1. Ch. 20 Air Pollution

2. Layers of the Atmosphere
Fig p. 434
Troposphere- layer closest to Earth; 78% N, 21% O
Stratosphere = “sunscreen” thinning ozone layer (3O2+UV -> 2O3) due to CFC’s

3. Outdoor Air Pollution
Primary pollutants
Secondary pollutants

5. Effects

6. Air Quality Index (AQI) Real Time Data - by location

7. Smog – 2 TYPES Industrial Smog Burning coal; soot, CO, CO2
(Gray Smog)
China; NYC, India
London during Industrial Revolution 1952
Burning coal; soot, CO, CO2
Mercury and sulfur
– sulfur oxides

8. Smog – 2 TYPES Photochemical Smog (Brown smog) Fig. 20-5 p. 440
Mexico City
Los Angeles, CA
Photochemical oxidants
nitrous oxides
Fig p. 440
Low level Ozone
(Tropo.)

9. Temperature Inversions
Thermal inversion – how it forms and increases potential for consistent photochemical smog
Fig p. 443

10. Outdoor Air Pollution from Acid Deposition
Acid deposition- wet and dry
Fig p. 444

11. Acid Deposition in the US
Fig p. 445
Remember Limestone lab!
High levels of
calcium carbonate
in soil helps neutralize
the effects of acid rain!

12. Acid Deposition Effects
Respiratory diseases
Metal leaching –Al ions (toxic)in soil; Mg ions loss for plant uptake (non-toxic)
Damage to structures, especially containing calcium carbonate
Decreased visibility
Fish declines
Coral bleaching

13. Emission Acid deposition SO2 H2O2 PANs NOX O3 Others Increased
Susceptibility
to drought,
extreme cold,
insects, mosses,
and disease
organisms
Direct damage
to leaves and bark
Reduced
photosynthesis
and growth
Soil acidification
Tree death
Leaching of
Soil nutrients
Release of
toxic
metal ions
Root
damage
Reduced nutrient
and water uptake
Acid
Groundwater

14. Indoor Air Pollution
Fig
p. 450

15. Effects of Air Pollution on People
Respiratory diseases (see Fig p. 452)
Asthma
Air purifiers – Consumer Reports best for removing small particulates (allergies)
Lung cancer
Chronic bronchitis
Emphysema
Premature death

17. Solutions: Preventing and Reducing Air Pollution
Clean Air Act (1970, amended 1990)
National Ambient Air Quality Standards (NAAQS)
Emissions trading
Cleaning technologies:
Electrostatic precipitators (electrodes; particulates)
Scrubbers (sulfur dioxides =smoke stacks=coal)
Cleaning coal to remove sulfur before burning

18. Clean Air Act 1970 Set stricter standards to air quality
Imposed emissions limits
Funds for pollution control research
amended include reduction in vehicle emission; catalytic converter technology (reduced 98% of 1960’s vehicle emissions) and Clean Air Facts of vehicle technology
1990
Strengthened air quality standards
Emission trading program for SO2

19. (See minimum levels on EPA website)
EPA Standards (NAAQS)
6 Main “Criteria” Pollutants:
Carbon monoxide (CO)
Sulfur dioxide (SO2)
Nitrogen dioxide (NO2)
Tropospheric ozone (O3)
Particulate Matter (PM10, PM2.5)
Lead (Pb)
*Volatile Organic Compounds (VOCs)- hydrocarbons from burning methane, propane, butane
(See minimum levels on EPA website)

20. More serious health risks!
Particulate Matter
More serious health risks!

21. Particulate Matter Collectors

22. Emission Reduction - Scrubbers = smoke stacks of coal plants
Fig a p. 457

23. Climate Change and Ozone Loss
Chapter 21
Climate Change and Ozone Loss

24. Past Climate Changes Past global temperatures
Recent trends in global temperatures
Fig p. 463

25. How Scientists Monitor Climate change
Ocean sediment cores
Fossils of plankton
Isotopes of various chemicals
Depths of different layers/particle size
Fossil record
Fossil pollen
Fossil flora
Fossil fauna
Tree cores
Ice cores
Isotopes of oxygen in ice (related to temperature)
C02 concentrations
Sea Level Changes

27. Major Greenhouse Gases
Water vapor
Carbon Dioxide (highest concentrations)
CFCs (Chlorofluorocarbons)
Ozone (O3)
Methane (CH4)
Nitrous Oxide (N2O)
These gases absorb infrared radiation.
CH4 = Burning biomass, production of Coal and natural gas
Ag. Activities (anaerobic decomposition)
CFC/ HCFC/HFC = Anthropogenic only
Air Conditioners, refrigerators
*use to be the major propellant
of aerosol sprays
CO2 = Fossil fuels
Deforestation
N2O = Fertilizers
Burning of fossil fuels, livestock wastes, nylon products
CFC and methane accumulate faster than CO2.
CFC’s stay in the stratosphere longer.

