Ozone: what you should know about it

Ozone - a term that is often associated with climate action and climate change. But what is actually behind this word? Ozone is a gas consisting of three oxygen atoms (O₃). It occurs in the atmosphere in both the lower (troposphere) and upper layers (stratosphere), but plays a very different role in the two areas.

In the stratosphere, around 10 to 50 kilometers above the earth's surface, ozone is particularly important for us. There it forms what is known as the ozone layer, which forms a protective barrier and protects us from the sun's harmful UV radiation. Without this protective layer, much more ultraviolet radiation would reach the earth, which could lead to skin cancer, eye diseases and the death of plants, among other things. Ozone therefore acts like a natural sunshade.

However, there is also so-called "bad" ozone in the troposphere, the lower atmosphere that we need to breathe. Here, ozone is created by chemical reactions of air pollutants such as nitrogen oxides and volatile organic compounds, often in combination with sunlight. This process leads to smog formation and has negative effects on human and animal health. High ozone levels near the ground can cause respiratory problems and impair lung function.

So why is ozone so important for climate action and climate change mitigation? On the one hand, it is about protecting the ozone layer in the stratosphere, which has been severely damaged by the use of chlorofluorocarbons (CFCs), particularly in recent decades. These substances have been largely banned by international agreements such as the Montreal Protocol, as a result of which the ozone layer is now beginning to recover.

On the other hand, ozone also plays a role in climate change. As a greenhouse gas in the troposphere, it contributes to global warming. Even though ozone cools the earth in the upper atmosphere, it has the opposite effect near the ground: it warms the atmosphere.

In short, ozone is a fascinating and complex topic. It shows us how closely environmental and climate issues are linked. By protecting the ozone layer and preventing the formation of ozone near the ground, we can actively contribute to climate action.