Why do materials such as wood, metals, and plastics weather in the atmosphere?

Materials such as wood, metals, and plastics weather in the atmosphere primarily because they are in oxidation states lower than those that are stable in the Earth's oxidizing atmosphere.1

Because these materials are the products of technological or photosynthetic reductions, they possess a natural tendency to be reoxidized when exposed to the environment. This process is a form of oxidation-reduction reaction, a chemical process in which an atom, ion, or molecule loses electrons as it interacts with another chemical species.123

In this context, weathering is an oxidative process where the material's composition and energy state are altered as it reacts with the atmosphere. While metals undergo corrosion—a familiar example of this oxidative process—other materials like wood and plastics are similarly subject to these chemical changes as they seek a more stable, higher oxidation state.134