Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Robert C. Musselman; Allen S. Lefohn; William J. Massman; Robert L. Heath
    Date: 2006
    Source: Atmospheric Environment. 40: 1869-1888.
    Publication Series: Scientific Journal (JRNL)
    Station: Rocky Mountain Research Station
    PDF: Download Publication  (481.91 KB)


    Early studies of plant response to ozone (O3) utilized concentration-based metrics, primarily by summarizing the commonly monitored hourly average data sets. Research with the O3 concentration parameter led to the recognition that both peak concentrations and cumulative effects are important when relating plant response to O3. The US and Canada currently use O3 concentration-based (exposure-based) parameters for ambient air quality standards for protecting vegetation; the European countries use exposure-based critical levels to relate O3 to vegetation response. Because plant response is thought to be more closely related to O3 absorbed into leaf tissue, recent research has been focused on fluxbased O3 parameters. Even though flux-based indices may appear to be more biologically relevant than concentrationbased indices, there are limitations associated with their use. The current set of flux-based indices assumes that the plant has no defense mechanism to detoxify O3. This is a serious limitation. In this paper, we review the literature on exposureand flux-based indices for predicting plant response. Both exposure- and flux-based metrics may overestimate plant response. At this time, flux-based models that take into consideration detoxification mechanisms (referred to as effective flux) provide the best approach to relate O3 to plant response. However, because there is considerable uncertainty in quantifying the various defense mechanisms, effective flux at this time is difficult to quantify. Without adequate effectiveflux based models, exposure-based O3 metrics appear to be the only practical measure for use in relating ambient air quality standards to vegetation response.

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Musselman, Robert C.; Lefohn, Allen S.; Massman, William J.; Heath, Robert L. 2006. A critical review and analysis of the use of exposure- and flux-based ozone indices for predicting vegetation effects. Atmospheric Environment. 40: 1869-1888.


    dose, effective flux, nocturnal, threshold, uptake

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page