Air Pollution Primary Pollutants Any substance that causes
direct harm to the atmosphere and organisms Sulfur Oxides (SO x )
Nitrogen Oxides (NO x ) Particulates particles (Rocks) Volatile
Organic Compounds (VOCs) Carbon Monoxide (CO) Lead Rocks, SO x, NO
x,and VOCs COoperate to Lead to pollution.
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Sources of Primary Pollutants Burning Fossil Fuels Electrical
Power Sulfur and Nitrogen Oxides Transportation Carbon monoxide
VOCs Nitrogen Oxides Industrial Chemicals Cleaners, solvents,
paints VOCs, CO and SO x Construction/Agriculture particulates
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Secondary Pollutants Created by the reaction of one or more
primary pollutants Tropospheric Ozone Smog Acid Rain
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Good Ozone? GOOD Ozone Exists in the STRATOSPHERE Protects us
from UV rays UV rays can cause damage to skin cells (cancers) Eye
tissue (cataracts) Fish and amphibians phytoplankton
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Ozone Depletion Production of CFCs began in 1930s and were used
as coolants, propellants in aerosols, cleaners for electronics,
sterilants for hospitals, fumigants for granaries and cargo ships,
and insulation and packaging production CFCs remain in the
troposphere because they are not water soluable and are chemically
unreactive Over 11-20 years, they rise to stratosphere
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Ozone Depletion CFCs break apart when exposed to ultraviolet
radiation Halogen atoms break free and react with single oxygen
atoms Slows the rate of ozone formation in upper atmosphere CFCs
can last 65 385 years in the stratosphere (depending on type)
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Ozone Depletion Other halogenated organic gases also cause
ozone depletion Halons and HBFCs (fire extinguishers) Methyl
bromide (CH 3 Br) fumigants Carbon tetrachloride (CCl 4 ) toxic
solvent Methyl chlorogorm (C 2 H 3 Cl 3 ) solvent for dry cleaning
and propellant in consumer products N-propyl bromide solvent and
cleaner Hexachlorobutadiene cleaning solvent Hydrogen chloride
emitted by Space Shuttles
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Ozone Depletion Montreal Protocol, 1987 36 nations met and
agreed to stop production of CFCs In London in 1990, and again in
Copenhagen, Denmark in 1992, the representatives met again and
agreed to phase out other ozone-depleting compounds
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Tropospheric Ozone BAD Ozone Created by the chemical reaction
between nitrogen oxides (NO x ) from car exhaust, oxygen and
sunlight Causes respiratory problems Wheezing, asthma, bronchitis,
pneumonia Irritates eyes and throats BAD OZONE
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Tropospheric Ozone When fossil fuels are formed, pollutants are
emitted: Hydrocarbons (from unburned fuel) Nitrogen oxide (NO)
Nitrogen oxide reacts with oxygen to form nitrogen dioxide (NO 2 )
Brown gas contributed to urban haze NO 2 can also absorb sunlight
and break up releasing oxygen atoms that react with diatomic oxygen
gas (O 2 ) to form ozone (O 3 )
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Effects of Tropospheric Ozone Ozone is a toxic gas and
oxidizing agent Damages crops and forests Irritates eyes and
respiratory system Highly reactive with rubber materials and
fabrics
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Photochemical Smog Photochemical smog is the mixture of about
100 primary and secondary pollutants formed under the influence of
sunlight. Main pollutants: ozone, NO, NO 2, Volatile Organic
Compounds (VOCs) (mostly hydrocarbons), Peroxyacetyl Nitrates
(PANs) Occurs in cities with large populations (lots of vehicles),
and sunny, warm, dry climates.
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Photochemical Smog Occurrence depends on topography, climate,
population density, and fossil fuel use. Precipitation cleans the
air and winds disperse smog Thermal inversions trap smog in valleys
In valleys, cold air slides down valley sides to bottom, but traps
warm air layer above it A layer of warm air prevents mixing of
air
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Acid Deposition The pH scale pH is a measure of acidity of a
solution. It is a literal abbreviation of potential of hydrogen,
meaning that it measures the amount of hydrogen ions in solution.
