The Atmosphere, Climate, and Global Warming

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The Atmosphere, Climate, and Global Warming
Basic Atmospheric Composition
-Composed of gas molecules held close to Earth by
gravity and thermal movement of molecules.
-Major gases in the atmosphere
Nitrogen (78)
Oxygen (21)
Argon (0.9)
Carbon Dioxide (0.3)
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Other gases (and things) found in the atmosphere
Most are found in trace amounts, and may vary in
concentration over time, and area.
-methane
-ozone
-hydrogen sulfide
-hydrocarbons
-oxides of Nitrogen and Sulfur
-chlorofluorocarbons (CFCs)
-all kinds of particulates (aerosols)
-water vapor
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The Atmosphere as a Dynamic System
-The atmosphere is a dynamic, ever changing
system.
-Air masses with different characteristics move,
and produce weather and climate.
-Movement is caused by differing temperatures
day/night and regionally, energy from living
organisms (think rain forest), by human
industrial and agricultural activities.
-The atmosphere has been modulated primarily by
biological activity for 3.6 billion years.
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Important Atmospheric Layers
-there are two layers of the atmosphere which
are the most important to our environment.
1)Troposphere (where weather occurs)
-lower 10 to 12 km
-temperature decreases with elevation, 17C at
surface to 60C at 12km in elevation
-at the top of the troposphere, the tropopause
is a boundary with a constant temp. of 60C.
-the tropopause causes condensation of water
vapor, and keeps it within the troposphere.
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Atmospheric Profile
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2) Stratosphere

• reaches from the top of the tropopause to about
• 50 km in elevation.

-contains the ozone layer, which has its
greatest concentration at 25-30 km above the
Earth.
-Ozone (O3) is responsible for protecting life
from the effects of ultraviolet radiation from
the Sun.
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Atmospheric Profile
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Characteristics of the Atmosphere
Air masses are usually characterized by
three qualities.
1) Atmospheric pressure
The force per unit area of the atmosphere pushing
down on the Earth.
Pressure decreases as altitude increases because
there is less atmosphere pushing down from above.
Measured in N/m2 (Newtons per square meter) or in
lb./in2 (pounds per square inch)
Sea Level 105 N/m2 or 14.7 lb./in2
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2) Temperature
Measured in Fahrenheit, Celsius, or Kelvin
Most measurements are taken in Celsius, except in
the U.S., where the Fahrenheit scale is still
in use, (at least by the public and on T.V.)
The conversion from F to C Co 5/9(Fo 32)
Temperature is the measure of the amount of
kinetic energy within the atmosphere. The higher
the temperature, the more energy contained.
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Temperature Scale Relationships
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3) Moisture Content
Air masses are usually characterized by their
water vapor content.
Often referred to as humidity, the amount of
water vapor that can be carried is related to
the temperature and pressure of the air.
Relative humidity is a measure of how much
moisture the air can carry.
Air that can carry no more water vapor is called
saturated, and the relative humidity is 100
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Circulation of the Atmosphere
Atmospheric circulation results primarily from
the Earths rotation and differential heating of
Earths surface and the atmosphere.
This circulation produces global patterns that
include prevailing winds and latitudinal belts
of high and low air pressure from the equator to
the poles.
Rising columns of air at the equator produce low
pressure areas, producing precipitation.
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Generalized Circulation of the Atmosphere
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Belts of high pressure develop near 25o to 30o
north and south latitude.
The pervasive high pressure, and the resulting
low precipitation cause Earths major deserts to
be located at these latitudes.
The poles are also subject to high
pressure areas, and therefore actually get little
real precipitation.
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Climate
-Refers to the characteristic atmospheric conditio
ns for a region of Earth.
Climate is based upon temperature and
precipitation.
-Implies long periods of time, such as years or
decades.
Shorter term events are called weather conditions,
and are measured in days weeks, or sometimes
months.
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Classification of Climate by Latitude
The simplest way to categorize climates is by
their latitude on Earth.
Tropical
Subtropical
Midlatitudinal
Sub Arctic
Arctic
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Other Categories of Climate
Other categories include
Humid Continental
Mediterranean
Monsoon
Tropical wet-dry
It is important to recognize the fact that
climate is the key driver in determining what
type of biological systems will prevail in an
area.
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Microclimate
Localized areas may have climate conditions
different than a region.
May be caused by something like a lake or river.
Ex Areas around Great Lakes, or an oasis in a
desert.
Microclimate can also extend down to very
small areas, such as under a log or rock.
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Air Pollution
1) Sources of Air Pollution
Point Sources emit from one or more controllable
sites, such as smoke stacks
Fugitive Sources emit pollution from open areas
exposed to wind. Ex burning for agriculture,
open mines which create dust, construction sites
Mobile Sources emit pollution as they move. EX
automobiles, airplanes
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Major Air Pollutants
Ozone (03) strong irritant, aggravates asthma,
causes plants to die back or crops to be
reduced. Cracks paint, rubber, causes colors to
fade.
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Sulfur Dioxide (S02) Increase in respiratory
disease, bleaching and decay in plants,
dissolves Metal and stone. -When mixed with water
in air, creates acid rain
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Nitrogen Oxides (NOx) aggravates
respiratory problems, also a cause of acid rain,
causes bleaching of colors. -Responsible for
photochemical smog, reacts sunlight to form a
brown cloud at ground level
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Photochemical smog in the LA basin
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Photochemical smog in Mexico City
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Volatile Organic Compounds (VOCs) Hydrocarbon
compounds from solvents, fuels, paints, etc.. A
major source of VOCs are automobiles and
gasoline vapors
Also a component of photochemical smog
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Particulate Matter (PM 10 and PM 2.5) -PM 10 is
made of particles less than 10 um in diameter.
PM is made of dust particles from soil,
smoke, soot, heavy metals, asbestos, etc
PM 2.5 is very fine particulate matter, less
than 2.5 um in diameter.
High concern, because very fine PM is taken
deep Into lungs, and can sometimes cross into
blood. EX nitrates, sulfates
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Urban Air Pollution
In urban areas, especially if air is trapped, an
inversion may develop.
An inversion happens when air is not allowed to
circulate, and carry pollution away from the
urban area. Concentrations of pollutants can get
very high, and stay high.
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Los Angeles
Mexico City
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Pollution Controls
Sulfur Dioxide -switch to low sulfur coal -coal
gasification (converts coal to gas, which is low
in sulfur) -scrubbing flue gasses remove SO2 via
a filter
Gasses are passed through a slurry of water
and crushed limestone (CaCO3)
Calcium sulfite (CaSO3) is formed, removing
the sulfur from the gas
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Flue Gas Scrubbing
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Pollution Controls Automobiles
Since the mid-70s, automobiles have run
on unleaded gasoline, reducing the lead
pollution.
All automobiles are supposed to have a
catalytic converter, which reduces hydrocarbon
and carbon monoxide emissions.
Pollution controls are supposed to be checked in
the inspection process.
Reformulated gasoline has fewer pollutants, and
burns cleaner, making less pollution.
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Pollution Controls Particulates
Point source polluters have reduced their
pollution greatly in the past 50 years.
-settling chambers allow particulates to be
removed Ex ash and dust from power plants
Particulates from fugitive sources must be
controlled at the site of creation. (covers,
grass, wetting with water, etc..)
Diesel engines are being closely regulated to
lower the amount of particulates that they
produce.
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Indoor Air Pollution
For many pollutants, indoor concentrations
are greater than outdoor concentrations.
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The reason indoor pollution is greater is because
of the lack of good ventilation, and the need
to make houses more energy efficient.
Some common indoor pollutants
Second Hand tobacco smoke
Various molds
Radon gas
Pesticides of all kinds
Asbestos
Formaldehyde (from glues and plastics)
VOCs of all types (from paint to spray cans)
Carbon Monoxide (from poorly functioning heaters)
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Sick Building Syndrome
There have been cases of buildings which had to
be evacuated and or torn down because of poor
indoor air quality.

