Chemical composition of PM2.5 from two tunnels with different vehicular fleet characteristics

The chemical compositions of PM(2.)5 including OC, EC, water soluble ions, elements, and organic components such as polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes, emitted in Wuzushan (WZS) and Kuixinglou (IOW tunnels were determined. WZS tunnel is a major route for diesel vehicles traveling, while KXL tunnel has limited to diesel vehicles. The results showed that the proportions of the different constituents of PM2.5 in the Wuzushan (WZS) tunnel were OC (27.7%), EC (32.1%), elements (13.9%), and water soluble ions (9.2%). Whereas the chemical profile of PM2.5 in the Kuixinglou (KXL) tunnel was OC (17.7%), EC (10.4%), elements (8.90%), and water soluble ions (8.87%). The emission factors (EFs) of PM2.5 and proportions of SO42- and Pb were decreased by vehicle emission standards and fuel quality policy in China, and the higher molecular weight PAHs (4 + 5 + 6 rings) were more abundant than the lower molecular weight PAH5 (2 + 3 rings) in the two tunnels. The proportions of 17A( H)-21B(H)-30-Norhopane and 17A(H)-21B(H)-Hopane in the hopane and sterane were not dependent on the vehicles types. In addition, specific composition profiles for PM2.5 from gasoline -fueled vehicles (CV) and diesel-fueled vehicles (DV) emissions were drafted, which indicated that OC (0.974 mg.veh(-1).km(-1)) was the most abundant component in PM2.5, followed by Fe, CI, and Mg for GV. The relative proportions of the different constituents in the PM2.5 for DV were EC (35.9%), OC (27.2%), elements (12.8%), and water soluble ions (117%). Both the PM2.5 ER and EC proportions in DV were higher than those in GV, and the HMW PAHs were the dominant PAHs for both GV and DV. The PM2.5 emissions from the vehicles in Yantai were 581 +/- 513 tons to 1353 +/- 1197 tons for GV, and 19,627 +/- 2477 tons to 23,042 +/- 2887 tons for DV, respectively. (C) 2016 Elsevier B.V. All rights reserved.