Characteristics of trace metals in traffic-derived particles in Hsuehshan Tunnel, Taiwan: size distribution, potential source, and fingerprinting metal ratio

Abstract

Abstract. Traffic emissions are a significant source of airborne particulate matter (PM) in ambient environments. These emissions contain an abundance of toxic metals and thus pose adverse effects on human health. Size-fractionated aerosol samples were collected from May to September 2013 by using micro-orifice uniform deposited impactors (MOUDIs). Sample collection was conducted simultaneously at the inlet and outlet sites of Hsuehshan Tunnel in northern Taiwan, which is the second-longest freeway tunnel (12.9 km) in Asia. This endeavor aims to characterize the chemical constituents and size distributions, as well as fingerprinting ratios of particulate metals emitted by vehicle fleets. A total of 36 metals in size-resolved aerosols were determined through inductively coupled plasma mass spectrometry. Three major groups -namely, tailpipe emissions (Zn, Pb, and V in fine mode), wear debris (Cu, Cd, Fe, Ga, Mn, Mo, Sb, and Sn), and resuspended dust (Ca, Mg, K, and Rb) -of airborne PM metals were categorized on the basis of the results of enrichment factor, correlation matrix, and principal component analysis. Size distributions of wear-originated metals resembled the pattern of crustal elements, which were predominated by super-micron particulates (PM 1-10 ). By contrast, tailpipe exhaust elements such as Zn, Pb, and V were distributed mainly in submicron particles. By employing Cu as a tracer of wear abrasion, several inter-metal ratios -including Fe / Cu (14), Ba / Cu (1.05), Sb / Cu (0.16), Sn / Cu (0.10), and Ga / Cu (0.03) -served as fingerprints for wear debris. However, the data set collected in this work is useful for further studies on traffic emission inventory and human health effects of traffic-related PM.

Inorganic Chemical Composition of Fine Particulates in Medium-Sized Urban Areas: A Case Study of Brazilian Cities

“…Clements et al (2014) also found EF values of above 10 for Zn, Cu and Pb in Denver and Greeley, suggesting enrichment from sources other than the crust. In Taiwan, Lin et al (2015) found values above 10 for Cu and Cr, indicating anthropogenic origin and that the Cu and Mn elements originated from vehicular wear by abrasion and Zn and Pb indicate fuel combustion origins. However, the significant differences between the locations make it difficult to assign the elements found in these cities to the same sources.…”

“…The EF technique provided an overall assessment of the crustal contribution to the elemental composition of PM 2.5 collected in the cities of Londrina and Maringa (Clements et al, 2014;Fomba et al, 2015;Lin et al, 2015;Zhu et al, 2015). The EF compares elemental concentrations found in particulate matter with concentrations of these elements found in the Earth's crust, calculated according to Eq.…”

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

“…In addition, Zn and Cu were also abundant elements for E4, which was different from other excavators. Lin et al (2015) found that Zn and Cu originated from lubricating oil except for that used in brake linings. Therefore, we supposed that diesel and lubricating oil combustion were likely the main sources of the elements emitted from E4 (produced in 2004).…”

Effectiveness evaluation of temporary emission control action in 2016 in winter in Shijiazhuang, China

“…Factor 3 was represented by relatively high loadings of OC (55.9 %), EC (70.9 %), Cu (26.9 %), and Zn (26.5 %). OC and EC are generally predominant in the reported source profile of vehicle exhaust (Yao et al, 2016;Liu et al, 2016Liu et al, , 2017a, Zn is widely used as an additive for lubricant in two-stroke engines, and Cu is closely associated with brake wear (Begum et al, 2004;Canha et al, 2012;Shafer et al, 2012;Lin et al, 2015;Liu et al, 2017a). Therefore, factor 3 was identified as vehicle emissions.…”