How to interpret 40 CFR part 50 of the Code of Federal Regulations?

Post this in the General English section. Is CFR an abbreviation for Code of Federal Regulations? (Federal) U.S. law?

I know what CFR is; it stands for the Federal Rules of Procedure

In that case, what’s rather difficult to understand here is 40 CFR part 50; I guess it refers to part 50 of the 40th Federal Code?

CFR (Code of Federal Regulations) consists of 50 titles, some of which have subtitles, each representing a different area of federal regulations； Each chapter contains several sections; these sections are usually titled after the name of the authority that issued the regulation, and some sections are further divided into subsections ； Each section contains several parts (Part) within a specific regulatory area; some of these parts are further divided into subparts due to their extensive content. Each part consists of several sections containing specific regulations. It can be seen that the hierarchy of CFR consists of articles, chapters, sections, subsections, parts, subparts, and paragraphs. The first two paragraphs are from the Internet. I was fortunate enough to participate in the translation of some CFRs by the local standards management department, so I have some understanding of the structure of this regulation. The structure of its electronic version is: Title, Volume, Chapter, Browse, Parts, Regulatory Entity. The difficulties lie in 40 CFR Part 50 of the Code of Federal Regulations; this refers to Part 50 within Title 40, which is titled “Protection of the Environment” – specifically Part 50: National Primary and Secondary Ambient Air Quality Standards. http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?sid=cab9a47dc2aa35b7728433f72cc8e37d&c=ecfr&tpl=/ecfrbrowse/Title40/40cfrv2_02.tpl

That’s amazing. Is the “United States Federal Regulations” the electronic code of federal regulations? It feels like the translation isn’t right? And it’s only 40 pages. Thank you