National Ambient Air Quality Standards (NAAQS)
Standards established by the EPA that apply to outdoor
air throughout the country.
|
Nitric Oxide (NO)
A gas formed by combustion under high temperature and
high pressure in an internal combustion engine, and then converted
by sunlight and photochemical processes in ambient air to nitrogen
oxide. Nitric oxide is a precursor of ground-level ozone pollution,
or smog.
|
Nitrogen Oxide (NOx)
The result of photochemical reactions of nitric oxide
in ambient air. It is a major component of photochemical smog, a product
of combustion from transportation and stationary sources, and a major
contributor to the formation of ozone in the lower atmosphere and
to acid deposition.
|
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 precursors 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.
|
Nonrenewable Energy
Energy derived from depletable fuels (oil,
gas, coal) created through lengthy geological processes and existing
in limited quantities on the earth.
|
Nonrenewable Resource
A resource that cannot be replaced in the
environment (i.e., fossil fuels)
because it forms at a rate far slower than its consumption.
|
