Ozone

Ozone is created in the atmosphere when the sun’s rays split oxygen molecules into single atoms. These atoms combine with nearby oxygen to form a three-oxygen molecule, called ozone. Even as it’s being made, ozone is also destroyed by sunlight and reactions involving natural compounds that contain chlorine, nitrogen, and hydrogen. Most of the earth’s ozone is contained in the stratosphere, a layer of the atmosphere 10–40 km above the surface of the earth. The amount of ozone in the stratosphere is fairly constant when viewed globally. However, it changes throughout the year and from one place to another. Most of the world’s ozone is created over the Tropics, and is then pushed by stratospheric winds over the rest of the planet. The ozone layer is typically thicker over the poles than over the equator for three reasons. First, there is a lack of sunlight during an arctic winter to break it down. Second, seasonal weather systems and wind patterns in the upper atmosphere push more ozone toward the poles in winter. Third, the vertical structure of the atmosphere affects thickness. Near the equator, the troposphere makes up about 18 kilometres of the atmosphere. At the poles, it thins to only 8-kilometres thick. The boundary between the layers, called the tropopause.