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[A-3.2 Studies on Photochemical Reactions Related to Stratospheric Ozone Depletion]

[Contact Person]

Nobuaki Washida
Director, Atmospheric Environmental Division
National Institute for Environmental Studies
Environmental Agency
16-2 Onogawa, Tsukuba, Ibaraki 305 Japan
Phone +81-298-51-6111(Ext.350), Fax +81-298-51-4732

[Total Budget for FY1990-1992]

23,928,000 Yen

[Abstract]

　In order to make clear the detailed mechanism of ozone depletion by CFCs and other compounds, simulation experiments of the ozone loss by the addition of halocarbons have been performed by using a photochemical reaction chamber. The loss rates of ozone by CFCs, halons, and HCFCs were determined. The mechanisms of ozone depleatin by CFC and halon were discussed. Synergetic effect of halon on ozone depletion by CFC was first demonstrated experimentally. The rates of radical reactions related to ozone loss in the stratosphere have been measured by using a laser photolysis-photoionization mass spectrometry. The rate constant for rection of CCl₃+O₃ was first determined to be (9.0±0.8)×10^-13 cm³ molecule^-1 s^-1 at room temperature. It has been estimated that the reaction with ozone slightly contributed (<0.03%) to the fate of CCl₃ radicals in the stratosphere.

[Key Words]

Photochemical Chamber, Simulation Experiment, Photoionization Mass Spectrometry, Reaction Rate Constant