Sensor Cluster for Recording the Spread of Emissions in the Wake of a Vehicle

Progressive emission reductions and stricter legislation require a closer look at the emission behaviour of a vehicle, in particular non-exhaust emissions and resuspension. In addition to the analysis of emissions in isolation, it is also necessary to consider the impact of transport routes and dispersion potential. These factors provide insight into the movement of dust particles and, consequently, the identification of particularly vulnerable areas. Measurements using low-cost environmental sensors can increase the level of detail of dispersion analyses and allow a statement on the distribution of emissions in the vehicle's wake, as several measuring points can be covered simultaneously. A newly developed measurement setup allows vehicle emissions to be recorded in a plane behind the vehicle in a measurement area of 2 by 2 metres. The measuring grid consisting of 16 sensors (4x4 grid) can be variably positioned up to 1 metre from the rear of the vehicle. The sensors detect fine dust particles size-selectively (0.3 to 10 μm) in particle number and particle mass concentration, as well as VOC and NOx. The sensors also record air temperature and humidity to be able to establish correlations with the ambient conditions. It is shown that the particle dispersion in the flow wake of the vehicle changes with different driving scenarios. Furthermore, it is shown that the driving speed influences the turbulence potential due to resuspension and thus also the particle dispersion. The results obtained provide information on the particle movements behind a vehicle and thus on critical areas in the vicinity of roads. In this context, the resuspension of particles already deposited on the road surface is also becoming increasingly important.