Mrs. Sealy APES

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Ch. 17 Notes Air Pollution

• Mrs. Sealy APES

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I. Air pollution detectors

• canaries died in mines when there was too much
  methane
• lichens fungi and alga living together that
  can live almost anywhere for long periods of
  time

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II. Atmosphere - thin envelope of life-sustaining
gases surrounding the earth (divided into
several spherical layers)

• 1.  Troposhere innermost layer extending about
  17 km above sea level
• a.  contains about 75 of the mass of earths air
  
• b.  weather occurs here
• c.  78 nitrogen / 21 oxygen / 1 argon / 0.036
  carbon dioxide
• d.  average pressure exerted by gases in the
  atmosphere decreases with altitude because
  average density (mass of gases per unit of vol.)
  decreases with altitude

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Atmosphere

• 2. tropopause top zone of the troposphere where
  temperature declines with altitude but then
  abruptly begins to rise

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Atmospheric pressure (millibars)
0
200
400
600
800
1,000
120
75
110
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Thermosphere
100
90
55
80
Heating via ozone
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Mesosphere
70
60
Altitude (miles)
Altitude (kilometers)
35
50
Stratosphere
40
25
30
15
Ozone layer
20
Heating from the earth
Troposphere
10
5
Pressure 1,000 millibars at ground level
0
80
40
0
40
80
120
Fig. 17.2, p. 418
(Sea Level)
Temperature (C)
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Atmosphere

• 3. stratosphere atmospheres 2nd layer extending
  from 17-48 km above earths surface
• a. contains less matter than the troposphere but
  has similar composition
• b. calm air, little mixing - good for flying
  planes
• c. ozone global sunscreen keeps about 99 of
  UV radiation out
• i. allows humans and other life to exist
• ii. helps protect humans from sunburn, cancer,
  cataracts, damage to immune system
• iii. prevents oxygen in the troposphere from
  being converted to ozone, a harmful airpollutant
  which causes smog and damage to plants

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40
25
35
20
Stratosphere
30
25
Stratospheric ozone
15
Altitude (kilometers)
Altitude (miles)
20
10
15
10
5
Troposphere
5
0
0
0
5
10
15
20
Fig. 17.3, p. 419
Ozone concentration (ppm)
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III. Necessary natural processes in the
atmosphere

• Greenhouse effect traps heat in the troposphere
•  global warming caused by the addition of
  heat-trapping chemicals to the atmosphere
• ozone shield part of the stratosphere which
  filters out most UV radiation
• Ozone depletion reduction of the concentration
  of ozone

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IV. Disruption of Earths gaseous nutrient cycles

• 1. Burning fossil fuels and clearing forests
• a. disrupts ____________and can alter global
  climate and food-producing regions, cause huge
  heated air masses (heat islands) and dust domes
  over urban areas
• b. disrupts _____________-nitrous oxides are
  converted to nitric acid which falls as acid rain
  
• c. disrupts the sulfur cycle -sulfur dioxide from
  petroleum refining and burning of oil and coal
  causes acid rain

NOx
SOx
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AIR Pollution

• V. Air pollution the presence of 1 or more
  chemicals in the atmosphere in quantities and
  duration that cause harm to humans, other forms
  of life, and materials

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Types of pollutants

• Primary pollutants potential pollutants that
  have been directly added to the air by natural
  events or humans activities
• Secondary pollutants harmful chemicals formed in
  the atmosphere when a primary pollutant reacts
  with normal air components or other air
  pollutants

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Types of Sources of Pollution

• Stationary sources power plants and factories
•  mobile sources of pollution cars ( responsible
  for 80-88 of air pollution)
• Natural sources volcanoes, erosion

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Primary Pollutants
CO
CO2
Secondary Pollutants
SO2
NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended particles
H2O2
O3
PANs
Most
and
salts
Natural
Sources
Stationary
Mobile
Fig. 17.4, p. 422
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Photochemical Smog

• photochemical smog (brown-air smog) a mixture
  of primary and secondary pollutants formed under
  the influence of sunlight
• a. nitrogen and oxygen in air react at high temps
  found in automobile engines and boilers in
  industrial plants to produce colorless nitric
  oxide which reacts w/ oxygen to form nitrogen
  dioxide. Nitrogen dioxide causes the brownish
  haze over cities on sunny afternoons.

