Fig. 1. Absorption lines of H₂S, CO and CO₂

Fig. 2. Block diagram of gas measurement equipment

Fig. 3. The relationship between the amplitude and standard gas concentration for H₂S and CO absorption signals

Fig. 4. Allan variance of 10×10⁻⁶ mol/mol H₂S and 100×10⁻⁶ mol/mol CO absorption signals varying with integration time

Fig. 5. On-site measurement data of H₂S and CO concentrations for 48 hours