Observational models. Receptor models are potentially useful for flagging potential
importance of local sources, if any, in influencing measurements made in a Class I area. This
could lead to a refined treatment of a local source, either through a more finely resolved nested
grid model application or plume-in-grid modeling. Trajectory models may also be useful for
identifying the types of meteorological conditions most often corresponding to observed “worst”
and “best” visibility in various Class I areas. This, in turn, may enable States to draw inferences
about the orientation of areas containing sources most likely to influence visibility in a Class I
area on days with “poor” and “good” visibility. Grid model based techniques such as tagging,
DDM, or source apportionment may also be useful in identifying areas and emissions sources
most responsible for visibility impairment on the worst or best days.
Refinements to the recommended uniform rate of progress analysis. If a strategy for
meeting the glidepath appears generally successful, but the glidepath is not met in a limited
number of Class I areas, States may consider refining the recommended uniform rate of progress
analysis in some manner. Refinements are best made if they are based on local
observations/analyses which suggest that some of the underlying assumptions in the
recommended assessment may not be applicable. We list some potential refinements which
could be considered. The list is intended to illustrate types of additional analyses which could be
- Use an alternative light extinction equation such as the revised IMPROVE equation or
an area-specific version.
-Available speciated data and other information may be reviewed to see whether the
outcome of the test is being influenced by including one or more days with extraordinary
events (e.g., a nearby major forest fire lasting a number of days or transported dust
events). If convincing arguments can be made that the event is a “natural” one,
excluding these days from the calculations should be discussed with the appropriate U.S.
EPA regional office.
n701 - n702 - n703 - n704 - n705 - n706 - n707 - n707 - n709 - n710 - n711 - n712 - n713 - n714 - n715 - n716 - n717 - n718 - n719 - n720 - n721 - n722 - n723 - n724 - n725 - n726 - n727 - n728 - n729 - n730 - n731 - n732 - n733 - n734 - n735 - n736 - n737 - n738 - n739 - n740 - n741 - n742 - n743 - n744 - n745 - n746 - n747 - n748 - n749 - n750
castellano: DISPER CUSTIC DESCAR RADIA italiano:
deutsch: DIS CUS DES RAD
castellano: DIS CUS DES RAD english: DIS CUS DES RAD
português: DIS CUS DES RAD italiano: DIS CUS DES RAD
français: DIS CUS DES RAD