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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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  • Underground Storage Tanks in SPCC Plans

    If a gas station that has less than 42,000 gallons completely buried oil storage capacity and no aboveground oil storage capacity installs a new aboveground tank with a capacity greater than 1,320 gallons, must the facility’s Spill Prevention, Control, and Countermeasure (SPCC) Plan address the underground storage tanks (USTs) in…

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  • Container capacity less than 55 gallons

    Do facilities need to consider containers that are less than 55 gallons for applicability under 40 CFR Part 112? No. The third column of page 47066 of the July 17, 2002 Preamble states that "You need only count containers of 55 gallons or greater in the calculation of the regulatory…

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  • Oil-filled equipment capacity

    When counting against the 1,320 aboveground storage capacity threshold, would operational storage of oil (such as in a hydraulic press) be used? Oil which is contained in equipment is required to be factored into the storage capacity for the facility even though the oil may be only used for ancillary…

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  • If your farm does not have fuel storage that will flow into US waters by a ditch, river, stream, or lake, do you have to prepare a SPCC Plan?

    No. EPA suggests you use a common sense approach. If one of your oil storage tanks leaks, and the spilled oil would not flow into navigable waters or adjoining shorelines, you do not have to prepare a Plan. Remember that you still have the responsibility to clean up any spilled…

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  • To whom do I report an oil discharge?

    A facility should report discharges to the National Response Center (NRC) at 1-800-424-8802 or 1-202-267-2675 . The NRC is the federal government's centralized reporting center, which is staffed 24 hours per day by U.S. Coast Guard personnel. If reporting directly to NRC is not practicable, reports also can be made…

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  • Ground water pathways related to reasonably expected to discharge

    The SPCC Rule applies to facilities that could reasonably be expected to discharge into navigable waters (40 CFR §112.2(a)). Does a facility need to consider ground water pathways when determining if a discharge of oil could reasonably be expected to reach navigable waters? Owners and operators should consider whether on-site…

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  • When must I report an oil discharge to NRC?

    Any person in charge of a vessel or an onshore or offshore facility must notify the National Response Center (NRC) immediately after he or she has knowledge of the discharge.

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  • SPCC responsibility for tanks on leased property

    What if I leased some parcels, and there are tanks already present? Am I responsible for these tanks? You could be. If you plan to use these tanks, make sure in your lease agreement, it states who is responsible for these tanks. If the lease does not state who is…

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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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  • 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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