For decades, scientists have closely observed the ozone layer, which protects Earth from the sun’s harmful ultraviolet (UV) radiation. This year, just in time for World Ozone Day, the European Union’s Copernicus Atmosphere Monitoring Service (CAMS) announced the state of the ozone hole — its size is the smallest it has been in the past 30 years. Ozone is created in our atmosphere when the sun’s high-energy UV rays rupture the stable covalent bonds of atmospheric oxygen (O2) molecules, transforming them into free radicals.