Ozone

Ozone (O3)

Ozone is made up of three oxygen molecules, differently from the oxygen we breathe which is made up of two oxygen atoms. O3 occurs naturally in the upper atmosphere of the Earth, but closer to the surface, it is formed from chemical reactions with other air pollutants.

Learn more about good vs. bad ozone below!

Good ozone

source: Dailysweden.com

In the stratosphere, a layer of the atmosphere between 10 and 50 kilometers of altitude, there is a naturally formed ozone layer, which is beneficial for life on Earth. The ozone layer filters a lot of the ultraviolet radiation that comes from the sun. Excess of UV-A and UV-B can cause skin burns and eye irritation besides increasing changes of skin cancer.

Ozone Depletion

Human actions have caused the liberation of gases that contribute to the depletion of the ozone in the atmosphere. CFCs, used in refrigeration, air conditioning, and spray cans for example, are the main contributors for the hole in the ozone layer. This decrease in good ozone, has been causing the increase of harmful radiation reaching Earth's surface.

Look at how the hole in the ozone layer has increased over the years!

source: Nasa Earth Observatory

Bad ozone

source: climatecentral.org

Ozone in the upper atmosphere is natural and offers a protective shield for life on Earth. However, ground-level ozone, also called "bad ozone", is harmful for both plants and animals. Bad ozone is formed when nitrogen oxide gases, released by cars and industries, react with volatile componets in the air, meaning it is man-made. Exposure to ozone levels greater than 70 parts per billion (ppb) for over 8 hours is unhealthy. Additionally, ozone is a greenhouse gas and its excess contributes to climate change.