additional uncertainty into the model results (compared to modeling a full year). The conclusion
from the study was that at least 14 days are needed to represent each quarter. This assumes that
the model results are being used in a relative sense. The study also found that nitrate is the most
difficult of the species to adequately represent with a reduced number of modeling days.
Based on current information, for annual average PM2.5, we recommend modeling a full
year (or more). Reduced modeling of 15 or more days per quarter100 may be acceptable in some
cases, but areas where nitrate is an important component of PM2.5 should consider modeling a
full year (or at least the time periods when nitrates are high). Modeling less than a full year (e.g.
one month per quarter) can be useful for initial strategy development and sensitivity analyses. In
this way, information can be learned from partial year runs and can be supplemented with full
year model runs later in the process. This may save resources and allow more model runs to be
completed (relatively) quickly.
14.1.4 Regional Haze
The goals for regional haze focus on the 20% of days with best and worst visibility.
Sampling in Class I areas occurs once every three days. Thus, each year there will be about 24
“worst” days and 24 “best” days to choose from. Since the base period against which reasonable
progress is to be gauged is 5 years long, there could be as many as 120 “best” and “worst” days
to choose among for modeling.
n751 - n752 - n753 - n754 - n755 - n756 - n757 - n758 - n759 - n760 - n761 - n762 - n763 - n764 - n765 - n766 - n767 - n768 - n769 - n770 - n771 - n772 - n773 - n774 - n775 - n776 - n777 - n778 - n779 - n780 - n781 - n782 - n783 - n784 - n785 - n786 - n787 - n788 - n789 - n790 - n791 - n792 - n793 - n794 - n795 - n796 - n797 - n798 - n799 - n800
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