When you head out into the summer sun, do you lather up with sunscreen? We hope so! It’s important to protect your skin from the sun’s ultraviolet rays.

If you’ve ever had a bad sunburn, you probably already know the value of sunscreen. Would you believe the Earth has its own form of sunscreen? It’s true! It’s called the ozone layer.

Way up high (between 8 and 25 miles up!) in a part of the atmosphere known as the stratosphere, there’s a layer of ozone. Ozone is a gas molecule made up of three oxygen atoms. Its chemical symbol is O3.

Ozone occurs naturally in the atmosphere. It helps to protect the Earth by blocking many of the ultraviolet rays that come from the Sun.

Ozone is not always good for us, though. When ozone occurs closer to the surface of the Earth, it can be an air pollutant that makes it hard to breathe and hurts trees and crops. Ground-level ozone is one of the main parts of smog that you see in many big cities.

The ozone way up high in the ozone layer, though, is very helpful. Unfortunately, the ozone layer is under attack by man-made chemicals called ozone-depleting substances (ODS).

Common ODS include chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Many ODS could be found — and sometimes can still be found — in refrigerator and air conditioner coolants, fire extinguishers, pesticides and aerosol propellants.

When released into the air, ODS move very slowly toward the upper atmosphere. Up high, they are broken down by ultraviolet rays from the Sun and release harmful molecules that destroy the “good” ozone.

ODS make the ozone layer thinner and, in some areas (like over Antarctica), they can even create “holes” in it. When this happens, more ultraviolet light rays are allowed to pass through to the Earth.

As ultraviolet radiation on Earth increases, health issues — like skin cancer and cataracts — increase. Ultraviolet rays can also affect food chains by reducing crop yields and harming marine organisms, which are the base of the ocean food chain.

In 1987, the United States and over 180 other countries adopted an international treaty that called for phasing out ODS. Today, ODS have been greatly reduced.

Research shows that depletion of the ozone layer is diminishing worldwide. If the United States and other countries around the world continue to eliminate ODS, scientists believe natural ozone production should heal the ozone layer by around 2050.


11 Join the Discussion

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    • That’s something to WONDER about, isn’t it, Xavier? We think about that question sometimes, too. Would we have to wear special suits to protect us when we went outside? How would the plants and animals react? Our Wonder brains are really thinking about this one! :-)

    • We hope you have a good day, too, Xavier! We also hope you’ll give your question about the ozone layer some more thought with that WONDERful Wonder brain of yours and come up with even more creative “what if” answers for your assignment on your own! :-)

  1. I never knew that the ozone layer was so imporant or that we even had one. I guess it’s a good thing we do have an ozone layer to protect us from the ultraviolet rays that come from the sun.
    -Hannah ;)

  2. Hi! I liked today’s wonder a lot! It’s sad that humans are destroying the ozone layer by driving cars and cutting down trees and polluting the air. And polar bears are in danger because of us. I read in a book that if we don’t help the planet and pollute less, scientists predict that all the polar bears will be gone by 2050. That is thirty seven years from now. People could also help by driving cars that use less gas, or are electric, or a hybrid car, like a Prius. Thank you for today’s wonder! :) ;)

    • Hi there, Berkleigh! Thanks so much for sharing your comment with us- today’s Wonder is an important one! We are happy to hear that you’ve been reading about the dangers of the destruction of the ozone layer- it will take all of us to keep our world happy and healthy. Thanks for telling us about what you read about polar bears, Berkleigh, we think you’re on the right path when it comes to protecting the Earth. Keep up the great work, Wonder Friend, you make a difference! :)

      We hope you had a very happy birthday! :)

  3. I did, thank you! Me and my family went out to eat at the restaurant of my choice, and I got some very cool presents, including a fairy figurine that I wanted, but had been discontinued, and I found it at a toy store! I had a very yummy cake, too. It was a strawberry shortcake. I also got a pair of skates! Now me and my younger sister can skate together. We skated in the house yesterday. :) Thank you!! :) ;) :)

    • WOOHOO, we’re so glad you had a great birthday, Berkleigh! Thanks for telling us all about your great day and the awesome gift you received! WOOHOO for birthday fun! :)

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Have you ever wondered…

  • What is the ozone layer?
  • How do ozone-depleting substances hurt the ozone layer?
  • Can the ozone layer be saved?

Wonder Gallery

ozone_shutterstock_48725905Vimeo Video

Try It Out

Ready to get into the O Zone? Grab a few friends or family members and have fun checking out one or more of the following fun activities!

  • The Environmental Protection Agency wants you to become SunWise! It’s important to protect your skin from the Sun’s ultraviolet rays. Take the SunWise Survivor Challenge and follow the SunWise Action Steps to learn more about how to make good decisions to stay healthy.
  • Can you really make a difference in the fight to save the ozone layer? You sure can! Watch this fun video with Ozzy Ozone to learn more about what is attacking the ozone layer and how you can play an important role in the Earth’s future.
  • Up for a challenge? Do some Internet research on ODS. If you have some old cabinets in the house or the garage that haven’t been cleaned out in a long, long time, you might still have some old products that contain ODS lying around. Go on a hunt for old products, especially old propellant cans and aerosol products, that contain ODS. Go over what you find with your parents. Can you get rid of them? What’s the safest way to dispose of them without releasing the ODS into the atmosphere? Contact your local trash disposal experts for more information.


Still Wondering

Check out National Geographic Xpeditions’ The Arctic and Antarctic Circles lesson to learn more about the polar regions most affected by ozone depletion.


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