人体呼气中一氧化氮浓度（FeNO）与肺部呼吸道疾病有着紧密的联系，美国食品和药品管理局（FDA）、欧洲呼吸学会（ERS）和美国胸科学会（ATS）等权威机构相继将FeNO作为哮喘生物标志物，并将FeNO列为呼吸系统疾病的常规检查项目。针对FeNO高灵敏监测需求，发展了一套中红外波长调制激光吸收光谱检测仪，利用多元线性回归的方法解决了CO₂谱线交叉干扰问题，NO的检测限达到0.12×10-9。利用多浓度标准气体对样机性能进行了定标，在0~215×10-9体积分数范围内，仪器结果的线性相关性为0.994。最后，对中国中医科学院西苑医院的志愿者呼气样本进行了测量。

The fractional exhaled nitric oxide (FeNO) is closely related to lung and respiratory diseases. Authorities such as the US Food and Drug Administration (FDA), European Respiratory Society (ERS), and American Thoracic Society (ATS) have successively identified FeNO as an asthma biomarker and listed FeNO as a routine inspection item for respiratory diseases. In order to meet the needs of high-sensitivity monitoring of FeNO, a mid-infrared wavelength modulation laser absorption spectrometer is developed in this paper. The problem of cross interference of CO₂ spectral lines is solved by the method of multiple linear regression, and the detection limit of NO reaches 0.12×10-9. The performance of the prototype is calibrated by standard gases with different concentrations, and the linear correlation of the instrument results is 0.994 in the volume fraction range of 0-215×10-9. Finally, the breath samples of volunteers from Xiyuan Hospital of Chinese Academy of Chinese Medical Sciences are measured.