Search Frequent Questions

Displaying 1 - 15 of 59 results

• 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.

  • Last published: March 18, 2024

• 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

• How often does a facility need to complete an oil spill response training under the FRP requirements?

  Facilities subject to the Facility Response Plan (FRP) regulations in 40 CFR Part 112, Subpart D are required to develop a facility response training program to train those personnel involved in oil spill response activities (§112.21(b)). How often does a facility need to complete an oil spill response training under…

  • Last published: May 31, 2024

• What is a significant and substantial harm facility?

  Some substantial harm facilities may meet the criteria for a significant and substantial harm facility. After you have prepared and submitted your FRP, the RA may determine that your facility has the potential, not just for substantial harm, but for significant and substantial harm. If the RA makes that determination…

  • Last published: June 5, 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

• 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.

  • Last published: May 1, 2024

• 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…

  • Last published: May 1, 2024

• 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…

  • Last published: May 28, 2024

• PE certification for an FRP if an SPCC impracticability determination is made

  If the owner or operator of a facility subject to the SPCC regulations determines that the installation of any of the specified secondary containment structures or equipment is not practicable and accordingly provides in the facility’s SPCC Plan an oil spill contingency plan following the provisions of 40 CFR Part…

  • Last published: June 5, 2024

• 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

• 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.

  • Last published: August 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