title: Platinum in PM2.5 of the metropolitan area of Mexico City.
abstract: The increase in platinum (Pt) in the airborne particulate matter with size ≤2.5 µm (PM2.5) in urban environments may be interpreted as result of the abrasion and deterioration of automobile catalyst. Nowadays, about four million vehicles in Mexico City use catalytic converters, which means that their impact should be considered. In order to evaluate the contribution of Pt to environmental pollution of the metropolitan area of Mexico City (MAMC), airborne PM2.5 was collected at five different sites in the urban area (NW, NE, C, SW, SE) in 2011 during April (dry-warm season), August (rainy season) and December (dry-cold season). Analytical determinations were carried out using a ICP-MS with a collision cell and kinetic energy discrimination. The analytical and instrument performance was evaluated with standard road dust reference material (BCR-723). Median Pt concentration in the analyzed particulate was is 38.4 pg m(-3) (minimal value 1 pg m(-3) maximal value 79 pg m(-3)). Obtained Pt concentrations are higher than those reported for other urban areas. Spatial variation shows that SW had Pt concentration significantly higher than NW and C only. Seasonal variation shows that Pt median was higher in rainy season than in both dry seasons. A comparison of these results with previously reported data of PM10 from 1991 and 2003 in the same studied area shows a worrying increase in the concentration of Pt in the air environment of MAMC.
authors.affiliation: Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04150, Mexico, DF, Mexico, omorton@geofisica.unam.mx.
authors.forename: Ofelia
authors.initials: O
authors.lastname: Morton-Bermea
authors.forename: Omar
authors.initials: O
authors.lastname: Amador-Muñoz
authors.forename: Lida
authors.initials: L
authors.lastname: Martínez-Trejo
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hernández-Álvarez
authors.forename: Laura
authors.initials: L
authors.lastname: Beramendi-Orosco
authors.forename: María Elena
authors.initials: ME
authors.lastname: García-Arreola
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring; D013058:Mass Spectrometry / Q000379:methods; D008800:Mexico; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D010984:Platinum / Q000032:analysis*; D012621:Seasons
chemical_list: D000393:Air Pollutants; D004391:Dust; D052638:Particulate Matter; D010984:Platinum
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