The phrase "ozone layer" refers to a protective layer in the Earth's atmosphere made up of a gas called ozone. It acts like a shield, preventing harmful ultraviolet (UV) rays from the Sun from reaching us on the Earth's surface. Full definition
Changes in ozone layer concern mainly the stratosphere and I used to think there are very few molecules (even atoms, in fact) upward. (realclimate.org)
Now, thanks to global warming and a depleted ozone layer, they can exist above ground. (parentpreviews.com)
She has done research on ozone layer protection and nuclear chemistry, including environmental chemistry, specifically. (ieer.org)