1. Chapter 20: air pollution
Pollution unit

2. 20.1 Layers of the Atmosphere

3. Atmospheric pressure (millibars) Altitude (kilometers)
200
400
600
800
1,000
120 75
Highlights:
Pressure decreases with altitude until it reaches zero
Troposphere is the layer we live in; mostly N and O; weather; colder as you go up
Stratosphere: has the ozone layer; warmer as you go up
Environmental science focuses mostly on those two layers
Temperature
110
Pressure 65
100
Thermosphere 90 55 80
Heating via ozone
Mesosphere 45 70
Altitude (kilometers) 60
Altitude (miles) 35 50
Stratosphere 40 25 30 15
Ozone “layer” 20
Heating from the earth
Troposphere 10 5
Pressure = 1,000
millibars at
ground level
(Sea
Level)
–80
–40 40 80
120
Temperature (˚C)

4. What SPF is that ozone?
Stratospheric ozone absorbs 95% of UV radiation
3O UV  2 O3
Tropospheric ozone is harmful to plants, animals, and humans.
Tropospheric ozone is made when air pollutants undergo chemical reactions because of UV exposure.

5. Which ozone is which?
The oxygen atom generated from the initial reaction reacts with atmospheric, diatomic oxygen, to form ozone.
This polluting ozone of the lithosphere, traps heat and contributes to thermal inversion.

6. 20.2 Outdoor Air Pollution .

7. Primary & Secondary Pollutants
Play intro video

8. Primary vs. Secondary Primary Pollutants CO CO2 Secondary Pollutants
SO2 NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended
particles
H2O2 O3
PANs
SO4 2 –
Most
NO3 –
and
salts
Sources
Natural
Stationary
Mobile
Primary vs. Secondary

9. Tip – Can’t remember what organic compounds are???
View my PS (Chapter 9) PPT online for a quick refresher.

10. Table 20-1 Page 436 Major classes of air pollutants Class
Carbon oxides
Sulfur oxides
Nitrogen oxides
Volatile organic compounds (VOCs)
Suspended particulate matter (SPM)
Photochemical oxidants
Radioactive substances
Hazardous air pollutants (HAPs), which cause health effects such as cancer, birth defects, and nervous system problems
Examples
Carbon monoxide (CO) and carbon dioxide (CO2)
Sulfur dioxide (SO2) and sulfur trioxide (SO3)
Nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O) (NO and NO2 often are lumped together and labeled NOx)
Methane (CH4), propane (C3H8), chlorofluorocarbons (CFCs)
Solid particles (dust, soot, asbestos, lead, nitrate, and sulfate salts), liquid droplets (sulfuric acid, PCBs, dioxins, and pesticides)
Ozone (O3), peroxyacyl nitrates (PANs), hydrogen peroxide
(H2O2), aldehydes
Radon-222, iodine-131, strontium-90, plutonium-239 (Table 3-1, p. 49)
Carbon tetrachloride (CCl4), methyl chloride (CH3Cl), chloroform (CHCl3), benzene (C6H6), ethylene dibromide (C2H2Br2), formaldehyde (CH2O2)
Table 20-1 Page 436

11. Carbon Monoxide CARBON MONOXIDE (CO)
Table 20-2 Major Outdoor Air Pollutants
CARBON MONOXIDE (CO)
Description: Colorless, odorless gas that is poisonous to air-breathing animals; forms during the incomplete combustion of carbon-containing fuels (2 C + O2 2 CO).
Major human sources: Cigarette smoking (p. 409), incomplete
burning of fossil fuels. About 77% (95% in cities)comes from motor vehicle exhaust.
Health effects: Reacts with hemoglobin in red blood cells and reduces the ability of blood to bring oxygen to body cells and tissues. This impairs perception and thinking; slows reflexes; causes headaches, drowsiness, dizziness, and nausea; can trigger heart attacks and angina; damages the development of fetuses and young children; and aggravates chronic bronchitis, emphysema, and anemia. At high levels it causes collapse, coma, irreversible brain cell damage, and death.
Carbon Monoxide

12. Table 20-2 Page 438 Nitrogen Dioxide NITROGEN DIOXIDE (NO2)
Table 20-2 Major Outdoor Air Pollutants
Table 20-2 Page 438
NITROGEN DIOXIDE (NO2)
Description: Reddish-brown irritating gas that gives photochemical smog its brownish color; in the atmosphere can be converted to nitric acid (HNO3), a major component of acid deposition.
Major human sources: Fossil fuel burning in motor vehicles (49%) and power and industrial plants (49%).
Health effects: Lung irritation and damage; aggravates asthma and chronic bronchitis; increases susceptibility to respiratory infections such as the
flu and common colds (especially in young children and older adults).
Environmental effects: Reduces visibility; acid deposition of HNO3 can damage trees, soils, and aquatic life in lakes.
Property damage: HNO3 can corrode metals and eat away stone on buildings, statues, and monuments; NO2 can damage fabrics.
Nitrogen Dioxide

