Abstract：The PM2.5 and hydrocarbon (HC) samples emitted from heavy-duty diesel vehicles including Euro Ⅱ, Euro Ⅲ and Euro Ⅳ technologies were collected by on-board emission measurements. The PM2.5 chemical compositions were determined by inductively coupled plasma mass spectrometry, ion chromatograph, and the thermal/optical carbon analyzer. HC was analyzed online by five-gas analyzer. Results demonstrated that the emission factors of PM2.5 and HC were (0.22±0.12) g/km and (0.57±0.45) g/km, respectively. Emission reductions of PM2.5 and HC had been achieved as the control technology become more rigorous. EC and OC were the major components of PM2.5, accounting for 38.87%~42.87% and 16.22%~19.96% of the total PM2.5 mass, respectively. The abundance species of water soluble ions were SO42-, NH4+, and NO3-, accounting for 7.64%~8.85%, 2.22%~3.97%, 1.91%~2.73%, respectively. The abundance species of elements were S, Na, Ca, Fe, and Al. It was also found that PM2.5 and HC emission factors were dropped with the increase of the speed.
