Detection of Sulfur Dioxide by Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS)

Area of Science:

• Atmospheric Chemistry
• Spectroscopy
• Environmental Monitoring

Background:

• Sulfur dioxide (SO2) is a key precursor to atmospheric sulfate aerosol and acid rain.
• Accurate measurement of SO2 is crucial for understanding atmospheric processes and environmental impact.

Purpose of the Study:

• To develop and validate a Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) instrument for SO2 measurement.
• To achieve a low limit of detection for SO2 in atmospheric monitoring.

Main Methods:

• Utilized BBCEAS with high-reflectivity mirrors and a deep UV LED light source.
• Employed a spectral range of 305.5-312 nm with an effective absorption path length of 610 m.
• Validated SO2 concentrations against fluorescence standard measurements.

Main Results:

• Achieved a minimum limit of detection of 0.75 ppbv (3-σ) for SO2 with a 5-min averaging time.
• Demonstrated excellent correlation (R² = 0.9998) with fluorescence standard measurements.
• Confirmed no interference from other species, unlike fluorescence methods.

Conclusions:

• The developed BBCEAS instrument provides a highly accurate and sensitive method for SO2 measurement.
• This technique offers a reliable alternative to standard methods, with improved specificity.
• The instrument is suitable for ambient SO2 monitoring and atmospheric research.