A 13-week comparison of passive and continuous ozone monitors at forested sites in north-central Pennsylvania

John M. Skelly, James E. Savage

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Ogawa passive O3 samplers were used in a 13-week study (June 1-September 1, 1999) involving 11 forested and mountaintop sites in north-central Pennsylvania. Four of the sites were collocated with TECO model 49 O3 analyzers. A significant correlation (p < 0.0001) was found for 24-hr average weekly O3 concentrations between the two methodologies at the four sites with collocated monitors. As expected, there were positive relationships between increasing elevation of the sites and increasing O3 concentrations. No O3 exposure patterns were found on a west-to-east or south-to-north basis; however, the area known for lower O3 exposures within a smaller subsection of the study area showed consistently lower O3 exposures. Preliminary results regarding relationships of symptom responses within O3-sensitive bioindicators are also presented with black cherry (Prunus serotina, Ehrh.) and common milkweed (Asclepias syriaca, L.) showing clear evidence of increasing injury with increasing O3 exposures. Due to the extremely dry conditions encountered in north-central Pennsylvania during the 1999 growing season, O3-induced symptoms were sporadic and quite delayed until late-season rains during the latter portion of the observation period.

Original languageEnglish (US)
Pages (from-to)1280-1287
Number of pages8
JournalJournal of the Air and Waste Management Association
Issue number9
StatePublished - Sep 2001

All Science Journal Classification (ASJC) codes

  • Waste Management and Disposal
  • Pollution
  • Atmospheric Science
  • Management, Monitoring, Policy and Law


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