The amount of H + determines if it is a base or an acid. Scale of
0-14, with 0 = acid, 7=neutral, 14=base logarithmic scale
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Acid Deposition Formation Can be wet (acid rain) or dry
(particulate matter) Acid deposition comes from pollutants put out
by vehicles and industrial and power- generating plants Primary
pollutants are sulfur oxides and nitrogen oxides Sulfur oxides
released from burning coal Nitrogen Oxides release from car
exhaust
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Acid Deposition Formation Acid Deposition does not always fall
where the pollutants are released The areas of greatest acidity
(lowest pH values) are located in the Northeastern United States.
caused by the large number of cities, the dense population, and the
concentration of power and industrial plants in the Northeast. In
addition, the prevailing wind direction brings storms and pollution
to the Northeast from the Midwest soil and rocks in the NE United
States is less likely to neutralize the acidity
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Acid Rain in the US Why are The acid Rain Concentrations Higher
in the East than in The west?
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Chemical reactions natural rain fall has a pH of 6 because of
the interaction of CO 2 and water vapor, forming weak carbonic
acid. CO 2 + H 2 0 H 2 CO 3 Acid Rain has a pH below 5.6 because or
reactions between water vapor and SO X and NO X.
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Chemical reactions Acid Rain from Sulfur Compounds: Sulfur
dioxide reacts with water to form sulfurous acid: SO 2 + H 2 0 H 2
S0 3 Sulfur dioxide can be oxidized to sulfur trioxide 2SO 2 + 0 2
2SO 3 Sulfur trioxide reacts with water to form sulfuric acid: SO 3
+ H 2 0 H 2 SO 4 Acid Rain from Nitrogen Compounds: 2NO 2 + H 2 O
HNO 2 + HNO 3
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Effects of Acid Rain Damages buildings and marble statues by
reacting with calcium carbonate to form soluble calcium bicarbonate
CaCO 3 + acid rain Ca(HCO 3 ) 2 Leaches aluminum and calcium from
soil into groundwater, lakes, and rivers poisoning fish and plant
roots. Aluminum reacts with gill causing an increase in mucous, and
suffocation Reduces production of chlorophyll in plants, and
sulfuric acid kills the plant.
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Acid Rain Process
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Transboundary Air Movement Sulfur dioxide can remain in the
atmosphere 3-4 days before reacting to form acid Therefore, it can
travel for hundred or thousands of miles (depending on the winds)
before becoming acid rain. Nitrogen oxides only remain in the air
for about 12 hours, enabling them to travel only tens or hundreds
of miles.
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Transboundary Air Movement Acid Deposition is a regional
problem not a local one In the US, the prevailing winds come from
the southwest traveling towards the northeast. Nine largest coal
burning states are in the Midwest and Ohio River Valley causing
much of the acid rain to fall in the NE US and eastern Canada.
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Reducing Acid Deposition coal containing less sulfur scrubbers
on smokestacks (limestone) natural gas instead of coal catalytic
converters (remove NO X from cars) use alternative energy sources
Full cost accounting cradle to grave accounting costs of clean-up,
restoration, reforestation, remediation, etc. coal, hydropower, and
nuclear power seem cheap, but do not account for all cost
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Reducing Acid Deposition Restoring acidified soils and waters:
Liming adding lime or limestone to acidic lakes to neutralize the
acidity expensive, only treats the symptom not the cause, can
affect plant productivity temporary must be repeated regularly
dredging expensive and temporary
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Climate Change
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Global Warming Caused by increased carbon dioxide and other
greenhouse gases in the troposphere that increase the natural
greenhouse effect Increased greenhouse effect raises the average
global temperature Increased temperature affects numerous aspects
of global climate system
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Past Climate Change Changes in climate have happened numerous
times over the past 400,000 years. Each time the world entered a
new ice age it was after a significant increase in Carbon Dioxide
in the atmosphere and an increase in global temperatures. Current
data shows our CO 2 levels to be higher than at any time in earths
history.
