Studying Ozone and Air Quality
Steve Schneider
Deborah Carlisle
Measuring Ground-level Ozone
VOC’s + NOX + sunlight  O3
Motor vehicles are the single largest contributor to groundlevel ozone.
Measuring Ground-level Ozone
O3 levels above 120 ppb are considered
unhealthy. They can be generated by some
electrical equipment or from photochemical
reactions with smog:
VOC’s + NOX + sunlight  O3
Motor vehicles are the single largest contributor
to ground-level ozone.
In this project we are adapting the relatively
easy-to-make Schoenbein papers for classroom
use, and using ADI to analyze the color changes
quantitatively.
0-50
51-100 101-150
151-200 201-300
301-500
Commercial Papers:
Ecobadge, Ozone badge
Findings:
 Commercial cards had significant variability and were
expensive.
 Researched making Schoenbein papers
 Inexpensive and safe to make
Schoenbein Papers
Ozone was discovered by C.F. Schoenbein in 1839. He developed
an ozone-sensitive test paper that was widely used historically, and
more recently in classrooms.
The standard protocol for using the papers calls for an 8-hour
exposure to the air out of direct sunlight. Various studies have
shown a dependence on humidity, and there are a variety of
recommendations for moistening the strips prior to exposure.
Control
low O3
exposure
high O3
exposure
History
Despite the method's early limitations,
starting in the mid-1800s, more than 300
stations recorded ozone exposures in
countries such as Austria, Australia,
Belgium, England, France, Germany,
Russia, and the United States.
Learning Goals :
 Analyze different relative amounts of ozone found
in various locations using test results.
 Understand that ozone is found near the earth’s
surface (ground level) in the troposphere as well as
the stratosphere.
 Understand that ozone test strips/Schoenbien
paper detect ozone gas through a chemical reaction
that is caused by ozone in the air.
 Use technology to more precisely analyze relative
color changes obtained with ozone test strips.
Some Testing Ideas:
 Test for ozone at different times of day and look for
patterns. When are ozone concentrations the
highest?
 Test for ozone in various locations and see what
areas are the highest.
 Look at the effects of wind patterns on ozone
 Students research and brainstorm where ozone
might be found and what equipment/machines
produce ozone
Making Schoenbein Papers
Classroom Use Made Easier:
1. Test strips can be stored in a double plastic zip lock
bag, until you are ready to read your results.
2. To look at results simply dip your exposed test strip
in a beaker of water. You will see a visible color
change.
3. Compare the relative colors to the control.
4. Use digital analysis to measure RGB values and
compare between test strips.
Testing Ozone Levels
 Groups of 4
 Select a test site
Things to Consider
 Avoid direct sunlight
 Free air circulation around your strip
 Run a control with your group
 Label an index card with date/time/location
Outdoor exposure
Carrying Out the Experiment:
 Discuss experimental design in your groups to come
up with a plan for testing
 Run tests (place test strips and control)
 Collect test strips and place in zip-lock baggies
 Return to lab and expose strips by dipping in water
 Photograph test strips
 Data Analysis and share results
Data Analysis
How do Ozone Test Strips
Work?
Ozone is a strong oxidizer. It rapidly reacts with the iodide
ion, I- in the KI salt applied to the filter paper.
KI + H2O + O3  I2 + O2 + K+
I2 + I- + starch  I3- + starch
Last step :
I3- (linear)+ starch (helix)
(Turns Blue)
Combination of I3- and helix causes light
reflection to be in the blue/violet range of visible
spectrum
Schoenbein Papers
Cntrl
80
100
120
140+
Comparing Test Strips
Calibration of Test Strips
Amount of Ozone
60
50
Intensity %
40
y = -0.4007x + 75.428
R² = 0.9695
30
20
10
0
0
20
40
60
80
ppb Ozone
100
120
140
160
National Science Education Standards
 Science as Inquiry: Grades 5-8 and 9-12
Ability to perform scientific inquiry,
understanding about scientific inquiry
 Science and Technology: Grades 5-8 and 9-12
Understanding about science and technology
 Science in Personal & Social Perspectives: Grades 9-12
Environmental quality, changes in environments