Which type of chemical degradation involves no biological activity?

The type of chemical degradation that involves no biological activity is chemical degradation. This process refers to the breakdown of chemicals through purely chemical reactions rather than biological means. This can occur through various mechanisms such as hydrolysis, oxidation, or thermal degradation.

In contrast, microbial action refers specifically to the degradation caused by the metabolic activities of organisms like bacteria and fungi, which is inherently biological. Photodegradation involves the breakdown of substances through the action of light, particularly ultraviolet light, and is also not a chemical process in itself but instead a physical change influenced by environmental factors. Volatility entails the transformation of a substance from a liquid to a vapor phase, allowing it to escape into the atmosphere, which is a physical change rather than a breakdown of the compound itself. Thus, chemical degradation stands out by being a reaction that does not rely on living organisms or light exposure, emphasizing its nature as a strictly chemical process.