Atmospheric Chemistry of Volatile Organic Compounds and their Atmospheric Reaction ProductsEPA Grant Number: R825252
Title: Atmospheric Chemistry of Volatile Organic Compounds and their Atmospheric Reaction Products
Investigators: Atkinson, Roger , Tuazon, Ernesto C. , Arey, Janet
Institution: University of California - Riverside
EPA Project Officer: Hahn, Intaek
Project Period: November 1, 1996 through October 31, 1999 (Extended to October 31, 2000)
Project Amount: $387,254
RFA: Air Quality (1996) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Description:APE SCIEX direct air sampling, atmospheric pressure ionization tandem mass spectrometer (API-MS/MS) will be used in conjunction with in situ Fourier transform infrared (FT-IR) spectroscopy, gas chromatography (GC-FID, GC-FTIR and GC-MS), and product derivatization with GC analyses to investigate the atmospherically important reactions of selected VOCs and of their reaction products. Specifically, it is planned to:
- Use a derivatization method, involving the conversion of alcohol -OH groups to the trimethylsilyl, (-OSi(CH3)3), group, to identify and quantify the _-hydroxycarbonyls formed in the OH radical-initiated reactions of isoprene and n-butane through n-octane, and the dihydroxycarbonyls formed from the OH radical reactions of 1-butene through 1-octane. The products of the OH radical-initiated reactions of a series of branched alkanes, and of the NO3 radical and O3 reactions with selected alkenes, will be investigated by analyses of the reaction products by API-MS/MS, in situ FT-IR absorption spectroscopy, and gas chromatography, with derivatization and GC analyses of hydroxy-carbonyls and hydroxynitrates. The studies of the straight and branched alkanes will provide quantitative data concerning the relative importance of isomerization, decomposition and reaction with O2 for alkoxy radicals in the troposphere.
- Investigate the atmospheric chemistry of hydroxycarbonyls formed from the alkanes and of dihydroxycarbonyls formed from alkenes, using API-MS/MS, in situ FT-IR absorption spectroscopy, and GC with and without derivatization. These experiments will include rate constant measurements as well as product studies of a series of commercially-available and/or synthesized ?-, _-, _- and _-hydroxycarbonyls. Also, investigate the products formed from selected carbonyl compounds, using gas chromatography, in situ FT-IR absorption spectroscopy and API-MS/MS.
- Investigate the products of the OH radical-initiated reactions of toluene, ethylbenzene and trimethylbenzenes in the presence and absence of NOx using API-MS/MS, in situ FT-IR absorption spectroscopy and gas chromatography. The atmospheric chemistry of the unsaturated dicarbonyls observed (by API-MS/MS) from the OH radical-initiated reactions of aromatic hydrocarbons will also be studied. Also, investigate the products of the gas-phase reactions of OH radicals and NO3 radicals with phenol and o-cresol, using primarily API-MS/MS.
The data obtained in this program will provide critically important information concerning the products formed, and their yields, from the gas-phase reactions of selected VOCs and of their first-generation reaction products with OH radicals, NO3 radicals and O3 under atmospheric conditions. This data will allow the formulation of more scientifically correct chemical mechanisms for inclusion into airshed models than is presently the case.