SO2 Transformation in controlled atmosphere leading to the production of aerosol particles

Formation and evolution of ultrafine particles produced by radiolysis and photolysis

“…Nucleation process, that is, the source of the fine range of the atmospheric aerosol, make necessary intervening species which may be excited molecules, free radicals, and ionic species produced by UV irradiation [Boulaud et al, 1975] and a, fi, or ¾ rays [Chamberlain et al, 1957;Megaw and Wiffen, 1961;McGreevy, 1968]. As to the radioactivity, it was shown [Cabane et al, 1978] that ions of a given polarity can initiate the production of condensation nuclei.…”

“…The experimental system we use [Perrin et al, 1978] is illustrated schematically in Figure 1. It is composed of three parts: (1) an air circulation circuit which consists of a spherical vessel (800 1) preceded or not by two high-efficiency particulate air (HEPA) filters, (2) an aerosol production device for radiolytic experiments; an air flow circulates over a radioactive source of actinium-227 and the radioactive gas (Actinon) is then introduced into the vessel (as to photolytic experiments, a high-pressure mercury vapor lamp enables the continuous creation of particles after injecting SO2 in the reaction chamber [Boulaud et al, 1975]), and (3) measuring circuits include a 'honey comb structure' diffusion battery [Sinclair, 1975] coupled with a condensation nuclei counter. The evolution with time of the aerosol size distribution is determined by a new method using a computer [Maigne, 1977].…”