Search Frequent Questions

Displaying 1 - 15 of 15 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

• Redoing calculations if RMP*Comp is updated

  Will RMP*Comp be updated? If so, would I have to redo calculations I might already have made with an earlier version? No, you do not have to redo your work if you have already completed your consequence analyses. RMP*Comp is based on the EPA's Offsite Consequence Analysis Guidance (OCA Guidance)…

  • Last published: May 22, 2024

• Different distances to toxic endpoints with different versions of RMP*Comp

  I've noticed that for certain chemicals, RMP*Comp gives substantially different distances to the toxic endpoint than previous versions. Why? In the current version of RMP*Comp, we have incorporated new chemical-specific distance tables for ammonia, chlorine, and sulfur dioxide. The generic tables are still used for other chemicals (you can see…

  • Last published: May 22, 2024

• Distance to endpoint calculations used by RMP*Comp

  Does RMP*Comp perform some math or modelling in order to arrive at an endpoint distance, or is it simply interpolating from the tables in the EPA's Offsite Consequence Analysis Guidance (OCA Guidance)? RMP*Comp follows the procedures set out in the OCA Guidance . This means that for some scenarios, the…

  • Last published: May 22, 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

• If I certify a nonroad flexible-fuel engine under 40 CFR Part 1054, are owners and operators prohibited from using gasoline-ethanol blended fuels containing greater than 10 volume percent ethanol under 40 CFR 80.1504(a)(1) in my nonroad flexible-fuel engi

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . No, owners and operators of nonroad engines, vehicles, and equipment where the nonroad engine is certified under 40 CFR Part 1054 as a flexible-fuel engine are not prohibited from using gasoline-ethanol blended fuels containing greater than 10 volume…

  • Last published: July 15, 2024

• What sources make up the Sectors or Tiers used in the emissions data summaries?

  Tier 1 and Sector 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 and Sector assignments can be downloaded from the EPA SCC website in Comma Separate Values (CSV) format.

  • Last published: May 1, 2024

• RMP*Comp and emergency response

  Can I use RMP*Comp for emergency response? No. It's a planning tool. Many other tools are available for response, including ALOHA . You can learn more by reading CAMEO tools for RMP .

  • Last published: May 22, 2024

• Minimum and Maximum Distance to Endpoint

  The Chemical Accident Prevention Provisions require the completion of a worst-case release scenario analysis (40 CFR §68.25). This analysis includes estimating the greatest distance to endpoint as defined by the parameters in §68.22. Is there a required minimum or maximum distance for the distance to endpoint in the worst case…

  • Last published: May 22, 2024

• Where can I obtain the hourly data from Continuous Emissions Monitors (CEMs)?

  The CEM emissions data are available from the EPA Clean Air Markets Program Data website.

  • Last published: August 15, 2024

• How can I get more detailed information? What measurements/sensors are used to measure emissions?

  Access the latest NEI data set . Under 'Sector Summaries - Criteria and Hazardous Air Pollutants by 60 EIS emission sectors', > choose National > for Pollutant, choose PM10 Primary and/ or PM2.5-PRI > Sector, choose all sectors >Submit Query to see results at bottom of page. Open the results…

  • Last published: March 18, 2024

• Local meteorological data for alternative release scenarios

  For alternate release scenarios, RMP*Comp uses set values for meteorological conditions like humidity, wind speed, temperature, stability class, and so on. Is there a way to change those values? I want to use meteorology data from my own location. RMP*Comp indeed uses fixed values for certain atmospheric parameters, and does…

  • Last published: May 22, 2024

• Different results using ALOHA and RMP*Comp

  I tried running the same scenarios in ALOHA and in RMP*Comp. I got different answers. Why? The results you obtain using RMP*Comp may not closely match the results you obtain running the same release scenario in a more sophisticated air dispersion model such as ALOHA or DEGADIS. That's because of…

  • Last published: May 28, 2024

• Can product codes satisfy the product transfer documentation requirements set forth at 40 C.F.R. 80.1503(a)?

  See More Frequent Questions about Fuels Registration, Reporting, and Compliance Help . EPA believes that parties normally are able to meet the product transfer requirements by including the required information in the documents that the parties currently use to memorialize the transfer of title or custody of the gasoline. Product…

  • Last published: July 15, 2024

• Where can I get maps and/or emissions of facility emissions data?

  The EPA provides emissions maps in two ways. First, each of the last three NEI years have a “Facility Mapping” tab available on the main NEI page for that inventory year (for example, see the 2020 NEI page). With this tool, maps can be created for one state at a…

  • Last published: January 7, 2025