Causes of haze in the Columbia River Gorge

Journal Article · Wed Aug 15 00:00:00 EDT 2007 · Journal of the Air and Waste Management Association

OSTI ID:20939554

Green, Mark; Xu, Jin ^[1]

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1. Desert Research Institute, Reno, NV (United States)

Visibility impairment in the Columbia River Gorge National Scenic Area is an area of concern. A field study conducted from July 2003 to February 2005 was followed by data analysis and receptor modeling to better understand the temporal and spatial patterns of haze and the sources contributing to the haze in the Columbia River Gorge in the states of Washington and Oregon. The nephelometer light scattering and surface meteorological data at eight sites along the gorge showed five distinct wind patterns, each with its characteristic diurnal and spatial patterns in light scattering by particles (b{sub sp}). In summer, winds were nearly always from west to east (upgorge) and showed decreasing b{sub sp} with distance into the gorge and a pronounced effect of the Portland, OR, metropolitan area on haze, especially in the western portions of the gorge. Winter often had winds from the east with very high levels of b{sub sp}, especially at the eastern gorge sites, with sources east of the gorge responsible for much of the haze. The major chemical components responsible for haze were organic carbon, sulfate, and nitrate. Positive matrix factorization (PMF) using chemically speciated Interagency Monitoring of Protected Visual Environments data indicated seven source factors in the western gorge and five factors in the eastern gorge. Organic mass is a large contributor to haze in the gorge in all seasons, with a peak in fall. Approximately half of the organic mass is biomass smoke, with mobile sources as the second largest contributor. PMF analysis showed nitrates mainly attributed to a generic secondary nitrate factor. Sulfate is a significant contributor in all seasons, with peak sulfate concentrations in summer. Sources east of the gorge, likely a coal-fired power plant, nearby dairy farm, and upriver cities, appear to be major contributors to wintertime haze in the gorge. 22 refs., 11 figs., 6 tabs.

• OSTI ID: 20939554
• Journal Information: Journal of the Air and Waste Management Association, Vol. 57, Issue 8; Other Information: [e-mail]; ISSN 1047-3289
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
USA
COLUMBIA RIVER
VALLEYS
POLLUTION SOURCES
VISIBILITY
AIR POLLUTION
MATHEMATICAL MODELS
WASHINGTON
OREGON
MOUNTAINS
PARTICULATES
AEROSOLS
BIOMASS
WOOD FUELS
SULFATES
NITRATES
VEHICLES
FIRES
SEASONAL VARIATIONS
FUEL OILS
COAL
INDUSTRIAL PLANTS
SMOG
FOSSIL-FUEL POWER PLANTS
PAPER INDUSTRY
SPATIAL DISTRIBUTION
AIR POLLUTION MONITORING
WIND
ENVIRONMENTAL TRANSPORT
CARBON
LIGHT SCATTERING
CARBONACEOUS MATERIALS
DATA ANALYSIS