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b. Reaction

•    photochemical oxidants NO2, O3 and PANs
  (peroxyacyl nitrates)
• a. react with (oxidize) certain compounds in the
  atmosphere that normally arent oxidized by
  reaction with oxygen  
• b. irritate the respiratory tract, damage plants

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Solar radiation
Ultraviolet radiation
NO Nitric oxide
O2 Molecular oxygen
NO2 Nitrogen dioxide
H2O Water
Hydrocarbons
PANs Peroxyacyl nitrates
O3 Ozone
Aldehydes (e.g., formaldehyde)
HNO3 Nitric acid
Photochemical smog
Fig. 17.5, p. 424
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40
Nitric oxide
Nitrogen dioxide
Ozone
30
20
Parts per million
10
0
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
A.M.
Noon
P.M.
Time
Fig. 17.6, p. 424
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Industrial Smog

• Industrial Smog gray-air smog) consists of
  sulfur dioxide, suspended droplets of sulfuric
  acid, and a variety of suspended solid particles
  and droplets
• a. when burned, carbon in coal oil is converted
  to CO2 and CO. Unburned carbon ends up in the
  atmosphere as suspended particulate matter
  (soot). Sulfur dioxide (colorless, suffocating
  gas) and sulfur trioxide (SO3) cause sulfuric
  acid
• b. rarely a problem in todays developed
  countries but bad in countries where large
  quantities of coal are burned with inadequate
  pollution controls

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VI. Factors influencing the formation of
photochemical and industrial smog

•  local climate and______________, population
  density, amt. of industry, and the fuels used in
  industry, heating, and transportation
• hills, mountains, and cities reduce air flow and
  allow pollutants to build up at ground level

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VI. Factors influencing the formation of
photochemical and industrial smog

• temperature/ thermal inversion a layer of dense,
  cool air trapped under a layer of dense, warm air
  preventing upward-flowing air currents from
  developing
• a. prolonged inversions cause air pollution in
  the trapped layer to build up to harmful levels
• b. L.A. is the air-pollution capital of the US
  because they have ideal conditions for
  photochemical smog and frequent inversion layers

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Warmer air
Inversion layer
Cool layer
Mountain
Mountain
Valley
Fig. 17.8a, p. 426
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Inversion layer
Mountain range
Fig. 17.8b, p. 426
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How to tell if your shoes are causing air
pollution.
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VII. Acid Deposition

• 1. dilution solution to air-pollution to
  reduce local air pollution and meet government
  standards without having to add expensive
  pollution control devices, most coal-burning
  plants, ore smelters, etc. use taller smokestacks
  to emit sulfur dioxide high into atmosphere
• 2.    increases pollution downwind

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VII. Acid Deposition

• 3. chemicals reach ground 
• a. Wet acid rain, snow, fog, cloud vapor
• b. Dryacidic particles
• c. mixture causes acid deposition (acid rain)

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VII. Acid Deposition

• 4. pH a numerical measure of the concentration
  of hydrogen ions in a solution (1 digit change
  equals 10X change in acidity)
• a. levels less than 7 - acid (natural
  precipitation)
• b. levels greater than 7 - Base
• c. typical rain in east US
• is now about 10 times
• more acidic (pH 4.3)

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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)
Dry acid deposition (sulfur dioxide gas and
particles of sulfate and nitrate salts)
Sulfur dioxide (SO2) and NO
Nitric oxide (NO)
Acid fog
Farm
Ocean
Lakes in shallow soil low in limestone become acid
ic
Lakes in deep soil high in limestone are buffered
Fig. 17.9, p. 428
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5. What areas are most affected by acid
deposition?

