Air Pollution

1
Air Pollution

• Chapter 18

2
Core Case Study South Asias Massive Brown Cloud

• Asian Brown Cloud
• Causes
• Chemical composition
• Areas impacted
• Air pollution connects the world
• Steps taken in China and India to reduce air
  pollution

3
The Asian Brown Cloud
4
Air Pollution in Shanghai, China, in 2004
5
18-1 What Is the Nature of the Atmosphere?

• Concept 18-1 The atmosphere is structured in
  layers, including the troposphere, which supports
  life, and the stratosphere, which contains the
  protective ozone layer.

6
The Atmosphere Consists of Several Layers

• Atmosphere varies in
• Density
• Atmospheric pressure

7
Air Movements in the Troposphere Play a Key Role
in Earths Weather and Climate

• Troposphere
• 7580 of the earths air mass
• Closet to the earth's surface
• Chemical composition of air
• Rising and falling air currents weather and
  climate
• Involved in chemical cycling

8
The Stratosphere Is Our Global Sunscreen

• Stratosphere
• Similar composition to the troposphere, with 2
  exceptions
• Much less water
• O3, ozone layer, filters UV
• Location

9
Atmospheric pressure (millibars)
1,000
0
200
400
600
800
120
75
Temperature
110
65
Thermosphere
100
90
55
Mesopause
80
Mesosphere
45
70
Altitude (kilometers)
Altitude (miles)
60
Stratopause
35
50
Stratosphere
40
25

30
Tropopause
15
Ozone layer
20
10
Pressure
Troposphere
5
(Sea level)
0
Pressure 1,000 millibars at ground level
80
40
80
120
40
0
Temperature (C)
Fig. 18-3, p. 470
10
18-2 What Are the Major Outdoor Pollution
Problems?

• Concept 18-2 Pollutants mix in the air to form
  industrial smog, mostly the result of burning
  coal, and photochemical smog, caused by motor
  vehicle, industrial, and power plant emissions.

11
Air Pollution Comes from Natural and Human
Sources (1)

• Air pollution
• Natural sources
• Dust blown by wind
• Pollutants from wildfires and volcanoes
• Volatile organics released by plants
• Withdrawing groundwater

12
Case Study Air Pollution in the Past The Bad
Old Days (1)

• Discovery of fire
• Middle Ages
• Industrial Revolution
• London, England
• 1850s
• 1952 yellow fog
• Clean Air Act of 1956

13
Case Study Air Pollution in the Past The Bad
Old Days (2)

• United States
• 1948 Donora, PA first U.S. air pollution
  disaster
• 1963 New York City
• Global problem

14
Some Pollutants in the Atmosphere Combine to Form
Other Pollutants

• Primary pollutants
• Secondary pollutants
• Air quality improving in developed countries
• Much more needs to be done in developing
  countries
• Indoor pollution big threat to the poor

15
Primary Pollutants
Secondary Pollutants
CO
CO2
SO2
NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended particles
H2O2
O3
PANs
Most NO3- and SO42- salts
Sources
Natural
Stationary
Mobile
Fig. 18-4, p. 472
16
What Are the Major Outdoor Air Pollutants? (1)

• Carbon oxides
• Carbon monoxide (CO)
• Carbon dioxide (CO2)
• Sources
• Human health and environmental impact

17
What Are the Major Outdoor Air Pollutants? (2)

• Nitrogen oxides (NO) and nitric acid (HNO3)
• Sources
• Acid deposition
• Photochemical smog
• Human health and environmental impact
• Sulfur dioxide (SO2) and sulfuric acid (H2SO4)
• Sources
• Human health and environmental impact

18
What Are the Major Outdoor Air Pollutants? (3)

• Particulates
• Suspended particulate matter (SPM)
• Fine
• Ultrafine
• Sources
• Human health and environmental impact

19
What Are the Major Outdoor Air Pollutants? (4)

• Ozone (O3)
• Sources
• Human and environmental impact
• Volatile organic compounds (VOCs)
• Hydrocarbons and terpenes
• Sources
• Human and environmental impact

20
Chemical Reactions That Form Major Outdoor Air
Pollutants
21
Stepped Art
Table 18-1, p. 473
22
Statue Corroded by Acid Deposition and Other
Forms of Air Pollution, RI, U.S.
23
Science Focus Detecting Air Pollutants

• Chemical instruments
• Satellites
• Nanotechnology
• Biological indicators
• Lichens

24
Natural Capital Lichen Species, Vulnerability
to Air Pollutants
25
Case Study Lead Is a Highly Toxic Pollutant (1)

• Does not break down in the environment
• Sources
• Human health and environmental impact
• Most vulnerable

