Search Frequent Questions

Displaying 1 - 15 of 23 results

• 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…

  • Last published: April 17, 2024

• 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…

  • Last published: April 17, 2024

• Please clarify whether oxygenates blended into either conventional gasoline or Reformulated Blendstock for Oxygenate Blending (RBOB) downstream of the refinery need to be included in sulfur compliance calculations.

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . Section 80.205(c) provides that a refiner or importer may include oxygenates added downstream from the refinery or import facility if the requirements under § 80.69(a) or § 80.101(d)(4)(ii) of the RFG/CG regulations are met. Therefore, a refiner or…

  • Last published: August 2, 2024

• 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: January 7, 2025

• In the NPRM, the sulfur standards were expressed without decimal places, but the final rule provides that the standards are expressed with two decimal places (§§ 80.195, 205). Why did EPA include this change?

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . EPA included the decimal places to ensure that the sulfur standards are not exceeded by rounding down actual average sulfur levels. We do not believe reporting the average sulfur level to two decimals creates any additional burden as…

  • Last published: July 15, 2024

• It is our understanding that, if a portion of the gasoline produced by a refinery located within the GPA is sold outside of the United States, that gasoline is not subject to the sulfur standards and it only has to meet the standards of the country to whi

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . Gasoline that is exported for sale outside the United States is not subject to the requirements of the gasoline sulfur rule, including gasoline produced by a refiner located within the GPA. See § 80.200(c).

  • Last published: July 15, 2024

• 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: January 7, 2025

• 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: January 7, 2025

• 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: March 18, 2024

• What is included in the emissions “Tiers”?

  The Tiers are assigned by a Source Classification Code (SCC), which has the most detail about the emissions processes that generate the emissions. The full list of SCCs, their associated Tiers, and the SCC descriptions is available online at https://ofmpub.epa.gov/sccwebservices/sccsearch/ .

  • Last published: March 18, 2024

• 6. Is commingling of different types of ethanol permitted? If so, what systems must be employed?

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . With one exception, the RFS program places no restrictions on the mixing of ethanol produced in different facilities, by different feedstocks, or through different processes. Also, RINs assigned to ethanol are fungible, in that a specific assigned RIN…

  • Last published: July 15, 2024

• If a facility is grandfathered, is it also exempt from the requirement that feedstocks must be renewable biomass?

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . Even if a facility is exempt from the 20% GHG reduction requirement, in order to generate RINs, the facility is still required to use feedstocks that meet the definition of renewable biomass. The definition of renewable fuel in…

  • Last published: July 15, 2024

• 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: January 7, 2025

• What does an annual emissions value in the NEI represent (one year or multiple years)?

  The NEI provides total annual emissions for a single year.

  • Last published: January 7, 2025

• 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: January 23, 2025