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 · § 51.150

§ 51.150. Classification of regions for episode plans.

251 words·~1 min read·/us/cfr/t40/s§ 51.150·

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

(a)This section continues the classification system for episode plans. Each region is classified separately with respect to each of the following pollutants: Sulfur oxides, particulate matter, carbon monoxide, nitrogen dioxide, and ozone.
(b)Priority I Regions means any area with greater ambient concentrations than the following:
(1)Sulfur dioxide—100 µg/m 3 (0.04 ppm) annual arithmetic mean; 455 µg/m 3 (0.17 ppm) 24-hour maximum.
(2)Particulate matter—95 µg/m 3 annual geometric mean; 325 µg/m 3 24-hour maximum.
(3)Carbon monoxide—55 mg/m 3 (48 ppm) 1-hour maximum; 14 mg/m 3 (12 ppm) 8-hour maximum.
(4)Nitrogen dioxide—100 µg/m 3 (0.06 ppm) annual arithmetic mean.
(5)Ozone—195 µg/m 3 (0.10 ppm) 1-hour maximum.
(c)Priority IA Region means any area which is Priority I primarily because of emissions from a single point source.
(d)Priority II Region means any area which is not a Priority I region and has ambient concentrations between the following:
(1)Sulfur Dioxides—60-100 µg/m 3 (0.02-0.04 ppm) annual arithmetic mean; 260-445 µg/m 3 (0.10-0.17 ppm) 24-hour maximum; any concentration above 1,300 µg/m 3 (0.50 ppm) three-hour average.
(2)Particulate matter—60-95 µg/m 3 annual geometric mean; 150-325 µg/m 3 24-hour maximum.
(e)In the absence of adequate monitoring data, appropriate models must be used to classify an area under paragraph
(b)of this section, consistent with the requirements contained in § 51.112(a).
(f)Areas which do not meet the above criteria are classified Priority III. [51 FR 40668, Nov. 7, 1986, as amended at 58 FR 38822, July 20, 1993]
Connections92 cite this
Cited by 92 sections · top 58
register
Citation graph
cites case law
§ 51.150
Classification of regions for episode plans.
Fed. Reg.×92
Cites 0Cited by 92 across 1 source
★   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.