JFK High School, Environmental Science, Mr. Kent Name : Period: Date: 3. Why is ozone important to us and other organisms?

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1 JFK High School, Environmental Science, Mr. Kent Name : Period: Date: AIM: How have people been destroying the ozone layer? HW: 39e 1. What chemical is ozone? 2. How does ozone form in the atmosphere? 3. Why is ozone important to us and other organisms? 4. Where is the ozone layer thinner on the Earth? 5. Why is the ozone layer thinner there? 6. What chemical destroys ozone? 7. What are some industrial uses of this chemical? 8. How long does this chemical last in the atmosphere? 9. What are some alternatives to using this chemical? 10. What have you been doing in your lifestyle to destroy the ozone layer? 11. What can you do to stop destroying the ozone layer?

2 Brief Questions and Answers on Ozone Depletion What is the ozone layer and why is it important? How does ozone depletion occur? How do we know that natural sources are not responsible for ozone depletion? What is being done about ozone depletion? Is there general agreement among scientists on the science of ozone depletion? Will the ozone layer recover? Can we make more ozone to fill in the hole? What is the ozone layer and why is it important? The ozone layer is a concentration of ozone molecules in the stratosphere. About 90% of the planet's ozone is in the ozone layer. The layer of the Earth's atmosphere that surrounds us is called the troposphere. The stratosphere, the next higher layer, extends about kilometers above the Earth's surface. Stratospheric ozone is a naturally-occurring gas that filters the sun's ultraviolet (UV) radiation. A diminished ozone layer allows more radiation to reach the Earth's surface. For people, overexposure to UV rays can lead to skin cancer, cataracts, and weakened immune systems. Increased UV can also lead to reduced crop yield and disruptions in the marine food chain. UV also has other harmful effects. Back to top. How does ozone depletion occur? It is caused by the release of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS), which were used widely as refrigerants, insulating foams, and solvents. The discussion below focuses on CFCs, but is relevant to all ODS. Although CFCs are heavier than air, they are eventually carried into the stratosphere in a process that can take as long as 2 to 5 years. Measurements of CFCs in the stratosphere are made from balloons, aircraft, and satellites. When CFCs reach the stratosphere, the ultraviolet radiation from the sun causes them to break apart and release chlorine atoms which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than 100,000 ozone molecules. Other chemicals that damage the ozone layer include methyl bromide (used as a pesticide), halons (used in fire extinguishers), and methyl chloroform (used as a solvent in industrial processes for essential applications). As methyl bromide and halons are broken apart, they release bromine atoms, which are 40 times more destructive to ozone molecules than chlorine atoms.

3 Back to top. How do we know that natural sources are not responsible for ozone depletion? While it is true that volcanoes and oceans release large amounts of chlorine, the chlorine from these sources is easily dissolved in water and washes out of the atmosphere in rain. In contrast, CFCs are not broken down in the lower atmosphere and do not dissolve in water. The chlorine in these human-made molecules does reach the stratosphere. Measurements show that the increase in stratospheric chlorine since 1985 matches the amount released from CFCs and other ozone-depleting substances produced and released by human activities. Back to top. What is being done about ozone depletion? In 1978, the use of CFC propellants in spray cans was banned in the U.S. In the 1980s, the Antarctic "ozone hole" appeared and an international science assessment more strongly linked the release of CFCs and ozone depletion. It became evident that a stronger worldwide response was needed. In 1987, the Montreal Protocol was signed and the signatory nations committed themselves to a reduction in the use of CFCs and other ozone-depleting substances. Since that time, the treaty has been amended to ban CFC production after 1995 in the developed countries, and later in developing countries. Today, over 180 countries have ratified the treaty. Beginning January 1, 1996, only recycled and stockpiled CFCs will be available for use in developed countries like the US. This production phaseout is possible because of efforts to ensure that there will be substitute chemicals and technologies for all CFC uses. EPA coordinates numerous regulatory programs designed to help the ozone layer and continues to be active in developing international ozone protection policies. Individuals can also help, primarily by ensuring that technicians working on air conditioning and refrigeration equipment are certified by EPA, that refrigerants are recaptured and not released, and by educating themselves about the issue of ozone depletion. A longer article explains EPA's ozone protection efforts in more detail. Back to top. Will the ozone layer recover? Can we make more ozone to fill in the hole? The answers, in order, are: yes and no. We can't make enough ozone to replace what's been destroyed, but provided that we stop producing ozonedepleting substances, natural ozone production reactions should return the ozone layer to normal levels by about It is very important that the world comply with the Montreal Protocol; delays in ending production could result in additional damage and prolong the ozone layer's recovery. More detail on these questions is provided elsewhere on this web site.

