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The Atmosphere and Atmospheric Pollution
Owensboro Up-to-Date Air Quality http://adelie.spd.louisville.edu/ozone/fcst/oz_fcst_evv.html
The Atmosphere and Atmospheric Pollution
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I). The Atmosphere
Each layer is characterized by abrupt changes in temperature.
A). Troposphere: (0-11 miles above sea level)
Located close to the earth
It primarily consists
Nitrogen
Oxygen
Carbon dioxide
Water vapor
B). Stratosphere (11-30 miles above sea level)
The ozone concentration is 1000x greater than the troposphere.
This filters UV radiation and
Allow life to exist on land
Protects humans from sunburn, skin cancer and cataracts
Prevents the O2 from the troposphere from being converted into ozone.
II). Successes
Declines in level of pollutants
1. Lead Levels
2. Ozone Depleting Chemicals in the Troposphere
3. Acid Precipitation Chemicals
III). Origin of pollution
A. Source
1. Point source
Specific points of origin of pollutants
2. Non-Point Source
General sources that can not be pointed to
B. Natural Pollutants
C. Primary & Secondary Pollution
1. Primary Pollution
The initial pollution direct from the source
2. Secondary Pollution
Occurs when there is a chemical reaction in the atmosphere
IV. Types of Air Pollution
These are all different problems with different causes & different effects on the environment
A). Particulate Matter
Occurs in the troposphere.
Consists of soot, dust, etc.
B). Smog
Occurs in the troposphere
Caused by:
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Local climate and topography |
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Population density |
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Amount of industry |
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Fuels used in industry, heating, and transportation |
1. Industrial Smog
grayish mixture of moisture and soot that occurs where industry are concentrated and coal is used as energy
2. Photochemical Smog
brownish haze that forms on sunny days over cities with a lot of automobile traffic
C. Ozone O2 -> O3
Ground level ozone is a health hazard –
and a major constituent of photochemical smog
D). Temporal Inversion or Thermal Inversion
Low cool air is trapped under a layer of less dense warm air in an urban valley or basin.
This prevents the dispersion and dilution of pollutants.
V). Acid Deposition
Occurs in the troposphere
The falling of acids and acid-forming compounds from the atmosphere
Natural precipitation is slightly acidic
(pH 5.0-5.6)
Acidic deposition can be 10 to 1000 times more acidic
(pH 4.3-2.3)
A. Effects of Acid Deposition
The falling of acids and acid-forming compounds from the atmosphere
· Contributes to respiratory diseases
· Damages statues made of limestone and marble.
· Destroys tree foliage and weakens trees so they are more susceptible to other damage.
B. Types of Acid Deposition
Wet deposition:
acidic rain, snow, fog and cloud water.
Dry Deposition:
acidic particles
C. Acidic pollutants
Sunlight creates nitric acid & sulfuric acid
From acid forming sulfates and nitrate salts.
D. Acid deposition is caused by
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Coal burning-power plants |
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Ore smelters |
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Other industrial plants |
VI). Ozone Depletion
A. Ozone Shield:
natural process that blocks UV radiation from the sun.
Location: Stratosphere
What gases are involved: O2 & ozone (O3)
B). Is Ozone Depletion a Serious Problem?
During seasonal thinning UV radiation can increase 3-20%.
Possible effects include:
1. To People
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Sunburns |
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Cataracts & eye-burning |
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Skin cancers |
(the number has increased 4x in 2 decades)
12 million more cases of skin cancer are caused by the ozone damage already done.
