"Net Air Quality Benefit" means:

(i) Offsets obtained result in a reduction in concentration at a majority of the modeled receptors and the emission increases from the proposed source or modification will result in less than a significant impact level increase at all modeled receptors; or

2 sources that were trying to provide NAQB: Dry Creek Landfill in Medford and Klamath Falls biomass facility, located in PM2.5 NAA.

Basis for language in Division 225:

Talked with Dave Bray about this who has better understanding on this way back when. Tried to work to match EPA’s intent.

PA: 2 tests:

1) offsets result in a reduction at the majority of modeled receptors –looking at a number of receptors

2) concentrations at less than SIL at all modeled receptors – look at concentration

Can we interpret “all” as all modeled receptors, interpreted as EACH. If we can interpret “all” an average, we could average modeled receptors (above and below) then. Should be each receptor, not an average.

Cannot find an example of when it was applied. Offsets make Pat ill and are too old. If we give up this dead horse, we can all breathe. Offsets are phony: getting rid of landfill emissions and offset with new incinerator, plants that died years ago that still had permit and offset with new source.

When language first came into rule when? Lloyd Kostow wrote in 70s or early 80s, Pat revised in 90s. When Pat revised, went over extensively with Dave Bray. Cannot have a NAQB at every receptor! Cannot have an offsetting source in the same area, still in AQMA but still technically able to build and use offsets. Intent to have in same airshed.

No language in CFRs, just offsets, potential we could simplify our rule and makes it simpler to apply. Relax a rule that cannot be used? Stacks cannot be co-located. Receptors around one plant and around another plant and model. The second test where you have to look at each and every receptor and show value below SIL….highly improbable. Put in to make it easier, not harder.

Modeled receptors at new plant, with negative contribution from offsetting source, below SIL? No, that’s not what it says…Pat.

Pat reads as OR. The first part says majority show benefit. OR being less than SIL. Either one would satisfy. But the rule says AND.

Unless same stack from new and offsetting source, very difficult to make test.

The other option would be if new source would have impact less than SIL but then you wouldn’t need offsets.

Would this be viewed as a relaxation if it’s a demonstration that can’t be made? Pat did with 2 different facilities….proposed garbage burner in OR City and wood facility in Medford.

Contemporaneous and like emissions for offsets. Road dust (fraction PM2.5)?

Dave Kauth: Intent is to improve AQ. Need to offset to create a benefit. Makes sense to require but cannot attain if not co-located. Needs to happen to get area back into attainment. Most of them are within or the average is within attainment, then could just offset. Offset average so average impact is significant.