13. Table 20-2 Page 438 Sulfur Dioxide SULFUR DIOXIDE (SO2)
Table 20-2 Major Outdoor Air Pollutants
Table 20-2 Page 438
SULFUR DIOXIDE (SO2)
Description: Colorless, irritating; forms mostly from the combustion of sulfur containing fossil fuels such as coal and oil (S + O2 SO2); in the atmosphere
can be converted to sulfuric acid (H2SO4), a major component of acid deposition.
Major human sources: Coal burning in power plants (88%) and industrial processes
(10%).
Health effects: Breathing problems for healthy people; restriction of airways in people with asthma; chronic exposure can cause a permanent condition similar to bronchitis. According to the WHO, at least 625 million people are exposed to unsafe levels of sulfur dioxide from fossil fuel burning.
Environmental effects: Reduces visibility; acid deposition of H2SO4 can damage trees, soils, and aquatic life in lakes.
Property damage: SO2 and H2SO4 can corrode metals and eat away stone on buildings, statues, and monuments; SO2 can damage paint, paper, and leather.
Sulfur Dioxide

14. Suspended Particulate Matter
Table 20-2 Major Outdoor Air Pollutants
Table 20-2 Page 438
SUSPENDED PARTICULATE MATTER (SPM)
Description: Variety of particles and droplets (aerosols) small and light enough to remain suspended in atmosphere for short periods (large particles) to long periods
(small particles; Figure 20-6, p. 441); cause smoke, dust, and haze.
Major human sources: Burning coal in power and industrial plants (40%), burning diesel and other fuels in vehicles (17%), agriculture (plowing, burning off fields), unpaved roads, construction.
Health effects: Nose and throat irritation, lung damage, and bronchitis; aggravates bronchitis and asthma; shortens life; toxic particulates (such as lead, cadmium, PCBs, and dioxins) can cause mutations, reproductive problems, cancer.
Environmental effects: Reduces visibility; acid deposition of H2SO4 droplets can
damage trees, soils, and aquatic life in lakes.
Property damage: Corrodes metal; soils and discolors buildings, clothes, fabrics, and paints.
Suspended Particulate Matter

15. Table 20-2 Major Outdoor Air Pollutants
Table 20-2 Page 438
LEAD
Description: Solid toxic metal and its compounds, emitted into the atmosphere as particulate matter.
Major human sources: Paint (old houses), smelters (metal refineries), lead manufacture, storage batteries, leaded gasoline (being phased out in developed countries).
Health effects: Accumulates in the body; brain and other nervous system damage and mental retardation (especially in children); digestive and other health problems; some lead-containing chemicals cause cancer in test animals.
Environmental effects: Can harm wildlife.
Lead

16. Table 20-2 Page 438 Ozone OZONE (O3)
Table 20-2 Major Outdoor Air Pollutants
Table 20-2 Page 438
OZONE (O3)
Description: Highly reactive, irritating gas with an unpleasant odor that forms in the troposphere as a major component of photochemical smog (Figures 20-3 and 20-5).
Major human sources: Chemical reaction with volatile organic compounds (VOCs, emitted mostly by cars and industries) and nitrogen oxides to form photochemical smog (Figure 20-5).
Health effects: Breathing problems; coughing; eye, nose, and throat irritation; aggravates chronic diseases such as asthma, bronchitis, emphysema, and heart disease; reduces resistance to colds and pneumonia; may speed up lung tissue aging.
Environmental effects: Ozone can damage plants and trees; smog can reduce visibility.
Property damage: Damages rubber, fabrics, and paints.
Ozone

17. 20.3 Photochemical and Industrial Smog

18. Smog
Photochemical: “brown air smog” Caused by UV reacting with chemicals (NOx, VOCs in the atmosphere) Found in modern cities, especially in warm, sunny areas.
Industrial smog: “gray air smog” Caused by burning of fossil fuels, adds sulfur to air. Rare in developed countries now as soot is removed by filters..

19. Photochemical Smog
Nitrogen oxide is an essential ingredient of photochemical smog that is produced during the high temperatures associated with combustion of vehicle’s engines.
Be sure to look at sheet “Chemistry is indeed relevant to APES.”

20. Initial reaction of nitrogen dioxide with sunlight

21. Factors in smog formation
Decrease smog
Increase smog
Urban buildings
Hills and mountains
High temperatures
“Grasshopper Effect”
Precipitation
Salty sea spray
Wind
Reduce factory/car emissions

22. “Grasshopper Effect”
This is one reason why the dangerous chemicals Canada banned more than 20 years ago continue to turn up in the Great Lakes.

