A category of substances in the air that are known or suspected
of causing cancer or other health problems in humans, and for
which a National Ambient Air Quality standard (NAAQS) does not
exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur
dioxide, nitrogen oxide).

A group of organic chemicals where an oxygen atom is
double-bounded to a carbon atom. Examples include: Acetone,
Acrolein, Formaldehyde, Methyl Ethyl Ketone.

A level of chemical concentration in ambient air, at or below
which a chemical or defined mixture of chemicals is not likely to
cause an adverse health effect to the general public when
exposure occurs over a prescribed period of time.

Sites where the MPCA has spent federal or state funds to
investigate potentially contaminated properties. Sites
included in this category vary, ranging from abandoned
industrial properties to small commercial businesses to
publicly-owned land where there is a concern about
potential contamination.

Area sources are smaller sources of air emissions that are not
required to submit criteria pollutant data to the MPCA. Examples
of area sources include gas stations, dry cleaners and auto body
shops. Individually, these sources do not emit much air
pollution, but collectively release large amounts of one or more
toxic air pollutants.

The state of quality of the air in the surrounding environment.

The total number of particles of solid or liquid matter - such as
soot, dust, aerosols, fumes and mist - found in a sample of
ambient air.

The ranking of this facility's emissions compared to other point
sources that emitted this pollutant during this reporting year.

The relative amount of this pollutant emitted from this facility
during this reporting year, expressed as a percentage of the
total amount emitted in Minnesota during this reporting year.

"Secondary ambient air quality standards" or "secondary
standards" mean levels established to protect the public welfare
from any known or anticipated adverse effects, such as injury to
agricultural crops and livestock, damage to or deterioration of
property, annoyance and nuisance of persons, or hazards to air
and ground transportation. (From MN Rule 7009.0010)