In-use emission factors of 11 pieces of construction equipment were collected using a portable emission measurement system. These vehicles include excavators, bulldozers and loaders. Both regulated pollutants and PM carbonaceous compositions were tested. The emission factors of CO, HC, NOx and PM for these vehicles are 13–91 g kg–1, 12–63 g kg–1, 1.4–27 g kg–1, and 2.5–13 g kg–1 respectively. Their fuel consumption rates are also provided. The vehicles in the idling mode are higher in the emission factors of CO and HC than those in the other operating modes. The vehicles certified to different emission standards are significantly different in PM carbonaceous compositions. The analysis by GC-MS shows that the majority of particle-phase PAHs from these vehicles are 2- or 3-ring PAHs, while high-molecular-weight PAHs are seldom detected. There is a great difference in the emission factors of PM and OM between the vehicles at the start-up phase and those in the normal idling mode. Some conclusions and recommendations are made by comparing this study with some others.