Air pollution and iodine from the ocean contribute to damage of Earth’s ozone layer.
A new paper quantifying small levels of iodine in Earth’s stratosphere could help explain why some of the planet’s protective ozone layer isn’t healing as fast as expected. The paper posits a set of connections that link air pollution near Earth’s surface to ozone destruction much higher in the atmosphere. That higher-level ozone protects the planet’s surface from radiation that can cause skin cancer and damage crops.
“The impact is maybe 1.5 to 2 percent less ozone,” said lead author Theodore Koenig, a postdoctoral researcher at CIRES and the University of Colorado Boulder, referring to ozone in the lower part of the ozone layer, around Earth’s tropics and temperate zones. “That may sound small, but it’s important,” he said. A slightly thinner ozone layer means more UVB radiation can get through to Earth’s surface.
Koenig’s paper, the first “quantitative detection” of iodine in the stratosphere, is published this week in the Proceedings of the National Academy of Sciences, with co-authors from CIRES, CU Boulder and other institutions.
Chemicals once used widely in refrigeration, spray cans and solvents can eat away at Earth’s ozone layer. After scientists discovered the stratospheric “ozone hole” in the 1980s, nations around the world signed the international Montreal Protocol agreement to protect the ozone layer, limiting the emission of ozone-depleting chemicals.
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