中文摘要：

大气中NO2的含量在10-9量级。研究了一种以发光二极管（LED）为光源的光纤耦合长光程差分吸收光谱（DOAS）系统,用于测量大气NO2。对比了四种不同类型和波段的蓝光LED,确定以中心波长451nm的CREE宝蓝LED为测量光源。在0.8km的测量光程、2min的测量时间分辨率的情况下,在445nm~465nm光谱反演波段内得到NO2的探测限为3.36×10-9。利用系统对大气NO2的浓度进行了一整天的连续观测,通过对吸收光谱的分析计算,反演出的大气NO2浓度在（7~31）×10-9之间变化。测量结果表明,将光纤耦合技术与LED光源的长光程DOAS系统相结合后,可实现大气NO2的高灵敏、高时间分辨率探测。

英文摘要：

NO2in the atmosphere are in the 10-9 levels.An system based on the optical fiber coupling long path differential optical absorption spectroscopy（DOAS）for measuring atmospheric NO2 is researched,which uses a blue light-emitting diode（LED）as the light source.A royal blue led（CREE,center wavelength @ 451nm）is used as the light source by comparing four leds with different types and wavebands.When the measurement path is 0.8km and the measurement time is 2minute,NO2 detection limit is 3.36×10-9 retrieved over 445nm~465nm.Continuous observations of the atmospheric NO2 using the system are carried out for a whole day.The concentrations of atmospheric NO2 range from（7~31）×10-9.The measurement results show that it is feasible for the high sensitivity and high time-resolved detection of atmospheric NO2 by long path LED-DOAS system with optical fiber coupling technology.