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Title: Consideration of air quality standards for vegetation with respect to ozone

Conference ·
OSTI ID:6469772

There is an increasing body of evidence that ozone is the most damaging of all air pollutants affecting vegetation. It is the principal oxidant in the photochemical smog complex. Concentrations measured with an ultraviolet photometer, considered specific for ozone, have exceeded 0.5 part per million (ppM) in the Los Angeles area. Only one-tenth of this level, or 0.05 ppM, for 8 hours is known to injure very sensitive tobacco varieties. Studies in several laboratories show that a broad spectrum of plant species is visibly affected after a few hours exposure at concentrations much lower than 0.5 ppM. There is also some evidence that ozone reduces plant growth. Many factors must be taken into account in considering standards for possible use in the protection of vegetation from ozone damage. These include ozone concentration and methods of measurement, time of exposure, possible additive effects of other pollutants, sensitivity of species to ozone, their economic value, and the extent of injury which can be tolerated. The response of a species to the pollutant is conditioned by genetic factors and environmental conditions. The lack of routine, specific methods for measuring ozone in ambient air is a handicap. California and Colorado established standards for oxidants at 0.15 ppM and 0.10 ppM, respectively, for 1 hour. How these standards relate to the dosage of ozone that causes acute and chronic injury to various plant species is discussed. 28 references.

OSTI ID:
6469772
Report Number(s):
CONF-680679-
Resource Relation:
Conference: Air pollution control association annual convention, St. Paul, MN, USA, 23 Jun 1968
Country of Publication:
United States
Language:
English