In this work we use numerical simulation to estimate possible errors of the differential-absorption retrieval of concentrations of such gaseous biomarkers as СН4, СО, NH3, N2O, С2Н6, and H2S from the three-component gas mixture absorption spectra in the 2-4μm spectral region. The gas mixture is supposed to simulate an expired air. The absorption spectra were calculated with a resolution of 2cm-1 using the HITRAN database. The impact of subtraction of the water vapor absorption from the simulated spectra on the error in retrieved concentrations of the gases-biomarkers was studied. The water vapor concentration in the mixture was determined from absorption at 3800 cm-1.
expired air, gas analysis, gaseous biomarker, water vapor