• occurs on a local rather than global basis b/c
  acidic components only remain in the air for a
  few days
• areas downwind from coal and oil burning power
  plants, industrial plants and urban areas
• ecosystems containing acidic soils without
  natural buffering of bases
• growing problem in China (40 of its land),
  former Soviet Union, India, Nigeria, Brazil,
  Venezuela, Columbia

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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. 17.11, p. 429
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China
Iran
Pakistan
Saudi Arabia
India
Myanmar
Arabian Sea
Thailand
Bay of Bengal
Ethiopia
Indian Ocean
Equator
Percentage of direct sunlight intercepted
Very heavy 3545
Heavy 2035
Medium 1020
Fig. 17.12a, p. 429
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Water boatman
Whirligig
Yellow perch
Lake trout
Brown trout
Salamander (embryonic)
Mayfly
Smallmouth bass
Mussel
6.5
6.0
5.5
5.0
4.5
4.0
3.5
Fig. 17.13, p. 430
pH
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6. What are the effects of acid deposition?

•  medium-risk ecological problem, high-risk to
  human health
• human respiratory diseases (bronchitis, asthma),
  damages statues, buildings, metals, plastics and
  paints
• damages tree foliage, makes trees more
  susceptible to cold temps, disease, insects,
  drought, fungi
• harmful to aquatic species

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Effects of Weather
Emissions
Dry weather
Low precipitation
SO2
NOX
Acid deposition
Increased susceptibility to frost, pests,
fungi, mosses, and disease
H2O2
O3
Increased evapotranspiration
PANs
Others
Direct damage to leaves and needles
Dead leaves or needles
Increased transpiration
Water deficit
Reduced photosynthesis and growth
Bark damage
Nutrient deficiency
Soil acidification
Damage to tree crown
Tree death
Kills certain essential soil microorganisms
Nitrate
Sulfate
Acids
Aluminum
Calcium
Magnesium
Potassium
Release of toxic metal ions
Leaching of soil nutrients
Disturbance of nutrient uptake
Damage to fine roots
Acids and soil nutrients
Disturbance of water uptake
Lake
Groundwater
Fig. 17.14, p. 432
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Fig. 17.10, p. 428
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D. What can be done to reduce acid deposition?

• prevention
• 1) reducing energy use thus air-pollution by
  improving energy efficiency
• 2) switching from coal to cleaner-burning natural
  gas
• 3) removing sulfur from coal before it is burned
• 4) burning low-sulfur coal
• 5) removing SO2 particles, particulates, and
  nitrogen oxides from smokestack gases
• 6) removing nitrogen oxides from combustion
  engines

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D. What can be done to reduce acid deposition?

• reducing coal use is economically politically
  difficult
• clean-up approaches are expensive and mask
  symptoms w/ out treating causes
• acidified lakes can be neutralized by treating
  them or the surrounding soil with large amounts
  of limestone or lime. This is an expensive and
  temporary remedy

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Prevention
Cleanup
Reduce air pollution by improving
energy efficiency
Add lime to neutralize acidified lakes
Add phosphate fertilizer to neutralize acidified
lakes
Reduce coal use
Increase natural gas use
Increase use of renewable resources
Burn low-sulfur coal
Remove SO2 particulates, and NOx from
smokestack gases
Remove from NOx motor vehicular exhaust
Fig. 17.15, p. 433
Tax emissions of SO2
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Ultra Fine Particles
Fine Particles
Large Particles
Sea salt nuclei
Fly ash
Carbon black
Pollens
Paint pigments
Tobacco smoke
Cement dust
Milled flour
Combustion nuclei
Coal dust
Oil smoke
Metallurgical dust and fumes
Photochemical smog
Insecticide dusts
Fig. 17.7, p. 425
0.001
0.01
2.5
10.0
100.0
Average particle diameter (micrometers or microns)
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VIII. Indoor air-pollution

• levels of 11 common pollutants are generally 2-5
  times higher inside homes and commercial
  buildings than outdoors
•  health risks high b/c people spend 70-98 of
  their time indoors
•  source of cancer risk
• greatest risk people - smokers, infants
  children under 5, the old, the sick, pregnant
  women, people with respiratory or heart problems,
  factory workers causes dizziness, headaches,
  coughing, sneezing, nausea, burning eyes, chronic
  fatigue,

