基于腔衰减相移光谱法的二氧化氮分析仪的设计与应用

基于腔衰减相移光谱法设计了一套二氧化氮在线分析仪，通过优化测量参数，该仪器可长期稳定运行，其时间分辨率为60 s，检出限为0.191 ppb，在0~300 ppb范围内，NO₂气体浓度与相位正切信号值具有较好的二次拟合关系，R²为0.9995.另外，该仪器在泰安站进行了长期外场观测，并与改装后的进口商品化仪器PKU-Thermo 42i-TL进行比对实验，结果表明，两者的测量结果一致性较好，R²=0.9811，表明其具有良好的运行稳定性和测定结果准确性，适用于环境大气二氧化氮浓度的在线监测.外场观测结果表明，春季泰安站二氧化氮浓度均值为12.39 ppb，有明显日变化规律.

The design and application of an online nitrogen dioxide analyzer based on cavity attenuated phase shift spectroscopy

An online nitrogen dioxide (NO₂) analyzer has been developed based on cavity attenuated phase shift spectroscopy (CAPS) technique (NO₂-CAPS). Under optimized instrumental settings, the instrument is shown to be running stably for long time period. The detected NO₂ concentration within 0 ppb to 300 ppb depends quadratically on the tangential phase signal (R² = 0.9995). The time resolution and the limit of detection is determined to be 60 s and 0.191 ppb, respectively. The newly developed NO₂-CAPS was running in parallel with a chemiluminescence-based commercial instrument (PKU-Thermo 42i-TL) during a field observation campaign. Good agreement is found for the NO₂ concentrations measured by both instruments (R²=0.9811), which indicated that the NO₂-CAPS is capable for online measurement of atmospheric NO₂ with good stability and accuracy. During the campaign, NO₂ showed clear diurnal variation pattern with an average concentration of 12.39 ppb.