Quantitative Remote Sensing of Sulfur Dioxide Emissions from Industrial Plants Using Passive Fourier Transform Infrared (FTIR) Spectroscopy

The remote monitoring and quantification of industrial gas emissions, such as sulfur dioxide (SO2), are critical for environmental protection. This research demonstrates an integrated methodology for estimating SO2 emission rates (kg/s) from an industrial chimney using passive Fourier transform infrared (FTIR) spectroscopy combined with atmospheric dispersion modeling. Infrared spectra were acquired at a stand-off distance of 570 m within the 7–14 μm spectral range at a resolution of 4 cm−1. Path-integrated SO2 concentrations were determined through cross-sectional scanning of the gas plume. To translate these optical measurements into an emission rate, the atmospheric dispersion of the plume was modeled using the Pasquill–Briggs approach, incorporating source parameters and meteorological data. Over two experimental series, the calculated average SO2 emission rates were 15 kg/s and 22 kg/s. While passive FTIR spectroscopy has long been applied to remote gas detection, this work demonstrates a consolidated framework for retrieving industrial emission rates from stand-off, line-integrated measurements under real industrial conditions. The proposed approach fills a niche between local in-stack measurements and large-scale remote sensing systems, which contributes to the development of flexible ways to monitor industrial emissions.