Search Frequent Questions

Filter By:

Active filters:

Remove all filters

Displaying 1 - 11 of 11 results

  • Where can I download hourly emissions data from continuous monitoring?

    Hourly emissions data files are available from the Clean Air Markets Division of EPA, collected as part of 40 CFR Part 75. The download location has changed in February, 2023. The new location is https://campd.epa.gov/data/bulk-data-files . Once on this new site, use the menu (at the left) and the Keyword…

    • Last published:

  • 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 (CAPs) are expected to…

    • Last published:

  • 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 inventory methods from the…

    • Last published:

  • 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 provided on the Air Pollutant Emissions…

    • Last published:

  • How do I determine what SCCs have changed between inventory years?

    These are available in the EIS (Reporting Code table) or public website: https://sor-scc-api.epa.gov/sccwebservices/sccsearch/ Filter on “last inventory year” to remove SCCs no longer active. If this column has a date in it, then the SCC has been retired as of that date. The “last updated date” (column J) indicates when…

    • Last published:

  • 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…

    • Last published:

  • Where can I find biomass emission limits for biomass burning in industry? I am looking for limits on particulate matter, SO2 and NOx.

    For information on EPA air emission standards for industrial sources, please visit this website. If you need additional help with specific questions, please use the contact us link on one of these pages to inquire further with staff in the emission standards program. New Source Performance Standards

    • Last published:

  • 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 and beyond, the EPA is trying to publish only a single…

    • Last published:

  • Are the GHGs in the National Emissions Inventory Complete?

    No, the 2020 National Emissions Inventory (NEI) does not comprehensively capture all sources and sinks of greenhouse gases (GHGs) in the United States. For this information, users should review the EPA’s annual Inventory of U.S. Greenhouse Gas Emissions and Sinks . However, the NEI does report GHG emissions for select…

    • Last published:

  • 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 onroad and nonroad sources (except…

    • Last published:

  • 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/locals to report to…

    • Last published: