Spectroscopic behavior of oxygenated combustion by -products

The oxygenated species, massively produced in the energy production plants based on combustion processes, constitute one of the most numerous categories of Hazardous Air Pollutants and play a significant role in the atmospheric chemistry being involved in the chemical pathways leading to the formation of the principal constituents of secondary aerosol pollutants.
The identification of oxygenated compounds presence has been carried out on fuel rich premixed ethylene flames by measuring the peculiar spectroscopic fluorescence features of the carbonyl compounds in the ultraviolet. Fluorescence spectra typical of aldehydic functionality were detected in the first oxidation region of the premixed flames at various equivalence ratios.
Based on the different spectroscopic features of oxygenated and pyrolytic species two main spatial regions, characterized by the prevailing presence of the two species and whose extents depend on the flame conditions, were identified. The temperature history along the flame can be directly correlated to the positions and extents of these regions. This correlation can be easily interpreted in view of the temperature profiles measured along the flame.