Air pollution is becoming a more and more important aspect for transportation, particularly car emission in urban area. The objective of this paper is to evaluate the global emission of a transport network based on probe car and sensor data. Probe vehicles allow an accurate estimation of the emission at different points in the network and these results could be extrapolated to the whole network by using traffic sensor data. To begin, data emission which can be extracted from probe car must be tested. Therefore, the first task is an evaluation of the differences between the simulated vehicle emission (provided by using the microsimulator; AIMSUN) and estimation of vehicle emission from a sample of simulated vehicles representing the population of probe vehicles. The aim of the second part of this study is to determine the optimal penetration rate of probe vehicles. Then, the global emission and its accuracy could be determined. This methodology shows that using probe car gives good estimation of the real data emission (90-95 %). Furthermore, depending of the network configuration a penetration rate of 10-15 % of probe car is enough to obtain satisfactory results of the global emission data.