All of the following are considered ionizing radiation except:

Ionizing radiation refers to radiation that has enough energy to remove tightly bound electrons from atoms, creating ions. Gamma rays, x-rays, and beta particles are all forms of ionizing radiation because they possess sufficient energy to ionize atoms.

Gamma rays are high-energy electromagnetic waves emitted from radioactive decay. They have no mass or charge and can penetrate most materials. X-rays are also a form of electromagnetic radiation, similar to gamma rays but typically produced by interactions with matter rather than radioactive decay. Beta particles are high-energy, high-speed electrons or positrons emitted from certain types of radioactive decay, and they can indeed ionize materials as they pass through them.

Ultraviolet (UV) light, while it can cause chemical reactions and damage to biological tissues (such as sunburn), is generally classified as non-ionizing radiation. This is because it lacks the energy necessary to ionize atoms in the same way that gamma rays, x-rays, and beta particles can. Thus, UV light does not have the same capacity to directly produce ions or cause ionization, making it distinct from the other forms of radiation listed. This differentiates it from ionizing radiation, confirming that ultraviolet light is not considered ionizing.