depletion of ozone ozone levels holes in our protective ozone layer rapid depletion Ozone Depletion ozone layer more UVB rays environment.nationalgeographic.com depletion of the ozone environment.nationalgeographic.com "Ozone Depletion" ozone depletion more UVB rays National Geographic shields the Earth's surface National Geographic more UVB rays National Geographic Ozone depletion National Geographic Magazine more UVB rays nationalgeographic.com depletion of ozone environment.nationalgeographic.com... National Geographic reports National Geographic ozone layer more UVB rays www.environment.nationalgeographic.com National Geographic degrades the ozone layer shields us holes in our protective ozone layer more UVB rays environment.nationalgeographic.com reports National Geographic environment.nationalgeographic.com