Environmental Engineering Reference
In-Depth Information
with water vapour and interspersed with aerosol suspensions. However, this is
subject to strong fluctuations depending on time and location.
The basic mass, dry, pure air, consists of a mix of gases that cannot enter into
the liquid or solid phase under atmospheric conditions (i.e. permanent gases).
Their condensation or solidification temperatures are far below the temperatures
occurring within the atmosphere. Apart from the main components nitrogen (N
2
)
and oxygen (O
2
), there are also small traces of argon (Ar) and carbon dioxide
(CO
2
). Additionally, there are traces of further noble gases such as neon (Ne),
helium (He), krypton (Kr) and xenon (Xe) as well as small amounts of ozone (O
3
)
and hydrogen (H
2
) in the atmosphere. Particularly the proportions of the two last
gases vary depending on time and location (see also /2-2/, /2-3/, /2-5/, /2-5/).
Table 2.1
Composition of the air (see /2-2/)
Components independent from time and space
nitrogen (N
2
)
oxygen (O
2
)
argon (Ar)
78.08 vol. %; 75.53 mass %
20.95 vol. %; 23.14 mass %
0.93 vol. %; 1.28 mass %
traces
further noble gases (He, Ne, Kr, Xe)
Components dependent on time and space
steam (H
2
O)
depending on meteorological conditions up to 4 %
0.03 vol. %; 0.05 mass %; tendency currently increas-
ing
carbon dioxide (CO
2
)
admixtures
gases
ozone (O
3
)
radon (Rn)
sulphur dioxide (SO
2
)
carbon monoxide (CO)
methane (CH
4
)
VOC
from the high atmosphere
from radioactive soil respiration
from e.g. volcanoes, post-volcanic activities
oxidizes into carbon dioxide (CO
2
) in the short term
from e.g. animal digestion, anaerobic fermentation
from plants
Aerosols
gaseous aerosols
dust
plant ash
sea water salt
biomass
from gaseous reactions (sulphates, nitrates etc.)
for example plain, desert, or volcano dust
from forest and steppe fires
transferred into the air with breaking wave crests
for example micro-organisms, pollen
mass % mass percentage; vol. % volume percentage.
2.1.3
Balance of energy flows
Energy from the three primary renewable energy sources sun, geothermal heat,
and planetary gravitation and motion, occurs on the earth in very different forms
(e.g. heat, fossil energy carriers or biomass) or causes very different effects (e.g.
waves, evaporation and precipitation). Fig. 2.5 shows a flow diagram allocating
these forms and effects to the corresponding energy sources. Additionally, the
non-renewable energies or energy carriers are also shown to give a complete im-
pression of the situation. However, only the main routes and coherences are
shown in this diagram, as it is not always possible to make a definite allocation.
Thus wind energy, for example, is a result of air movements within the atmos-
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