An Experimental Study on Ozone Destruction Reaction by Emission from Airplanes in Stratosphere

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An experimental study on the effect of jet exhaust gas on the stratospheric ozone layer was conducted. The stratospheric condition was simulated using a large vacuum chamber, where the ambient pressure was sustained at 2.67 kPa and an ultraviolet ray source was directed. This ambient pressure is almost equal to that at the altitude 25km. A low-pressure mercury lamp was used as a source of ultraviolet rays. Two types of experiments were conducted.One is for the behavior of ozone and NOx with photochemical reactions when the NOx injected from airplanes is fully diffused in the ambience. After evacuating the chamber, a certain amount of NO and NO2 was injected into the chamber and was diluted by Air and N2. Then ultraviolet rays started emitting and the concentration of NO and NO2 were measured by LIF method. Calculations using properties in the stratosphere were conducted to compare with experimental results. As a result, the tendencies of reactions including NO, NO2, ozone in the strato … More sphere are explored and the chemical reaction model in this calculation is verified.The other is for the reaction between ozone and NOx in the jet plume near the exit of the nozzle of airplanes. NO gas, which was diluted by nitrogen, was injected from a nozzle as an exhaust gas in the simulated ozone layer. NO and NO2 concentration in the jet stream were measured by LIF methods, and the reaction amounts between NO and ozone were derived from LIF images. The reaction rate derived NO-LIF was much bigger than the actual one, because ozone absorbed laser beam near 226.1 nm to simulate NO molecular and NO-LIF signal. It was not proper to use NO-LIF method to determine the reaction amount between NO and ozone. However, it was useful to visualize the flow in this condition because of its strong intensity. The reaction amount derived from NO2-LIF was valid compared with a result of simplified calculations. The NO2-LIF method can be available for the measurement of reaction rate quantitatively between NO and ozone in the ozone layer. Less