基于腔减相移光谱技术低浓度NO_(2)监测的研究

Research on NO_(2) Low Concentration Monitoring Based on Cavity Attenuated Phase Shift Spectroscopy Technique

空气中NO_(2)浓度比较低,监测方法分辨率需要低至十亿分之一水平。因此,对监测设备检测的下限、线性度及稳定性都有更高有要求。为了解决低浓度NO_(2)测量方法存在的不足,本文研究基于腔减相移光谱(CAPS)技术在低浓度NO_(2)的测量应用。为有效评估检测能力和综合应用情况,研究中搭建了一套基于CAPS技术的大气NO_(2)浓度测量的CPAS系统,同时选用基于国家标准方法(化学发光法)的澳大利亚ECOTECH的Serinus 40型分析仪作为参比设备,在相同的自然环对空气中NO_(2)进行连续7天的实时测量,并将测量结果和国控点数据进行比较分析。经过测量,CPAS系统检测下限0.025ppb,低于Serinus 40的0.4ppb;7天测量的线性度达到了99.99%。证明CAPS技术满足在低浓度NO_(2)监测需求。

The concentration of NO_(2) in the air is relatively low,and the resolution of monitoring methods needs to be as low as one billionth level.Therefore,higher requirements exist for the detection limit,linearity,and stability of monitoring equipment.To address the shortcomings of low-concentration NO_(2) measurement methods,research on the measurement application of cavity-enhanced phase shift spectroscopy(CAPS)technology for low-concentration NO_(2) has been conducted.To effectively evaluate the detection capability and comprehensive application situation,a set of CPAS system for atmospheric NO_(2) concentration measurement based on CAPS technology was built during the study.At the same time,an Serinus 40 analyzer based on the national standard method(chemical luminescence method)from Australia's ECOTECH company was selected as the reference device.A real-time measurement of NO_(2) in the air was conducted continuously for 7 days under the same natural environment,and the measurement results were compared and analyzed with the national control data.After measurement,the detection limit of the CPAS system was 0.025 ppb,which is lower than that of Serinus 40 at 0.4 ppb.The linearity of the 7-day measurement reached 99.99%.This proves that the CAPS technology meets the monitoring requirements for low-concentration NO_(2).