Platinum Group Elements in Airborne Particles in Mexico City
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- 作者：Sebastien Rauch ; Bernhard Peucker-Ehrenbrink ; Luisa T. Molina ; Mario J. Molina ; Rafael Ramos ; Harold F. Hemond
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：December 15, 2006
- 年：2006
- 卷：40
- 期：24
- 页码：7554 - 7560
- 全文大小：190K
- 年卷期：v.40,no.24(December 15, 2006)
- ISSN：1520-5851
文摘
Automobile exhaust catalysts using platinum groupelements (PGE) have been mandatory on new cars in theMexico City Metropolitan Area (MCMA) since 1991.Platinum, Pd, Rh, Ir, and Os concentrations and the isotopiccomposition of Os were determined in PM10 samplesfrom the MCMA. Samples were prepared by isotope dilutionNiS fire assay, and analysis was performed by magneticsector ICP-MS using a single collector instrument for Pt, Pd,Rh, and Ir analysis and a multicollector instrument forOs analysis. Pt, Pd, and Rh concentrations at a downtownlocation (Merced) increased from 
f">1.7 pg of Pt m-3, 2.7(4.0) pg of Pd m-3, and 1.2 ± 0.9 pg of Rh m-3 in 1991 to 9.6± 1.8 pg of Pt m-3, 10.2 ± 1.8 pg of Pd m-3, and 2.8 ±0.6 pg of Rh m-3 in 2003. Concentrations at five sites in MCMAin 2003 averaged 9.3 ± 1.9 pg of Pt m-3, 11 ± 4 pg ofPd m-3, and 3.2 ± 1.0 pg of Rh m-3. In contrast, Ir andOs concentrations and Os isotopic composition remainedrelatively constant and were 0.08 ± 0.04 pg of Ir m-3, 0.030± 0.007 pg of Os m-3, and 0.60 ± 0.04, respectively, inthe MCMA in 2003. Elevated Pt, Pd, and Rh concentrationsin the MCMA are attributed to automobile catalysts. A Pt-Pd-Rh concentration peak in 1993 suggests that earlycatalysts emitted a larger amount of PGE, possibly due tofactors inherent in the technology or the use of inappropriategasoline. Therefore, this study suggests that the currentintroduction of automobile catalysts in developing countriesmay result in elevated PGE concentrations if it is notaccompanied by infrastructures and policy measuressupporting their efficient use.
f">1.7 pg of Pt m-3, 2.7(4.0) pg of Pd m-3, and 1.2 ± 0.9 pg of Rh m-3 in 1991 to 9.6± 1.8 pg of Pt m-3, 10.2 ± 1.8 pg of Pd m-3, and 2.8 ±0.6 pg of Rh m-3 in 2003. Concentrations at five sites in MCMAin 2003 averaged 9.3 ± 1.9 pg of Pt m-3, 11 ± 4 pg ofPd m-3, and 3.2 ± 1.0 pg of Rh m-3. In contrast, Ir andOs concentrations and Os isotopic composition remainedrelatively constant and were 0.08 ± 0.04 pg of Ir m-3, 0.030± 0.007 pg of Os m-3, and 0.60 ± 0.04, respectively, inthe MCMA in 2003. Elevated Pt, Pd, and Rh concentrationsin the MCMA are attributed to automobile catalysts. A Pt-Pd-Rh concentration peak in 1993 suggests that earlycatalysts emitted a larger amount of PGE, possibly due tofactors inherent in the technology or the use of inappropriategasoline. Therefore, this study suggests that the currentintroduction of automobile catalysts in developing countriesmay result in elevated PGE concentrations if it is notaccompanied by infrastructures and policy measuressupporting their efficient use.