4 What Can I Do to Protect the Ozone Layer? Car Air Conditioner Tips Go only to service facilities with EPA-certified technicians Make sure refrigerants from your vehicle will be recovered and recycled during servicing Repair all leaks in the a/c system (not required by federal law, but helpful in protecting the ozone layer) Although not required by federal law, this is one of the single best ways to do your part to protect the ozone layer. About million cars on the road today use CFC refrigerants in their air-conditioning (AC) systems. If leaky systems were repaired, it would prevent the release of millions of pounds of CFCs into the atmosphere each year. If your air conditioner needs major repairs, talk to your certified service professional about having it converted to use an alternative refrigerant. Home Appliance Tips Repair air conditioners Although not required by federal law, this step prevents ozone-depleting refrigerants from escaping. Make certain the refrigerant is recovered before servicing. See a fact sheet on this topic. If you purchase a new A/C system or heat pump, purchase one that uses non-ozone-depleting refrigerant. See a fact sheet on this topic. Remove the refrigerant from refrigerators, air conditioners, and dehumidifiers before disposing of them Removing the refrigerant before disposal of old refrigerators alone would prevent the release of about 4 million pounds of CFCs each year. The used refrigerant can be recycled and reused. Ask your local government or waste hauler if the refrigerant will be removed before the appliance is discarded. Make sure your service technician is EPA certified. Work with local officials Help start a refrigerant recovery and recycling program in your area if none exists. Not only will a responsible appliance disposal help to protect the ozone layer, but the recovered CFC-12 from appliances can be resold, helping to recoup a portion of the costs of the program. Report Violations If you suspect or witness unlawful releases of refrigerant or other improper service practices, you can file a report easily and anonymously by calling the Stratospheric Ozone Information Hotline at You can also obtain a complaint form online.

5 Ozone Science Crossword Puzzle Clues Across 3. Microscopic animals harmed by excess UV 6. Especially harmful band of UV radiation 11. One atom of this can destroy over 100,000 ozone molecules 12. Unnatural thinning of the ozone layer by human activities 13. Skin : One of the worst health effects of too much sun 14. conditioning: one type of equipment that used CFCs 15. Unit for measuring column ozone 17. osphere: Part of the atmosphere containing the ozone layer Down 1. The southernmost continent; location of the ozone hole 2. Wind pattern over Antarctica that isolates the ozone hole 4. Ozone : region containing most atmospheric ozone 5. Montreal : Treaty protecting the ozone layer 7. Chemical that makes methyl bromide an ozone-depleting substance 8. Molecule that absorbs UVB radiation from the sun, protecting Earth 9. A substitute for CFCs that's much less damaging to the ozone layer 10. Ultra : Harmful solar radiation 16. Measure of how much a chemical harms the ozone layer Words Cancer Dobson Violet Plankton HCFC UVB Depletion Antarctica Strat ODP Ozone Air

6 UV Radiation Crossword Puzzle Test your knowledge of UV radiation and its effects in this crossword puzzle. You may print out the puzzle, the clues, and online version. Clues Across 5. An electric light that mimics the sun's harmful rays 8. With a wide brim, it protects your face, neck, and ears 10. EPA's program to help teach kids about sun safety 11. Skin : One of the worst health effects of too much sun 12. People get % of their sun exposure by age Only amount of sun exposure that's safe 15. Daily forecast of UV exposure Down 1. Clouding of the eye's lens 2. After too much UV, this system can't fight off disease as well 3. With SPF of 15 or more, protects skin against the sun 4. Sun : Shades for your eyes 6. Sunglasses, sunscreen, and hats do it 7. Chemical in CFCs that destroys ozone 9. Layer that protects the Earth from the Sun's UVB 13. Type of UV that's especially harmful Words Immune Glasses UV Index Sunlamp Sunscreen Sunwise School Eighty Cataract Cancer Ozone

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