2. To Nature
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Lower crop yields |
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Decline in forest productivity & CO2 uptake. |
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Reduction in the productivity of surface dwelling plankton, which will affect fisheries. |
C. Human Inputs:
| CFCs chlorofluorocarbons |
| Halons (in fire extinguishers) |
| carbon tetrachloride (toxic solvent) |
| methyl chloroform (cleaning solvent and propellants) |
| Methyl bromide (a fumigant) |
| halogen containing gases. |
| Hydrogen chloride (from space shuttles) |
D. Chlorofluorocarbons (CFCs)
Ozone depletion started with the discovery of chlorofluorocarbons in 1931 (Freon)
CFCs are produced by:
| Leaking air conditioners and refrigerators |
| Evaporation of industrial solvents |
| Production of plastic foams |
| Aerosol propellants |
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3. How Do CFCs Affect the Ozone Layer?
| The UV radiation breaks down the CFCs into chlorine atoms. |
| The chlorine atom reacts with O3 (ozone) creating O2. |
40-50% of the ozone is destroyed in the upper stratosphere. Some years this almost 100%.
During the spring and early summer in the Antarctic 40-50% of the ozone is destroyed in the upper stratosphere.
Some years this almost 100%.
In 1998 this seasonal ozone thinning covered an area larger than North America
It takes about 11-20 years for CFCs to make it into the stratosphere where it can stay for 65-120 years.
Even if we eliminate all ozone depleting chemicals it will take 100 years to return the ozone layer to pre-1950 levels.
Treaties aim to ban all use of CFCs
VII). Climate Change ----Global Warming
A. Greenhouse effect (Natural process)
traps heat in the atmosphere near the earth’s surface.
Important for life to survive
It is not the same thing as global warming
Location: troposphere
Greenhouse effect is good
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B. What gases are involved:
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C. Global climate change is…..
Any change in the earth’s climate including storms, precipitation and temperature.
Since 1860 global temperature has risen 1.3°F.
With the 15 warmest years occurring in the last 2 decades
D. Effects of climate change
Between 1990 and 2100 the mean surface temperature should rise between 2.3° and 7.3°F
1.Change in precipitation that will include more violent storms
2. Increase in the retreat of some Northern glaciers.
3. Loss of biodiversity
4. Northern migration of some warm-climate fish and trees.
5. Spread of tropical diseases away from the equator.
6. Increased bleaching of some coral reefs7. Raising of sea level & loss of land mass
E. Gases
1. CO2
Between 1850 & 1998 atmospheric CO2 levels rose from 280 parts per million to 370 ppm.
Carbon dioxide is responsible for 50-60% of global warming.
CO2 is produced from:
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Fossil fuel burning (70-75%) |
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Land clearing and plant burning (20%) |
CO2 stays in the atmosphere for 50-200 years
2). Methane (CH4)
CH4 accounts for 20% of global warming
CH4 is produced by:
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Swamps and other wetlands |
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Rice paddies |
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Landfills |
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The intestinal tracts of cattle, sheep, and termites. |
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Leaks in pipelines |
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Incomplete burning of organic matter. |
CH4 stays in the atmosphere for 9-15 years
3. Nitrous Oxide (N2O)
N2O is produced from:
| Nylon production |
| Burning of biomass and nitrogen-rich fuels |
| Catalytic converters of vehicles |
| Nitrogen fertilizers in soils |
N2O can stay in the atmosphere for 120 years and traps 200x as much heat per molecule as CO2
F. Controversy
| Are we really experiencing global warming or is this just the normal ups and downs of global temperature? |
| Can we accurately predict what the future will hold? |
| Should we do more research or act now? |
| Is global warming a threat? |
| Can we slow global warming? |
| Is it worth the cost to try? |
VIII. Indoor Air Pollution
There 11 common pollutants that are generally 2 to 5 times greater indoors.
Including:
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cigarette smoke |
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formaldehyde (from furniture & carpeting) |
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radon gas |
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pesticides |
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asbestos |
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Indoor pollutants can cause:
| sick building syndrome |
| dizziness, headaches |
| coughing |
| burning eyes |
| flu-like symptoms. |
| leading cancer risk. |
The effect is magnified because people spend 70-98% of their times indoors
The problem is worse in newer energy efficient buildings that allow limited air exchange
IX). Solutions
A). The Clean Air Act has lowered the concentrations of major air pollutants by 32%.
B). How is this accomplished:
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Pollution credits |
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Tall smokestacks that disperse pollutants and scrubbers |
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Switching to low sulfur coal |
