Light absorbance analysis apparatus and program record medium for recording programs of light absorbance analysis apparatus

A program recording media that records a program used for a light absorbance analysis apparatus comprising a detector that detects an intensity of light that transmits a gas, a total pressure sensor that measures a total pressure of the gas, and an absorbance calculating part that calculates an absorbance based on an output value of the detector and a previously set zero reference value, wherein producing functions as a partial pressure—absorbance relation storing part that stores a partial pressure—absorbance relational data that indicates a relationship between a partial pressure of an interference gas that exists in a measurement area of the detector and the absorbance calculated by the absorbance calculating part,

• a partial pressure calculating part that calculates an interference gas partial pressure, in a known concentration state wherein the interference gas whose concentration is known exists in the measurement area, based on the total pressure measured by the total pressure sensor and the known concentration,
• an absorbance estimating part that estimates an interference gas absorbance based on the interference gas partial pressure and the partial pressure— absorbance relational data, and
• a calibrating part that conducts the zero calibration that updates the zero reference value based on the interference gas absorbance and the output value of the detector in the known concentration state.