Record Display for the EPA National Library Catalog

RECORD NUMBER: 694 OF 2622

OLS Field Name OLS Field Data
Main Title DOAS Urban Pollution Measurements.
Author Stevens, R. K. ; Vossler, T. L. ;
CORP Author Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Research and Exposure Assessment Lab.
Publisher 1991
Year Published 1991
Report Number EPA/600/D-91/044;
Stock Number PB91-176966
Additional Subjects Air pollution detection ; Urban areas ; Gas analysis ; Xylenes ; Absorption spectroscopy ; Pollution sources ; Exhaust emissions ; Chemical analysis ; Gas chromatography ; Concentration(Composition) ; Toluene ; Benzene ; Ammonia ; Nitrogen oxide(NO) ; Air pollution sampling ; Ozone ; Sulfur dioxide ; Nitrogen dioxide ; Nitrous acid ; Formaldehyde ; Differential optical absorption spectrometers
Holdings
Library Call Number Additional Info Location Last
Modified
Checkout
Status
NTIS  PB91-176966 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 09/04/1991
Collation 13p
Abstract
During July and August of 1990, a differential optical absorption spectrometer (DOAS) made by OPSIS Inc. was used to measure gaseous air pollutants over three separate open paths in Atlanta, GA. Over path 1 (1099 m) and path 2 (1824 m), ozone (O3), sulfur dioxide (SO2), nitrogen dioxide (NO2), nitrous acid (HNO2), formaldehyde (HCHO), benzene, toluene, and o-xylene were measured. Nitric oxide (NO) and ammonia (NH3) were monitored over path 3 (143 m). The data quality and data capture depended on the compound being measured and the path over which it was measured. Benzene, toluene, and o-xylene concentrations measured over path 2, which crossed over an interstate highway, were higher than concentrations measured over path 1, implicating emissions from vehicles on the highway as a significant source of these compounds. Federal Reference Method (FRM) instruments and a gas chromatograph (GC) were located near the DOAS light receivers and operated concurrently. Correlation coefficients greater than 0.85 were obtained between the DOAS and FRM's for O3, NO2, and NO; however, there was a difference between the mean values obtained by the two methods for O3 and NO. Correlation coefficients of about 0.66 were obtained between the DOAS and GC measurements of benzene and o-xylene. However, the correlation coefficient between the DOAS and GC measurements of toluene averaged only 0.15 for the two DOAS measurement paths. The lack of correlation and other factors indicate the possibility of a localized source of toluene near the GC.