SO3 and sulfuric acid (H2SO4) aerosol detection by UV absorption spectroscopy of liquid H2SO4 solution

SO 3 and sulfuric acid (H 2 SO 4 ) aerosol are common air pollutants in the burning process of coal. Detection of SO 3 and sulfuric acid (H 2 SO 4 ) aerosol in gaseous form is difficult and expensive. A concentration detection sensor system for sulfuric acid-water solution is developed based on ultraviolet absorption spectroscopy in 185–210 nm wavelength range in this work. An absorption at 193 nm for sulfuric acid (H 2 SO 4 ) is observed. Spectra of sulfuric acid-water solution in different concentration are measured at room temperature of 294 K. When the concentration is below 500 ppm w, the absorption intensity is proportional to solution concentration. By continuous monitoring, a detection limit of 2 ppm w is obtained with 0.5 s sampling time for this system.