Record Display for the EPA National Library Catalog


Main Title Potential Bias from Non-Continuous Monitoring of Ambient Ozone Concentrations for Characterizing Hourly and Daily 7- and 12-Hour Average Concentrations.
Author Lefohn, A. S. ; McEvoy, L. R. ; Tingey, D. T. ; Sebaugh, J. L. ; Hogsett, W. E. ;
CORP Author A.S.L. and Associates, Helena, MT. ;Sebaugh's Information Services, Lake Ozark, MO.;Corvallis Environmental Research Lab., OR.
Publisher c1993
Year Published 1993
Report Number EPA-68-03-3225; EPA/600/J-93/156;
Stock Number PB93-191534
Additional Subjects Ozone ; Air pollution monitoring ; Air pollution sampling ; Study estimates ; Concentration(Composition) ; Bias ; Quality control ; Data quality ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB93-191534 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 9p
The authors investigated the uncertainties associated with limited sampling to characterize (1) hourly average and (2) daily 7- and 12-h average O3 concentrations. As expected, accuracy increased with increased sampling; over- and under-estimation of hourly values was directly related to whether the actual concentrations were increasing, decreasing or stable from one hour to the next. When non-continuous sampling was used at sites experiencing small changes from one hour to the next, more than 85 and 60% of the estimated hourly average values were within + or - 5 and + or - 2.5 ppb of the actual values, respectively. For a site where average O3 concentrations changed rapidly from one hour to the next, a greater error was observed. For the daily 7- and 12-h average values, when hourly average concentrations did not change rapidly from one hour to the next, 85% or more of the estimated values agreed within + or - 2 ppb, independent of sampling frequency. Greater uncertainty was experienced when hourly average concentrations changed at a faster rate. When considering the uncertainties associated with non-continuous sampling, investigators should specify the level of accuracy needed to characterize hourly average concentrations and then select the number of samples per hour required to meet that objective. (Copyright (c) 1993 Pergamon Press Ltd.)