A concentration sensor assembly can include a vaporization chamber having a compound. The concentration sensor assembly may include a first flow path coupled to the vaporization chamber. The first flow path may direct a first gas to the vaporization chamber. A second flow path can direct a second gas out of the vaporization chamber. The second gas can include the compound and the first gas. A first sensor is disposed along the first flow path. The first sensor measures first data indicative of a first mass flow rate of the first gas. A second sensor is disposed along the second flow path. The second sensor measure second data indicative of a second mass flow rate of the second gas. A computing device may determine a concentration of the vaporizable substance within the second gas based on the first data and the second data.