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RECORD NUMBER: 126 OF 526

OLS Field Name OLS Field Data
Main Title Co-Occurrence of Potentially Phytotoxic Concentrations of Various Gaseous Air Pollutants.
Author Lefohn, A. S. ; Tingey, D. T. ;
CORP Author Corvallis Environmental Research Lab., OR. ;ASL and Associates, Helena, MT.
Year Published 1984
Report Number EPA/600/J-84/245;
Stock Number PB85-177848
Additional Subjects Air pollution ; Exposure ; Ozone ; Sulfur dioxide ; Nitrogen dioxide ; Vegetation ; Concentration(Composition) ; Sampling ; Sites ; Assessments ; Experimental design ; Reprints ; Air quality ; Air pollution effects(Plants)
Holdings
Library Call Number Additional Info Location Last
Modified
Checkout
Status
NTIS  PB85-177848 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 8p
Abstract
Studies on impacts of air pollutants on vegetation have focused primarily on individual pollutants: ozone, sulfur dioxide and nitrogen dioxide. The impacts of pollutant combinations have not been extensively studied and there has been no concerted effort to ensure that experimental regimes for combined pollutant exposures are representative of ambient pollutant concentration, frequency, duration and time intervals between events. Most studies concerning the impact of pollutant combinations on vegetation have used concentrations of 0.05 ppm and greater. Therefore, co-occurrence was defined as the simultaneous occurrence of hourly averaged concentrations of 0.05 ppm or greater for pollutant pairs (SO2/NO2, O3/SO2, or O3/NO2). Air quality information from three data bases (EPA-SAROAD, EPRI-SURE and TVA) was analyzed to determine the frequency of co-occurrence for pollutant pairs. Ambient air quality data representing a diverse range of monitoring sites (e.g. rural, remote, city center, urban near urban, etc.) were used in the analysis. Results showed that at most sites (1) the co-occurrence of two-pollutant mixtures lasted only a few hours per episode, (2) the time interval between episodes was generally large (weeks, sometimes months) and (3) most studies have used more intense exposure regimes than occurred at most monitored sites. When designing vegetation experiments for assessing pollutant mixture effects, it may be desirable to give greater emphasis to sequential patterns of exposure. (Copyright (c) 1984 Pergamon Press Ltd.)