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INDUSTRIAL REVOLUTION CURRENT LEVEL HISTORICAL LEVEL
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Interpretation of Graphics Carbon Dioxide levels and
temperature correlate The carbon dioxide level never exceeded 290
ppm until after the industrial revolution (around 1800s) Current
Carbon Dioxide levels exceed historical levels by nearly 70 ppm or
25% of historical records
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Greenhouse Gases 1992 Earth Summit Rio de Janeiro, Brazil UN
Framework Convention on Climate Change approved by 106 nations,
establishing two basic principles: Scientific uncertainty must not
be used to avoid precautionary action. Industrial nations, the
greatest historical contribution to climate change, must take the
lead in reducing greenhouse gases and slowing global warming.
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Greenhouse Gases Nations committed to reduce CO 2 levels to
1990 levels by 2000. But, it did not require them to reach the
goal.
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Greenhouse Gases 1997 Conference of Parties Kyoto, Japan 161
nations were represented to negotiate a new treaty to slow global
warming. Three agreements: 38 developed countries required to
reduce GHG emissions to 1990 levels by 2012. Developing countries
not bound to requirement of treaty Emission Trading allowed between
participating countries.
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Ways to reduce greenhouse gas emissions: Reduce use of fossil
fuels increase use of renewable energy sources hydrogen fuel cells,
tidal, geothermal, solar, wind, biomass, hydroelectric,
nuclear
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Ways to reduce greenhouse gas emissions: Energy efficiency use
more energy efficient cars, lighting, heating, cooling and other
machinery, better building insulation Increase use of public
transportation (trains, buses, etc.) uses less energy less
pollution environmental benefits: traffic, noise, road
building
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Ways to reduce greenhouse gas emissions: Implement ideas such
as: carbon tax carbon credits use carbon and nitrogen filters in
power station collect all the methane that leaks from land fill
sites (methane can be used as a fuel) reduce deforestation,
increase reforestation
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Impacts of Global Climate Change Present day Predicted
Distribution forest grassland arid woodland shrub land shrub land
woodland grassland Arid deserts in Southwestern U.S. will shrink as
precipitation increases Savanna/shrub/woodland systems will replace
grasslands in the Great Plains Eastern U.S. forests will expand
northerly weather conditions will become more severe Southeastern
U.S. increasing droughts will bring more fires triggering a rapid
change from broadleaf forests to Savannas
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Impacts of Global Climate Change Increases in evaporation in
tropical areas Results in a change in global rain patterns
Increased precipitation resulting in increased flooding Decreased
precipitation may result in drought, crop failures and famine
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Impacts of Global Climate Change Increased melting of land ice
raises ocean levels Increases flooding of coastal areas Inundates
groundwater systems with salt water
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Impacts of Global Climate Change Coastal residents forced to
migrate inland Results in overcrowding of inland cities Lack of
infrastructure to support population Result in shortages of
resources
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Impacts of Global Climate Change Increase in sea temperatures
Results in more intense hurricanes and typhoons Results in melting
sea ice which changes the density of sea water
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Impacts of Global Climate Change Increased spread of disease
Increased temperatures create higher incidence of heat related
illness and death Increased precipitation increases mosquito
population and spread of diseases Increases flooding and chances
for drinking water contamination from sewage
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Impacts of Global Climate Change Migration of people causes
overcrowding Breeding ground for diseases such as typhoid, cholera
and diarrheal diseases
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Impacts of Global Climate Change Increased temperature also
changes the density of ocean water Affects the upwelling of deep
ocean water Affects the global conveyor belt that moves the heat
energy around the planet This could ultimately push the world
climate into another ice age
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Solutions to Global Warming Changes in human consumption of
fossil fuels is essential to reducing the carbon dioxide emissions
Integration of alternative forms of energy for electrical power
must be done soon: Wind/Biomass/Geothermal/Solar/Hydro Mass
acceptance and use of alternative energy for transportation
Distribution of alternative energy technology to developing
countries so that they can transition their economy without
creating additional carbon dioxide problems.