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[Display omitted] • An improved WMS-Y 1f method is suitable for the full range of concentration. • The interference of background gas is well eliminated under low modulation depth. • The relative errors are all less than 1%. At present, gas sensors are extremely susceptible to interference from background gases in the field environment, which leads to greatly reduced accuracy. For this reason, we propose an improved method of recovering integral absorbance (IA) using Y component of first harmonic to achieve accurate prediction of the full range of concentration (not reaching absorption saturation). This approach can eliminate the interference of background gas at a low modulation depth (m < 0.25). When the background gas is pure nitrogen and a mixture of nitrogen and carbon dioxide, the recovery effect of this method on methane is both close to the theoretical value when the background gas is air. The linear fitting coefficients for the methane concentration range of 2000–7000 ppm are all greater than 0.999. The prediction effect is satisfactory regardless of the background gas, with a relative error of less than 1%. In summary, this method has considerable application prospects. [ABSTRACT FROM AUTHOR]

[Display omitted] • The CH 4 /C 2 H 6 dual gas sensor using a single mid-infrared laser is developed. • The cross-interference of C 2 H 6 on CH 4 is eliminated. • High sensitivity, strong stability, fast response speed and simple system structure. Methane (CH 4) and ethane (C 2 H 6) dual gas sensor with low system complexity and strong stability is proposed. The correction method based on absorbance spectrum is applied, and the cross-interference of C 2 H 6 to CH 4 is eliminated. In the single gas concentration measurement, linear fitting is performed between the absorbance and concentration of CH 4 and C 2 H 6 , and the correlation coefficients of R2 = 0.99959 and R2 = 0.99994 are obtained respectively, which proves that the accuracy of the dual gas sensor is robust. In the dual gas concentration measurement, we carry out continuous measurement of five mixed gases and a long-term measurement of a mixture of gases, which verifies that our sensor has the fast response speed and strong stability. The minimum detectable column densities of 0.62 ppm·m for CH 4 and 0.1 ppm·m for C 2 H 6 are achieved, respectively. The CH 4 /C 2 H 6 dual gas sensor assisted by the correction method has high sensitivity and strong robustness to cross-interference, and has great potential for application in various scenarios. [ABSTRACT FROM AUTHOR]