Your body is currently saturated with oxygen and nitrogen (along with other trace elements) at a partial pressure equal to the partial pressure of the gas in the alveolar air. Alveolar air is contained in the alveoli within our lungs. According to Henry's Law, the amount of nitrogen absorbed is directly proportional to the partial pressure of the gas. At a depth of 10 meters, the absolute pressure is 2 bar and the partial pressure of nitrogen (ppN2) will have doubled to 1.58 bar (2 x 0.79).