title: Traffic tracers in a suburban location in northern Spain: relationship between carbonaceous fraction and metals.
abstract: PM10 and black smoke were monitored at a suburban sampling station located in the northern Spanish city of Gijón. Thirty-two metals and total carbon (TC) (i.e., organic carbon (OC) and elemental carbon (EC)) were analyzed over a year. The study of air-mass origin based on 5-day back trajectories was carried out to assess its influence on the recovery data. Different strategies were implemented to infer the influence of traffic in the area. On average, TC accounted for 29 % of the PM10 fraction, with OC forming 77 % of this TC. The influence of traffic was clearly reduced during intense Atlantic advection episodes, when OC and EC decreased up to 0.39 and 0.22 μg C/m(3), respectively. In contrast, the highest values were reported during regional episodes, exceeding 10 μg C/m(3) of OC and 2 μg C/m(3) of EC. The correlation between EC and OC was found to notably improve when considering the days with high traffic flow (from R (2) = 0.46 to R (2) = 0.74). This pattern was also reproduced by black smoke and EC (from R (2) = 0.49 to R (2) = 0.59). Cu and Sn were found to be reliable traffic tracers given their high dependence on EC (R (2) = 0.82 and R (2) = 0.79, respectively). Nevertheless, Sn, Ba, and Sb showed a better correlation with Cu than EC, suggesting a common origin. In the case of Sn, R (2) improved from 0.79 to 0.91. The Cu/Sb ratio had a mean value of 6.6 which agrees with diagnostic criterions for brake wear particles. The relationships and ratios between EC, Cu, Sb, Sn, Ba, and Bi pointed out to non-exhaust emissions, playing a significant role in the chemical composition of PM10. Brake wear was presented as the most likely origin for Cu, Sb, and Sn.
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, University of Oviedo, Gijón Campus, 33203, Gijón, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Megido
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, University of Oviedo, Gijón Campus, 33203, Gijón, Spain. negralluis@uniovi.es.
authors.forename: L
authors.identifier: http://orcid.org/0000-0001-8384-9541
authors.initials: L
authors.lastname: Negral
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, University of Oviedo, Gijón Campus, 33203, Gijón, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Castrillón
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, University of Oviedo, Gijón Campus, 33203, Gijón, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Marañón
authors.affiliation: Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, University of Oviedo, Gijón Campus, 33203, Gijón, Spain.
authors.forename: Y
authors.initials: Y
authors.lastname: Fernández-Nava
authors.affiliation: Department of Materials Science and Metallurgiscal Engineering, Polytechnic School of Engineering, University of Oviedo, Gijón Campus, 33203, Gijón, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Suárez-Peña
mesh_terms: D000336:Aerosols / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring; D008670:Metals / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis; D013030:Spain
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D008670:Metals; D052638:Particulate Matter
keywords: Air-mass origin; Brake wear; EUSAAR2; Non-exhaust emissions; Particulate matter; Road traffic; Trace metals