23. View “Chemistry is indeed relevant to APES.”
See equation – reactants and products of photochemical smog on sheet.
Hydrocarbons (including VOC’s), carbon monoxide, and nitrogen oxides from vehicle exhausts are irradiated by sunlight in the presence of oxygen gas.
The resulting reactions produce a potentially dangerous mixture that include other NOx, ozone, and irritating organic compounds (VOC’s), as well as CO2 and H2O vapor

24. That’s just smoke out your…….

25. 20.4 Regional Outdoor Air Pollution from Acid Deposition

26. Acid Rain
Play intro video

27. Chemistry and Acid Rain
The pH of rainwater is normally slightly acidic, at about 5.6, due mainly to reaction of carbon dioxide with water to form carbonic acid.
Refer to “Chemistry is indeed relevant to APES.”

28. Gases from natural events
Volcanic eruptions, forest fires, and lightning produce sulfur dioxide, sulfur trioxide, and nitrogen dioxide.
These gases can react with atmospheric water in much the same way that carbon dioxide does to produce sulfurous acid, sulfuric acid, nitric acid and nitrous acid.
Refer to “Chemistry is indeed relevant to APES.”

29. Acid Rain formation 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
acidic
Ocean
Lakes in
deep soil
high in limestone
are buffered
Acid Rain formation

30. Which location does sulfuric & nitric acids transform?
Wind X Z Y
Farm
Ocean
Which location does sulfuric & nitric acids transform?

31. Identify the type of acid deposition at point Y
Wind
Transformation to
sulfuric acid (H2SO4)
and nitric acid (HNO3) Z Y
Farm
Ocean
Identify the type of acid deposition at point Y

32. Identify the type of acid deposition at point Z
Wind X Z
Dry acid
deposition
Farm
Ocean
Identify the type of acid deposition at point Z

33. Wind X
Wet acid deposition Y
Farm
Ocean
Great Job!!

34. Which chemicals lower the pH of rain?
Primary Pollutants CO
CO2
Secondary Pollutants
SO2 NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended
particles
H2O2 O3
PANs
SO4 2 –
Most
NO3 –
and
salts
Sources
Natural
Stationary
Mobile
Which chemicals lower the pH of rain?

35. Secondary Pollutants in RED
Primary Pollutants CO
CO2
Secondary Pollutants
SO2 NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended
particles
H2O2 O3
PANs
SO4 2 –
Most
NO3 –
and
salts
Sources
Natural
Stationary
Mobile
Secondary Pollutants in RED

36. pH levels of US soil

37. Effects of Acid Rain Decrease soil pH (more acidic)
Decrease pH of rivers, lakes, ponds, etc
Fish kills
Lung/respiratory problems
Degrade metal pipes, leading to water pollution
Plants become susceptible to disease, parasites, etc

38. Acid Rain Prevention and Solution
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
Acid Rain Prevention and Solution
Burn low-sulfur coal
Remove SO2 particulates, and Nox from smokestack gases
Remove Nox from motor vehicular exhaust
Tax emissions of SO2

39. 20.5 Indoor Air Pollution

40. Go outside and play Indoor air is typically a greater threat
People are inside up to 98% of their time
Less air flow to remove pollutants
Top pollutants: cigarette smoke, formaldehyde, radon, particulate matter.
“Sick building” Typically newer buildings because of less air leaks. Symptoms: headache, coughing, sneezing, tiredness.

41. Formaldehyde
Found in: plywood, furniture, upholstery, floor adhesives, dry cleaning chemicals.
Causes: breathing problems, headache, sore throat, dizziness, eye irritation in those sensitive to low levels.
Chronic exposure to higher levels can lead to cancer.
Radon
Naturally occurring from radioactive decay of U-238.
Occurs in soils, bedrock and can get into homes through cracks.
Can’t get out and builds up
Can lead to lung cancer

42. 1, 1, 1- Nitrogen Oxides: Tobacco Smoke Carbon Monoxide
Para-dichlorobenzene: air fresheners, moth balls; cancers
Tetrachloroethylene: dry cleaning residue; nerve, liver, kidney problems
Chloroform: chlorine-treated hot water; cancers
Formaldehyde: from processed wood; eye, nose, throat, lung irritant
1, 1, 1-
Trichloroethane: aerosals; dizziness, irregular breathing
Benzo-a-pyrene: from smoke; lung cancer
Nitrogen Oxides:
Gas ovens, kerosene heaters, un-vented gas burning; lung irritation, headaches
Styrene: from carpet/plastic. Kidney/liver problems
Tobacco Smoke
Asbestos: old floor tile,
Pipe insulation;
lung problems, cancer
Radon-222: from soils, lung disease
Carbon Monoxide
Methylene Chloride: paint stripper, thinner; nerve, diabetes

