Canadian Forest Service Publications

The North American ozone air quality standard: efficacy and performance with two northern hardwood forest tree species. 2006. Percy, K.E.; Nosal, M.; Heilman, W.; Dann, T.; Sober, J.; Karnosky, D.F. Pages 85-90 in G. Wieser and M. Tausz, editors., Proceedings: UN-ECE Critical Levels of Ozone: Further Applying and Developing the Flux-based Concept. November 14-19, 2005, Obergurgl, Tyrol, Austria. Federal Research and Training Center for Forests, Natural Hazards and Landscape (BFW), Vienna, Austria.

Year: 2006

Issued by: Atlantic Forestry Centre

Catalog ID: 26574

Language: English

Availability: Order paper copy (free)

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In many forested regions of North America, background ozone levels have been rising despite the fact that hourly maximum concentrations have been decreasing. Unlike Europe, where critical levels based on a response threshold are used to assess risk, Canada and the United States use the best available scientific knowledge balanced by social, economic and political considerations to establish ambient air quality standards for air quality compliance purposes. These ambient air quality standards do not assume the existance of a concentration threshold. The United States (1997) and Canada (2000) established the ozone standard as the 3-year average of the annual fourth highest daily maximum 8-hour ozone concentrations, with target values set at 65 ppb and 80 ppb, respectively. Here we use 5 years of basal area growth in one control and one ozone Aspen FACE ring to evaluate the performance of five ozone indices, including AOT40 and the North American air quality standard. With our data, this standdard outperformed AOT40, SUM60, SUM00 and 1-hour maximum as a single predictor of growth response. We also evaluate the potential of a standard-based, simple dose response function developed from Aspen FACE to predict productivity in Populus tremuloides and Betula papyrifera.