Green Traffic-Oriented Heavy-Duty Vehicle Emission Characteristics of China VI Based on Portable Emission Measurement Systems

With a continuous increase in vehicle ownership, vehicle emissions have become one of the main sources of air pollution in China. Serious air pollution is a great threat to human health and life. The China VI regulations, which adopt strict particulate matter (PM) and nitrogen oxide (NO
_x
) limitations, have been implemented. As one of the best technologies for measuring vehicle emissions, portable emission measurement systems (PEMSs) have gained attention. In this work, the characteristics of China VI heavy-duty vehicle emissions were investigated with a PEMS. The effects of road conditions on NOx, hydrocarbon (HC), carbon monoxide (CO), PM and particle number (PN) pollutants were analyzed based on distance-based emission factors. The results show that the gaseous pollutant levels of NO
_x
, HC and CO for China VI vehicles are much lower than those for China V vehicles. The average distance-based emission factors of NOx CO and HC decreased by 88%, 98%, and 62.7%, respectively. Based on the power-based window method, the PEMS test results for NO
_x
, HC and CO are 460 mg·(kWh)
^-1
, 192 mg·(kWh)
^-1
and 37.5 mg·(kWh)
^-1
, respectively. According to the PEMS tests, approximately 88%-95% of the particles are in the 10-100 nm class based on three typical operational modes, which represent approximately 0.08%-0.13% of the total particle mass. These heavy-duty vehicles can satisfy the requirements of the PEMS China VI standards. This study emphasizes the importance of obtaining real-world measurements of heavy-duty vehicles to improve the accuracy of emission factors in the development of emission inventories in China.