Morton-Bermea Ofelia, Amador-Muñoz Omar, Martínez-Trejo Lida, Hernández-Álvarez Elizabeth, Beramendi-Orosco Laura, García-Arreola María Elena
Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04150, Mexico, DF, Mexico,
Environ Geochem Health. 2014 Oct;36(5):987-94. doi: 10.1007/s10653-014-9613-8. Epub 2014 Apr 13.
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.
城市环境中粒径≤2.5微米的空气颗粒物（PM2.5）中铂（Pt）含量的增加，可能是汽车催化剂磨损和老化的结果。如今，墨西哥城约有400万辆汽车使用催化转化器，这意味着其影响值得关注。为了评估Pt对墨西哥城大都市区（MAMC）环境污染的贡献，于2011年4月（干暖季）、8月（雨季）和12月（干冷季）在市区的五个不同地点（西北、东北、中心、西南、东南）采集了空气PM2.5。使用带碰撞池和动能歧视功能的电感耦合等离子体质谱仪（ICP-MS）进行分析测定。用标准道路灰尘参考物质（BCR-723）评估分析和仪器性能。分析的颗粒物中Pt浓度中位数为38.4皮克/立方米（最小值1皮克/立方米，最大值79皮克/立方米）。所获得的Pt浓度高于其他城市地区的报告值。空间变化表明，西南地区的Pt浓度仅显著高于西北和中心地区。季节变化表明，雨季的Pt中位数高于两个旱季。将这些结果与之前报道的1991年和2003年同一研究区域的PM10数据进行比较，结果显示MAMC空气环境中Pt浓度令人担忧地增加。
