40 C.F.R. § 81.261
The Southeast Iowa Intrastate Air Quality Control Region consists of the territorial area encompassed by the boundaries of the following jurisdictions or described area (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 Iowa: Cedar County, Davis County, Henry County, Iowa County, Jefferson County, Johnson County, Keokuk County, Van Buren County, Wapello County, Washington County.
Note: For purposes of identification, the Regions are referred to by Iowa authorities as follows:
Sec.
81.256 Northeast Iowa Intrastate Air Quality Control Region: Region 1.
81.257 North Central Iowa Intrastate Air Quality Control Region: Region 2.
81.258 Northwest Iowa Intrastate Air Quality Control Region: Region 3.
81.259 Southwest Iowa Intrastate Air Quality Control Region: Region 4.
81.260 South Central Iowa Intrastate Air Quality Control Region: Region 5.
81.261 Southeast Iowa Intrastate Air Quality Control Region: Region 6.
40 C.F.R. §81.261