Transcript Document

Chapter 12
Air and
Air Pollution
Fig. 18.3
The Atmosphere
Atmospheric pressure (millibars)
0
120
Exosphere
Thermosphere
Mesosphere
Stratosphere
Troposphere
600
800
1,000
75
Pressure
100
65
Thermosphere
90
55
Mesopause
80
Heating via ozone
Mesosphere
70
45
60
Stratopause
50
Stratosphere
25
40
Tropopause
30
Ozone “layer”
20
0
15
Heating from the earth
Troposphere 5
10
(Sea
Level)
35
Altitude (miles)





400
Temperature
110
Altitude (kilometers)
 78% Nitrogen,
 21% Oxygen
 Varnish on globe
 5 different layers
200
–80
–40
0
40
80
Temperature (˚C)
120
Pressure = 1,000
millibars at
ground level
Let’s talk layers…
• Troposphere:
– Contains 75% of the Earth’s air
– It is the lowest layer that surrounds us now
– Think of the earth as an apple, it would be as thick
as the skin of the apple
Continued…
• Contains a constantly changing mixture of
gases
• Mainly 99% of clean, dry air with 1% polluted
and containing moisture
• This part of the atmosphere contains mass and
gives the properties that are unique to
suction…how?
Stratosphere:
• The second layer of the atmosphere
• Contains less mass than the troposphere but
contains a unique gas: Ozone
• The ozone layer is the global sunscreen
– It blocks UVA and UVB radiation
• The O3 is only
found in the stratosphere
Major Air Pollutants
• Air pollutants vary from one another
• An air-pollutant is something in the wrong
place in the wrong concentration
• Ex.) Ozone: Good in the stratosphere
– Horrible in the troposphere (kills everything)
History of Air Pollution
• Nothing new
– 2000 years ago Seneca complained about the foul
air of Rome
– 1273 King Edward I ordered “dirty” coal to no
longer be burned
• One man was evened hanged for disobeying
the first “clean air act”
Primary Pollutants:
These are pollutants that arise from:
1.) Humans (activities from humans, VOC’s)
2.) Earth’s natural processes (dust storms,
volcanoes, SO2)
Secondary Pollutants:
• These are primary pollutants that mix together
– Ex.) Acid Rain (Car exhaust and dust mixed with
water)
Pollution of both kinds have been here forever but
have increased more dramatically since the
industrial revolution
Who is more polluted?
• Cities tend to be more polluted with secondary
pollutants…why?
• These areas are also prone to Smog:
– Industrial
– Photochemical
The smog brothers…
• Photochemical: smog activated by light
– This is smog formed by the mixing of primary and
secondary by light
– N2 + O2 = 2NO (this creates the brown smog)
• Industrial: (Gray-Air smog) caused by sulfuric
acid drops in the air
– Caused by burning coal, rarely a problem today
Temperature Inversions
-A factor that influences smog creation and problems
-An inversion is when cold air is trapped below a layer of
warm air
-This inhibits winds from blowing and moving pollutants
through the air
Figure 18-11
Industrial Air Pollution:
• Emits high levels of SO2 and NO
– Why?
– Very inefficient processes are used to generate
electricity and power
• Cleaning it up:
– Smoke stack scrubbers (machine that sprays water)
– Electro static Precipitators (electrically
charged dust)
12-3: Acid Precipitation
Air Pollution from Acid Deposition
• Acid deposition: When dry chemicals such as
SO2 mix with water they create acid rain
– Acidity is expressed in ph
– <7 = acid
– >7= basic
– 7= neutral
*This shows up all over the US
(East coast is 10 times more acidic with a ph of 4.3)
What are the effects?
• Harmful ecological effects
– Destroys aquatic environments (next slide)
– Ruins tree foliage and makes them more
susceptible to disease, winter and summer
• Harmful to humans
• Respiratory illnesses (asthma and bronchitis)
• Weakens structures (buildings and statues)
Acid Deposition and Aquatic Systems
• Fish declines
Water
boatman
Whirligig
• Undesirable
species
• Acid shock
Yellow perch
Lake trout
Brown trout
Salamander
(embryonic)
Mayfly
Smallmouth
bass
Mussel
6.5
6.0
5.5
5.0
pH
4.5
4.0
3.5
Acid Deposition, Plants, and Soil
 Nutrient
leaching
 Heavy metal
release
 Weakens trees
Fig. 18-14
What can we do?
• First, is it serious? (1990)
– Gov’t: Yes but not a crisis
– Coal and Oil: Costs more than the health risks
– Since the Clean Air act was passed things have
changed. Oil and Coal are required to watch SO2
levels released
– Acid rain rates since then have fallen 35%
12-2: AIR POLLUTION
• Indoor air pollution usually is a greater threat to
human health than outdoor air pollution.
– People spend 70-80% more time indoors then
outdoors
• According to the EPA, the four most dangerous
indoor air pollutants in developed countries are:
–
–
–
–
Tobacco smoke.
Formaldehyde.
Radioactive radon-222 gas.
Asbestos
Inside Air pollutants:
• Have been linked to many diseases
• Also causes: “sick building syndrome”
– When at least 20% of individuals are chronically
sick
• Formaldehyde is the #1 culprit to sick building
syndrome
1.) Formaldehyde:
• Used in dissection materials
• How does it get in your house?
– Plywood
– Paneling
– Particle Board
*Causes rashes, dizziness, and headaches
2.) Radioactive Radon
• Radon-222:
radioactive gas
found in some soils
and rocks
Sources and paths of entry
for indoor radon-222 gas.
– can seep into some
houses and increase
the risk of lung
cancer
– 2nd leading cause of
lung cancer
Figure 18-18
3.) Asbestos
• A commercially
used product
– Fire retardant and
insulator
• Can cause lung
cancer and
mesothelioma
• Banned now but not
always
– Roseau High School
Noise Pollution:
• Noise can also cause air pollution
– Measured in decibels (dB)
• Ex.) Traffic, cities
– Permanent deafness results
after 120 dB
Light Pollution:
• Does not present a direct hazard to health
– Hurts aesthetic value
• Results from inefficient lighting uses
– Wastes energy
– Burns more fossil fuels
Using the Marketplace to
Reduce Outdoor Air Pollution
• To help reduce SO2 emissions, the Clean Air Act
authorized and emission trading (cap-and-trade)
program.
– Enables the 110 most polluting power plants to buy
and sell SO2 pollution rights.
– Between 1990-2002, the emission trading system
reduced emissions.
– In 2002, the EPA reported the cap-and-trade system
produced less emission reductions than were
projected.
PREVENTING AND
REDUCING AIR POLLUTION
• Environmental scientists point out several
deficiencies in the Clean Air Act:
– The U.S. Congress has failed to increase fuelefficiency standards for automobiles
• Obama has now increased all motor vehicle standards
– Regulation of emissions from motorcycles and twocycle engines remains inadequate.
– There is little or no regulation of air pollution from
oceangoing ships in American ports.