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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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  • 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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  • Change of owner and RMP facility ID number

    If a facility is sold to a new owner, does it keep its' original RMP Facility ID number? Yes. The facility will keep the ID number assigned by EPA.

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  • Facility ID number and re-registering a facility

    If a facility deregisters, then reregisters, should the facility use the original RMP Facility ID or will it be assigned a new ID? The facility should use the original ID assigned by EPA.

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  • Resubmission of RMP for a facility that previously deregistered

    A covered facility deregisters its RMP because it no longer has more than a threshold quantity of a regulated substance in a covered process. If the facility becomes subject to the CAA §112(r) risk management program regulations at a later date and submits a new RMP, should the facility submit…

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  • RMP Records Maintained Onsite

    Pursuant to 40 CFR Part 68, Subpart G, the owner or operator of a stationary source subject to the risk management program regulations in Part 68 must develop and submit a risk management plan (RMP). Does the owner or operator have to maintain a written copy of the RMP on…

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  • Change of Ownership

    If a facility that is subject to the risk management program regulations in 40 CFR Part 68 is sold to another owner, is the facility required to make a correction or a full update of its risk management plan (RMP)? If there are no changes in the covered operations at…

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  • RMP*eSubmit preparer access

    How does a new Preparer get access to a Risk Management Plan (RMP) via RMP*eSubmit? First, the person must register with CDX. To register with CDX, go to https://cdx.epa.gov/ and complete the registration process for a Risk Management Plan “Preparer”. Once set up as a “Preparer”, the Certifying Official needs…

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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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  • 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…

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  • How does EPA verify accuracy and completeness of RMPs?

    What does EPA plan to do to verify the accuracy and completeness of submitted Risk Management Plans (RMPs)? All RMPs received by EPA go through an electronic verification process that checks the submission for its completeness. This completeness check determines whether information has been provided for all of the required…

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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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