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 concentration of CO2 was measured during driving the automobile and during standing. VOCsconcentration was measured during standing. Two ventilation modes were prepared; 1) all fresh airmode and 2) all re-circulation mode in the car compartment. The windows of the automobile werealways closed during this measurement. The ventilation rate and the airchange rate were determinedby the concentration of CO2.