The overarching purpose of this report is to present analysis of the 2008 NEI and comparison to previous years of inventory data, with a primary focus on the last full NEI - the 2005 NEI. We describe the national and regional patterns of CAP/HAP emission distributions in the 2008 NEI and which sources contribute to these releases. We do not assess nor predict the absolute risks to human health and ecosystems that may be associated with the presence of any of these specific air pollutants, but rather focus on the intensity of emission releases that may pose elevated risks. Pollutants of greatest interest include not only those that contribute to ozone and particle pollution, but also HAPs that are predicted by the 2005 NATA to be the most harmful to human health. To facilitate a more concise document, we have included just 27 pollutants in the report, which are listed in Table 1. Eight of these 27 pollutants are either CAPs or precursors to CAPs, and the remaining 19 are HAPs that were selected based on criteria that will be discussed later in this report.

"EPA-454/R-13-005." Project Officer: Venkatesh Rao. Includes bibliographical references (page 67).

1. Highlights -- 2. Introduction -- 2.1. Purpose and contents of this report -- 2.2. Background -- 3. National emissions information -- 3.1. Total national emissions and emission density maps -- 3.2. Current year emissions and national emission trends by sector -- 3.3. Emissions by sector comparisons for 2005 and 2008 -- 3.4. Biogenic emissions and wild land fire emissions -- 3.5. Focus on the 2008 NEI, summary of CAPs and select HAPs -- 3.6. Mercury emissions in the 2008 NEI -- 4. Regional emissions information -- 4.1. National Climatic Data Center (NCDC) regions -- 4.2. Regional CAP and HAP emissions characterization -- 4.3. Regional intensity for ozone and PM formation, HAPs and CAPs -- 4.4. Regional CAP/HAP emissions, top sector contributions -- 5. Local emissions information -- 5.1. Nexus of air quality issues for local area -- 5.2. Local profiles for two nexus areas -- 5.3. Examples and recommendations for developing local scale inventories -- 6. Improvements for 2008 and future NEIs -- 7. Concluding remarks -- References -- Acronym list.