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  • Where can I find older NEI data (prior to 2008)?

    The raw data and summaries that are still available (dating back to 1990) can be obtained from the web page https://www.epa.gov/air-emissions-inventories/pollutant-emissions-summary-files-earlier-neis . Starting with 2001 data, a more limited selection of summary files are available.

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  • How do the different parts of particulate matter (PM) fit together?

    The various parts of PM in the NEI are related as follows. PM10-FIL > PM25-FIL because PM10-FIL includes PM25-FIL PM25-PRI = PM25-FIL + PM-CON This equation only applies at the process level. Because some sources only can report PM2.5 (due to test method differences), this equation does not apply to…

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  • How does PM2.5 relate to PM species such as EC, OC, SO4, NO3, PMFINE, and DIESEL-PM25?

    Primary PM2.5 estimates are speciated into the five PM species in the NEI: elemental (black) carbon (EC), organic carbon (OC), nitrate (NO3), sulfate (SO4), and the remainder of PM25-PRI (PMFINE). Diesel engine PM25-PRI and PM10 emissions are also labeled as DIESEL-PM25 and DIESEL-PM10 for mobile source diesel engines. For all…

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  • What is defined as a structure (home or place of business)?

    While generally defined as a building, a structure under the structural cleaning program will include only those habitable spaces where indoor occupancy is frequent and regularly occurring on a daily or near-daily basis. Examples of residential structures include primary residences and living spaces, and examples of commercial structures include offices…

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  • Why is cleaning of homes and places of businesses happening?

    Norfolk Southern, with EPA oversight, is providing indoor cleaning to eligible occupants in response to concerns about the impact of the derailment and cleanup work on homes and places of businesses. The cleaning is to address potential dust that may have been generated as part of the train derailment and…

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  • May I generate RINs that I produced and sold for non-road use in the past so that I can reinstate those RINs under RFS2?

    See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . Section 80.1426(c)(2) provides that RINs are assigned to a volume of renewable fuel when ownership of the RIN is transferred along with ownership of the volume of renewable fuel. A comparable provision appear in the RFS1 regulations, at…

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  • What work still needs to be done at the derailment site?

    Although contaminated soil has been excavated and removed from the derailment site, some additional work remains. Soil sampling continues to check all areas where cleanup operations took place. Stream assessments continue, and culvert clean out has started. Groundwater and drinking water sampling also continues. Expect these investigations and possible additional…

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  • 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…

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  • What sources make up the Tier 1 categories used in the emissions trends?

    Tier 1 categories are assigned by source classification codes (SCCs) that are the most specific processes available in the NEI. The latest SCC list with the Tier 1 assignments can be downloaded from the EPA SCC website in Comma Separate Values (CSV) format.

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  • What is the cause of the large decrease in electric utility emissions, particularly sulfur dioxide, starting in 1995?

    SO2 emissions reductions from utilities during this time are primarily attributed to the impacts of the acid rain program. As described on EPA’s Acid Rain Program web page, Phase 1 of this program began in 1995 and affected 263 units at 110 most coal-burning electric utility plants in 21 eastern…

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  • Can I get access to the Emissions Inventory System if I am not a data provider to EPA?

    The Emission Inventory System (EIS) is a secured database for EPA and State/Local and Tribal Air Agencies only. The EIS is used to develop the National Emission Inventory (NEI). While you cannot have access to EIS, you can have access to the current and past NEIs through EPA’s NEI website…

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  • Does this mean my home or place of business is contaminated?

    No. However, indoor cleaning is being offered to address potential dust emissions that may have been generated as part of the train derailment and cleanup work. This service is being offered as an additional service to interested members of the community.

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  • May I generate RINs for renewable fuel that I produced and sold for non-motor vehicle use in the past so that I can reinstate those RINs under RFS2?

    See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . No. RINs that were previously generated in 2009 and 2010 may be reinstated if they were retired for non-motor vehicle use. However, RINs may not be generated for renewable fuel produced in the past in order to retire…

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  • Are biogenic emissions included in the emissions trends Tier 1 data?

    No, the biogenic emissions are not included in the emissions trends Tier 1 data. If needed, users can add the biogenic data either as a separate Tier, or specify its inclusion in the “Miscellaneous” Tier 1 group.

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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 (CAPs) are expected to…

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