human
I've heard that the ozone hole is shrinking. Is this true?
assistant
Yes, it's true. The ozone layer is a thin layer of gas in the stratosphere that absorbs ultraviolet radiation from the sun. When chlorine and bromine compounds were added to refrigerators and other air conditioning systems, these chemicals reacted with the ozone molecules and broke them down. This caused the ozone layer to thin and allowed more UV radiation to reach the Earth's surface.