Ozone in western Washington forests and Douglas-fir seedling response

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:6028483

Basabe, III, F A

Ozone data from 7 urban and rural site and 11 sites in or adjacent to forested areas were used to determine the spatial and temporal patterns of ozone in western Washington forests. Maximum average hourly ozone concentrations in forested areas ranged from 130 to 196 ppb from 1985 to 1988. The highest ozone concentrations occurred downwind, i.e. to the southeast of Seattle, Washington and Vancouver, British Columbia. During this time period ozone levels in the urban areas were consistently lower than those in downwind forests. Vertical ozone profiles in a semi-closed canopy Douglas-fir forest located 50 kilometers southeast Seattle in 1986 and 1988 indicated that potentially phytotoxic ozone concentration occurred in the canopy and near the forest floor. Aircraft ozone measurements taken August and September 1988 indicated that relatively high ozone concentrations (80 to 167 ppb) during daylight hours (1100 to 1800 PST) were generally confined below temperature inversions at 900 m. Ozone profiles above the inversion layer were relatively uniform throughout the day compared to those at lower elevations. The daylight average at the highest elevation site was similar to that of a low elevation site, although higher ozone concentrations were observed at the lower site. Open top chamber studies which used simulated ozone concentrations similar to those occurring in the highest ozone episode in 1988 caused reductions in photosynthesis and leaf conductance. Temperature caused the greatest reduction in photosynthesis and leaf conductance and the combined effects of temperature and ozone were synergistic. Phytotoxic ozone episodes may have occurred in some western Washington forests for at least 15 years.

• Research Organization: Washington Univ., Seattle, WA (United States)
• OSTI ID: 6028483
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
FORESTS
BIOLOGICAL EFFECTS
OZONE
ECOLOGICAL CONCENTRATION
SEEDLINGS
BRITISH COLUMBIA
FIRS
PHOTOSYNTHESIS
TEMPERATURE INVERSIONS
TREES
URBAN AREAS
WASHINGTON
CANADA
CHEMICAL REACTIONS
CONIFERS
DEVELOPED COUNTRIES
NORTH AMERICA
PHOTOCHEMICAL REACTIONS
PINOPHYTA
PLANTS
SYNTHESIS
USA
560300* - Chemicals Metabolism & Toxicology