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The Good and Bad Effects of Ozone
Vocabulary:
ozone
fossil fuels
molecule
oxygen
atmosphere
pollutants
nitrogen
Ozone Action Day
ultraviolet
Are you confused when an Ozone Action Day is announced? You remember from science class that the ozone layer is becoming
thinner, so how can ozone be a problem if there is not enough of it? If you are confused, you are not alone. Ozone, a form of
oxygen that has three oxygen atoms in each molecule instead of the usual two, is both helpful and harmful to people.
Located in the upper layer of the stratosphere (approximately 30 miles up), ozone (a gas) protects Earth from the ultraviolet
radiation of the Sun. Ozone filters out much of these harmful rays. Ultraviolet radiation on Earth can cause sunburn, skin cancer,
skin damage, and damage to our eyes. “Good” ozone, using sunscreen, wearing protective clothing and hats protect us from these
harmful rays. This is the good effect of ozone.
On the other hand, “bad” ozone is part of smog, a combination of fog and air pollutants. Smog forms when water droplets
condense on particles in the air. The particles can be from coal or wood smoke, for example, or chemicals released into the
atmosphere as the result of human activities. Today’s smog is primarily photochemical smog which is caused by the action of
sunlight (photo means light) on chemicals. Ozone forms when the hydrocarbons released while burning fossil fuels (i.e., burning
gasoline in a car engine), the nitrogen oxides (also released by automobiles and trucks), and other air pollutants react with each
other in the presence of sunlight. High temperatures, minimal or no cloud cover, and no wind are perfect conditions for groundlevel ozone formation. This ozone, which is toxic, irritates breathing airways, harms plants, and may damage rubber and paint. On
Ozone Action Days, people are encouraged to NOT burn fossil fuels or at least to reduce their use. Ozone is the major chemical
found in smog. This is the bad effect of ozone.
By the way, the protective ozone layer in the stratosphere would not be a good or healthy place to live and breathe. It does,
however, keep out those harmful ultraviolet rays. This is the good and bad of ozone.
Questions:
1. Name three possible consequences that may occur if there is a continued thinning of the ozone layer in the atmosphere.
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2. Photochemical smog is MOST likely to occur where it is
a. rainy
b. sunny
c. hot
windy
3. Photochemical smog is a result of:
a. a physical change
b. a state of matter change
c. a chemical change
d. an oxygen change
4. Compare and contrast “good” and “bad” ozone. A T-chart would be a good way to organize your thinking.
Good ozone
bad ozone