417
OIL ON BEACHES, vehicle exhaust fumes, litter, and other waste products
are called pollutants, because they pollute (dirty) our environment.
Pollutants can affect our health and harm animals and plants. We pollute
our surroundings with all kinds of chemical waste from factories and power
stations. These substances are the unwanted results of modern living.
Pollution itself is not new—100 years ago factories sent out great clouds of
poisonous smoke. Today, there are many more factories and many more
pollutants. Pollution has spread to the land, air, and water of every corner on
Earth, even to Antarctica and Mount Everest. Scientists are worried that
the gases released by factories and vehicles are even changing the atmosphere
and causing the surface temperature of the planet to rise. We can reduce
pollution by recycling waste and using biodegradable
materials that eventually break down in the soil.WASTE duMPINg
In many parts of the world people bury toxic
(poisonous) chemicals and other dangerous waste
products. These substances leak into the soil and water,
killing wildlife. We treat the seas as waste dumps, and the
North Sea is now seriously polluted. For the wildlife in the
seas to survive, we must produce less harmful waste products.Pollution 417-
Besides everyday pollution, there
is also accidental pollution—for
example, when a ship leaks oil and
creates a huge oil slick in the ocean.
This kind of pollution causes damage
to the environment and kills millions
of fish and seabirds, like the
oil-covered birds shown above.ACId rAIN
Vehicle exhausts produce fumes
that contain nitrogen oxides. The
coal we burn in power stations
produces sulfur dioxide. When
these two substances mix with
water in the air, they turn into
acids and then fall as acid rain.
Acid rain damages trees, eats
into buildings, and kills
wildlife in rivers. Today, it
is possible to reduce the
amount of sulfur
dioxide given off by
power stations,
but the process
is expensive.TrAFFIC POLLuTION
Truck, car, and bus exhausts
belch out lead (which can
damage the nervous system),
carbon monoxide, carbon
dioxide, and nitrogen oxides,
which cause acid rain and the
smog called photochemical
smog. Some of these harmful
substances are reduced by
special catalytic converters
attached to vehicle exhausts.ATMOSPHErIC POLLuTION
Ozone is a kind of oxygen present
in the atmosphere. It forms a
protective layer that blocks out
the sun’s ultraviolet radiation,
which can cause skin cancer
in humans. Chemicals called
CFCs (chlorofluorocarbons)
damage the ozone layer.Many factories release pollutants
as a by-product.Pollution
Recycling
If we save the glass, metal,
plastics, and paper that we
use every day, they can be
recycled and used again. This
helps preserve Earth’s natural
resources. recycling cuts
down litter, reduces air and
water pollution, and can save
energy. Many towns have
“bottle banks” to collect glass
for recycling.Ships
leak oil
into the
sea, which
is harmful to
sea creatures.gLOBAL WArMINg
Burning fossil fuels
releases carbon gases
into the atmosphere.
They act like the panes
of glass in a greenhouse,
trapping the heat. Many
scientists now believe that
Earth is becoming too
warm. If Earth becomes
just a few degrees warmer,
sea levels will rise, drowning
low-lying coastal cities.Farmers spray crops
with fertilizers to help them
grow and pesticides to control
pests and weeds, but these
chemicals can harm the other kinds of
wildlife that live and feed on the crops.Every day we drop litter on the
ground—candy wrappers, paper
bags, empty tin cans, and
bottles. Litter is ugly,
unhygienic, and a fire
risk, and it can kill
animals that eat it.US_417_Pollution_1.indd 417 22/01/16 4:46 pm