(a) 1-hour NAAQS means the 1-hour primary and secondary ozone national ambient air quality standards codified at 40 CFR 50.9.

(b) 1997 NAAQS means the 1997 8-hour primary and secondary ozone national ambient air quality standards codified at 40 CFR 50.10.

(c) 2008 NAAQS means the 2008 8-hour primary and secondary ozone NAAQS codified at 40 CFR 50.15.

(d) 1-hour ozone design value is the 1-hour ozone concentration calculated according to 40 CFR part 50, appendix H and the interpretation methodology issued by the Administrator most recently before the date of the enactment of the CAA Amendments of 1990.

(e) 8-hour ozone design value is the 8-hour ozone concentration calculated according to 40 CFR part 50, appendix P.

(f) CAA means the Clean Air Act as codified at 42 U.S.C. 7401 - 7671q (2010).

(g) Attainment area means, unless otherwise indicated, an area designated as either attainment, unclassifiable, or attainment/unclassifiable.

(h) Attainment year ozone season shall mean the ozone season immediately preceding a nonattainment area's maximum attainment date.

(i) Designation for the 2008 NAAQS shall mean the effective date of the designation for an area for the 2008 NAAQS.

(j) Higher classification/lower classification. For purposes of determining whether a classification is higher or lower, classifications under subpart 2 of part D of title I of the CAA are ranked from lowest to highest as follows: Marginal; Moderate; Serious; Severe; and Extreme.

(k) Initially designated means the first designation that becomes effective for an area for the 2008 NAAQS and does not include a redesignation to attainment or nonattainment for the 2008 NAAQS.

(l) Maintenance area means an area that was designated nonattainment for a specific NAAQS and was redesignated to attainment for that NAAQS subject to a maintenance plan as required by CAA section 175A.

(m) Nitrogen Oxides (NO_X) means the sum of nitric oxide and nitrogen dioxide in the flue gas or emission point, collectively expressed as nitrogen dioxide.

(n) Ozone season means for each state, the ozone monitoring season as defined in 40 CFR part 58, appendix D, section 4.1(i) for that state.

(o) Applicable requirements for an area for anti-backsliding purposes means the following requirements, to the extent such requirements apply to the area pursuant to its classification under CAA section 181(a)(1) for the 1-hour NAAQS or 40 CFR 51.902 for the 1997 ozone NAAQS at the time of revocation of the 1997 ozone NAAQS:

(p) CSAPR means the Cross State Air Pollution Rule codified at 40 CFR 52.38 and part 97.

(q) CAIR means the Clean Air Interstate Rule codified at 40 CFR 51.123, 52.35 and part 95.

(r) NO_X SIP Call means the rules codified at 40 CFR 51.121 and 51.122.

(s) Ozone transport region (OTR) means the area established by CAA section 184(a) or any other area established by the Administrator pursuant to CAA section 176A for purposes of ozone.

(t) Reasonable further progress (RFP) means both the emissions reductions required under CAA section 172(c)(2) which EPA interprets to be an average 3 percent per year emissions reductions of either VOC or NO_X and CAA sections 182(c)(2)(B) and (c)(2)(C) and the 15 percent reductions over the first six years of the plan and the following three percent per year average under § 51.1110.

(u) Rate-of-progress (ROP) means the 15 percent progress reductions in VOC emissions over the first 6 years required under CAA section 182(b)(1).

(v) Revocation of the 1-hour NAAQS means the time at which the 1-hour NAAQS no longer apply to an area pursuant to 40 CFR 50.9(b).

(w) Revocation of the 1997 ozone NAAQS means the time at which the 1997 8-hour NAAQS no longer apply to an area pursuant to 40 CFR 50.10(c).

(x) Subpart 1 means subpart 1 of part D of title I of the CAA.

(y) Subpart 2 means subpart 2 of part D of title I of the CAA.

(z) I/M refers to the inspection and maintenance programs for in-use vehicles required under the 1990 CAA Amendments and defined by subpart S of 40 CFR part 51.

(aa) An area “Designated nonattainment for the 1-hour ozone NAAQS” means, for purposes of 40 CFR 51.1105, an area that is subject to applicable 1-hour ozone NAAQS anti-backsliding requirements at the time of revocation of the 1997 ozone NAAQS.

(bb) Base year inventory for the nonattainment area means a comprehensive, accurate, current inventory of actual emissions from sources of VOC and NO_X emitted within the boundaries of the nonattainment area as required by CAA section 182(a)(1).

(cc) Ozone season day emissions means an average day's emissions for a typical ozone season work weekday. The state shall select, subject to EPA approval, the particular month(s) in the ozone season and the day(s) in the work week to be represented, considering the conditions assumed in the development of RFP plans and/or emissions budgets for transportation conformity.