Detection of high-emitters: Variables affecting particle number emissions in Finnish vehicle fleet
研究了芬兰车辆定期技术检测和高速公路行驶中，哪些车辆参数（如车龄、发动机大小）导致高颗粒物排放，发现10%的车辆贡献了50%的总排放。
Periodical technical inspection (PTI) measurements are used for emission control in terms of PN, mainly to detect DPF malfunction. However, the real goal is to reduce PN driving emissions. In this study, we attempted to understand what properties of vehicles lead to high emissions in PTI and motorway driving. Two datasets were used: PTI dataset introduced in this study and chase dataset from earlier literature. The impact of vehicle parameters on emissions was modeled. Vehicle parameters, especially model year and engine size, had significant effect on average emissions of a vehicle. The effect of engine size was different for diesel and gasoline vehicles, highlighting the processes affecting the formation of PN emissions. As expected, the effect of high emitters on the total PN emissions were significant: 50 % of total emissions were produced by 10 % of vehicles in motorway driving and by under 5 % in PTI.