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 NOx and typical airborne cycloalkene, cyclohexene, by the irradiation of high power UV (with 184.9 nm wavelength) lamps. The removal efficiency of NOx 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 NOx by the addition of cyclohexene could be ascribed to the competitive reaction of OH radicals with NOx 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.
During the period from July 27 to August 3, 1993, an intensive observation was performed at the summit of Mt. Fuji (3,776 m) and at Tarobo JMA shelter, 1,300 high on the southern slope. Aerosol, gases, and precipitation samples were obtained for chemical analyses. During this observation period, typhoon (9306) passed Honshu Island. The concentration of sulfate ion in the aerosol at the summit abruptly increased after the typhoon. The change of the concentrations of other chemical species, such as ammonium, nitrate and calcium, was less pronounced in the same aerosol samples. The concentrations of sulfur dioxide gas and hydrogen chloride gas were low with less pronounced change throughout this period, while the concentration of ammonia gas showed diurnal change, high during the day time and low at night, indicating some effect of mountain climber. On the other hand, concentration of the surface ozone showed similar tendency as sulfate ion in the aerosol. Meteorological data suggest an air mass from the west which advected after the typhoon was responsible for the high concentration of sulfate in the aerosol and the ozone.