Texas City Ground Level Ozone
Blocker Middle School
Middle or Junior High (6-9)
Is There Ground Level Ozone In Texas City?
Testing for Ground Level Ozone in my home.
Ozone Module from NCAR, Lesson on Schoenbein paper, Text Book, Science Interactions, chapter 14. A film about the air in Mexico City, from PBS.
Schoenbein Paper Preparation. . . . . . . . . . . . . . . .
1.Place 100 ml of water in a 250ml beaker then add 5g of corn starch.
2.Heat and stir mixture until it gels. The mixture is gelled when it thickens and becomes
3.Remove the beaker from the heat and add 1g of potassium iodide and stir well. Cool the
4.Lay a piece of filter paper on a glass plate and carefully brush the paste onto the filter paper.
Turn the filter paper over and do the same on the other side. Apply the paste as uniformly as
possible. The paper can be exposed for immediate testing at this point.
5.Allow the paper to dry. Do not set in direct sunlight. A low-temperature drying oven works
best. To save time, place the paper on a microwave-safe plate and microwave on high for 30
to 60 seconds.
6.Cut the filter paper into 1inch wide strips, place them in a zipper-lock plastic bag or glass jar
out of direct sunlight.
*Wash hands thoroughly with soap and scrub under fingernails with a brush after working
with the potassium iodide mixture.
Testing Procedure. . . . . . . . . . . . . . . . . .
1.Dip a strip of test paper in distilled water and hang it at a data collection site out of direct
sunlight. Make sure the strip can hang freely.
2.Expose the paper for approximately eight hours. Seal it in an airtight container if the results
will not be recorded immediately.
3.To observe and record test results, dip the paper in distilled water. Observe the color and
determine the Schoenbein Number using the Schoenbein color scale.
4.Determine the relative humidity of the data collection site by using a bulb psychrometer or
local weather data. Round off the relative humidity reading to the nearest 10 percent. (High
relative humidity makes the paper more sensitive to ozone, and a higher Schoenbein Number
is observed. To correct for this, the relative humidity must be determined and figured into the
calculation of ozone contration.) Refer to the Relative Humidity Number Chart. Along the
bottom of the chart, find the point that corresponds to the Schoenbein number that you
recorded. From that point, draw a line upward until it intersects with the curve that
corresponds to your humidity reading. To find the ozone concentration in parts per billion,
draw a perpendicular line from the Schoenbein number/relative humidity point of intersection
to the left side of the chart.
Results of the Study
I found out that we must of had a lot of ozone in our house. My Schoenbein paper turned really purple. I tested on October 24. there must of been an error in the test because the news reported little ozone in our air. Our Classes tested and we found very little ozone with most of the purple Schoenbein paper located close to Blocker.
My explanation for the ozone in our air is because of the chemical plants close to our school. I feel the smoke from the chemical plants and the cars caused the ozone.
Texas City should do like Mexico City from a film we saw. The people were required to leave their cars at home several days a week and take the bus or walk to work and school. This cuts down on the car exhaust. The chemical plants had to use 'Cat Cracker' to clean the smoke from refining oil and a Scrubber for smoke stacks.
We plotted all our classes results on a city map to see were most of the ozone was found. The color of the Schoenbein paper was mostly white to a light yellow with a few purples. This lets you see the streets and the areas of town that might have ozone