43. 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
Ban smoking or limit it to well-ventilated areas
Increase intake of outside air
Change air more frequently
Set stricter formaldehyde emissions standards for carpet, furniture, and building materials
Circulate building’s 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

44. Particulates - Aka: particulate matter (PM)
What are they? aerosols or fine particles, are tiny particles of solid (a smoke) or liquid (an aerosol) suspended in a gas.
Size: < 10 nm - > 100 µm in diameter.
Who do they effect? Sensitive populations such as children, the elderly, and individuals suffering from respiratory disease.

45. Particulate Matter (PM)
Larger particles are generally filtered in the nose and throat and do not cause problems.
PM smaller than about 10 µm, referred to as PM10, can settle in the bronchi and lungs and cause health problems.

46. Particulate Matter (PM)
Includes a wide range of pollutants –
road dust
diesel soot
fly ash
wood smoke
sulfate aerosols (suspended as particles in the air)
These particles are a mixture of visible and microscopic solid particles and minute liquid droplets known as aerosols.

47. Take a deep breath… Asthma: on the rise! WHY?? Varying opinions:
Overly sterile environment as children; don’t build up natural immunity
Exposure to allergens
Genetic make up
Exposure to pollution
Lung cancer
Chronic bronchitis
Emphysema

48. National Ambient Air Quality Standards (NAAQS)
Standards established by the EPA that apply for outdoor air throughout the country.
Primary standards are designed to protect human health.
Secondary standards are designed to protect public welfare (e.g. building facades, visibility, crops, and domestic animals).

49. EPA’s watchful eye
NAAQS requires the EPA to set standards on six criteria pollutants:
Ozone (O3)
Particulate Matter
Carbon monoxide (CO)
Sulfur dioxide (SO2)
Nitrogen oxides (NOx)
Lead (Pb)

50. Temperature Inversions (pg. 442) and Heat Islands (online activity)

51. Temperature Inversion
Warmer air
Inversion layer
Increasing altitude
Cool layer
Mountain
Mountain
Valley
Decreasing temperature
Traps pollutants near surface. Mountains prevent wind in area and shadow sun to keep lower air cool.

52. Temperature Inversion
Descending warm air mass
Inversion layer
Increasing altitude
Sea breeze
Mountain
range
Decreasing temperature
Traps pollutants near surface. Mountains prevent pollutants leaving. Sea breeze blows in, not out This is what is happening in LA Video clip

53. 20.7 Preventing and Reducing Air Pollution

54. Stationery Source Air Pollution
Solutions
Stationery Source Air Pollution
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

55. Out-put or Control Methods
See text pg Fig 20-18

56. Cleaned gas
Electrodes
Dust discharge
Dirty gas
Electrostatic Precipitator – static plates collect particles

57. Bags
Cleaned gas
Dirty gas
Dust discharge
Baghouse Filter – only one to remove hazardous fine particles

58. Wet Scrubber – Expensive
Dirty gas
Cleaned gas
Clean
water
Wet
gas
Dirty water
Remove 98% of SO2 and
PM from emissions
Wet Scrubber – Expensive

59. Cyclone Separator - Cheap
Cleaned gas
Dirty gas
Does NOT produce hazardous
materials like other
Dust discharge
Cyclone Separator - Cheap

60. Solutions for mobile emissions
Motor Vehicle Pollutions
Solutions for mobile emissions
Prevention
Cleanup
Mass transit
Emission control
devices
Bicycles and walking
Less polluting engines
Less polluting fuels
Improve fuel efficiency
Car exhaust
Inspections
twice a year
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

61. 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.

62. Clean Air Acts US Congress in 1970, 1977, 1990
EPA regulation of emissions that contribute to global warming, ozone depletion and air pollution. View clip
You should read ALL case studies in the chapter!
Ea: The Bad Old Days, A Burning Controversy and section 20-7 specifically.

63. VI. Pollution (25-30%) Air pollution
Sources-primary and secondary (20.2 & air pollution lab)
major air pollutants (20.2 & pollutant chart)
measurement units (air pollution lab & emissions trading game)
smog (20.3 & Demo: Smog in a jar)
acid deposition-causes and effects (20.4, pH/acid rain lab, video)
heat islands (online activity) and temperature inversions (20.3)
indoor air pollution (20.5 &  air particulate lab)
remediation and reduction strategies (air pollution allowance trading article, emissions trading game) and Fig )
Clean Air Act and other relevant laws (Law sheet, NAAQS)