An inexpensive technique for measuring vehicle emissions in real driving conditions is described in this paper. Results of this study provide a method of assessing the effects of route attributes such as terrain, road geometry and intersection type on vehicle emission rates. The technique described has been used to make on-road measurements. Emission rates were measured for flat, uphill and downhill roads and for regulated intersections and roundabouts. Emission components such as carbon monoxide (CO), nitrogen oxide (NO) and total hydrocarbons (HC) were measured simultaneously with vehicle speed, travelled distance, and exhaust gas velocity and temperature. The technique has been validated by firstly determining vehicle emission rates, measured in real time with one second measuring interval and expressed as g/sec. Simultaneously exhaust gases were collected in a plastic bag and subsequently analysed with the exhaust gas analyser. Emission rates were expressed as g/km over the defined driving cycle and compared with the integrated real time emission rates determined by the first method. This instrumented vehicle technique, tested in these experiments, provides real time emission profiles which can be used for example as an input data for microscale pollution dispersion models. (A)
Abstract