One aspect of the invention relates to a system adapted to calibrate a determination of information related to one or more gaseous analytes in a body of gas being delivered to an objective by a gas source. In one embodiment the system comprises a partial pressure sensor, a total pressure monitor, a partial pressure module, and a calibration module. The partial pressure sensor generates an output signal related to the partial pressure of the one or more gaseous analytes in the body of gas. The total pressure monitor determines the total pressure of the body of gas. The partial pressure module determines the partial pressure of the one or more gaseous analytes in the body of gas according to a partial pressure function, wherein the partial pressure function describes the partial pressure of the one or more gaseous analytes in the body of gas as a function of the output signal generated by the partial pressure sensor. The calibration module that calibrates the partial pressure module by determining the partial pressure function.