Record Display for the EPA National Library Catalog
RECORD NUMBER: 4 OF 1132
|OLS Field Name||OLS Field Data|
|Main Title||A Chamber and modeling study to assess the photochemistry of formaldehyde /|
|Author||Jeffries, H. E. ; Sexton, K. G. ; Arnold, J. R. ; Bai, Y. ; Li., J. L.|
|CORP Author||North Carolina Univ. at Chapel Hill. School of Public Health.;Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Research and Exposure Assessment Lab.|
|Publisher||U.S. Environmental Protection Agency, Atmospheric Research and Exposure Assessment Laboratory,|
|Subjects||Formaldehyde--Measurement. ; Formaldehyde--Analysis.|
|Additional Subjects||Atmospheric chemistry ; Formaldehyde ; Photochemical reactions ; Assessments ; Test chambers ; Mathematical models ; Reaction kinetics ; Calibrating ; Sampling ; Gas analysis ; Quality assurance ; Performance evaluation ; Spectrophotometry ; Colorimetric analysis ; Air pollution detection ; Chemical reaction mechanisms ; Fluorimeters|
|Collation||313 pages ; 28 cm|
A new analytical method for formaldehyde (HCHO) was implemented for use in the UNC outdoor smog chamber. HCHO measurements obtained with this method were compared with those obtained using other analytical techniques. Six different calibration standards for HCHO were found to agree within + or -2%, and the different HCHO analytical methods had precisions of + or -10%. New experiments in which HCHO was produced chemically were performed. An explicit chemical reaction mechanism for ethene and propene was formulated to explain the chamber observations. The ethene mechanism showed excellent agreement with the observed data; the propene mechanism, however, did not perform as satisfactory. A comparison of these explicit mechanisms with the Carbon Bond IV (CB4) mechanism showed excellent agreement for ozone (<10% error), nitrogen oxides, and hydrocarbon oxidation rates; the CB4, however, consistently underpredicted the HCHO maximum by about 13%. An analysis of a simulation of an urban scenario showed that chemical production of HCHO was the dominant factor governing afternoon HCHO concentrations. Ethene and other olefins were the source of 58-62% of the HCHO produced and aromatics were responsible for 10-12%. It was concluded that the CB4 mechanism can be used to predict ambient HCHO levels with an error of about 20%.
Caption title. "Final report February 1988 - February 1990." "July 1990." "EPA/600/3-90/052." Microfiche.