we have been researching air cleaning technology using gas-to-particle conversion of atmospheric gaseous pollutants by UV light irradiation. We measured removal efficiency of NO
x and typical airborne cycloalkene, cyclohexene, by the irradiation of high power UV (with 184.9 nm wavelength) lamps. The removal efficiency of NO
x increased with increasing water vapor concentration. More than 90 % removal efficiency could be achieved when the relative humidity was more than 50 %. Cyclohexene was almost removed even under low relative humidity (25 % RH). Larger particles were formed in NO- cyclohexene-air system than in NO-air system. The decrease in the removal efficiency of NO
x by the addition of cyclohexene could be ascribed to the competitive reaction of OH radicals with NO
x and cyclohexene. Absorption bands of carboxyl groups were visible in FT-IR spectra of collected particles which were formed in NO-cyclohexene-air-photoirradiation experiments. This technique can be applied to larger-scale air treatments if more UV lamps are added.
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