29. Factors Affecting the Earth’s Temperature
Changes in solar output
Changes in Earth’s albedo (ability of white ice caps to reflect 80-90% of incoming sunlight)
Moderating effect of oceans
Clouds and water vapor
Air pollution

30. Courtesy of

31. Climate Change and Human Activities
Increased use of fossil fuels
Deforestation
Global warming
Melting icecaps and glaciers
Rising sea level

32. Possible Benefits from a Warmer Atmosphere (depending on where you live)
Less severe winters
More precipitation in some dry areas
Less precipitation in some wet areas
Increased food production in some areas
Expanded population and ranges of some species (spruce bark beetle)
Refer to Fig p. 476

33. Some Possible Effects of a Warmer World
GLOBAL EFFECTS of Climate change

34. Solutions: Dealing with the Threat of Climate Change
Fig p. 479
Options
Do nothing
Do more research
Act now to reduce risks
Precautionary principle

35. through abandoned oil field
Coal
power plant
Tanker delivers
CO2 from plant
to rig
Oil rig
Tree
plantation
CO2 is
pumped down
from rig for deep
ocean disposal
Abandoned
oil field
Switchgrass
Crop field
CO2 is pumped
down to reservoir
through abandoned oil field
Spent oil reservoir is
used for CO2 deposit
= CO2 deposit
= CO2 pumping

36. Reducing Greenhouse Gas Emissions
Kyoto Treaty (1997) – 39 countries agreed to
reduce their greenhouse gas emissions; by 2004 it included more
than 120 countries!
U.S. withdraws from Kyoto Treaty
(2001)- controversial
Other reductions in CO2 – schools,
businesses, and homes converting to use of more energy efficient
products
Refer to Fig p. 483

37. Global Warming vs. Ozone Depletion
Involves troposphere
Substances involved: greenhouse gases that trap heat (CO2, CH4, N2O)
Problem: burning of FF, deforestation increase trapping of heat and increase Earth’s temp.
Consequences: changes in climate, agric. productivity, H2O supplies, and sea level
Responses: decrease fossil fuel use and deforestation; prepare for climate change
Ozone Depletion
Involves stratosphere
Substances involved: O3, O2, CFC’s
Problem: human activities and CFC’s destroy ozone allowing more UV radiation to reach Earth
Consequences: increase skin cancer, cataracts, damage to crops/phytoplankon
Responses: Eliminate/substitute for CFC’s and ODC’s

38. Ozone Stratospheric Ozone – good thing! 97% of all UV absorbed by 03
Formed from O2 – life driven

40. Former Uses of CFCs Air Conditioners Refrigerators Spray cans
Cleaners for electronic parts
Sterilizing medical instruments
Fumigants for granaries and cargo ships

41. movie Ultraviolet light hits a chlorofluorocarbon
(CFC) molecule, such as CFCl3, breaking
off a chlorine atom and leaving
CFCl2.
Sun Cl Cl C
Once free, the chlorine atom is off
to attack another ozone molecule
and begin the cycle again. Cl F
UV radiation
movie Cl Cl O O
A free oxygen atom pulls
the oxygen atom off
the chlorine monoxide
molecule to form O2.
The chlorine atom attacks
an ozone (O3) molecule, pulling an oxygen atom
off it and leaving
an oxygen
molecule (O2). Cl Cl O O O O O
The chlorine
atom and the
oxygen atom join
to form a chlorine
monoxide molecule (ClO). Cl O
Summary of Reactions
CCl3F + UV Cl + CCl2F
Cl + O3 ClO + O2
Cl + O Cl + O2
Repeated
many times O O

42. Seasonal Ozone Layer Thinning at the Poles
Ozone thinning (hole)
Polar vortex

45. Effects of Ozone Depletion
Wildlife
• Increased eye cataracts in some species
• Decreased population of aquatic species
sensitive to UV radiation
• Reduced population of surface
phytoplankton
• Disrupted aquatic food webs from reduced
Air Pollution and Materials
• Increased acid deposition
• Increased photochemical smog
• Degradation of outdoor paints and plastics
Global Warming
• Accelerated warming because of decreased
ocean uptake of CO2 from atmosphere by
phytoplankton and CFCs acting as
greenhouse gases
Human Health
• Worse sunburns
• More eye cataracts
• More skin cancers
• Immune system suppression
Food and Forests
• Reduced yields for some crops
• Reduced seafood supplies from reduced phytoplankton
Decreased forest productivity for
UV-sensitive tree species

46. Solutions: Protecting the Ozone Layer
CFC substitutes
Montreal Protocol limits/ bans CFC’s ;
production stopped in 1995; India and China not a part of the treaty
Fig p. 489
Copenhagen
Protocol