Name: ___________________________________________________ Date: ____________ Period: ____
Environmental Science: Ozone – The Good, the Bad, and the Ugly.
Objectives
a) Differentiate between the good and bad ozone,
b) Locate the position in the atmosphere where the good and bad ozone reside
c) Plot yearly ozone data
d) Understand the ground level ozone effects on humans and plants.
The Good, the Bad, and the Ugly of Ozone
Background
Ozone (O3) is a pale blue gas and consists of three oxygen atoms (the third oxygen
makes it highly reactive). There are two main types of ozone: the good ozone and
the bad ozone. The good ozone is found in the upper atmosphere (located in the
stratosphere). There it filters potentially damaging ultraviolet light from reaching
the Earth's surface, preventing it from hurting humans. The bad ozone, also known
as ground-level ozone (located in the troposphere), is an air pollutant with harmful
effects on the respiratory systems of animals and humans. Ground level ozone is
related to emissions from burning and internal combustion engines, especially
those from industrial plants and vehicles, but also from charcoal grills and lawn
mowers. To reduce the production of ozone, cars and trucks are required to have
air pollution controls that are regularly inspected.
Ground level ozone has also been shown to affect plant growth. Typically plants
will begin to exhibit damage when the ozone level reaches 40 ppb (parts per
billion). This means that for every one billion molecules of air, there are 40
molecules of ozone. Now this doesn’t seem like much, but the plants begin to show
signs of biological change. If the level reaches greater than 80 ppb, the result is
more evident, damaging their leaves and resulting in a 10% decrease in growth in
susceptible species. This bad ozone is at its highest level during the hot and dry
months of the year, typically over the summer. Studying the effects of ground level
ozone is easily done on plant life, since leaves are replaced each year and it is
easier to evaluate sources of damage on leaves then in people’s lungs.
Name: ___________________________________________________ Date: ____________ Period: ____
Environmental Science: Ozone – The Good, the Bad, and the Ugly.
Procedure
1. Using the data from the Table 1 below, plot the “Highest Concentration of O3”versus “Date”
on a piece of graph paper. Use a pencil and be sure to plot all points. Then after all of the points
have been plotted connect the dots carefully.
2. If you recall from the reading, ground level ozone can cause damage to certain plants if its
levels are too high. On your graph, using a yellow color pencil, lightly shade in the range of
values where plants would have chronic exposure of 40 to 80 ppb. Then using a red pencil,
lightly shade on your graph where the plants would get acute exposure > 80 ppb.
3. Answer questions.
Exhibit 2-47. Ambient ozone, PM 10, and PM2.5 concentrations in U.S. counties in the U.S.Mexico border area, (Region 9 includes: San Diego, Imperial, Yuma, Pima, Santa Cruz,
Conchise Counties) 1986-2008
Averaging
Period
1986-1988
1987-1989
1988-1990
1989-1991
1990-1992
1991-1993
1992-1994
1993-1995
1994-1996
1995-1997
1996-1998
1997-1999
1998-2000
1999-2001
2000-2002
2001-2003
2002-2004
2003-2005
2004-2006
2005-2007
2006-2008
R9 Border
Counties
(ppm)
.089
.090
.092
.092
.089
.087
.084
.082
.081
.080
.079
.076
.075
.073
.075
.074
.073
.072
.073
.072
.071
www.epa.gov
R9 Border
Counties
(ppb)
National
Average
(ppm)
.097
.097
.094
.089
.088
.086
.085
.087
.087
.087
.086
.087
.086
.084
.084
.085
.082
.079
.078
.079
.077
National
Average
(ppb)
Name: ___________________________________________________ Date: ____________ Period: ____
Environmental Science: Ozone – The Good, the Bad, and the Ugly.
Questions:
1. How many types of ozone are there?
2. What does each type do to the environment?
3. On the diagram below, please label where the good ozone and the bad ozone
are located.
Name: ___________________________________________________ Date: ____________ Period: ____
Environmental Science: Ozone – The Good, the Bad, and the Ugly.
4. What is the overall trend of your graph?
5. Based upon the data in your graph, determine the number of time periods
that local plants in these counties might have suffered from chronic exposure
(40 – 80 ppb)?
6. Based upon the data in your graph, determine the number of time periods
that local plants in these counties might have suffered from acute exposure
(> 80 ppb)?
7. Too much ozone contributes to the creation of smog. Smog is a kind of air
pollution; the word ‘smog’ is a combination of smoke and fog. Smoke
comes from burning or vehicular/industrial emissions that are acted on in the
atmosphere by sunlight. List three things that would cause bad ozone and
smog to increase in a community.
a.
b.
c.
8. List three things that a community can do to help reduce their emission of
pollutants into the atmosphere.
a.
b.
c.