What unit measures radiation exposure in the air?

The unit that measures radiation exposure in the air is the Roentgen (R). It specifically quantifies the amount of ionization in air produced by X-rays or gamma rays. The Roentgen is defined based on the ability of radiation to ionize air and is primarily used in radiology to assess exposure levels, making it a practical choice for evaluating levels of radiation that can affect living tissues.

In contrast, the Gray (Gy) measures the absorbed dose of radiation, indicating how much energy is deposited in a material, regardless of the type of radiation. The Sievert (Sv) is utilized to assess biological effects and risk by weighing the absorbed dose according to the type of radiation and its impact on human tissue. The Curie (Ci) is a unit of radioactivity that measures the rate at which a radioactive substance decays, not directly related to exposure in the air.

Understanding these distinctions highlights why the Roentgen is specifically relevant for measuring exposure in air, while the other units serve different purposes in the field of radiology.