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Para-dichlorobenzene
Tetrachloroethylene
Chloroform
1, 1, 1- Trichloroethane
Formaldehyde
Benzo-a-pyrene
Nitrogen Oxides
Styrene
Tobacco Smoke
Asbestos
Radon-222
Methylene Chloride
Carbon Monoxide
Fig. 17.16, p. 435
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Indoor Air Pollution

• Sick building syndrome - flu-like symptoms from
  indoor pollution
• a. a building is sick when at least 20 of its
  occupants suffer persistent symptoms that stop
  when they go outside new buildings are more
  commonly sick b/c of reduce air exchange,
  chemicals from building materials
• b. costs about 100 billion per yr. in
  absenteeism, reduced productivity, and health
  costs
• c. caused by mineral fibers, fiberglass,
  formaldehyde(extremely irritating gas)  
• d. burning of wood, dung and crop residues in
  open fires in developing countries is responsible
  for many respiratory illnesses

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IX. What should be done about asbestos?

• Asbestos several different fibrous forms of
  silicate minerals widely used since the 1940s for
  fireproofing and thermal insulation
• if breathed they can remain in the lungs for
  years
• used for fireproofing, soundproofing, insulation
  of heaters pipes, brake linings, etc cause
  asbestosis a chronic, sometimes fatal disease
  that eventually makes breathing nearly impossible
  
• causes mesothelioma an inoperable cancer of the
  chest cavity lining cause lung cancer those
  affected - asbestos miners, insulators, pipe
  fitters, shipyard employees, workers in
  asbestos-producing factories most asbestos
  factories have gone out of business or moved to
  other countries

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X. Is your home contaminated with radon gas?

• Radon a colorless, odorless, tasteless,
  naturally occurring radioactive gas produced by
  the radioactive decay of uranium-238
• if inhaled can expose lung tissue to large
  amounts of ionizing radiation
• lifetime exposure in a home responsible for
  13,600 deaths a yr.
•  

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Radon levels in the US
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Outlet vents for furnaces and dryers
Slab joints
Wood stove
Cracks in floor
Clothes dryer
Furnace
Sump pump
Radon-222 gas
Uranium-238
Slab
Radium-222
Soil
Fig. 17.17, p. 436
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XI. How is human health harmed by air pollutants?

• 1) lung cancer
• 2) asthma typically and allergic reaction
  causing sudden episodes of acute shortness of
  breath  
• 3) chronic bronchitis persistent inflammation
  and damage to the cells lining the bronchi and
  bronchioles, causing mucus buildup, painful
  coughing and shortness of breath
• 4) emphysema irreversible damage to air sacs or
  alveoli leading to abnormal dilation of air
  spaces, loss of lung elasticity, and acute
  shortness of breath CO reduces the ability of
  blood to carry oxygen which impairs perception,
  things, causes headaches, dizziness, nausea, and
  can trigger heart attacks, damage fetuses

http//kidshealth.org/kid/health_problems/allergy/
asthma.html
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Nasal cavity
Oral cavity
Pharynx (throat)
(see figure 17.18b)
Trachea (windpipe)
Bronchus
Right lung
Bronchioles
(see figure 17.18c)
Fig. 17.18a, p. 437
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Epithelial cell
Cilia
Mucus
Fig. 17.18b, p. 437
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Bronchiole
Alveolar sac (sectioned)
Alveolar duct
Alveoli
Fig. 17.18c, p. 437
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How many people die prematurely from air
pollution?

• a. outdoor pollution deaths 65,000 - 200,000 /
  yr
• b. total pollution deaths 150,000 - 350,000 /
  yr
•  

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Outdoor Exposure
Developing countries (urban) 93
Developed countries (urban) 7
Indoor Exposure
Total deaths 0.2 million
Developing countries (urban) 23
Developing countries (rural) 67
Developed countries (rural) 1
Developed countries (urban) 9
Fig. 17.20, p. 439
Total deaths 2.8 million
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XII. How are plants damaged by air pollutants?