26
Case Study Lead Is a Highly Toxic Pollutant (2)

• Reduction of lead (Pb)
• Unleaded gasoline
• Unleaded paint
• Still problems
• 2007 toys with Pb paint recalled
• Global ban on lead in gasoline and paint

27
SOLUTIONS
Lead Poisoning
Prevention
Control
Replace lead pipes and plumbing fixtures
containing lead solder
Phase out leaded gasoline worldwide
Phase out waste incineration
Remove leaded paint and lead dust from older
houses and apartments
Ban use of lead solder
Sharply reduce lead emissions from incinerators
Ban use of lead in computer and TV monitors
Remove lead from TV sets and computer monitors
before incineration or land disposal
Ban lead glazing for ceramicware used to serve
food
Test for lead in existing ceramicware used to
serve food
Ban candles with lead cores
Test existing candles for lead
Test blood for lead by age 1
Wash fresh fruits and vegetables
Fig. 18-7, p. 476
28
Burning Coal Produces Industrial Smog

• Chemical composition of industrial smog
• Reduction of this smog in urban cities of the
  United States
• China and smog
• Human deaths

29
Stepped Art
Fig. 18-8, p. 476
30
Sunlight Plus Cars Equals Photochemical Smog

• Photochemical Smog
• Chemical composition
• Sources
• VOCs NO2 Heat Sunlight yields
• Ground level O3 and other photochemical oxidants
• Aldehydes
• Other secondary pollutants
• Human health and environmental impact

31
PANS and other pollutants
Volatile organic compounds (VOCs)
Ozone (O3)
Oxygen (O2)
Nitric oxide (NO) Oxygen atom (O)
Water vapor (H2O)
Hydrocarbons
UV radiation
Peroxyacyl nitrates (PANs)
Nitrogen dioxide (NO2)
Oxygen (O2)
Nitric oxide (NO)
Oxygen (O2)
Burning fossil fuels
Nitrogen (N) in fossil fuel
Fig. 18-9, p. 477
32
Global Outlook Photochemical Smog in Santiago,
Chile
33
Denvers Brown Cloud
http//www.infrastructurist.com/wp-content/uploads
/brown-cloud.jpg
34
Several Factors Can Decrease or Increase Outdoor
Air Pollution (1)

• Outdoor air pollution may be decreased by
• Settling of particles due to gravity
• Rain and snow
• Salty sea spray from the ocean
• Winds
• Chemical reactions

35
Several Factors Can Decrease or Increase Outdoor
Air Pollution (2)

• Outdoor air pollution may be increased by
• Urban buildings
• Hills and mountains
• High temperatures
• Emissions of VOCs from certain trees and plants
• Grasshopper effect
• Temperature inversions

36
Descending warm air mass
Warmer air
Inversion layer
Inversion layer
Sea breeze
Increasing altitude
Decreasing temperature
Fig. 18-11, p. 478
37
18-3 What Is Acid Deposition and Why Is It a
Problem?

• Concept 18-3 Acid deposition is caused mainly by
  coal-burning power plant and motor vehicle
  emissions, and in some regions, threatens human
  health, aquatic life and ecosystems, forests, and
  human-built structures.

38
Acid Disposition Is a Serious Regional Air
Pollution Problem

• Acid deposition, acid rain
• Formation
• Local versus regional problems
• Effects of prevailing winds
• Buffers
• Where is the worst acid deposition?

39
Wind
Transformation to sulfuric acid (H2SO4) and
nitric acid (HNO3)
Windborne ammonia gas and some soil particles
partially neutralize acids and form dry sulfate
and nitrate salts
Wet acid depostion (droplets of H2SO4 and HNO3
dissolved in rain and snow)
Nitric oxide (NO)
Sulfur dioxide (SO2) and NO
Dry acid deposition (sulfur dioxide gas and
particles of sulfate and nitrate salts)
Acid fog
Lakes in shallow soil low in limestone become
acidic
Lakes in deep soil high in limestone are buffered
Fig. 18-12, p. 479
40
Potential problem areas because of sensitive soils
Potential problem areas because of air pollution
emissions leading to acid deposition
Current problem areas (including lakes and rivers)
Fig. 18-13, p. 480
41
Acid Deposition Has a Number of Harmful Effects
(1)

• Human respiratory disorders
• Aquatic ecosystems affected
• Release of toxic metals

42
Acid Deposition Has a Number of Harmful Effects
(2)

• Leaching of soil nutrients
• Loss of crops and trees
• Damage to buildings, statues, and monuments

