Oxidative Transformation of Model Oxygenated Hazardous Air PollutantsEPA Grant Number: R828175
Title: Oxidative Transformation of Model Oxygenated Hazardous Air Pollutants
Investigators: Taylor, Philip H. , Marshall, Paul
Institution: University of Dayton
Current Institution: University of Dayton , University of North Texas
EPA Project Officer: Shapiro, Paul
Project Period: July 20, 2000 through July 19, 2002
Project Amount: $215,900
RFA: Exploratory Research - Engineering, Chemistry, and Physics) (1999) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Water , Land and Waste Management , Air , Engineering and 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.
Approach: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.
Expected Results: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.
Publications and Presentations:Publications have been submitted on this project: View all 8 publications for this project
Journal Articles:Journal Articles have been submitted on this project: View all 4 journal articles for this project
Supplemental Keywords:air, tropospheric, toxics, VOCs, environmental chemistry., RFA, Scientific Discipline, Air, Waste, Environmental Chemistry, air toxics, tropospheric ozone, Engineering, Chemistry, & Physics, Incineration/Combustion, hydroxyl radical, risk assessment, combustion systems, hydrocarbon, oxidation, stratospheric ozone, Acetaldehyde, VOCs, hazardous air pollutants, HAPS, Clean Air Act , hydrocarbon oxidation, kinetic models, laser induced flouresence studies, chemical kinetics, combustion, acetone, hazardous air pollutants (HAPs), hydrocarbons, Volatile Organic Compounds (VOCs)
Progress and Final Reports:2000 Progress Report