Chapter 4 – Air Pollution
and Global Changes
How can local pollution
cause global changes?
I. The air pollution problem

A. Pollutants – harmful materials that enter the
environment

1. May be natural, such as sand and
dust storms, volcanic eruptions, and
forest fires

2. May be caused by human activities
B. History
1. Air pollution became a
widespread problem during the
Industrial Revolution of the 1700’s
due to increased burning of fossil
fuels and wood
2. Many air pollution disasters have been
recorded, caused by everyday industrial
pollution
a. 1952 – London, England: 3500-4000
dead
b. 1965 – New York, NY: 400 dead
II. Types of Pollutants
A. Outdoor Pollutants
1. Particulates – tiny solids suspended
in the atmosphere
a. pieces of ash, dust, and soot from
burning organic matter
b. liquid droplets in smoke or smog
c. traces of metals such as lead, iron, and
copper released from industrial processes
d. pesticide, herbicide, and fertilizer dust
e. plant pollen
2. Oxides – compounds of oxygen and another
element
a. most common oxides include carbon,
nitrogen, or sulfur
b. released when fossil fuels or other
organic materials are burned, especially
from automobiles or coal-burning power
plants
3. Photochemical Smog – a yellowbrown haze formed when sunlight
reacts with pollutants produced by cars
a. Includes the chemical ozone (O3)
i. very corrosive, poisonous to plants and
animals
ii. A ground-level ozone scale has been
devised that advises people of the dangers
of ozone pollution on a particular day;
code green = good, code orange =
dangerous for sensitive groups, code
purple = dangerous for all
b. Includes the chemical nitrogen
dioxide (NO2) – a brown gas that gives
smog its distinctive color
4. Hydrocarbons – compounds made
mostly of hydrogen and carbon Ex.
Methane – produced by microorganisms
in the digestive systems of livestock,
certain bacteria, and decaying organic
matter
5. Chloroflurocarbons (CFC’s) - manmade chemicals once used in
refrigerators, air conditioners, aerosol
cans, and in the production of
styrofoam.
Review Questions

1. Is air pollution a new problem? When
did it become a major concern?
In the 1700’s during the
industrial revolution.
2. Name 3 examples of natural air
pollution.
Sand and dust storms
 Volcanic eruptions
 Forest fires

3. Which types of air pollutants can you
see?
Smoke
 Smog
 Pollen
 Particulates
 Ash
 Soot

4. Name the 5 major types of outdoor
air pollutants
1.ash, dust or soot
2.Smoke and smog
3.Trace metals
4.Pesticides
5.Plant pollen
5. How is photochemical smog produced?
Why do you think it’s such a problem
during the summer months?
When sunlight reacts with pollutants from
cars.
Because the temperature increases ground
level ozone and there are more hours of
sunlight in the summer.
B. Indoor Air Pollution
1.
Indoor air can contain
very high levels of
pollution and can cause
serious health problems
a. Products such as plastics, insulation,
and cleaners give off harmful fumes
b. Air circulation in buildings is often
poor
c. People generally spend 16-18 hours
per day indoors
2. Major types of indoor air pollution
a. Cigarette smoke – contains a combination
of particulates, gases and other chemicals
b. Microorganisms – bacteria and fungi can
live in ventilation systems
c. Radon – a colorless, odorless, radioactive
gas that enters homes from the soil through
the basement
Review Questions

1. Give 2 reasons that indoor air can
contain high levels of pollution and
cause health problems
Because people spend a lot
of time inside and there is
inadequate air circulation.
2. Name 3 types of indoor air pollution

