Real-time vehicle emission monitoring along roadsides

In the worldwide efforts to reduce the emissions of greenhouse gasses in general and those emitted by vehicles in particular, vehicle emission monitoring is important. It provides accurate knowledge of real-world emissions of vehicles as input for vehicle emission models. Real-time emission monitoring along roadsides can be used in dedicated monitoring to eliminate airquality hotspots, by assessing and optimizing local emission reducing measures like traffic light schemes. Also, it can be used to identify high-emitter vehicles. The main focus of this paper is the roadside emission measurement experiment performed in 2009. In this experiment simultaneous concentration measurements of CO2, NOx, NO and NO2 were carried out with simultaneous measurements of particulate matter and TSP. This information was enhanced with vehicle speed and acceleration from radar measurements together with vehicle class information derived from video identified license plates. In total over 8000 vehicles were measured. The experiment showed that a combination of a limited number of measurements combined with emission and dispersion modelling may provide a reliable realtime estimation of air quality in complex situations