<< Chapter < Page Chapter >> Page >
Suggested Time: 65 minutes. Science TEKS: 3.11, 4.6, 5.1, 5.2, 5.3, 5.4, 5.5. Math TEKS: 5.11, 5.14, 5.15


Students have already learned about the most common gases in the atmosphere. Now they will begin to learn about how other substances in the atmosphere can strongly affect their health and the environment, even in minute concentrations. In this lesson, students will learn about stratospheric ozone and the difference between this high-level ozone (which protects the Earth from ultraviolet radiation) and low-level ozone (which is an air pollutant).

Stratospheric ozone forms naturally and protects us from ultraviolet radiation. Tropospheric ozone forms from air pollutant emissions and harms human health.Credit: U.S. EPA: “Ozone Good Up High, Bad Nearby”

Background information

Most of the oxygen in the atmosphere, and the type that we need to sustain life, has two atoms per molecule (O2). Ozone , by contrast, has three oxygen atoms (O3). Ozone forms naturally in the stratosphere when intense ultraviolet radiation from the Sun splits an oxygen molecule (O2) into two O atoms. Each O can then combine with another O2 to form O3. [Note: The concept of molecules composed of atoms is above the 5th grade level; for your explanation to students, you can state that the Sun’s intense UV radiation splits oxygen to form ozone].

About 90 percent of the ozone in the Earth’s atmosphere is found in what is known as the ozone layer in the stratosphere (about 10-30 miles above Earth’s surface). The ozone layer absorbs most of the Sun’s ultraviolet radiation to shield us from these damaging rays. Ultraviolet rays can cause a range of negative effects: they can cause cancer, burn skin, damage eyes, weaken the human immune system, and harm both plants and animals. In fact, estimates show that a one percent reduction in the ozone layer results in a two to five percent increase in the number of cases of cancer!

Certain air pollutants can damage the ozone layer. The most dramatic depletion of the ozone layer is the Antarctic ozone hole . In the early 1980s, scientists discovered major thinning of the ozone layer above Antarctica during springtime . In fact, they observed nearly 70% less ozone than had been found there previously! Scientists realized that the depletion of the ozone layer is caused by the release of certain chemicals such as chlorofluorocarbons (CFCs) into the atmosphere. Just a few decades ago, CFCs were used in air conditioners, aerosol sprays, and cleaning products. When CFCs reach the stratosphere, they react with the sunlight to release chlorine atoms, which can destroy ozone molecules. In 1989, an international agreement known as the Montreal Protocol was signed to ban the most destructive ozone-depleting gases and preserve the ozone layer. If the agreement is adhered to, it is hoped that the ozone layer will completely recover by 2050.

From September 21-30, 2006 the average area of the ozone hole was the largest ever observed. In this image, from Sept. 24, 2006, the Antarctic ozone hole was equal to the record single-day size of 11.4 million square miles.Credit: http://www.nasa.gov/centers/goddard/news/topstory/2006/ozone_record.html

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Rice air curriculum. OpenStax CNX. May 09, 2010 Download for free at http://cnx.org/content/col11200/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Rice air curriculum' conversation and receive update notifications?