in the nucleus.