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## 4.1.1. Step 1: Determine the Need for the Assessment 

The initial step in the process is aimed at determining when an air quality assessment is required. As previously discussed, air quality assessments for project/action may be necessary for compliance with the requirements of NEPA, the CAA, and other environmental regulations and 

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there is no FAA action to assess or disclose), but CAA, state/local, and other environmental regulations and directives may still require an air quality assessment. Furthermore, such projects/actions may still be subject to NEPA review , depending on policies and procedures of the project/action sponsor . For example, a proposed roadway interchange or private parking facility located off airport property does not require FAA 

directives. In addition, some states and/or local areas have air quality requirements that may also pertain to airports. Therefore, this section provides guidance on determining whether or not an air quality assessment is appropriat e. Note that an air quality assessment does not necessarily require creating an emissions inventory or doing dispersion modeling. See Section (4.1.2 (“Step 2: Select the Assessment Methodology ”) for types of air quality assessments. 

In most cases, the need to conduct an air quality assessment for FAA-supported projects or actions is project-specific, based largely on the consideration of various factors that, taken together, help to formulate the overall decision-making process. For ease of understanding, several of these factors are identified in Figure 4-2 ( Determine the Need for the Assessment ) and explained further below. Importantly, this information intended to be used in conjunction with Figure 4-3 ( Air Quality Assessment Decision Flow Diagram ) as a means of simplifying the decision-making process. 

Step 1.A. Project/Action Definition – The purpose of this step is to define the scope of the proposed project (or action), as well as the alternatives . This basic information provides necessary knowledge required in subsequent steps to determine when an air quality assessment is warranted and what type of assessment should be conducted. Such information may comprise (but is not limited to) th e proposed changes in the airport layout, supporting facilities and infrastructure, and/or the airport/aircraft operational characteristics. Ideally, the project sponsor’s planning process will provide the information documentation needed to obtain these details. 

Step 1.B. Determine FAA’s Involvement – This step is to establish whether or not FAA involvement ( e.g., approval, funding, permitting, etc.) is associated with the project/action. In those cases where FAA involvement is not required, an quality assessment for FAA purposes would not be necessary (as 

