Tribal Assessment: Phase I
Scope of Work
DRI has addressed the causes of haze at each tribal area within the member
states in the Western Regional Air Partnership and Nevada. The results of
the study are documented in the form of this web page, posted on the Causes
of Haze web site. Every tribal area in the WRAP region has an
entry on the web site, with links to the analysis for that area or to other
sites deemed to be representative of that tribal land.
Task 1: Class I Causes of Haze Analysis
For each of the 6 tribal class I areas, DRI has completed a full causes
of haze assessment, equivalent to that being performed for the mandatory
Federal class I areas. This includes: |
detailed descriptions of aerosol composition and reconstructed extinction; |
assessment of IMPROVE protocol monitoring sites for representativeness of
Tribal class I areas; |
evaluation of meteorology at local and regional scales; |
description of nearby and regional emissions sources; |
use of backtrajectory analysis to infer source regions affecting sites for
good, average, and poor visibility days; |
detailed episode analysis to better understand sources for specific poor
visibility days; |
Formation and documentation of conceptual models explaining the causes of
haze at Tribal class I areas; |
Refinement of conceptual models based upon detailed meteorological
analysis and/or receptor modeling as necessary and possible; |
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Task 2: Representativeness Assessment
For the remaining tribal lands within the WRAP region and Nevada, DRI
has used professional judgment to assess the representativeness of existing IMPROVE or IMPROVE protocol monitors for each
tribal area. We have considered factors such as: |
distance from monitoring site; |
intervening topography; |
location with respect to mesoscale meterological patterns; |
location with respect to emissions sources such as industrial sources,
urban areas, etc. |
Each tribal area has an entry in the causes of haze page that links to
the results for the IMPROVE or IMPROVE protocol site for which it is
represented. In some cases, when tribal land is located intermediate between
multiple IMPROVE sites the causes of haze may be estimated as some
combination of the sources affecting the IMPROVE sites.
Task 3: Recommendations
DRI has recommended general locations for additional monitoring with
IMPROVE monitors at tribal areas as deemed necessary to have a reasonable
representation of each tribal areas aerosol composition.
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