• There are two types
• Buildings with identifiable problems, such as
• mold. These can be fixed and the buildings
• re-occupied safely.

2) SBS, where the causes of symptoms are
not identifiable. Chronic health problems can
effect a large number of workers.
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Radon Gas
Colorless, odorless gas, naturally occurring
Seeps into basements through cracks/openings
Can be held in the materials used to build a
home Rocks, cement blocks, etc..
Radon causes damage because it is
radioactive, and is believed to cause lung cancer.
Radon can be eliminated from a home by
having good ventilation in the basement, and by
monitoring suspect homes for high levels
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CH25 Ozone Layer and Ozone Depletion
Ozone is a colorless, odorless gas, with the
formula of O3
Ozone is formed by the addition of a free
oxygen atom to an oxygen molecule. (25.3)
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The Importance of Ozone
Ozone acts as a screen for UV radiation in
the Stratosphere.
99 of incoming Solar UV is screened by the
ozone layer.
Without the ozone layer, life on Earth would not
be possible.
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Destruction of Stratospheric Ozone
Measurements of ozone have been going down since
measurements first took place.
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Ozone Depletion
It is widely held that man-made products,
especially chlorofluorocarbons (CFCs),
are responsible for the lowering amounts of
ozone.
Other products, such as Methyl Bromide and NOx
have also been shown to be potent ozone depleters
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The Effects of Less Ozone
Increased UV means increases in skin cancer
Lower crop yields, due to over exposure to UV
Lower photosynthetic rates in the oceans
Coral reef die-outs due to UV bleaching
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Fewer Frost Days
Annual Number of Frost Days 1948-1999
All U.S. - 0.8
NOAA
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Projected Precipitation Changes
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Changes in USDA Hardiness Zones

1990 Map
2006 Map
USDA
Arbor Day