Direct Measurement of SO2 in Air by Laser Induced Fluorescence Spectrometry Using a Nontunable Laser Source

Studies have been performed to evaluate a direct laser induced fluorescence (LIF) technique for measurements of atmospheric sulfur dioxide (SO2). The technique is novel in that it uses a nontunable laser source that is spectrally coincident with absorption of the SO2 molecule near 223 nm that allows sensitive measurements at environmentally relevant concentrations. In this report, the spectral characteristics and analytical capabilities of the nontunable LIF approach have been evaluated and preliminary measurements of ambient SO2 are reported. The current limit of detection is 0.5 ppb and compares well to other analytical spectroscopy methods used for atmospheric measurements of SO2. The results indicate strong feasibility for the nontunable LIF approach for SO2 measurements and suggest ways for method improvement.