Tap any paragraph to write a margin note. Your notes collect in the Desk below the text and file under cases with @. The side-by-side margin rail opens on a larger screen.

Code · CFR · Title 40 — Protection of Environment · Part 51 · § 51.903

§ 51.903. How do the classification and attainment date provisions in section 181 of subpart 2 of the CAA apply to areas subject to § 51.902(a)?

227 words·~1 min read·/us/cfr/t40/s§ 51.903·

A research copy — for the controlling text, always check the official state or federal source. Not legal advice.

(a)In accordance with section 181(a)(1) of the CAA, each area subject to § 51.902(a) shall be classified by operation of law at the time of designation. However, the classification shall be based on the 8-hour design value for the area, in accordance with Table 1 below, or such higher or lower classification as the State may request as provided in paragraphs
(b)and
(c)of this section. The 8-hour design value for the area shall be calculated using the three most recent years of air quality data. For each area classified under this section, the primary NAAQS attainment date for the 8-hour NAAQS shall be as expeditious as practicable but not later than the date provided in the following Table 1. Table 1—Classification for 8-Hour Ozone NAAQS for Areas Subject to § 51.902(a) Area class 8-hour design value (ppm ozone) Maximum period for attainment dates in state plans (years after effective date of nonattainment designation for 8-hour NAAQS) Marginalfrom up to 10.085 0.0923 Moderatefrom up to 10.092 0.1076 Seriousfrom up to 10.107 0.1209 Severe-15from up to 10.120 0.12715 Severe-17from up to 10.127 0.18717 Extremeequal to or above0.18720 1 but not including.
(b)A State may request a higher classification for any reason in accordance with section 181(b)(3) of the CAA.
(c)A State may request a lower classification in accordance with section 181(a)(4) of the CAA.
Connections85 cite this
Cited by 85 sections · top 57
register
Citation graph
cites case law
§ 51.903
How do the classification and attainment date provisions in section 181 of subpart 2 of the CAA apply to areas subject to § 51.902(a)?
Fed. Reg.×84
C.F.R.×1
Cites 0Cited by 85 across 2 sources
★   the supreme law of the land   ★
Don't Tread on Me
E Pluribus Unum — out of many, one

"If you don't know your rights, you don't have any."

Marginalia · a citizen's law index
A research desk, not legal advice. Always read the cited source before relying on a summary.
Questions or an issue? support@self-law.org
disclaimerMarginalia is a research index, not a law firm. Nothing on this site is legal, tax, or financial advice and no attorney–client relationship is formed by using it. Statutes, regulations, and case law change; summaries, search results, AI output, and member posts may be incomplete, out of date, or wrong. Any interpretation drawn from material on this site should be validated by a licensed attorney in your jurisdiction before you act on it.