George’s edits in rl/so:

(4) Except as provided in sections (5) and (6), the owner or operator must conduct an air quality analysis of the total impacts from the proposed new emissions as specified in subsections (a) through (d):

(a) The air quality analysis must comply with OAR 340-225-0030 and 340-225-0040;

(b) The air quality analysis must use a uniform receptor grid over the entire modeled area for the analyses required in subsections (c) and (d), except that different grid spacing may be approved for the analyses in subsections (c) and (d);

(c) Demonstrate that the offsets obtained result in a reduction in concentrations at a majority of modeled receptors within the entire designated area; and

(d) Comply with paragraph (A) or paragraphs (B) and (C):

(A) Using a single-source analysis, demonstrate that the impacts from the emission increases above the source’s netting basis are less than the Class II SIL at all receptors within the designated area; or

(B) Using a single-source analysis, demonstrate that the impacts from the emission increases above the source’s netting basis are less than the Class II SIL at an average of receptors within an area designated by DEQ as representing a neighborhood scale, as specified in 40 CFR part 58, Appendix D, a reasonably homogeneous urban area with dimensions of a few kilometers that represent air quality where people commonly live and work in a representative neighborhood, centered on the DEQ approved ambient monitoring sites; and

(C) Demonstrate that the impacts of the emission increases above the source’s netting basis, plus the impacts of emission increases or decreases since the date of the current area designation of all other sources within the designated area or having a significant impact on the designated area, are less than 10 percent of the AAQS at all receptors within the designated area, determined as follows:

(i) Subtract priority source offsets from the new or modified source’s emission increase if the priority sources are area sources. Area source emissions are spatially distributed emissions that can be generated from activities such as, but not limited to, residential wood heating, unpaved road dust, and non-road mobile sources;

(ii) If the source’s emissions are not offset 100 percent by priority sources that are area sources, conduct dispersion modeling of the source’s remaining emission increases after subtracting any priority source offsets allowed in subparagraph (i); and in addition, model all other sources with emission increases or decreases in or impacting the designated area since the date the area was designated, including offsets used for the proposed project, but excluding offsets from priority sources that are area sources; and

(iii) If the source’s emissions are offset 100 percent by priority sources that are area sources, no further analysis is required.

jinahar, 2015-01-28T09:23:00Z
The whole NAA or sustainment area or whatever area?

gdavis, 2015-01-28T09:17:00Z
Can the source subtract priority/area source emissions?

The way this is written, subtraction is only allowed for (C), not (B).

If source can subtract for (B), this needs to be restructured.

(B) is a single-source analysis, yes?