The Hole in Earth's Ozone Layer Is Healing

By Calla Cofield, Staff Writer | January 8, 2018 06:38pm ET

Efforts to heal the hole in Earth's ozone layer over Antarctica appear to be paying off, according to a new, first-of-its-kind study that looked directly at ozone-destroying chemicals in the atmosphere.

Earth's ozone layer protects the planet's surface from some of the sun's more harmful rays that can cause cancer and cataracts in humans, and damage plant life, according to NASA. In the mid-1980s, researchers identified a massive hole in the ozone layer over Antarctica and determined that it had been caused largely by human-produced chemicals called chlorofluorocarbons (CFCs).

Previous satellite observations have observed changes in the size of the ozone hole, noting that it can grow and shrink from year to year. But the new study is the first to directly measure changes in the amount of chlorine — the main CFC byproduct responsible for ozone depletion — in the atmosphere above Antarctica, according to a statement from NASA. The study showed a 20-percent decrease in ozone depletion due to chlorine between 2005 and 2016. [Earth's Atmosphere: Composition, Climate & Weather]

The new study looked at ozone data collected between 2005 and 2016 by the Microwave Limb Sounder (MLS) instrument aboard the Aura satellite. The instrument cannot directly detect chlorine atoms, but instead detects hydrochloric acid, which forms when chlorine atoms react with methane, and then bond with hydrogen. When Antarctica is bathed in sunlight in the Southern Hemisphere's summer, CFCs break down and produce chlorine, which then break apart ozone atoms. But during the winter months (early July to mid-September), the chlorine tends to bind with methane "once all the ozone has been destroyed" in its vicinity, according to the statement.

More:
https://www.livescience.com/61371-nasa-satellite-shows-healing-ozone-hole.html?utm_source=notification