43
Emissions
NOx
SO2 H2O2 PANs
Acid deposition
O3 Others
Increased susceptibility to drought, extreme
cold, insects, mosses, and disease organisms
Direct damage to leaves and bark
Reduced photosynthesis and growth
Tree death
Soil acidification
Release of toxic metal ions
Leaching of soil nutrients
Reduced nutrient and water uptake
Root damage
Acids
Lake
Groundwater
Fig. 18-14a, p. 481
44
Science Focus Hubbard Brook Study Effects of
Acid Rain

• White Mountains, NH, U.S.
• Experimentation supports
• Trees do not suffer from direct contact with acid
  rain
• Nutrients are leached out of the soil
• Effect of Ca2 on regrowth of the forest

45
We Know How to Reduce Acid Deposition

• Prevention approaches
• Clean up
• Add lime to neutralize acidified lakes and soil
• Add phosphate fertilizer to neutralize acidified
  lakes

46
SOLUTIONS
Acid Deposition
Prevention
Cleanup
Add lime to neutralize acidified lakes
Reduce coal use
Burn low-sulfur coal
Increase natural gas use
Add phosphate fertilizer to neutralize acidified
lakes
Increase use of renewable energy resources
Remove SO2 particulates and NOx from smokestack
gases
Remove NOx from motor vehicular exhaust
Tax emissions of SO2
Reduce air pollution by improving energy
efficiency
Fig. 18-15, p. 483
47
Indoor Air Pollution
48
18-4 What Are the Major Indoor Air Pollution
Problems?

• Concept 18-4 The most threatening indoor air
  pollutants are smoke and soot from wood and coal
  cooking fires (a hazard found mostly in
  developing countries) and chemicals used in
  building materials and products.

49
Indoor Air Pollution Is a Serious Problem (1)

• Developing countries
• Indoor burning
• Poor suffer the greatest risk
• Developed countries
• Indoor air pollution is greater than outdoor air
  pollution

50
Indoor Air Pollution Is a Serious Problem (2)

• Why?
• 11 of the common air pollutants higher inside
  than outside
• Greater in vehicles than outside
• Health risks magnified people spend 7098 of
  their time is indoors

51
Indoor Air Pollution Is a Serious Problem (3)

• Who are at greatest risk from indoor air
  pollution?
• Children under 5 and the elderly
• Sick
• Pregnant women
• People with respiratory disorders or heart
  problems
• Smokers
• Factory workers

52
Indoor Air Pollution Is a Serious Problem (4)

• Four most dangerous indoor air pollutants
• Tobacco smoke
• Formaldehyde
• Radioactive radon-222 gas
• Very small particles
• Sources of these pollutants
• Human health risks

53
Indoor Air Pollution Is a Serious Problem (5)

• Other possible indoor air pollutants
• Pesticide residue
• Pb particles
• Living organisms and their excrements
• E.g., Dust mites and cockroach droppings
• Airborne spores of molds and mildews
• Sick-building syndrome

54
Some Important Indoor Air Pollutants
55
Science Magnified View of a Household Dust Mite
in a Dust Ball
56
Case Study Radioactive Radon Gas

• Sources
• Human health risks
• Testing for radon
• Correcting a radon problem

57
Outlet vents for furnaces and dryers
Open
window
Cracks in wall
Openings around pipes
Slab joints
Wood stove
Cracks in floor
Sump pump
Clothes dryer
Furnace
Radon-222 gas
Slab
Uranium-238
Soil
Fig. 18-18, p. 485
58
18-5 What Are the Health Effects of Air
Pollution?

• Concept 18-5 Air pollution can contribute to
  asthma, chronic bronchitis, emphysema, lung
  cancer, heart attack, and stroke.

59
Your Bodys Natural Defenses against Air
Pollution Can Be Overwhelmed

• Respiratory system protection from air pollutants
• Role of cilia, mucus, sneezing, and coughing
• Effect of smoking and prolonged air pollution
  exposure
• Chronic bronchitis
• Emphysema

60
Major Components of the Human Respiratory System
61
Normal Human Lungs and the Lungs of a Person Who
Died of Emphysema
62
Air Pollution Is a Big Killer

• 3 Million deaths per year world-wide
• Mostly in Asia
• Main causes
• EPA proposed stricter emission standards for
  diesel-powered vehicles
• Link between international trade and air
  pollution
• Cargo ships and pollution

63
Premature Deaths from Air Pollution in the U.S.
64
18-6 How Should We Deal with Air Pollution?

• Concept 18-6 Legal, economic, and technological
  tools can help to clean up air pollution, but
  much greater emphasis should be focused on
  preventing air pollution.

