Abstract. This work describes improvements made to the in-situ laser induced fluorescence SO₂ instrument as originally described in Rollins et al. (2016). We report measurements of the SO₂ fluorescence emission spectrum. These measurements allow for the determination of the most appropriate bandpass filters to optimize the fluorescence signal while reducing the instrumental background. Because many aromatic species fluoresce in the same spectral region as SO₂, fluorescence spectra were also measured for naphthalene and anisole to determine if ambient SO₂ measurements may be biased in the presence of such species. In addition, the 216.9 nm laser linewidth was decreased in order to increase the online/offline signal ratio which in-turn increases the precision of the measurement. The effects of these improvements on the instrumental sensitivity were determined by analyzing the signal and background of the instrument using varying optical bandpass filter ranges and cell pressures and calculating the resulting limit of detection. As a result, we report an improvement to the instrumental sensitivity by as much as 50 %.

中文翻译：

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激光诱导的用于测量SO _2的荧光仪器的改进：对准确性和精密度的影响

摘要。这项工作描述了对Rollin等人最初描述的原位激光诱导的荧光SO ₂仪器的改进。（2016）。我们报告了SO ₂荧光发射光谱的测量结果。这些测量允许确定最合适的带通滤光片，以优化荧光信号，同时减少仪器背景。由于许多芳香族物质在与SO ₂相同的光谱区域发出荧光，因此还测量了萘和苯甲醚的荧光光谱，以确定环境中的SO ₂在此类物质的存在下，测量结果可能会有偏差。此外，减少了216.9 nm的激光线宽，以增加在线/离线信号比，进而提高了测量精度。这些改进对仪器灵敏度的影响是通过使用可变的光学带通滤波器范围和电池压力分析仪器的信号和背景并确定最终的检测极限来确定的。结果，我们报告仪器灵敏度提高了50％。