2. Pollutants Impair Air Quality
Major concerns regarding air pollution
Global warming
Destruction of the ozone layer
Acid precipitation
Smog production

3. Contributes to Air pollutant Source Halons (contain bromine, Br)
Figure 24.1
Halons (contain bromine, Br)
Chlorofluorocarbons (CFCs)
Nitrogen oxides (NxOx)
Ozone layer destruction
Carbon monoxide (CO)
Carbon dioxide (CO2 )
Hydrocarbons (HC)
Sulfur dioxide (SO2 )
Acid precipitation
Methane (CH4 )
Contributes to
Global warming
Air pollutant
Smog
Source
Vehicle exhaust
Fossil fuel burning
Paints
Deforestation
Farms
Refrigerants
Fire extinguishers
Plastic foam
Pesticides

4. Excessive Greenhouse Gases Lead to Global Warming
Trap heat from escaping the atmosphere
Cause atmosphere to heat up
Examples
Water vapor
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
Chlorofluorocarbons (CFCs)
Halons

5. Excessive Greenhouse Gases Lead to Global Warming
Greenhouse effect
Gases let sunlight through, but trap heat from radiating back outward into space
Greenhouse effect responsible for:
Global warming
Human activities have increased levels of CO2, a major greenhouse gas
Deforestation
Burning of fossil fuels

6. Radiated heat (reflected radiation)
Figure 24.2
Solar radiation
Radiated heat (reflected radiation)
Stratosphere
Clouds
Earth

8. CFCs Deplete the Ozone Layer
Ozone: two different atmospheric locations
Pollutant in troposphere (near Earth’s surface)
Toxic, causes respiratory difficulties
Protective shield in the stratosphere
Shields the Earth’s surface from UV light
Statospheric ozone layer
Depleted by reaction with chlorofluorocarbons (CFCs)
Concern about excess UV radiation exposure
CFCs come from refrigerants, aerosol sprays
CFC use has decreased due to international agreement

9. Figure 24.4
1979
1996
2011

10. Pollutants Produce Acid Precipitation
Sulfur dioxide from high-sulfur coal and oil
Nitrogen oxides from car exhaust
Sulfur dioxide + nitrogen oxide + water vapor = sulfuric acid + nitric acid
Acid precipitation damage includes
Corrosion of metal and stone
Disruption of forest and aquatic ecosystems
In North America, the northeastern United States and parts of Canada have been the most affected
Acid precipitation decreasing due to pollution abatement measures

11. Smog Blankets Industrial Areas
Smoke + fog = smog
Components of smog include:
Nitrogen oxides
Hydrocarbons
Eye and respiratory irritants
Small oil droplets, wood particles, coal ash, asbestos, lead, animal waste, dust
Major source: burning fossil fuels
Thermal inversion: atmospheric conditions that trap smog and prevent its dispersal
Control: air pollution abatement measures

12. Pittsburgh after programs were instituted to reduce smog.
Figure 24.5
Pittsburgh at the height of the steelmaking era, before smog cleanup efforts began.
Pittsburgh after programs were instituted to reduce smog.

13. Water Is Scarce and Unequally Distributed
Distribution of Earth’s water
Fresh water: •1%
Salt water: 97%
Glaciers/polar ice caps: 2%
Industrialized countries use 10 to 100 times more water than less industrialized countries
Some desert and semiarid countries have reached carrying capacity with regard to water supplies
Diversion of water impacts other human populations and other species

14. Urbanization Increases Storm Water Runoff
Combined sewage overflow (CSO) created
Storm water combined with sewage
CSO overwhelms receiving streams and oceans
Human disease spread by CSO-carried pathogens
Gastroenteritis
Ear and eye infections
Skin infections
Respiratory infections
Leads to stream erosion

15. Figure 24.6

16. Human Activities Pollute Freshwater
Organic pollutants
From sewage and industry
Inorganic pollutants
Nitrates
Phosphate fertilizers
Sulfates from detergents
May result in eutrophication
Rapid growth of plant life leading to death of animal life in a shallow body of water resulting from excessive organic or inorganic nutrients

17. Human Activities Pollute Freshwater
Toxic pollutants
Oil and gasoline
Pesticides
Herbicides
Heavy metals
Biological magnification: the concentration of toxic pollutants is higher in the tissues of organisms higher on the food chain
Example: accumulation of mercury in fish

18. Shark •1 ppm Herring 0.05 ppm Zooplankton 0.005 ppm
Figure 24.8
Shark •1 ppm
Herring 0.05 ppm
Zooplankton ppm
Bacteria ppm
Ocean ppm

19. Groundwater Pollution May Impair Human Health
Contaminates drinking water supplies
Very slow exchange of the groundwater pool: “cleans” slowly
Common contaminants
Organics, i.e., carbon tetrachloride, pesticides, fertilizers (nitrates), radioactive waste
Suspected effects
Miscarriages, skin rashes, nervous disorders, birth defects

20. Oil Pollution Damages Oceans and Shorelines
Oil pollution sources
50% seepage
30% runoff from land
20% accidents at sea
Ultimate fate of oil released at sea
25% evaporates
50% degraded by bacteria
25% sediments
Near shore: significant damage to shoreline ecosystems

21. Pollution and Overuse Damage the Land
1/3 of Earth’s landmass has been altered by human activity
50% of forests have been removed
Migration to cities: footprint of cities expands, consuming productive land and increasing water runoff issues
Desertification: transformation of marginal land into near desert conditions, unsuitable for future agriculture
Wars
Garbage disposal

22. Figure 24.9

23. Urbanization Is a Major Force for Environmental Change
Worldwide shift to cities
Less plant and animal diversity
Worldwide, cities cause
78% of carbon emission
60% of residential water usage
76% of wood use for industry
Ecological footprint much larger than city size

24. Energy: Many Options, Many Choices
Nonrenewable resources: fossil fuels
Coal, oil, gas
Renewable energy sources
Nuclear energy: safety, disposal issues
Biomass fuels (biofuels)
Use of plant materials for fuels
Land use issues (food or fuel?)
Hydroelectric power
Wind farms
Geothermal energy
Solar power

25. A solar power plant. This power plant is in Australia.
Figure 24.11
A wind farm. Wind farms are increasingly being used to generate power in areas that have sustained winds.
Photovoltaic solar panels. Photovoltaic panels can provide enough electricity to power a home.
A solar power plant. This power plant is in Australia.

26. Humans Are Creating a Biodiversity Crisis
Biodiversity: species richness, the assortment of living organisms on Earth
Currently, scientists have identified 1.75 million different species
Estimates of 10–30 million or more different species
Biodiversity represents the variety of all forms of life

27. Biodiversity Is Healthy for Humans
Plants (through photosynthesis) recycle carbon dioxide for oxygen
Plants: source of medicines
Food sources
Stability of ecosystems

28. Strategies to Support Sustainable Development
Consume less
Recycle more
Support sustainable agriculture
Support green roofs
Reduce rural world poverty
Conserve energy at home
Use environmentally preferable products
Protect ecosystems that provide ecoservices