65
Laws and Regulations Can Reduce Outdoor Air
Pollution (1)

• United States
• Clean Air Acts 1970, 1977, and 1990
• EPA
• National ambient air quality standards (NAAQs)
  for 6 outdoor criteria pollutants
• National emission standards for 188 hazardous air
  pollutants (HAPs)
• Toxic Release Inventory (TRI)

66
Laws and Regulations Can Reduce Outdoor Air
Pollution (2)

• Good news in U.S.
• Decrease in emissions
• Use of low-sulfur diesel fuel
• Cuts pollution
• Developing countries
• More air pollution

67
Case Study U.S. Air Pollution Can Be Improved
(1)

• Rely on cleanup more than prevention of pollution
• Raise fuel-efficiency for cars, SUVs, and light
  trucks
• Better regulation of emissions of motorcycles and
  two-cycle gasoline engines
• Regulate air pollution for oceangoing ships in
  American ports

68
Case Study U.S. Air Pollution Can Be Improved
(2)

• Why are airports exempt from many regulations?
• Regulate greenhouse gas emissions
• Ultrafine particles are not regulated
• Urban O3 levels too high

69
Case Study U.S. Air Pollution Can Be Improved
(3)

• What about indoor air pollution?
• Better enforcement of the Clean Air Acts
• Is intense pressure needed from citizens to make
  improvements?

70
We Can Use the Marketplace to Reduce Outdoor Air
Pollution

• Emission trading or cap-and-trade program
• Mixed reactions to program
• SO2 emissions down significantly
• NO2 will be tried in the future

71
There Are Many Ways to Reduce Outdoor Air
Pollution

• 1980 2006
• SO2 emissions from U.S. electric power plants
  decreased by 66
• NOx emissions by 41
• Particulate emissions by 28
• Older plants not governed by the same regulations
• New cars have better emissions

72
SOLUTIONS
Stationary Source Air Pollution
Prevention
Dispersion or Cleanup
Burn low-sulfur coal
Disperse emissions above thermal inversion layer
with tall smokestacks
Remove sulfur from coal
Remove pollutants after combustion
Convert coal to a liquid or gaseous fuel
Shift to less polluting energy sources
Tax each unit of pollution produced
Fig. 18-22, p. 491
73
SOLUTIONS
Motor Vehicle Air Pollution
Prevention
Cleanup
Use mass transit
Require emission control devices
Walk or bike
Use less polluting fuels
Inspect car exhaust systems twice a year
Improve fuel efficiency
Get older, polluting cars off the road
Give large tax write- offs or rebates for buying
low-polluting, energy efficient vehicles
Set strict emission standards
Fig. 18-23, p. 491
74
Reducing Indoor Air Pollution Should Be a
Priority

• Greater threat to human health than outdoor
  pollution
• What can be done?
• Prevention
• Cleanup

75
SOLUTIONS
Indoor Air Pollution
Prevention
Cleanup or Dilution
Clean ceiling tiles and line AC ducts to prevent
release of mineral fibers
Use adjustable fresh air vents for work spaces
Ban smoking or limit it to well-ventilated areas
Increase intake of outside air
Set stricter formaldehyde emissions standards for
carpet, furniture, and building materials
Change air more frequently
Circulate a buildings air through rooftop
greenhouses
Prevent radon infiltration
Use office machines in well-ventilated areas
Use efficient venting systems for wood-burning
stoves
Use less polluting substitutes for harmful
cleaning agents, paints, and other products
Use exhaust hoods for stoves and appliances
burning natural gas
Fig. 18-24, p. 492
76
What Can You Do? Indoor Pollution Ways to Reduce
Your Exposure
77
We Need to Put More Emphasis on Pollution
Prevention

• Output approaches
• New shift to preventing outdoor and indoor
  pollution
• Pressure from citizens

78
SOLUTIONS
Air Pollution
Outdoor
Indoor
Improve energy efficiency to reduce fossil fuel
use
Reduce poverty
Distribute cheap and efficient cookstoves or
solar cookers to poor families in developing
countries
Rely more on lower-polluting natural gas
Rely more on renewable energy (especially solar
cells, wind, and solar-produced hydrogen)
Reduce or ban indoor smoking
Transfer energy efficiency, renewable energy, and
pollution prevention technologies to developing
countries
Develop simple and cheap tests for indoor
pollutants such as particulates, radon, and
formaldehyde
Fig. 18-26, p. 493