|
|
|
Explanation of the main terms related to environment
monitoring
|
|
|
|
|
|
|
|
|
(1)
WECPNL
This is the abbreviation of Weighted Equivalent Continuous Perceived
Noise Level, and it is also called the 'aircraft noisiness index'.
This is a unit which expresses the magnitude of the aircraft
noise per day at a given location, and it is not the noise level
per aircraft, but it takes the duration time and the number
of aircraft into consideration and is expressed by the following
formula.
WECPNL = dB(A) + 10 Log10 (Nd- + 3
Ne + 10 Nn)- 27
dB(A): Power average for the total aircraft noise (peak level)
for a day
Nd: Number of aircraft from 07:00 to 19:00
Ne: Number of aircraft from 19:00 to 22:00
Nn: Number of aircraft from 22:00 to 07:00
In the environment standard for aircraft noise, WECPNL70 and
lower applies to areas used mainly for housing, while WECPNL75
and lower applies for areas other than the above, where normal
life must be maintained.
|
Quality of the atmosphere
|
|
|
(2)
Nitrogen oxides
Nitrogen oxides are created by reaction of the nitrogen in the
air at the time of combustion or when nitrogen contained in
fuel is oxidized. A large part is emitted as nitrogen monoxide
(NO), and it is oxidized in the atmosphere further to nitrogen
dioxide (NO2).
(3)
ppm
This is the abbreviation of parts per million. This indicates
one part in a million, and it is used mainly to indicate the
concentration of pollutants in the atmosphere.
(4)
Sulfur dioxide
Sulfur oxides are irritant gases created by combustion of the
sulfur in fuel, and the main part is sulfur dioxide (SO2).
(5) Suspended particulate Matter (SPM)
This are the floating particles in the atmosphere
which have a size of 10 ƒÊm or less. In addition
to emissions from factories and automobiles,
they are also caused by natural causes like
dust being carried by the wind etc.
(6)
Carbon monoxide
This is created by incomplete combustion of substances containing
carbon, and it combines easily with hemoglobin in the blood
and impedes the supply of oxygen.
(7)
Hydrocarbons
Hydrocarbons are one of the substances causing photochemical
smog, and this is the collective name for chemical compounds
(CnHm) composed of hydrogen atoms (H) and carbon atoms (C),
and there are many types according to the combination of hydrogen
and carbon. Hydrocarbons, one of the substances causing photochemical
smog, are divided into methane, which does not show a photochemical
reaction, and non-methane hydrocarbons (NMHC).
(8)
Photochemical oxidants
This is the collective name for oxidants created when hydrocarbons
or nitrogen oxides in the atmosphere absorb ultraviolet rays
from the sun etc., and in addition to the influence onto the
health by irritating mucous membranes and influencing breathing,
they also influence plants. They become the cause for photochemical
smog.
|
|
|
|
(9) Suspended solids (SS)
This is the name for the amount of substances floating in the
water. Measuring is done by weighing after drying, and a higher
value indicates higher pollution of the water. VSS (volatile
suspended substances) is the name for solids caused mainly by
plankton and other organic matter.
(10)
Turbidity
This is an index indicating the amount of suspended solids in
the water, and it is measured as the transmittance of light.
The light transmission is compared to a standard liquid with
kaolin in it, and the result is indicated as degrees (kaolin).
(11)
Transparency
This is expressed as the limit depth from the surface at which
a white disk with a diameter of 30 cm can be discriminated,
and it is an index indicating the degree of turbidity of the
water.
(12)
Chemical oxygen demand (COD)
This is the amount of oxygen required for chemical oxidation
analysis of the organic compounds in the water, and a higher
value indicates a higher quantity of pollutants in the water.
(13)
Hydrogen ion concentration (pH)
pH is an index indicating the acidity or alkalinity of water,
and it is the common logarithm of the inverse number of the
hydrogen ion concentration. A pH of 7 indicates neutrality,
while a higher value indicates alkalinity and a lower value
indicates acidity.
(14)
Dissolved oxygen (DO)
DO is the abbreviation of dissolved oxygen, and it is the amount
of oxygen dissolved in the water. The solubility of oxygen is
influenced by the water temperature, the salt content, the water
pressure, etc., and it decreases with increasing water temperature.
The dissolved oxygen is indispensable for self-cleaning of the
sea area and for the life of fish and other aquatic organisms.
(15)
n-hexane extractions
This is the collective name for non-volatile substances extracted
by n-hexane, and it is used to indicate the oil content in the
water.
(16)
Total nitrogen, total phosphorus (T-N, T-P)
This is the total amount of nitrogen and phosphorus included
in various forms in the water and the sediment. It is an index
indicating the degree of eutrophication.
(17)
Sediment grain composition
This indicates the distribution condition of the particle sizes
composing the sediment as a percentage of the total, and it
is expressed with classification into pebbles, coarse sand,
fine sand, silt, loam, etc.
(18) Solid residue
This is the difference in weight between the solid residue after
heating to 600ºC ± 25ºC and the weight before heating. The main
components are organic substances and volatile inorganic substances.
|
|
|
|
