- Full (HTML) - Full (PDF) - Related EHP Articles - PubMed:Related Articles - PubMed:Citation - Cited in PMC - Purchase This Issue

Jacob D. McDonald,¹ Ingvar Eide,² JeanClare Seagrave,¹ Barbara Zielinska,³ Kevin Whitney,⁴ Douglas R. Lawson,⁵ and Joe L. Mauderly¹

¹Lovelace Respiratory Research Institute, Albuquerque, New Mexico, USA; ²Statoil Research Centre, Trondheim, Norway; ³Desert Research Institute, Reno, Nevada, USA; ⁴Southwest Research Institute, San Antonio, Texas, USA; ⁵National Renewable Energy Laboratory, Golden, Colorado, USA

Abstract
In this study we investigated the statistical relationship between particle and semivolatile organic chemical constituents in gasoline and diesel vehicle exhaust samples, and toxicity as measured by inflammation and tissue damage in rat lungs and mutagenicity in bacteria. Exhaust samples were collected from "normal" and "high-emitting" gasoline and diesel light-duty vehicles. We employed a combination of principal component analysis (PCA) and partial least-squares regression (PLS ; also known as projection to latent structures) to evaluate the relationships between chemical composition of vehicle exhaust and toxicity. The PLS analysis revealed the chemical constituents covarying most strongly with toxicity and produced models predicting the relative toxicity of the samples with good accuracy. The specific nitro-polycyclic aromatic hydrocarbons important for mutagenicity were the same chemicals that have been implicated by decades of bioassay-directed fractionation. These chemicals were not related to lung toxicity, which was associated with organic carbon and select organic compounds that are present in lubricating oil. The results demonstrate the utility of the PCA/PLS approach for evaluating composition-response relationships in complex mixture exposures and also provide a starting point for confirming causality and determining the mechanisms of the lung effects. Key words: diesel exhaust, gasoline exhaust, hopane, mutagenicity, PAHs, particulate matter health effects, principal component analysis, semivolatile organic carbon, sterane, toxicity of motor vehicle emissions. Environ Health Perspect 112:1527-1538 (2004) . doi:10.1289/ehp.6976 available via http://dx.doi.org/ [Online 15 July 2004]

Address correspondence to J.D. McDonald, Lovelace Respiratory Research Institute, 2425 Ridgecrest Dr. SE, Albuquerque, NM 87108 USA. Telephone: (505) 348-9455. Fax: (505) 348-4980. E-mail: jmcdonal@lrri.org

E. Johanson and S. Rännar (Umetrics, Umea, Sweden) provided valuable discussions.

This work was supported by the Office of Freedom Car and Vehicle Technologies, U.S. Department of Energy. The views and opinions of the authors do not necessarily reflect those of the U.S. Government or any agency thereof.

The authors declare they have no competing financial interests.

Received 21 January 2004 ; accepted 14 July 2004.