Environmental Engineering Reference
In-Depth Information
land surface. The term 'built' environment has been
applied to areas such as cities created by human
activity.
environmental equilibrium
The tendency of the
components of the environment to achieve some
degree of balance in their relationships with each
other. The balance is never complete, but takes the
form of a
dynamic equilibrium
which involves a
continuing series of mutual adjustments to the
relationships.
environmental impact
studies Analyses of the potential
impact of various forms of human activities on the
environment.
environmental lapse rate
The rate at which
temperature falls with increasing altitude in the
troposphere.
Although the lapse rate varies with
time and place it is normally considered to
average—6.5°C per 1,000 m.
Environmental Protection Agency (EPA)
US agency
established in 1970 to coordinate government
action on environmental issues.
equilibrium models
A form of
general circulation
model
(GCM). Change is introduced into such a
model representing existing climate conditions, and
the model is allowed to run until a new equilibrium
is established. The new model climate can then be
compared with the original to establish the overall
impact of the change.
European Arctic Stratospheric Ozone Experiment
(EASOE)
An experiment undertaken during the
northern winter of 1991-92, using ground
measurements, balloons, aircraft and a variety of
modelling techniques to establish the nature and
extent of
ozone depletion
over the Arctic.
evaporation
The process of vaporization by which
water changes from a liquid to a gaseous state.
evapotranspiration
The transfer of water from the
terrestrial environment into the atmosphere. It
combines
evaporation
from the land surface with
transpiration
from plants. A distinction may be
made between actual evatranspiration—a specific
measurement—and potential evapotranspiration—
an estimate of the environment's capacity for
evapotranspiration.
reservoir for precipitation, or in normal arable
agriculture to allow the land to recover from the
effects of cropping.
famine
Acute food shortage leading to wide-spread
starvation. Usually associated with large scale
natural disasters such as
drought,
flooding or plant
disease producing crop failure and disruption of
food supply.
feedback
Occurs in integrated systems where change
in one part of a system will initiate change elsewhere
in the system. This involves the process of
autovariation.
The change may be fed back into
the system in such a way as to augment (positive
feedback) or diminish (negative feedback) the
effects of the original change.
field capacity
see
soil moisture storage
.
flue gas desulphurization (FGD)
The process by which
sulphur dioxide is removed from exhaust gases
produced by the burning of coal. (See also
scrubbers
.)
fluidized bed combustion (FBC)
The burning of a
mixture of crushed coal, limestone and sand in the
presence of high pressure air which causes the
mixture to behave like a boiling liquid. Continual
mixing ensures that combustion is very efficient,
with up to 90 per cent of the sulphur in the fuel
being absorbed by the limestone.
fossil fuels
Fuels formed from organic material, which
was buried by sediments and retained its stored
energy. It is that energy which is released when fossil
fuels are burned. Fossil fuels include coal, oil and
gas, the main energy sources in advanced industrial
societies. Fossil fuel consumption is a major
contributor to a number of current environmental
issues including
acid rain, atmospheric turbidity
and
global warming
.
Framework Convention on Climate Change
One of
the conventions signed at the
Earth Summit.
It grew
out of concern for
global warming,
but was signed
only after much controversy and ended up as a
relatively weak document lacking even specific
emission reduction targets and deadlines.
Freon
The commercial name for
chlorofluorocarbons
(CFCs)
.
fuel desulphurization
The reduction in the sulphur
content of fuels such as coal and oil prior to
combustion, (see also
coal gasification
and
coal
liquefaction
.)
fuel switching
One of the simplest approaches to the
control of acid gas emissions. It involves the
F
fallout
The deposition of particulate matter from the
atmosphere on to the earth's surface.
fallow
Arable land left unfilled or tilled, but unsown,
for a season. Used in
dry farming
to provide a soil
