Chemical composition of PM 2.5 from two tunnels with different vehicular fleet characteristics

Abstract

• Composition profiles of PM 2.5 were obtained in smaller city, Yantai.• Characteristics of PM 2.5 were changed by emission standards and fuel policy.• Source profiles of PM 2.5 for gasoline vehicles and diesel vehicles were given.• The diesel vehicles play a major role in PM 2.5 emissions in Yantai. 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 (KXL) 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 PM 2.5 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 PM 2.5 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 PM 2.5 and proportions of SO 4 2− 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 PAHs (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 PM 2.5 from gasoline-fueled vehicles (GV) G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o Contents lists available at ScienceDirectScience of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v 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 PM 2.5 , followed by Fe, Cl − , and Mg for GV. The relative proportions of the different constituents in the PM 2.5 for DV were EC (35.9%), OC (27.2%), elements (12.8%), and water soluble ions (11.7%). Both the PM 2.5 EFs 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 PM 2.5 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.

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

“…Therefore, the results obtained from the real-world conditions (on-road tests and tunnels) are different from those obtained in a laboratory. For organic matter, the proportion of PAHs, hopanes, and steranes to PM are consistent with the results of Schauer et al (1999) and Cui et al (2016). In this study, the most abundant n-alkane was C20, as measured by Schauer et al (1999), and pyrene was the most abundant PAH, as reported by Cui et al (2016).…”

“…In comparison, the total carbon emissions in this study are lower than those in previous studies, whereas the WSIs and elements fractions are higher (Alves et al, 2015a;Cui et al, 2016;Schauer et al, 1999;Wu et al, 2016). Several factors have influenced these differing results such as fuel quality, driving condition, engine parameters (fuel injection timing, compression ratio, and fuel injector design), and experimental methods (Sarvi et al, 2008a(Sarvi et al, , b, 2009Sarvi and Zevenhoven, 2010).…”

“…Fuel quality has a significant effect on PM emissions from vehicles (Cui et al, 2016;Liang et al, 2005;Zhang and Balasubramanian, 2014). Because various fuels are used in excavators and always have poor qualities, all of the corresponding fuels from each of the tested excavators were collected for quality analysis.…”

“…Before each measurement, the filters were balanced at 25 • C and 40 % relative humidity for 24 h. Each filter was weighed three times. WSIs were analyzed using ion chromatography (Dionex ICS3000, Dionex Ltd., Sunnyvale, California, United States) following the method of Cui et al (2016). Elements analysis was performed using inductively coupled plasma mass spectrometry (ICP-MS; ELAN DRC II type, Perkin Elmer Ltd., Hong Kong) (Cui et al, 2016).…”

“…WSIs were analyzed using ion chromatography (Dionex ICS3000, Dionex Ltd., Sunnyvale, California, United States) following the method of Cui et al (2016). Elements analysis was performed using inductively coupled plasma mass spectrometry (ICP-MS; ELAN DRC II type, Perkin Elmer Ltd., Hong Kong) (Cui et al, 2016). Because the organic compounds on the filters were insufficient for quantification, we merged filters of different operation modes or driving routes based on the proportion of sampling time during each mode or route for analyzing the PM characteristic for each diesel vehicle.…”