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  • How complete are the data in the National Emissions Inventory?

    While the goal of the National Emissions Inventory (NEI) program is to include all emissions data, there are always challenges meeting this goal. The answer about completeness of coverage of sources depends on the emissions sector and pollutant. In general, the criteria air pollutants and precursors

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  • Where is more information available about emissions estimation methods used by the EPA?

    For criteria air pollutants and precursors as well as for hazardous air pollutants, the methods are described in the technical support document (TSD) for the latest National Emissions Inventory (NEI) available from the main NEI page. For greenhouse gas emissions, you can find greenhouse gas

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  • How are emissions trends compiled?

    For criteria air pollutants and precursors, the emissions trends are based on the triennial National Emissions Inventory data, with some interim year data included for non-triennial years. The methods and interim-year approaches are described on the “Development of Data” tab included with the data

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  • Where are the NAICS/ SIC and SCC codes changes that have been implemented for the 2017NEI?

    Please refer to the NEI webpage for 2017 documentation, and follow the link for Appendix 2 - 2017 NEI Plan Code Changes. That Excel file describes anticipated changes for the SCCs and NAICS and includes a helpful read me. I'll just note in the next NEI/EIS email that SCC and NAICS changes for use in

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  • Products authorized for use on oil discharges

    Does EPA maintain a list of products that are authorized for use on oil discharges? If so, how can a manufacturer have their product included on the list? Section 311(d)(2)(G) of the Clean Water Act (CWA) directs EPA to prepare a schedule of dispersants, other chemicals, and oil spill mitigating

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  • Are the GHGs in the National Emissions Inventory Complete?

    No, the 2017 National Emissions Inventory (NEI) includes a subset of total national emissions of greenhouse gases (GHGs) for fires, mobile sources, and certain point sources. EPA provides a comprehensive assessment of all anthropogenic emissions and sinks of greenhouse gases in the annual Inventory

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  • How often are the NEI data updated and how frequently are the data published?

    The full NEI is created for every third inventory year (e.g., 2008, 2011, 2014, and 2017). The data for each version has been updated two times each for the 2008, 2011, and 2014 NEI cycles. For the 2017 NEI, the EPA is trying to publish only a single version, with draft versions being available to

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  • What are EPA’s plans for the 2020 National Emissions Inventory given the atypical situation from COVID-19 that is impacting emissions? What will it be used for?

    The EPA intends to prepare a 2020 National Emissions Inventory in collaboration with state, local, and tribal air agency partners. The Air Emissions Reporting Rule (AERR) requires states and delegated local and tribal agencies to report emissions from stationary sources and provide model inputs for

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  • What facilities are required to report to the NEI?

    The emissions reporting thresholds are in the Air Emissions Reporting Rule (AERR), 40 CFR Part 51, Subpart A, Appendix A, Table 1, which require state/local air agencies to report emissions as point sources for facilities that meet or exceed these emissions thresholds. The AERR requires states

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