The
Regional Haze Rule requires states to set "Reasonable Progress
Goals" toward improving visibility in the nation's national
parks and wilderness areas. The goal envisioned by the drafters
of the Regional Haze Rule is that visibility in Class I areas will
return to natural conditions within 60 years. The Regional Haze
Rule requires states to develop 10-year plans to demonstrate progress
toward that goal.
Visibility
data are collected through the Interagency Monitoring of Protected
Visual Environments monitoring network (IMPROVE). The IMPROVE data
are analyzed to determine three parameters, which in turn help determine
the reasonable progress goals for the area and are used to evaluate
progress in meeting those goals. Learn
more about how visibility is measured.
The parameters
are
•
Baseline conditions.
Data collected from 2001 and 2004 were analyzed to determine types
and sources of air pollution and overall visibility on the clearest
and haziest days, representing air quality conditions at the start
of the regional haze program.
•
Current conditions. Every
year, the most recent five-year block of data is analyzed to determine
types and sources of pollution on both the 20% clearest and 20%
haziest days. Current conditions are compared to baseline data to
measure progress toward improving visibility and meeting the goals
of the regional haze program.
•
Estimate of natural visibility
conditions. All data are analyzed to try to
determine the natural visibility possible in the absence of human-caused
impairment. Reasonable progress goals are set on the basis of this
potential for clarity.
For each
mandatory Class I federal area within the state, Idaho must establish
goals (expressed in deciviews)
that provide for reasonable progress toward achieving natural visibility
conditions. The reasonable progress goals must provide for an improvement
in visibility for the haziest days over the period of the implementation
plan and ensure no degradation in visibility for the clearest days
over the same period. |
