Use of available regional or national scale modeling applications that are suitable85 for

the local area,

! Use of other appropriate local modeling attainment demonstrations that include the

nonattainment area of interest,

! Use of photochemical source apportionment and/or process analysis modeling tools to

help explain why attainment is (or is not) demonstrated,

85 The resolution, emissions, meteorology, and other model inputs should be evaluated for
applicability to the local nonattainment area. Additionally, model performance of the regional
modeling for the local nonattainment area should be examined before determining whether the
regional model results are suitable for use in the local attainment demonstration.

Use of multiple air quality models / model input data sets (e.g., multiple meteorological

data sets, alternative chemical mechanisms or emissions inventories, etc.). For results to

be most relevant to the way we recommend models be applied in attainment

demonstrations, it is preferable that such procedures focus on the sensitivity of estimated

relative response factors (RRF) and resulting projected design values to the variations in

inputs or model formulations.

! Use of dispersion models to address primary PM2.5 contributions to monitors. In areas

with large spatial gradients of primary PM2.5, dispersion models are best suited to

characterizing the change in primary PM2.5 in the future. Areas that are relying on local

primary PM controls to reach attainment should submit a local area analysis as part of the

primary attainment demonstration. In other areas, a local area analysis may be useful as a

supplemental analysis.

! Application of the attainment test with alternative procedures compared to the default

recommendations in Sections 3, 4, and 5 of this guidance. Any alternate approaches

should be accompanied with a technical justification as to why the approach is

appropriate for the area in question and should be discussed with the appropriate 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


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