Nitrous oxide (N2O) is gaining interest in maritime applications for several reasons, primarily related to engine performance enhancement, emissions reduction, and auxiliary power supply. While N2O can enhance combus- tion efficiency and reduce certain emissions, uncontrolled use could result in increased NOₓ formation and other pollu- tants. Effective N2O monitoring is critical in maritime applications for ensuring operational safety, regulatory compli- ance, and optimal performance. We introduce an innovative first-principles N2O spectrometer designed specifically for maritime applications, such as monitoring emissions during and after combustion processes. This TDLAS based spec- trometer targets the P29e line at 4.55 μm spectral band and provides direct absolute mole fraction measurements, elim- inating the necessity for prior or routine calibration.