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OLS Field Name OLS Field Data
Main Title Prototype Concentration Monitor for Estimating Acidic Dry Deposition.
Author Durham, J. L. ; Ellestad, T. G. ;
CORP Author Environmental Sciences Research Lab., Research Triangle Park, NC.
Year Published 1984
Report Number EPA-600/D-84-147;
Stock Number PB84-201631
Additional Subjects Monitors ; Acidification ; Air pollution ; Concentration(Composition) ; Samplers ; Design criteria ; Laboratory equipment ; Field tests ; Sulfur dioxide ; Nitric acid ; Trace elements ; Dry deposition ; Ecosystems ; Precipitation washout ; Air pollution sampling
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB84-201631 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/23/1988
Collation 15p
Abstract Dry deposition contributes significantly to the acidification of the ecosystem. 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. To investigate sampling protocols for estimating the weekly averages of pollutant dry deposition, a sampler that performs over the period of about 0.25 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 an unstable transition flow to avoid bias from particle evaporation, and a particle filter. The sampler is the first reported application of unstable transition-flow mass transfer for the collection of trace atmospheric gases. Laboratory and limited field tests have shown that the sampler performs satisfactorily for HNO3(g) and SO2.
NTIS Title Notes Interim rept. Apr 83-Apr 84.
PUB Date Free Form Jun 84
Category Codes 14B; 68A
NTIS Prices PC A02/MF A01
Document Type NT
Cataloging Source NTIS/MT
Control Number 424416714
Origin NTIS
Type CAT