340-225-0090

Requirements for Demonstrating a Net Air Quality Benefit

Demonstrations of net air quality benefit for offsets must include the following:

(1) Ozone areas (VOC and NOx emissions). For sources capable of impacting a designated ozone nonattainment or maintenance area;

(a) Offsets for VOC and NOx are required if the source will be located within the designated area or within the Ozone Precursor Distance.

(b) The amount and location of offsets must be determined in accordance with this subsection:

(A)For new or modified sources locating within a designated nonattainment area, the offset ratio is 1.1:1. These offsets must come from within either the same designated nonattainment area as the new or modified source or another ozone nonattainment area (with equal or higher nonattainment classification) that contributes to a violation of the NAAQS in the same designated nonattainment area as the new or modified source.

(B) For new or modified sources locating within a designated maintenance area, the offset ratio is 1.1:1. These offsets may come from within either the designated area or the ozone precursor distance.

(C) For new or modified sources locating outside the designated area, but within the ozone precursor distance, the offset ratio is 1:1. These offsets may come from within either the designated area or the ozone precursor distance.

(D) Offsets from outside the designated area but within the Ozone Precursor Distance must be from sources affecting the designated area in a comparable manner to the proposed emissions increase. Methods for determining offsets are described in the Ozone Precursor Offsets definition (OAR 340-225-0020(11)).

(c) In lieu of obtaining offsets, the owner or operator may obtain an allocation at the rate of 1:1 from a growth allowance, if available, in an applicable maintenance plan.

(d) Sources within or affecting the Medford Ozone Maintenance Area are exempt from the requirement for NOx offsets relating to ozone formation.

(e) Sources within or affecting the Salem Ozone Maintenance Area are exempt from the requirement for VOC and NOx offsets relating to ozone formation.

(2) Non-Ozone areas (PM2.5, PM10, SO2, CO, NOx, and Lead emissions):

(a) For a source locating within a designated nonattainment area, the owner or operator must comply with paragraphs (A) through (E) of this subsection:

(A) Obtain offsets from within the same designated nonattainment area for the nonattainment pollutant(s);

(B) Except as provided in paragraph (C) of this subsection, provide a minimum of 1:1 offsets for each nonattainment pollutant and precursor with emission increases over the Netting Basis;

(C) For PM2.5; inter-pollutant offsets are allowed as follows:

(i) 1 ton of direct PM2.5 may be used to offset 40 tons of SO2;

(ii) 1 ton of direct PM2.5 may be used to offset 100 tons of NOx;

(iii) 40 tons of SO2 may be used to offset 1 ton of direct PM2.5;

(iv) 100 tons of NOx may be used to offset 1 ton of direct PM2.5.

(D) Provide a net air quality benefit within the designated nonattainment area. "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

(ii) For a small scale local energy project and any infrastructure related to that project located in the same area, a reduction of the nonattainment pollutant emissions equal to the ratio specified in this subsection, provided that the proposed major source or major modification would not cause or contribute to a violation of the national ambient air quality standard or otherwise pose a material threat to compliance with air quality standards in the nonattainment area.

(E) Provide offsets sufficient to demonstrate reasonable further progress toward achieving the NAAQS.

(b) For a source locating outside a designated nonattainment area but causing a significant air quality impact on the area, the owner or operator must provide offsets sufficient to reduce the modeled impacts below the significant air quality impact level (OAR 340-200-0020) at all receptors within the designated nonattainment area. These offsets may come from within or outside the designated nonattainment area.

(c) For a source locating inside or causing a significant air quality impact on a designated maintenance area, the owner or operator must either provide offsets sufficient to reduce modeled impacts below the significant air quality impact level (OAR 340-200-0020) at all receptors within the designated maintenance area or obtain an allocation from an available growth allowance as allowed by an applicable maintenance plan. These offsets may come from within or outside the designated maintenance area.

(A) Medford-Ashland AQMA: Proposed new major PM10 sources or major PM10 modifications locating within the AQMA that are required to provide emission offsets under OAR 340-224-0060(2)(a) must provide reductions in PM10 emissions equal to 1.2 times the emissions increase over the netting basis from the new or modified source, and must provide a net air quality benefit within the AQMA

. "Net Air Quality Benefit" means:

(i) A reduction in concentration at a majority of the modeled receptors and less than a significant impact level increase at all modeled receptors; or

Stat. Auth.: ORS 468.020
Stats. Implemented: ORS 468A.025

Hist.: DEQ 25-1981, f. & ef. 9-8-81; DEQ 5-1983, f. & ef. 4-18-83; DEQ 8-1988, f. & cert. ef. 5-19-88 (and corrected 5-31-88); DEQ 22-1989, f. & cert. ef. 9-26-89; DEQ 27-1992, f. & cert. ef. 11-12-92; DEQ 4-1993, f. & cert. ef. 3-10-93; DEQ 12-1993, f. & cert. ef. 9-24-93, Renumbered from 340-020-0260; DEQ 19-1993, f. & cert. ef. 11-4-93; DEQ 4-1995, f. & cert. ef. 2-17-95; DEQ 26-1996, f. & cert. ef. 11-26-96; DEQ 14-1999, f. & cert. ef. 10-14-99, Renumbered from 340-028-1970; DEQ 14-1999, f. & cert. ef. 10-14-99, Renumbered from 340-030-0111; DEQ 6-2001, f. 6-18-01, cert. ef. 7-1-01, Renumbered from 340-224-0090 & 340-240-0260; DEQ 11-2002, f. & cert. ef. 10-8-02; DEQ 12-2002(Temp), f. & cert. ef. 10-8-02 thru 4-6-03; Administrative correction 11-10-03; DEQ 1-2004, f. & cert. ef. 4-14-04; DEQ 1-2005, f. & cert. ef. 1-4-05; DEQ 3-2007, f. & cert. ef. 4-12-07; DEQ 10-2010(Temp), f. 8-31-10, cert. ef. 9-1-10 thru 2-28-11; Administrative correction, 3-29-11; DEQ 5-2011, f. 4-29-11, cert. ef. 5-1-11