Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

摘要

With the rapid growth in the number of both non-road and on-road diesel vehicles, the adverse effects of particulate matter (PM) and its constituents on air quality and human health have attracted increasing attentions. However, studies on the characteristics of PM and its composition emitted from diesel vehicles are still scarce, especially under real-world driving conditions. In this study, six excavators and five trucks that provided a wide range of emission standards and operation modes were tested, and PM emissions and their constituents - including organic carbon (OC), elemental carbon (EC), water-soluble ions (WSIs), elements, and organic species like polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and hopanes - as well as steranes were analyzed and characterized. The average emission factors for PM (EF_(PM)) from excavator and truck emissions were 829±806 and 498±234 mgkg~(-1) fuel, respectively. EF_(PM) and PM constituents were significantly affected by fuel quality, operational mode, and emission standards. A significant correlation (R~2 = 0:79, p < 0:01) was found between EF_(PM) for excavators and the sulfur contents in fuel. The highest average EF_(PM) for working excavators was 904±979 mgkg~(-1) fuel as a higher engine load required in this mode. From pre-stage 1 to stage 2, the average EF_(PM) for excavators decreased by 58 %. For trucks, the average nonhighway EF_(PM) at 548±311 mgkg~(-1) fuel was higher than the highway EF_(PM) at 497±231 mgkg~(-1) fuel. Moreover, the reduction rates were 63.5 and 65.6% when switched from China II and III to China IV standards, respectively. Generally, the PM composition emitted from excavators was dominated by OC (39.2±21.0 %) and EC (33.3±25.9 %); PM from trucks was dominated by EC (26.9±20.8 %), OC (9.89±12 %), and WSIs (4.67±5.74 %). The average OC/ EC ratios for idling and working excavators were 3 to 4 times higher than those for moving excavators. Although the EF_(PM) for excavators and trucks w