Air Pollution

1
Air Pollution

• Chapter 15

2
Key Concepts

• Structure and composition of the atmosphere
• Types and origins of major outdoor air pollutants
• Two types of smog
• Acid deposition and how it can be reduced
• Harmful effects of air pollutants
• Preventing and controlling air pollution

3
When is a Lichen Like a Canary?

• Mine canaries
• Lichens
• Detectors of air pollution
• Isle Royale in Lake Superior
• Chernobyl

Fig. 15-1, p. 345
4
When is a Lichen Like a Canary?
Fig. 15-1, p. 345
5
Earths Atmosphere

• Troposphere
• 78 N2, 21 O2
• Stratosphere
• Ozone layer

Fig. 15-2, p. 347
6
Earths Atmosphere
Atmospheric pressure (millibars)
0
200
400
600
800
1,000
120
75
Temperature
110
Pressure
65
100
Thermosphere
90
55
Heating via ozone
80
Mesosphere
45
70
60
Altitude (kilometers)
Altitude (miles)
35
50
Stratosphere
40
25
30
15
Ozone layer
20
Heating from the earth
10
5
Troposphere
0
80
40
0
40
80
120
Pressure 1,000 millibars at ground level
(Sea Level)
Temperature (C)
Fig. 15-2, p. 347
7
Outdoor Air Pollution

• What is air pollution?
• Stationary and mobile sources
• Primary pollutants
• Secondary pollutants
• How air pollutants migrate
• Health threats
• Major air pollutants (Table 15-1, p. 349)
• Volatile organic compounds (VOCs)
• Carbon dioxide a pollutant?

8
Sources and Types of Air Pollutants
Primary Pollutants
CO
CO2
Secondary Pollutants
SO2
NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended particles
H2O2
O3
PANs
Most
and
salts
Sources
Natural
Stationary
Mobile
Fig. 15-3, p. 348
9
Table 15-1, p. 349
10
Photochemical Smog

• Photochemical reactions
• Photochemical smog
• Natural and human origins
• Brown-air smog
• Temperature effects
• Urban areas

11
Photochemical Smog in Mexico City
Fig. 15-4, p. 351
12
Industrial Smog

• Science Spotlight, p. 350 Air Pollution in the
  Past The Bad Old Days
• Composition of industrial smog (sulfur dioxide
  and sulfuric acid)
• Gray-air smog
• Situation better in developed countries
• Serious problem in industrializing countries,
  such as China
• Black Triangle of eastern Europe
• Asian brown cloud

13
Industrial Smog in India
Fig. 15-5, p. 351
14
How Natural Eliminates Smog

• Rain and snow
• Salty sea spray
• Winds

15
Factors Influencing the Formation of Smog

• Urban buildings
• Topography
• High temperatures
• Grasshopper Effect
• Temperature inversions

16
Acid Deposition

• Sulfur dioxide and nitrogen oxides
• Wet and dry acid deposition
• Acid rain
• Regional air pollution
• Ohio Valley
• Buffers
• Wind transportation

17
Acid Deposition
Wind
Transformation to sulfuric acid (H2SO4) and
nitric acid (HNO3)
Windborne ammonia gas and particles of cultivated
soil partially neutralize acids and form dry
sulfate and nitrate salts
Wet acid deposition (droplets of H2SO4 and HNO3
dissolved in rain and snow)
Nitric oxide (NO)
Dry acid deposition (sulfur dioxide gas and
particles of sulfate and nitrate salts)
Sulfur dioxide (SO2) and NO
Acid fog
Farm
Lakes in shallow soil low in limestone become acid
ic
Ocean
Lakes in deep soil high in limestone are buffered
Fig. 15-6, p. 353
18
pH Measurements at US Sites
Fig. 15-7, p. 354
19
Current and Potential Problems with Acid
Deposition
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. 15-8, p. 355
20
Harmful Effects of Acid Deposition

• Respiratory diseases in humans (bronchitis and
  asthma)
• Leaches metals from water pipes
• Damages statues and other property
• Decreases atmospheric visibility (Grand Canyon)
• Kills fish and other aquatic organisms
• Leaches plant nutrients from soils
• Weakens trees (mountaintop forests)

21
Impacts of Air Pollution on Trees and Water
Emission
Acid deposition
SO2 H2O2 PANs
NOX O3 Others
Increased Susceptibility to drought, extreme
cold, insects, mosses, and disease organisms
Reduced photosynthesis and growth
Direct damage to leaves and bark
Soil acidification
Tree death
Root damage
Reduced nutrient and water uptake
Leaching of soil nutrients
Release of toxic metal icons
Acid
Groundwater
Fig. 15-9, p. 356
22
Tree Damage from Acid Deposition
Fig. 15-10, p. 356
23
Reducing Acid Deposition
Solutions
Acid Deposition
Prevention
Cleanup
Reduce air pollution by improving energy
efficiency
Add lime to neutralize acidified lakes
Reduce coal use
Add phosphate fertilizer to neutralize acidified
lakes
Increase natural gas use
Increase use of renewable resources
Burn low-sulfur coal
Remove SO2 particulates, and Nox from
smokestack gases
Remove Nox from motor vehicular exhaust
Tax emissions of SO2
Fig. 15-11, p. 357
24
Indoor Air Pollution

