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A non-invasive CO₂ gas temperature sensing technique at or close to the room temperature range based on quantum cascade laser absorption spectroscopy is presented. The method probes thermally populated ground state and hot-band rotational-vibrational transitions of CO₂ in the frequency range from 2349 to 2351 cm⁻¹ from which the gas temperature is obtained from Boltzmann statistics. Transmission spectra are recorded by injection-current driven frequency-scans, the so-called inter pulse mode, of a pulsed distributed feedback quantum cascade laser. The statistical uncertainty (1<inline-formula><math display="inline"><semantics><mi>σ</mi></semantics></math></inline-formula>) in temperature for single frequency scans with time resolution of 10 ms is 4 K and can be further reduced down to ∼50 mK by long-time averaging of about 1 min. The technique is evaluated with particular emphasis on implementation, data acquisition, data analysis and potential improvements.