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 50 · § 50.17

§ 50.17. National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

130 words·~1 min read·/us/cfr/t40/s§ 50.17·

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

(a)The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts per billion (ppb, which is 1 part in 1,000,000,000), measured in the ambient air as sulfur dioxide (SO2).
(b)The 1-hour primary standard is met at an ambient air quality monitoring site when the three-year average of the annual (99th percentile) of the daily maximum 1-hour average concentrations is less than or equal to 75 ppb, as determined in accordance with appendix T of this part.
(c)The level of the standard shall be measured by a reference method based on appendix A or A-1 of this part, or by a Federal Equivalent Method
(FEM)designated in accordance with part 53 of this chapter. [75 FR 35592, June 22, 2010]
Connections212 cite this
Cited by 212 sections · top 60
register
Citation graph
cites case law
§ 50.17
National primary ambient air quality standards for sulfur oxides (sulfur dioxide).
Fed. Reg.×211
C.F.R.×1
Cites 0Cited by 212 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 Statutes, regulations, and case law change; summaries, search results, AI output, and member posts may be incomplete, out of date, or wrong.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.