• Pollutants often at higher concentrations indoors
• Pollution inside cars
• Most people spent most of their time indoors
• Cancer risks
• Sick-building syndrome
• Mold and allergies
• Serious problem in developing countries

25
Major Indoor Air Pollutants

• Tobacco smoke
• Formaldehyde
• Radon
• Very fine particles

26
Major Indoor Air Pollutants
Para-dichlorobenzene
Chloroform
Formaldehyde
Tetrachloro-ethylene
1, 1, 1- Trichloroethane
Styrene
Nitrogen Oxides
Benzo-a-pyrene
Particulates
Radon-222
Tobacco Smoke
Asbestos
Methylene Chloride
Carbon Monoxide
Fig. 15-12, p. 358
27
Radon

• Radioactive Rn-222
• Lung cancer threat
• With uranium in rocks and soils
• Testing homes
• Remedies

Fig. 15-13, p. 359
28
Radon
Outlet vents for furnaces and dryers
Slab joints
Wood stove
Cracks in floor
Sump pump
Clothes dryer
Furnace
Slab
Radon-222 gas
Uranium-238
Soil
Fig. 15-13, p. 359
29
Harmful Effects of Air Pollution

• Human respiratory system
• Asthma
• Lung cancer
• Chronic bronchitis
• Emphysema
• Health effects of major air pollutants (Table
  15-1, p. 349)
• Premature deaths
• Serious threat of indoor air pollution
• Impact of coal-fired power plants
• Cancer from diesel exhausts

30
Human Respiratory System
Fig. 15-14a, p. 360
31
Human Respiratory System
Nasal cavity
Oral cavity
Pharynx (throat)
Trachea (windpipe)
Bronchus
Right lung
Bronchioles
Fig. 15-14a, p. 360
32
Human Respiratory System
Epithelial cell
Cilia
Goblet cell(secretingmucus)
Mucus
Fig. 15-14b, p. 360
33
Human Respiratory System
Bronchiole
Alveolar duct
Alveolar sac (sectioned)
Alveoli
Fig. 15-14c, p. 360
34
Healthy and Diseased Human Lungs
Fig. 15-15, p. 360
35
Premature US Deaths from Air Pollution
Fig. 15-16, p. 361
36
Preventing and Reducing Air Pollution

• U.S. Clean Air Acts
• National Ambient Air Quality Standards
• Criteria from risk assessments
• Primary standards
• Secondary standards
• Hazardous air pollutants
• Toxic Release Inventory
• Right to Know laws
• Emissions trading

37
Solutions Stationary Source Air Pollution
Solutions
Stationery Source Air Pollution
Dispersion or Cleanup
Prevention
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
Tax each unit of pollution produced
Shift to less polluting fuels
Fig. 15-17, p. 363
38
Solutions Motor Vehicles
Solutions
Motor Vehicle Pollutions
Prevention
Cleanup
Mass transit
Emission control devices
Bicycles and walking
Less polluting engines
Less polluting fuels
Car exhaust Inspections twice a year
Improve fuel efficiency
Get older, polluting cars off the road
Give buyers tax write- offs for buying
low- polluting, energy- efficient vehicles
Stricter emission standards
Restrict driving in polluted areas
Fig. 15-18, p. 364
39
Solutions Indoor Air Pollution
Solutions
Indoor Air Pollution
Prevention
Cleanup
Cover ceiling tiles and lining of AC ducts to
prevent release of mineral fibers
Use adjustable fresh air vents for work spaces
Increase intake of outside air
Ban smoking or limit it to well-ventilated areas
Change air more frequently
Set stricter formaldehyde emissions standards for
carpet, furniture, and building materials
Circulate buildings air through rooftop
greenhouses
Prevent radon infiltration
Use exhaust hoods for stoves and appliances
burning natural gas
Use office machines in well-ventilated areas
Use less polluting substitutes for harmful
cleaning agents, paints, and other products
Install efficient chimneys for wood-burning
stoves
Fig. 15-19, p. 364
40
Solutions Air Pollution
Solutions
Air Pollution
Prevention
Cleanup
Improve energy efficiency to reduce fossil fuel
use
Reduce poverty
Distribute cheap and efficient cookstoves 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
Develop simple and cheap test for indoor
pollutants such as particulates, radon, and
formaldehyde
Transfer technologies for latest energy
efficiency, renewable energy, and pollution
prevention to developing countries.
Fig. 15-20, p. 365
41
What Can You Do?
What Can You Do?
Indoor Air Pollution

• Test for radon and formaldehyde inside your home
  and take corrective measures as needed.
• Do not buy furniture and other products
  containing formaldehyde.
• Remove your shoes before entering your house to
  reduce inputs of dust, lead, and pesticides.
• Test your house or workplace for asbestos fiber
  levels and for any crumbling asbestos materials
  if it was built before 1980.
• Don't live in a pre-1980 house without having its
  indoor air tested for asbestos and lead.
• Do not store gasoline, solvents, or other
  volatile hazardous chemicals inside a home or
  attached garage.
• If you smoke, do it outside or in a closed room
  vented to the outside.
• Make sure that wood-burning stoves, fireplaces,
  and kerosene- and gas-burning heaters are
  properly installed, vented, and maintained.
• Install carbon monoxide detectors in all sleeping
  areas.

Fig. 15-21, p. 365