FUNDAMENTAL STUDY ON PARTICLES, ULTRA-FINE PARTICLES AND OZONE IN THE CAR COMPARTMENT

The concentrations of ozone, particles (PM10 and PM2.5) and ultra-fine particles were measured duringdriving the automobile and during standing. Two ventilation modes were prepared; 1) all fresh air modeand 2) all re-circulation mode. The windows of the automobile had been always closed during thismeasurement. The indoor/outdoor ratio of the concentrations and the correlation among thosesubstances were reported. The concentrations of particles (PM10 and PM2.5) and ultra-fine particleswere dramatically had been increased while the automobile followed the trailer bus. The averageindoor/outdoor ratio of ozone during all fresh air mode was higher than that during all re-circulationmode. The correlation coefficient between indoor ozone concentration during all fresh air mode andthat during all re-circulation mode was fairly high at 0.63. There were no significant correlation betweenindoor/outdoor ratio of particles and that of ozone. The ozone deposition velocity in the carcompartment was calculated to be 3 m/h by using the measured air-change rate and indoor/outdoorratio of ozone.