Acid Rain
What is acid rain?
Acid Rain is rain that has been
contaminated by air pollution and as a
result causes harm to the environment
when it falls to the earth.
What causes Acid Rain?
Acid rain is a result of air pollution. When
any type of fuel is burnt, chemicals and gases
are produced in the form of smoke.
Holy Smoke!
So smoke doesn’t just contain the sooty
grey particles that you can see - it also
contains lots of invisible gases and
chemicals that you can’t see. These
chemicals can be harmful to our
environment.
Power stations, factories
and cars all burn fuels and
therefore they all produce
smoke containing harmful
chemicals and gases.
Some of these gases mix
with the tiny droplets of
water in clouds to form
sulfuric and nitric acids.
The rain from these clouds
then falls as weak acid which is why it is known as
"acid rain".
From the City to the Country
Whew!
Very strong acids will burn if they touch
your skin and can even destroy metals.
But acid rain is much, much weaker than
this . . . never acidic enough to burn your
skin.
But even so…
When rain has become acidic, it affects
nearly everything it falls on . . . trees,
lakes, buildings and farmland. Sometimes
acid rain is not very strong and does not
cause a lot of problems. But when it is
strong, it can be very harmful to the
environment.
Effect on Trees
Acid rain can effect trees in several different ways.
It may:
 Dissolve and wash away the nutrients and
minerals in the soil which help the trees to grow.
 Cause the release of harmful substances such
as aluminum into the soil.
 Wear away the waxy protective coating of
leaves, damaging them and preventing them
from being able to photosynthesize
properly.
Not just the trees. . .
A combination of these effects weakens the trees
which means that they can be more easily attacked by
diseases and insects or injured by bad weather. It is not
just trees that are affected by acid rain, other plants may
also suffer.
. . . but the water too.
As acid rain falls on
a forest it trickles
through the leaves of
the trees and runs
down into the soil
below. Some of it
finds its way into
streams and then into
rivers and lakes.
As a result. . .
Forests all over the world are dying.
Whole sections of forests in Germany have
been wiped out. In Scandinavia there are
dead lakes, which are crystal clear and
contain no living creatures or plant life. The
fish have all died. Many of the U.K.'s
freshwater fish are threatened and there
have been reports of deformed fish being
hatched.
What about buildings?
Nearly every type of building
material will become eroded
sooner or later by the natural
effects of weather such as wind,
ice and snow. Unfortunately, acid
rain just makes it worse. Statues,
buildings, vehicles, pipes and
cables can all suffer when
exposed to acid rain. Buildings
and structures made from
limestone or sandstone suffer the
worst as these types of rock are
particularly susceptible to
corrosion caused by acids.
Where does it come from?
Until recently air pollution has been seen
as a local issue not a national problem. It
was in southern Norway in the late 1950's
that the problems of acid rain were first
observed, and it was then that people
began to realize that the origins of this
pollution were far away in the U.K. and
Northern Europe.
The problem is that . . .
Air pollution can be
carried over long
distances. When acid
gases are released,
they go high up in the
sky, and then they are
pushed by strong winds
towards other countries.
So . . .
The acid rain in Sweden
is caused by air pollution
in the U.K. and other
countries of Europe. The
pollution produced in the
U.K. ends up mostly in
Scandinavia - countries
in northern Europe
including Sweden,
Norway and Denmark.
That didn’t work!
One early answer to
industrial air pollution
was to build very tall
chimneys. Unfortunately
all that did was to push
the polluting gases up
into the clouds so the
pollution could just float
away. The wind carried
the pollution many
hundreds of miles away
where it eventually fell as
acid rain.
Bad Guys!
Over ninety percent of Norway's acid
pollution comes from other countries. The
worst European polluters are Germany,
U.K., Poland and Spain, each of them
producing over a million tons of sulfur
pollution in 1994.
Acid Rain in Europe
What’s being done?
European governments are now beginning to
admit that acid rain is a serious environmental
problem and many countries are now taking
steps to reduce the amount of sulfur and
nitrogen emissions from their factories. But it
may be too little and too late for many forests
and lakes.