Document Detail

Causes of haze in the Columbia River Gorge.
MedLine Citation:
PMID:  17824285     Owner:  NLM     Status:  MEDLINE    
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 (bsp). In summer, winds were nearly always from west to east (upgorge) and showed decreasing bsp 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 bsp, 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. The PMF analysis suggests that approximately half of the organic mass is biomass smoke, with mobile sources as the second largest contributor. PMF analysis showed nitrates (important in fall and winter) mainly attributed to a generic secondary nitrate factor, with the next largest contributor being oil combustion at Mt. Zion, WA and mobile sources at Wishram, WA. Sulfate is a significant contributor in all seasons, with peak sulfate concentrations in summer.
Mark Green; Jin Xu
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of the Air & Waste Management Association (1995)     Volume:  57     ISSN:  1096-2247     ISO Abbreviation:  J Air Waste Manag Assoc     Publication Date:  2007 Aug 
Date Detail:
Created Date:  2007-09-10     Completed Date:  2007-10-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9503111     Medline TA:  J Air Waste Manag Assoc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  947-58     Citation Subset:  IM    
Desert Research Institute, Reno, NV 89512, USA.
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MeSH Terms
Air Pollutants / analysis*,  chemistry*
Air Pollution / analysis*
Particulate Matter / analysis,  chemistry
Time Factors
Reg. No./Substance:
0/Air Pollutants; 0/Particulate Matter

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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