You are using an unsupported browser. This web site is designed for the current versions of Microsoft Edge, Google Chrome, Mozilla Firefox, or Safari.
The Office of the Federal Register publishes documents on behalf of Federal agencies but does not have any authority over their programs. We recommend you directly contact the agency associated with the content in question.
If you have comments or suggestions on how to improve the www.ecfr.gov website or have questions about using www.ecfr.gov, please choose the 'Website Feedback' button below.
If you would like to comment on the current content, please use the 'Content Feedback' button below for instructions on contacting the issuing agency
Enhanced content is provided to the user to provide additional context.
This content is from the eCFR and is authoritative but unofficial.
Navigate by entering citations or phrases (eg: 1 CFR 1.1 49 CFR 172.101 Organization and Purpose 1/1.1 Regulation Y FAR).
Choosing an item from citations and headings will bring you directly to the content. Choosing an item from full text search results will bring you to those results. Pressing enter in the search box will also bring you to search results.
Background and more details are available in the Search & Navigation guide.
The in-page Table of Contents is available only when multiple sections are being viewed.
Use the navigation links in the gray bar above to view the table of contents that this content belongs to.
42 U.S.C. 7401, et seq.
36 FR 22421, Nov. 25, 1971, unless otherwise noted.
This content is from the eCFR and may include recent changes applied to the CFR. The official, published CFR, is updated annually and available below under "Published Edition". You can learn more about the process here.
Subscribe to: 40 CFR 81.12
No changes found for this content after 1/03/2017.
View the most recent official publication:
These links go to the official, published CFR, which is updated annually. As a result, it may not include the most recent changes applied to the CFR. Learn more.
Information and documentation can be found in our developer resources.
The Code of Federal Regulations (CFR) is the official legal print publication containing the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. It is not an official legal edition of the CFR.
Learn more about the eCFR, its status, and the editorial process.
The National Capital Interstate Air Quality Control Region (District of Columbia, Maryland, and Virginia) consists of the territorial area encompassed by the boundaries of the following jurisdictions (including the territorial area of all municipalities (as defined in section 302(f) of the Clean Air Act, 42 U.S.C. 1857h(f)) geographically located within the outermost boundaries of the area so delimited);
In the State of Maryland: Montgomery County; Prince Georges County.
In the State of Virginia: Arlington County; Fairfax County; Loudoun County; Prince William County.
(As so delimited, the Virginia portion of the region will include the city of Alexandria, the city of Fairfax, and the city of Falls Church.)