Composition of the atmosphere.
The five most abundant gases in the
atmosphere (listed here in alphabetical order): argon (Ar), carbon
dioxide (CO2), nitrogen (N2), oxygen (O2),
and water vapor
(H2O)
(you should know approximate concentrations of most of these).
Greenhouse gases: water vapor (H2O), carbon dioxide (CO2)
and others.
What do they do? International agreement has led to a
decrease in the usage
of one of the greenhouse gases? Which one? Why else is that
particular gas of
concern? Which of these gases is a source of latent
heat energy? What weather variable is commonly used to measure
atmospheric water vapor content?
Atmospheric evolution.
About how old is the earth? What was the
earth's first atmosphere composed of? Where is our present
atmosphere thought to have come from? What are the three most
abundant gases emitted by volcanoes. What important atmospheric
constituent in our present atmosphere did not come from volcanoes?
What is the principal source of this gas?
Carbon dioxide and climate
change. Concentrations of CO2 (and other
greenhouse
gases) are increasing. When did this increase begin? What
processes (natural and man-made) add CO2 to
(source) and remove CO2 from (sink) the atmosphere?
Atmospheric CO2 concentrations have been measured since 1958
(Keeling
curve). How were CO2 concentrations determined before
1958?
Why is increasing CO2
concentration of
concern? What changes have there been in global average surface
temperature in the past 150 years or so?
Air pollution. Primary and
secondary pollutants. Air Quality Index
(AQI). A pollutant is considered unhealthy when the AQI exceeds
what value?
Carbon monoxide (CO).
Toxic. Most abundant of the primary
pollutants. What produces most of the CO in Tucson air? Incomplete
combustion (what would complete combustion produce). Early morning
and wintertime pollutant. What is a surface radiation inversion
layer, when do they form? Would a surface inversion layer act to
concentrate or disperse CO?
Tropospheric
ozone (O3).
Ozone
aggravates existing respiratory diseases,
is harmful to plant life, and damages materials such as rubber.
Ozone is a secondary pollutant and is a key component of
photochemical smog (also known as Los Angeles-type smog). To produce
smog, ozone reacts with hydrocarbons. Peak ozone and photochemical
smog concentrations occur on summer afternoons.
Sulfur dioxide (SO2).
Toxic
and aggravates existing respiratory
diseases. The world's first pollutant. Natural and manmade sources.
Involved in some of the world's worst air pollution disasters: Great
London Smog of 1952, Donora (Pennsylvania) 1948 (see p. 346). The
word smog was first used to describe the combination of sulfurous
smoke + fog; the term London-type smog is now used.
Reacts in clouds to form acid rain.
Sample
questions (from the Fall
2000 quiz packet) Practice Quiz: 1, 3, 4, 5, 6, 7, 9, 12,
16a, 20,
EC1 Quiz #1: 1, 2,
4a Final Exam: 2, 25
***
Chap. 1 (pps 8-13), Chap. 6 (pps 142-148) ***
Mass, weight,
density, and
pressure. Mass is the amount of a
particular substance. On the earth gravity pulls downward on a mass
producing weight. Pressure at any level in the atmosphere is a
measure of the weight of the air above (this is one way of thinking
about and understanding pressure). Pressure is defined as force
divided by area and acts like a force (a force that pushes upward,
downward, and sideways). Common pressure units and typical sea level
pressure values. What instrument is used to measure air pressure?
About when was it invented? Pressure and air density (density = mass
divided by volume) both decrease with increasing altitude (you should
be able to explain why). What relationship is there between the rate
of pressure decrease and air density (i.e. does pressure decrease
most rapidly in high or low density air)?
Layers of the atmosphere.
Troposphere: lowest layer in the
atmosphere, decreasing temperature with increasing altitude (why is
the warmest air found near the ground), contains most of the water
vapor and clouds, can be unstable (strong vertical air motions
possible). Tropopause. Stratosphere: isothermal layer and
temperature inversion layer (what causes the warming in the
stratosphere), stable layer, contains the ozone layer. Approximate
altitudes of these layers. Units: meters, kilometers, feet, miles.
Sample questions Practice Quiz: 8?, 15,
16b, EC2, EC3
Quiz
#1: 3, 17, EC2
Final Exam:
6, 11, 19, 48