1 of 4 pages

List of Projects

1. Mechanism of Non-genotoxic Occupational Carcinogens

2. Mechanistic Studies of the Transformation of Polychlorinated Dibenzo-p-Dioxins via Hydroxyl Radical Attack

3. Trace-level Measurement of Complex Combustion Effluents and Residues using Multi-dimensional Gas Chromatography-Mass Spectrometry (MDGC-MS)

4. Oxidative Transformation of Model Oxygenated Hazardous Air Pollutants

5. Development of a Membrane-Based Electrostatic Precipitator

6. Development of a Heterogeneous Catalyst for Hydroformylation in Supercritical CO

7. Formation of Chlorinated PAHs in the Combustion and Thermal Processing of Chlorine Containing Materials

8. Investigation of the Elementary Reaction Mechanisms of Fly-Ash Mediated Formation of PCDD/F

9. Kinetic and Mechanistic Studies of the Reactions of Hydroxyl Radical with the Chloroethenes over an Extended Temperature Range

10. Factors Controlling the Dust Mite Population in the Indoor Environment

11. Back-End Modifications of Portland Cement Plants to Reduce Emissions of Hazardous Air Pollutant Funded by NSF

12. Pollution Prevention Technology Transfer for the Printing Industry

13. Pollution Prevention Assistance in Automotive Supply Chain

14. Catalytic Reduction of Nitric Oxide

15. Exposure of Non Smoking Patrons and Employees to Environmental Tobacco Smoke in Restaurants with Designated Smoking and Non Smoking Areas not Ventilated Separately

EPA Grant Number: R828083
Title: Mechanism of Non-genotoxic Occupational Carcinogens
Investigators: Michael A. Pereira
Institution: Medical College of Ohio
EPA Project Officer: David Reese
Project Period: April 20, 2000 to April 19, 2003
Project Amount: $834,714
Research Category: Mechanistic-based Cancer Risk Assessment Method
Description:  

Understanding the mechanism of carcinogens present in the workplace and the environment has become increasingly important because of the use of mechanism-based approaches to extrapolate results from laboratory animals to humans. There is great uncertainty in interspecies extrapolation because the dose levels used in animal studies are usually much greater than doses resulting from human exposure. High dose levels are required in animal carcinogenesis studies because of the low sensitivity of the bioassay. The uncertainty in the extrapolation is especially great for non-genotoxic carcinogens. This is because non-genotoxic carcinogens are likely to have dose-response curve that are not linear and that include a threshold. Furthermore, they could induce cancer in animals by a mechanism that is not applicable to humans. Knowledge of the mechanism of these carcinogens allows the development of molecular and biological markers for their activity. One of these biomarkers is the hypomethylation of DNA and protooncogenes. Biomarkers could be used to determine whether the mechanism applies to humans and to better define the dose-response relationship extending it to exposures/dose levels not applicable to carcinogenesis bioassay. Lung and mouse liver non-genotoxic carcinogens will be investigated, since the lung is a major site of occupational-related cancer and mouse liver is a major target organ in carcinogenesis bioassays.

back to top

EPA Grant Number: R828189
Title: Mechanistic Studies of the Transformation of Polychlorinated Dibenzo-p-Dioxins via Hydroxyl Radical Attack
Investigators: Dr. Philip H. Taylor
Institution: University of Dayton
EPA Project Officer: Mitch Lasat
Project Period: October 1, 2000 – September 30, 2003
Project Amount: $320,000
Research Category: Combustion Emissions
Description:  

Polychlorinated dibenzo-p-dioxins (PCDD) are considered among the most toxic organic chemicals associated with our industrial society. The gas-phase transformation of these chemicals under high-temperature incineration (destruction) conditions is not well understood. Experimental and modeling studies have repeatedly shown that OH radical reactions are among the most important elementary steps under these reaction conditions. A review of the literature demonstrates that knowledge of the rate of reaction of OH with dibenzo-p-dioxin and PCDD is limited to three low temperature experimental studies, or inferred by estimates of room temperature reactivity. The mechanism of reaction is completely uncharacterized. We propose to study the high-temperature reaction kinetics of OH radicals with dibenzo-p-dioxin (DD) and selected chlorinated dioxins using a modified laser photolysis/laserinduced fluorescence technique. This technique will be used in conjunction with a specially fabricated high-temperature fused silica test cell operated under atmospheric pressure, slow flow, single reaction conditions. In the absence of reactant thermal decomposition, accurate rate constant measurements with this apparatus can span a temperature range of 295 to ~1000 K. This extended range encompasses temperatures in the incinerator post-flame zone and allows for more precise extrapolation of rate constants to higher temperature combustion environments. Mechanistic experiments will include studies of the effect of pressure on observed rate coefficients, and product analysis using a highly sensitive Saturn 2000 ion trap GC-MS-MS analytical system. The mechanistic studies will be used to guide and interpret quantum RRK modeling of the various reactions. This study will identify key gas-phase pathways for the transformation of PCDD at elevated temperatures. These pathways. with formation pathways being studied in complementary research programs by the P1 and other investigators, are important inputs in the development of a comprehensive gas-phase model of the transformation of PCDD for a wide range of conditions. This model can be used to manage risk by preventing and controlling formation and emission. The fundamental data and models developed in this study will contribute to the infrastructure of knowledge of reactions of chlorinated hydrocarbons and their impact on the environment.

