Determination of Photolysis Frequencies for Selected Carbonyl Compounds in the EUPHORE Chamber

摘要

Small carbonyl compounds are formed during the photochemical oxidation of many volatile organic compounds (VOC's), in urban as well as in rural areas. Photolysis and reaction with the OH radical are the most important initiation reactions for the atmospheric degradation of these compounds, and lead to the formation of peroxy radicals in the former case and either stable molecules and/or free radicals in the latter case (Finlayson-Pitts and Pitts, 1999). About 580 actinic flux spectra recorded under different meteorological conditions (clear sky, partially cloudy or overcast) in the EUPHORE smog chambers, have been used to calculate the photolysis frequencies for various small carbonyl compounds that are considered to be important from the atmospheric chemistry point of view. The results are presented here.