OAR 340-225-0020
Definitions
(1)
“Allowable emissions” means the emissions rate of a stationary source calculated using the maximum rated capacity of the source (unless the source is subject to federally enforceable limits which restrict the operating rate, or hours of operation, or both) and the most stringent of the following:(a)
The applicable standards as set forth in 40 CFR parts 60, 61, 62 and 63;(b)
The applicable SIP emissions limitation, including those with a future compliance date; or(c)
The emissions rate specified as a federally enforceable permit condition.(2)
“Baseline concentration” means:(a)
Except as provided in subsection (c), the ambient concentration level for sulfur dioxide and PM10 that existed in an area during the calendar year 1978. Actual emission increases or decreases occurring before January 1, 1978 must be included in the baseline calculation, except that actual emission increases from any major source or major modification on which construction commenced after January 6, 1975 must not be included in the baseline calculation;(b)
The ambient concentration level for nitrogen oxides that existed in an area during the calendar year 1988.(c)
For the area of northeastern Oregon within the boundaries of the Umatilla, Wallowa-Whitman, Ochoco, and Malheur National Forests, the ambient concentration level for PM10 that existed during the calendar year 1993. DEQ may allow the source to use an earlier time period if DEQ determines that it is more representative of normal emissions.(d)
For PM10 in the Medford-Ashland AQMA: the ambient PM10 concentration levels that existed during the calendar year 2006, the year that EPA redesignated that AQMA to attainment for PM10.(e)
The ambient concentration level for PM2.5 that existed in an area during the calendar year 2007.(f)
If no ambient air quality data is available in an area, the baseline concentration may be estimated using modeling based on actual emissions for the years specified in subsections (a) through (e).(3)
“Baseline concentration year” means the calendar year used to determine the baseline concentration for a particular regulated pollutant in a particular designated area.(4)
“Competing PSD increment consuming source impacts” means the total modeled concentration above the modeled baseline concentration resulting from increased and decreased emissions of all other sources since the baseline concentration year that are expected to cause a significant concentration gradient in the vicinity of the source. Determination of significant concentration gradient may take into account factors including but not limited to ROI formula, spatial distribution of existing emission sources, topography, and meteorology. Allowable emissions may be used as a conservative estimate of increased emissions, in lieu of actual emissions, in this analysis.(5)
“Competing AAQS source impacts” means total modeled concentrations of the subject pollutant resulting from allowable emissions of all other sources expected to cause a significant concentration gradient in the vicinity of the source or sources under consideration. Determination of significant concentration gradient may take into account factors including but not limited to ROI formula, spatial distribution of existing emission sources, topography, and meteorology.(6)
“FLAG” refers to the Federal Land Managers’ Air Quality Related Values Work Group Phase I Report — REVISED, published at 75 Federal Register 66125, Oct. 27, 2010.(7)
“General background concentration” means impacts from natural sources and unidentified sources that were not explicitly modeled, and may be determined based on either site-specific ambient monitoring or, with DEQ approval, on representative ambient monitoring from another location.(8)
“Nitrogen deposition” means the sum of anion and cation nitrogen deposition expressed in terms of the mass of total elemental nitrogen being deposited. As an example, nitrogen deposition for NH4NO3 is 0.3500 times the weight of NH4NO3 being deposited.(9)
“Predicted maintenance area concentration” means the future year ambient concentration predicted by DEQ in the applicable maintenance plan as follows:(a)
The future year (2015) PM10 concentrations for the Grants Pass UGB are 89 µg/m3 (24-hour average) and 21 µg/m3 (annual average).(b)
The future year (2015) PM10 concentrations for the Klamath Falls UGB are 114 µg/m3 (24-hour average) and 25 µg/m3 (annual average).(c)
The future year (2025) PM10 concentrations for the Lakeview UGB are 126 µg/m3 (24-hour average) and 27 µg/m3 (annual average).(10)
“Range of influence formula or “ROI formula” means the calculation of the distance in kilometers from the source impact area of the new or modified source to other emission sources that could impact that area. If there is no source impact area, the distance is calculated from the new or modified source. Any location that is closer to the source than the ROI may be considered to be “within the range of influence” of the source. The ROI formula is as follows:(a)
For PSD Class II and Class III areas, the Range of Influence formula of a competing source (in kilometers) is defined by:(A)
ROI (km) = Q (tons/year) / K (tons/year km).(B)
Definition of factors used in paragraph (a):(i)
Maximum ROI is 50 km.(ii)
Q is the emission rate of the potential competing source in tons per year.(iii)
K (tons/year km) is a regulated pollutant specific constant as follows:(I)
For PM2.5, PM10, SOx and NOx, K = 5;(II)
For CO, K = 40; and(III)
For lead, K = 0.15.(b)
For PSD Class I areas, the Range of Influence formula of a competing source includes emissions from all sources that occur within the modeling domain of the source being evaluated. DEQ determines the modeling domain on a case-by-case basis.(11)
“Single source impact” means the modeled impacts from an increase in emissions of regulated pollutants from a source without including the impacts from other sources.(12)
“Source impact area” means an area, or locations, where predicted impacts from the source or modification equal or exceed the Class II significant impact levels set out in OAR 340-200-0020 (General Air Quality Definitions). This definition only applies to PSD Class II areas and is not intended to limit the distance for PSD Class I modeling.(13)
“Sulfur deposition” means the sum of anion and cation sulfur deposition expressed in terms of the total mass of elemental sulfur being deposited. As an example, sulfur deposition for (NH4)2SO4 is 0.2427 times the weight of (NH4)2SO4 being deposited.
Source:
Rule 340-225-0020 — Definitions, https://secure.sos.state.or.us/oard/view.action?ruleNumber=340-225-0020.