• breaks down waxy coating that prevents water loss
  and damage from diseases, pests, drought, frost
• interferes w/ _________________ plant growth,
  reduces nutrient uptake, causes leaves to turn
  yellow brown conifers at high elevations are
  especially vulnerable

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XIII. How can air pollutants damage aquatic life

• Acid shock caused by the sudden runoff of large
  amts, of highly acidic water aluminum ions into
  lakes and streams, when snow melts or after
  unusually heavy rains
• decline in net primary productivity
• kill all fish because Al reduces slime layer
•  in US 9,000 lakes are seriously threatened
  (Great Lakes)

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XIV. What are the harmful effects of air
pollution on materials?

• costly cleaning needed, break down exterior paint
  on cars and houses, deteriorate roofing
• deface irreplaceable marble statues, historic
  buildings, stained glass windows
• 5 billion per yr. damage in the US

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Prevention
Dispersion or Cleanup
Burn low-sulfur coal
Disperse emissions above thermal inversion layer
with tall smokestacks
Remove sulfur from coal
Convert coal to a liquid or gaseous fuel
Remove pollutants after combustion
Shift to less polluting fuels
Tax each unit of pollution produced
Fig. 17.21, p. 442
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XV. How have laws been used to reduce air
pollution in the US?

• 1. Clean Air Act (1970, 1977, 1990) - federal
  regulations enforced by each state
• a. require standards set for 7 outdoor pollutants
  that specify a max level, averaged over a
  specific period, for a certain pollutant
  prevention of significant deterioration
• b. national emissions standards for toxic air
  pollutants
•  

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2.How could US air-pollution laws be improved?

• a. rely on pollution prevention rather than
  cleanup
• b. sharply increase the fuel efficiency standards
  for cars and light trucks
• c. require stricter emission standards for fine
  particulates  
• d. dont give municipal trash incinerators 30-yr
  permits
• . setting strict standards for air-pollution
  emissions from incinerators  
• f. reduce emissions of carbon dioxide and other
  greenhouse gases

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  3.Should we use the marketplace to reduce
pollution?

• a. a power plant is given a certain of
  pollution credits or rights each yr that allow it
  to emit a certain amount of SO2. If they emit
  less SO2 than the limit they receive more
  pollution credits.
• b. get older, high-polluting vehicles off the
  road stricter emission laws for lawnmowers,
  chainsaws, leaf blowers, etc

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4.Californias South Coast Air Quality Management
District Council

• a. developed a drastic program to produce and 80
  reduction in ozone, photochemical smog, and other
  major air pollutants in L.A. by 2009

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5. How can we reduce indoor air pollution?  

• a. rooftop greenhouses, breathing wall to absorb
  dirty air and exhale clean air

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Fig. 17.22a, p. 442
Electrostatic Precipitator
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Cleaned gas
Dirty gas
Fig. 17.22b, p. 442
Baghouse Filter
Dust discharge
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Dirty gas
Fig. 17.22c, p. 442
Cyclone Separator
Dust discharge
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Dirty gas
Clean water
Dirty water
Fig. 17.22d, p. 442
Wet Scrubber
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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
Restrict driving in polluted areas
Stricter emission standards
Fig. 17.23, p. 443
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Prevention
Cleanup or Dilution
Cover ceiling tiles and lining of 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 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 cleanin
g agents, paints, and other products
Install efficient chimneys for wood-burning stoves
Fig. 17.24, p. 443
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6. How can we protect the atmosphere?

• a. emphasis on pollution prevention
• b. improve energy efficiency reduce use of fossil
  fuels (coal oil)
• c. slow population growth  
• d. integrate air-pollution, water-pollution,
  energy, land-use, population, economic, and trade
  policies  
• e. regulate air quality for an entire region or
  air shed  
• f. phase in full-cost pricing, mostly by taxing
  the production of air pollutants
• g. distribute cheap efficient cook stoves
  solar cook stoves in developing countries
• h. transfer latest technologies to developing
  countries