## • Step 1 : Select Appropriate Comparison Year(s) 

The selection of years for which a de minimis comparison should be conducted must be selected with discretion to ensure that General Conformity requirements are fully addressed. These years include the following: 

− The attainment year specified in the approved SIP, or the latest attainment year possible under the CAA; 

− The last year for which emissions are projected in a maintenance plan; 

− The year during which the total direct and indirect emissions from the action is expected to be greatest on an annual basis; and 

− Any year for which the approved SIP contains an emissions budget. 

Of note, the comparison years required for General Conformity may or may not be aligned with timeframes utilized in the NEPA document for an air quality impact assessment. As such, it is advantageous for both the NEPA and General Conformity processes to be considered during project scoping and planning such that all requirements can be satisfied as needed. 

## • Step 2 : Prepare Emissions Inventories 

Compute an inventory of all “reasonably foreseeable direct and indirect emissions” associated with the action once implemented (i.e., the proposed action emissions). 102 Also inventory emissions that would occur irrespective of the action (i.e., the no action emissions). Subtract the no action emissions from the proposed action emissions to determine the net increase associated with the action’s operation. 

For actions involving construction activities, prepare an emissions inventory for each year of planned construction, including all reasonably foreseeable direct and indirect emissions (e.g., on-site equipment and off-site haul trucks). 

## • Step 3 : Identify Emissions Reductions Measures 

Features of an action that by design have an emissions reducing effect are called “design measures” and are typically accounted for in the emissions inventories of the action prepared in Step 2 . For instance, if an action includes installing additional terminal gates, and these gates are equipped with gate electrification infrastructure, the resulting emissions benefit of defrayed APU usage would then by virtue be included in the emissions inventory. 

