Aviation Emissions and Air Quality Handbook  • To provide guidance, procedures, and methodologies appropriate for use in carrying out  air quality assessments prepared in association with FAA -supported projects and/or  actions; • To help ensure that these air quality assessments adequately disclose air quality impacts  in accordance with NEPA and meet the requirements of the General Conformity Rule and  NAAQS of the CAA; and • To provide a process for users to determine when an air quality assessment is considered  necessary, the type of analysis that is appropriate, and the level of effort that is warranted.  1.2. Intended Users of the  Handbook  This  Handbook  was purposefully prepared for use by the FAA, its lines of business , and staff  offices as well as airport sponsors and/or their representatives that are involved in the assessment  of air quality impacts associated with aviation-related projects and/or actions. In addition, other  stakeholders may also find it useful including the U.S. Environmental Protection Agency (EPA),  federal, state/local governmental agencies, and others with an interest in ensuring that nation’s airports are continually modernized while safeguarding the nations’ air quality. Notably,  the  Handbook  is designed to be used by both seasoned practitioners and newcomers to the air  quality assessment process.  This  Handbook  was developed to assist the FAA, its partner agencies , and other stakeholders in  assessing  a viation-related air quality impa cts  associated  with  a  wide  as sortment of  aviation/airport projects and/or actions. Therefore,  it is n ecessarily broad and extensive.  Moreover, it cannot be expected to provide the level of detail necessary for every type of project,  action, or circumstance. Rather, it is designed to provide the user with a sufficient overview of  the overall approaches and the assessment methods for conducting the analyses.  The earliest version of the  Handbook  was published in 1982 by the FAA and the U.S. Air Force.  This document was fully updated in 1997 by the FAA and subsequently updated by  Addendum  in  2004. While some of the materials contained in these earlier versions are reused, it is intended  that this version of the  Handbook  replace and supersede these documents. As of the publication  of this version of the  Handbook , previous versions are cancelled. However, as a technical manual  or guidance document, the  Handbook  is not intended to replace laws, regulations, or requirements pertaining to airport air quality.  In the case of any discrepancies or differences  found between these and the  Handbook , readers should defer to the specific language requirements contained in the governing documents.  The contents of the  Handbook  are organized around a framework of topics and sections that  build upon one another in a progressive fashion. However, for those that wish to focus particular topics of interest, each section is designed to be self -supporting and comprehensive.  The following provides a summary description of each section:  1.3. Use of the  Handbook  1.4. Contents of the  Handbook  2$_{ }$