以大气颗粒物测量为目标,实验研究了作为背景的空气分子的激光诱导击穿光谱(laser induced breakdown spectrometry,LIBS),以NIST原子发射谱线数据库为参考,对其中的O,N,H等主要元素的特征谱线进行了标识。 研究了CCD光谱仪实验参数对空气等离子体发射谱线的影响,得出积分延时大于7 μs时可以较好地减小空气分子所产生的干扰谱线,积分时间宽度大于仪器最小值(1.1 ms)时对谱线信号强度影响较小等结论。 还研究了水汽的激光诱导击穿光谱,分析了O,N,H等元素的发射谱线信号强度的变化,发现H的发射谱线信号强度与水汽含量之间具有很好的线性关系。 这些结果对于在大气环境条件下,对大气颗粒物的识别具有重要的指导意义。

The present article investigated the laser induced breakdown spectra of atmosphere molecules as background spectrum for the measurement of airborne particles. The authors detailedly analyzed the spectral lines of oxygen,nitrogen and hydrogen in the laser induced breakdown spectra of atmosphere molecules corresponding to the National Institute of Standards and Technology atomic spectroscopy database line data. In addition,the authors studied the intensity of emitted spectral lines induced by laser breakdown process at different time delays and signal integration width. As a result,the authors obtained the conclusion that the intensity of signal depends on variations of delay time strongly,and with a delay time more than 7 μs the interference resulting from the presence of atmosphere molecule can be reduced effectively in the application of laser induced breakdown spectroscopy. Also,the variations in signal integration width have few effects while it is longer than the instrument minimum of 1.1 ms. Besides,this paper investigated the relative intensities of spectral lines of oxygen,nitrogen and hydrogen in the condition of different contents of water vapor in atmosphere,and the authors observed that the intensities of atomic emission line of hydrogen have a linear trend varying with the moisture in atmosphere. These results can be useful for the further application of laser induced breakdown spectroscopy in detecting and monitoring of airborne particles in the air.