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Fresh Water Pollution
A pollutant is a waste material that pollutes air, water or soil.
There are two types of pollutants:
Point Pollution: pollution that is discharged from a single source such as a
factory.
Nonpoint Pollution: pollution that comes from many sources rather than a
single source such as homes, lawns, farms etc.
Water pollution is the introduction of a chemical, physical or biological material
into water that degrades the quality of the water and affects the organisms that
drink it and live in it.
Two causes: industrialization and human population explosion.
Air Pollution
Air Pollution: the air contains substances that are harmful to living things. These
can come from smoke or other harmful gases Ex: oxides of carbon, nitrogen and
sulfur
Two Types of Air Pollutants: Primary and Secondary
Primary Pollutant: a pollutant that is put directly into the atmposphere by human
activity Ex: soot from smoke, exhaust from cars.
Secondary Pollutant: a pollutant that forms when a primary pollutant or a
naturally occurring substance such as water comes into contact with other primary
pollutants and a chemical reaction takes place.
Ex: ozone production
Major Air Pollutants
Carbon Dioxide: produced by incomplete burning of fossil fuels. Sources:
vehicles and industrial processes. Harmful effects: interfers with oxygen transport
in the blood causing drowsiness, headaches and death.
Nitrogen Oxides (NOx): nitrogen and oxygen combine when combustion
temperatures exceed 5380C. Sources include: vehicles and power plants. Harmful
effects:respiratory infections, lung diseases, cancer.
Sulfur Dioxide (SO2): produced by reactions between sulfur and oxygen.
Sources: burning fossil fuels (smelters, paper mills). Harmful Effects: acid
rain, harm plant life, irritate respiratory systems.
Volatile Organic Compounds (VOC): organic chemicals that vaporate into
toxic fumes (gasoline). Sources:burning fuels from solvents, cars. Harmful Effects:
smog, cancer, harm plants.
Particulates: Smoke, ash etc from burning fuels. Sources: industrial
processes, vehicles, burning wood. Harmful Effects:produce clouds that
reduce visibility, cancer.
Greenhouse Effect
Natural warming makes the Earth livable
Natural gases in our atmosphere act like a blanket or a glass in a greenhouse- they
keep the surface of the Earth warm.
Increases in gases i.e. CO2 from human activity add to the natural Greenhouse
Effect and trap more heat than we need this results in global warming.
The blanket surrounding the earth becomes larger and more heat is traped,
increasing temperatures on Earth.
Major Greenhouse Gases
CO2 - carbon dioxide - emitted when fossil fuels are burned in cars, factories and
powerplants.
CFC's - used in making some plastics, foam insulation, and electric equipment, it
is in car air conditioners, fridges and spray cans.
methane - the main source is from cows and livestock
nitrous oxide - produced naturally, but humans have increased it by using
chemical fertilizers
ozone - car exaust and coal burning plants
What is Global Warming/Climate Change?
Global Warming = an increase in the earth's average atmospheric temperature that
causes corresponding changes in climate and that may result from the greenhouse
effect
Climate Change = any long-term significant change in the weather patterns of an
area
= can be natural or caused by changes people have made to the
land or
atmosphere.
Ozone Layer
The stratosphere contains the Earth's ozone layer.
Ozone is formed by three oxygen atoms and it absorbs most of the UV light
from the Sun.
It acts like a sunscreen to protect the Earth from damaging UV rays.
Chlorofluorocarbons (CFCs)
CFCs were believed to be miracle chemicals used in coolants, Styrofoam
making and in everyday products like hair spray.
CFC molecules can be broken apart high in the stratosphere where UV
radiation is absorbed. When CFCs go up into the atmosphere, the
chlorine atoms destroy ozone. Each CFC molecule has 4 chlorines and
each chlorine can destroy 100,000 ozone molecules.