• If specific exemptions allowed in the General Conformity Rule apply;  • If the action, or portions thereof, are included on the federal agency’s list of “presumed to  conform activities” (see Section 8.1.1.3);  • If total direct and indirect air emissions associated with the action are above or below the  General Conformity  de minimis  levels; and  • If an EPA-approved SIP has an emissions budget against which the emissions associated  with the action could be compared (i.e., a facility-wide emissions budget) and whether or  not the budget is inclusive of the action.  If an action is not exempt or presumed to conform, or found to cause emissions above applicable  de minimis levels  in any nonattainment or maintenance area, the agency must prepare a General  Conformity Determination prior to taking the action.  Best practices for each item of determination in an applicability analysis are discussed below.  The EPA’s  Green Book  is a publicly available resource for identifying whether or not an action  occurs in a current or historical nonattainment or maintenance area for any NAAQS -regulated  pollutant(s). 98  It identifies both current and historical nonattainment or maintenance areas each county within each U.S. state (as well as the U.S. territories of Guam and Puerto Rico).  Some nonattainment and maintenance areas include an entire county or counties, whereas others  only encompass a portion of a county (i.e.,  “partial”). For partial counties within nonattainment  or maintenance areas, the location of an action within the exact jurisdictional boundaries of the  area should be verified with either EPA or the state/local air quality control agency prior to  ascribing any General Conformity applicability. Situations may arise where an action will occur  at a facility whose footprint is only partially contained within a nonattainment or maintenance  area. Conversely, emissions associated with an action can sometimes span nonattainment areas or portions thereof.  Interagency coordination is also beneficial for actions occurring in maintenance areas that have a  federally enforceable maintenance plan, as the duration and characteristics of these plans can  vary. Further, per the “anti-backsliding” regulations of the CAA, areas designated nonattainment  or maintenance of a NAAQS that has since been revoked ( i.e., 1-hour O$_{3}$) may still hold a  continuing program responsibility to enforce the applicable plan, or components thereof. 99  In  these instances, interagency coordination involving EPA and state/local air quality governance  can be beneficial in reaching accordance in how General Conformity should be addressed for an  action.  8.1.1.2.  Conformity Exemptions  8.1.1.1.  Nonattainment/Maintenance Status for the Purposes of General Conformity  Aviation Emissions and Air Quality Handbook  98 EPA,  The Green Book Nonattainment Areas for Criteria Pollutants,  July 2013,  http://www.epa.gov/oar/oaqps/greenbk/index.html.  99  Codified at 40 CFR 51.900, the anti-backsliding provisions of the CAA prevent the rescission of measures or  requirements applicable to areas in which a NAAQS is revoked or relaxed by the EPA, such that requirements continue to apply to an area after revocation or relaxation of the NAAQS in question (i.e., the 1 - hour O$_{3 }$NAAQS), if the requirements were applied in the area based on the area's prior designation.  70$_{ }$