Analysis of the PM2.5 Distribution and the Transfer Characteristic in a Car-Cabin

Abstract

In order to investigate the transfer characteristics of PM2.5 in a car-cabin, several experiments were done through real-time online monitoring the concentration of PM2.5 and CO2 in the car-cabin under different ventilation modes (Circulation with the outdoor air and Recirculation without fresh air) under the minimum of mechanical ventilation and the same experimental route condition. PM2.5 concentration distribution characteristics and the ratio of inside to outside concentration I/O were analyzed. The ventilation rate was determined by the CO2 concentration change during the experiment and further was used to analyze the transfer characteristic of PM2.5. The results showed that under the circulation with the outdoor air condition, average I/O is 0.6, while it is 0.25 under recirculation condition. I/O value increases with the increase of the driving speed. It could be concluded that ventilation mode have a significant impact on the cabin concentration of PM2.5 and plays a decisive role in PM2.5 levels in the car-cabin. The quantitative evaluation PM2.5 transfer characteristic analysis under circulation with outdoor air condition shows that the ventilation, penetration and deposition accounted for 69.3%, 22.8%, and 7.9%, respectively. While under recirculation condition, penetration accounted for 72%, and deposition accounted for 28%.