What unit is used to measure radiation exposure in air?

The unit used to measure radiation exposure in air is the roentgen (R). This unit specifically quantifies the amount of ionization produced in air by X-rays or gamma rays and is essential for understanding the potential biological effects of radiation exposure.

The roentgen is defined based on the ionization of air, making it particularly relevant in contexts where air exposure is being assessed, such as in radiography and radiation safety. This differentiates it from other units like gray (Gy), which measures absorbed dose, specifying the energy deposited in any material, or sievert (Sv), which accounts for the biological effect of radiation on human tissue. Millisieverts (mSv) is simply a subunit of sieverts.

Thus, when evaluating radiation in the context of air exposure, the roentgen is the appropriate unit to use.