1. cigarette smoke
2. Micro organisms
3. chemicals
3. If you hear on the news that ozone
levels are high, would you always be
better off going inside? Why or why
not?
Stay indoors if there is air
conditioning.
III. Air Pollution and Living Things
A. Effects on human health
1. Long-term exposure may cause
diseases and chronic health
problems, or may worsen existing
conditions
2. Examples:
a. Carbon monoxide binds to
hemoglobin in blood more easily than
oxygen; exposure reduces the amount
of oxygen in the bloodstream and
causes headache, dizziness, and even
death
b. Ozone, and nitrogen and sulfur oxides
irritate the lungs and respiratory tract;
cause difficulty breathing, or may trigger
asthma, allergy attacks, or more serious
diseases such as bronchitis and
emphysema
c. Particulates in the air have been
linked to cancers, especially lung
cancers
B. Effects on other organisms
1. Ozone and sulfur oxides can
damage plants directly; affects forests
and crops
2. Loss of plants in an ecosystem can
disrupt the food web and deprive animals
of nourishment
3. Animals may suffer from the same
pollution-related health problems as
humans
4. Industrial air pollution can
contaminate rangeland, accumulating on
grasses and entering groundwater that
grazing animals consume
Review Questions
1. Why do many people now have a
carbon monoxide detector in their
homes?
Because CO can be deadly
2. Why is it dangerous to participate in
strenuous outdoor activities on days
when the ozone levels are high?
Because ozone can impair
respiratory function
3. Why should we be concerned about
how air pollutants affect plants?
Because our food and oxygen
comes from plants.
IV. Global Effects of Air Pollution
A. Acid Deposition
1. Rain or snow that is more acidic
than normal precipitation is called
acid precipitation
a. Normal rain is slightly acidic (5.6 on
the pH scale) – water reacts with carbon
dioxide in the atmosphere to form
carbonic acid
b. Much stronger acids form when water
reacts with sulfur or nitrogen oxides in
the atmosphere to form sulfuric or nitric
acid
2. Sulfur and Nitrogen oxides are
released through the burning of fossil
fuels
3. As acid precipitation falls, it is
deposited on land or in aquatic
environments
a. Damages crops and trees directly, and
also makes the soil less fertile
b. Accumulates in lakes and lowers the
overall pH, making them too acidic for
many fish to survive
c. Also causes economic damage by
eroding stone and damaging paint
Review Questions
1. Why is normal rain slightly acidic?
Because some acids are
naturally occurring
2. Where do the pollutants that cause
acid precipitation come from?
BURNING FOSSIL
FUELS!!!!
3. Name one way that acid
precipitation affects humans and one
way that it affects other living things
Causes paint to peel and it can kill
fish and trees.
B. Ozone Depletion
1. Although ground level ozone is a
dangerous, corrosive gas, there is a layer
of ozone in the stratosphere that
protects Earth’s life from harmful UV
radiation
2. In the early 1980’s, scientists discovered
a “hole”, or thinning of the ozone near
the South Pole
a. This thinning causes an increase in
the amount of UV radiation reaching
Earth
b. Effects:
i. In humans, increased incidence of
sunburn, vision problems, and skin
cancer
ii. Also damages crop plants and
forests, disrupting food webs
b. CFC’s are stable and inert (don’t react
with other compounds) in the lower
atmosphere, and therefore eventually
rise into the stratosphere
c. In the stratosphere, CFC’s are exposed
to UV radiation and break down,
releasing chlorine and fluorine atoms
that destroy ozone
d. CFC’s stay in the atmosphere for
hundreds or thousands of years, so
although the use of CFC’s has been
banned in most products, they continue
to cause problems
Review Questions
1. Is the ozone in the stratosphere a
different chemical compound than
ground-level ozone?
They are the same chemical but react
differently in the different
atmospheric layers.
2. Why is the thinning of the ozone
layer such a dangerous situation?
Because harmful UV radiation
gets in.
3. How do CFC’s break down ozone?
Chlorine and flourine break
down ozone.
4. If CFC’s are now banned in most of
the world, why do they continue to
cause problems?
Because they stay in the atmosphere
for 1000’s of years.
C. Global Warming
1. Earth’s atmosphere allows light
energy from the sun to enter, but gases
in the atmosphere trap heat and warms
the surface of the Earth – this
“greenhouse effect” allows life to exist
on this planet
2. Greenhouse gases that trap heat
include carbon dioxide, methane,
nitrogen and sulfur oxides, ozone, CFC’s,
and water vapor
a. Data on levels of greenhouse gases can
be obtained through ice cores – long
cylinders of ice that are drilled and
removed from a sheet of polar ice
b. Ice cores contain air bubbles that
have been trapped in the ice for 100’s or
1000’s of years
c. From ice core data, we have evidence
that levels of CO2 and other greenhouse
gases are rising steadily; a similar
increase in CO2 occurred at the end of the
last ice age
3. Global warming – an increase in
Earth’s average surface temperature
caused by an increase in greenhouse
gases
a. Computer models project a 2-4
degree Celsius rise in Earth’s
temperature
b. Ice caps will melt, oceans expand,
and sea levels rise
c. Lowlands and coastal cities flood,
displacing large populations of people
d. Saltwater enters groundwater,
affecting drinking water supplies
e. Weather patterns change, affecting
agriculture and ecosystems
Review Questions
1. How is the greenhouse effect different
from global warming?
The global warming is caused by the the
greenhouse effect.
2. Why is the Earth getting warmer?
Because the greenhouse gases have
increased and is trapping the heat from
the sun.
3. How do we obtain data about gases
in the Earth’s atmosphere 100’s of
years ago?
Ice core samples
4. Name 3 effects of global warming.
-loss of habitats
-rising sea levels
-increase in intensity of storms
V. Controlling Air Pollution
A. Natural Controls
1. Precipitation removes particulates
from the air by binding the particle
and carrying it to the ground
2. Carbon dioxide is removed by plants as
they photosynthesize
B. Human Controls
1. Air Pollution Legislation
a. 1963, 1965, 1977 – Clean Air Act and
amendments
b. 1987, 1990 – Montreal Protocol:
International treaty to ban the
use of CFC’s
2. Results of legislation
a. Emission control standards for cars
have been set since burning
gasoline is a major source of air pollution
b. Coal-burning power plants use
various techniques, such as
“scrubbers”, to remove pollutants
before they are released
3. There continues to be much debate
between industries and
environmentalists surrounding the use
of pollution control devices –
industries argue that these devices are
too expensive and difficult to
implement, while environmentalists
argue that these steps are
necessary to preserve our air quality
Review Questions
1. How can plants help us stop global
warming
Plants use the greenhouse gas
CO2.
2. Name 2 pieces of legislation aimed at
controlling air quality
Clean air act
Montreal protocol
3. Why do you think it’s so important to
have your car inspected each year?
Because a car that is not
running properly can add more
than normal amounts of
greenhouse gases.