Record Display for the EPA National Library Catalog

RECORD NUMBER: 7 OF 7

OLS Field Name OLS Field Data
Main Title Transition-Flow Reactor Tube for Measuring Trace Gas Concentrations.
Author Durham, J. L. ; Ellestad, T. G. ; Stockburger, L. ; Knapp, K. T. ; Spiller, L. L. ;
CORP Author Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Sciences Research Lab.
Year Published 1986
Report Number EPA/600/J-86/308;
Stock Number PB87-176699
Additional Subjects Gases ; Atmospheric composition ; Concentration ; Reactivity ; Aerosols ; Air pollution ; Nitric acid ; Reprints ; Dry deposition ; Transition flow reactor ; Acid precipitation
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB87-176699 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/21/1988
Collation 7p
Abstract
Dry deposition contributes significantly to the acidification of ecosystems. However, difficulties in measuring dry deposition of reactive gases and fine particles make routine direct monitoring impractical. An alternate approach is to use the 'concentration monitoring' method in which dry deposition is estimated from the product of measured concentration and estimated deposition velocity. A sampling system that performs over the period of 6 hours to 7 days, depending on atmospheric concentrations, has been developed. It consists of a Teflon cyclone to exclude particles larger than about 2 micrometers, selective solid adsorption media for reactive gases - some of which are sampled from a transition flow to avoid bias from particle evaporation, a particle filter, and a final gas adsorption filter to collect the remaining trace gas. Laboratory and field tests have shown that the sampler performs well for HNO3(g).