back to top

EPA Grant Number: R828190
Title: Trace-level Measurement of Complex Combustion Effluents and Residues using Multi-dimensional Gas Chromatography-Mass Spectrometry (MDGC-MS)
Investigators: Wayne A. Rubey, Richard Striebich, and Philip Taylor
Institution: University of Dayton, Environmental Science and Engineering, Dayton, Ohio
EPA Project Officer: Mitch Lasat
Project Period: June 1,2000 – May 31, 2003
Project Amount: $335,000
Research Category: Combustion Emissions
Description:  

The identification and quantitation of combustion products in the environment are clearly becoming more of a concern to the public. In order to perform assessments of risk from combustion processes such as hazardous waste incinerators, analytical techniques are required which can identify or speciate as much of the total organic (TO) emissions as possible. The ultimate intent is to compare the amount of organic material identified and quantified by target analyte-specific methodologies to organic emissions quantified by the TO methodology. The greater the amount accounted for by the target analyte-specific methodologies, the less uncertainty may be associated with the risk assessments. A limitation of this approach is that the target analyte-specific methodologies do not routinely quantify compounds of low toxicological interest; nor do they target products of incomplete combustion (PICs). Thus, the analysis can miss both toxic and non-toxic compounds. As a result, it is unknown whether the uncharacterized fraction of the TO emission possesses toxic properties. The hypothesis that we propose to test is that organic emissions and organics extracted from particulate matter (PM) are more complex than standard GC-MS-based instrumentation can currently measure. This complexity will affect quantitation for toxic compounds, thereby affecting risk assessments. There is a pressing need to better characterize these organic emissions from hazardous waste incinerators and PM extracts from various other combustion sources. We will demonstrate that multidimensional gas chromatography-mass spectrometry (MDGC-MS) procedures significantly improve chromatographic separation for complex environmental samples. Sequential repetitive heart-cutting MDGC, with coupled ion trap mass spectrometry will be shown to be a complete analysis technique. Since sequential repetitive heart-cutting can take literally weeks to analyze one sample, we are proposing to incorporate a rapid GC technique called "thermal gradient programmed GC" (TGPGC). The entire package of MDGC, TGPGC and MS will be capable of fast and complete analyses of complex combustion effluents. We will apply these techniques to obtain more accurate risk assessments. We will demonstrate the ability of this hyphenated technique to disengage and conclusively characterize incinerator emissions and condensable organics from fine PM. We will examine samples from actual combustion effluents and residues and examine the relationship between combustion conditions and emissions. We will also demonstrate improved quantitation over conventional GC techniques and better qualitative identification of components. We anticipate that increased analytical information will provide more accurate risk assessments ,since identities and concentrations of emissions will be better understood.

back to top

EPA Grant Number: R828175
Title: Oxidative Transformation of Model Oxygenated Hazardous Air Pollutants
Investigators: Dr. Philip H. Taylor and Dr. Paul Marshall
Institution: University of Dayton
EPA Project Officer: Paul Shapiro
Project Period: July 20, 2000 - July 19, 2002
Project Amount: $215,900
Research Category: Exploratory Research - Environmental Chemistry
Description: 

Reaction with hydroxyl (OH) radicals is an important step in the oxidation of organic compounds in the atmosphere and in combustion systems. Formaldehyde (CH2O) and acetaldehyde (CH3CHO) are hazardous air pollutants (HAPs) regulated under Title III of the Clean Air Act Amendments. The overall goal of this research is to determine the rates and mechanisms of OH reactions with representative oxygenated hazardous air pollutants, i.e., formaldehyde, acetaldehyde, and acetone, under conditions that are representative of both atmospheric and combustion conditions. The kinetic and mechanistic studies will be used to validate comprehensive theoretical studies of these reactions. We propose to combine two existing techniques to study the kinetics and mechanism of the reaction of OH radicals with formaldehyde, acetaldehyde, and acetone over an extended temperature and pressure range. A refined pulsed laser photolysis/laser-induced fluorescence (PLP/LIF) technique will be used for the kinetic measurements. A recently developed pulsed laser photolysis/photo-ionization mass spectrometry (PLP/PIMS) technique will be used to obtain quantitative product data. In the absence of reactant thermal decomposition, accurate rate constant measurements and mechanistic data obtained by these combined techniques will span a temperature range from room temperature to ~1000 K and a pressure range of ~10 torr to ~740 torr. In addition to the detailed experimental plan, a thorough theoretical study is proposed through collaboration with Prof. Paul Marshall of the University of North Texas. Reaction pathways will be characterized by ab initio methods, at up to the Gaussian 2 and 3 levels of theory, and will be analyzed using variational transition state theory. The proposed research will be a valuable input to risk assessment models concerned with the transformation of these HAPs. This study will identify key gas-phase pathways for their destruction under both atmospheric and higher temperature combustion conditions. These pathways will be important contributions to comprehensive gas-phase models of the atmospheric transformation of these HAPs and the high-temperature destruction of conventional hydrocarbon fuels and alternative oxygenated fuels. The fundamental data and models developed in this study will also contribute to the infrastructure of knowledge of the combustion of hydrocarbon fuels and their impact on the environment.

back to top

Next

   [Home]        [Graduate Universities]        [Undergraduate Universities]        [Private Org.]        [Research Database]        [Govt. Agencies]