Atmospheric Transformation of Diesel Emissions

EPA Grant Number: R832347C147
Subproject: this is subproject number 147 , established and managed by the Center Director under grant R832347
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Health Effects Institute (2005 — 2010)
Center Director: Greenbaum, Daniel S.
Title: Atmospheric Transformation of Diesel Emissions
Investigators: Zielinska, Barbara
Institution: Desert Research Institue , Health Effects Institute
EPA Project Officer: Hunt, Sherri
Project Period: April 1, 2005 through March 31, 2010
RFA: Health Effects Institute (2005) RFA Text |  Recipients Lists
Research Category: Health Effects , Air Quality and Air Toxics , Air


Diesel exhaust (DE) is an important contributor to air pollution and consists of a complex mixture of hundreds of compounds in either gas or particle form. After emission, DE undergoes chemical and physical transformations, or “aging,” in the atmosphere as well as dispersion and transport. The aging process depends on the environment into which the DE is emitted; the atmosphere contains many compounds, including oxidizing and nitrating radicals, as well as organic and inorganic compounds from sources other than diesel engines. These compounds can influence the chemical composition and toxicity of DE as well as how long its various components remain in the atmosphere. Because of substantial changes in diesel engine technology and after-treatment over the past decade, there is a need to evaluate the newer technologies, including their emissions, the atmospheric processing of their emissions, and the corresponding health effects.

Dr. Barbara Zielinska of the Desert Research Institute in Reno, Nevada, and her colleagues propose studying the effects of photochemical transformations on DE constituents and whether such changes in chemical and physical form would be reflected in changes in toxicity. The investigators’ atmospheric aging experiments would be conducted at the European Photoreactor (EUPHORE) outdoor simulation chamber in Valencia, Spain. Samples would then be shipped to Dr. Zielinska’s laboratory in the United States for detailed chemical analyses and to her collaborator Dr. Jean Clare Seagrave at the Lovelace Respiratory Research Institute in Albuquerque, New Mexico, for toxicologic experiments in rodents.


DE will be generated at EUPHORE using a 2003-model-year Ford light-duty diesel engine run on a dynamometer at about 50% load. EUPHORE has two outdoor simulation chambers with a volume of about 200 m3 and a retractable cover that allows atmospheric reactions to take place in daylight (allowing photochemical reactions to occur) or in the dark, simulating nighttime conditions. In addition to DE, several compounds (precursors to hydroxyl [OH] or nitrate [NO3] radicals, toluene, or a mixture of volatile organic compounds [VOCs]) will be added to the atmospheric mixture to create various aging conditions. The mixture will then be allowed to react for 3 to 5 hours; after completion of the reactions, the chamber cover will be closed (if open), and integrated air samples will be collected overnight using Teflon filters to collect particles and XAD adsorbent-resin cartridges to collect gaseous species. Parallel samples will be collected for detailed chemical analyses and in vivo toxicologic experiments.

The investigators will measure a large number of compounds known to be present in DE, including alkanes, polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and polar compounds, as well as hopanes and steranes that are known to be present in lubricating oil. They will also measure elemental carbon (EC) and organic carbon (OC), NO3, and sulfate.

Two series of toxicologic experiments will be conducted.  The animals will be killed 24 hours after intra-tracheal instillation for evaluation of markers of inflammation in blood and lung lavage fluid as well as signs of inflammation, cytotoxicity, and parenchymal changes in lung tissue. The mice, in addition, will be evaluated for markers of oxidative stress and macrophage phagocytosis in lung tissue and lavage fluid cells, respectively.

Expected Results:

The investigators anticipate successfully conducting a complex study to characterize the atmospheric transformations of DE under the influence of sunlight, O3, radicals, and organic compounds. It is hope that this study will present novel results on the atmospheric aging of DE derived from a 2003-model-year light-duty engine under a variety of conditions. The study will include the use of state-of-the-art atmospheric chamber facilities, the use of a realistic set of atmospheric aging conditions, and the analysis of a large number of organic compounds.

Supplemental Keywords:

Health Effects, Air Quality, mobile source emisions, diesel exhaust

Relevant Websites: Exit

Main Center Abstract and Reports:

R832347    Health Effects Institute (2005 — 2010)

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R832347C135 Mechanisms of Particulate Matter Toxicity in Neonatal and Young Adult Rat Lungs
R832347C136 Uptake and Inflammatory Effects of Nanoparticles in a Human Vascular Endothelial Cell Line
R832347C138 Health Effects of Real-World Exposure to Diesel Exhaust in Persons with Asthma
R832347C140 Extended Follow-Up and Spatial Analysis of the American Cancer Society Study Linking Particulate Air Pollution and Mortality
R832347C141 Air Pollution Effects on Ventricular Repolarization
R832347C143 Measurement and Modeling of Exposure to Selected Air Toxics for Health Effects Studies and Verification by Biomarkers
R832347C144 Genotoxicity of 1,3-Butadiene and Its Epoxy Intermediates
R832347C145 Effects of Concentrated Ambient Particles and Diesel Emissions on Rat Airways
R832347C147 Atmospheric Transformation of Diesel Emissions