Search Frequent Questions

Displaying 1 - 15 of 16 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

• Why Doesn't my Output Vehicle Miles Traveled (VMT) Match my Input VMT?

  See More Frequent Questions about MOVES and Related Models . This problem usually occurs when the run specification does not include all possible vehicle and fuel types. MOVES internally allocates the input VMT to each of the source types and fuel types and only reports the VMT for the fuel…

  • Last published: July 10, 2024

• What does MOVES Assume for Future Year Fleet Fuel Efficiency and Emissions?

  See More Frequent Questions about MOVES and Related Models . MOVES reflects all fuel economy and emissions standards that were final as of the model release date. For a list of recent regulations accounted for in the most recent MOVES version, see the see the Overview of EPA’s Motor Vehicle…

  • Last published: October 23, 2024

• 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

• 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 does MOVES Calculate CO2 and CO2 Equivalent Emissions?

  See More Frequent Questions about MOVES and Related Models . MOVES calculates the energy it takes to operate an onroad vehicle based on energy consumption rates as explained in the technical reports Greenhouse Gas and Energy Consumption Rates for Onroad Vehicles MOVES3 (pdf) (November 2020, EPA-420-R-20-015) and Exhaust Emission Rates…

  • Last published: March 20, 2024

• Why Are There No Emissions for the Early and Late Hours of the Day for Certain Source Types?

  See More Frequent Questions about MOVES and Related Models . MOVES has no start emissions for the certain source types in certain hours of the day. While we know that a non-zero number of these source types do start late at night, our activity data on these trucks and buses…

  • Last published: July 10, 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

• 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

• Why do mobile source NOx emissions jump higher between 2001 and 2002 on the emissions trends?

  The emissions model used for mobile sources changed from MOBILE6.2 to MOVES 2010 in December 2009. This change included a notable increase in NOx emissions. The EPA adjusted data back to 2002 to reflect the change in models. The higher emissions in 2002 are because of this method change and…

  • Last published: May 1, 2024

• What Pollutants are Included in “oxides of nitrogen” in MOVES?

  See More Frequent Questions about MOVES and Related Models . The definition of NOx in MOVES (NO + NO2 + HONO) is different than the standard NOx definition of NOx (NO + NO2). This change has been made to correct the exhaust NOx emission in MOVES for potential interference with…

  • Last published: July 10, 2024

• What Drives Seasonal CO Emission Trends?

  See More Frequent Questions about MOVES and Related Models . Once a vehicle’s engine/catalyst reaches operating temperature, the ambient temperature has little effect on the emissions performance of the vehicle. These “running” emission rates in MOVES have no temperature adjustment. However, during summer months at warm temperatures, MOVES assumes extensive…

  • Last published: July 10, 2024

• Why do the PM2.5 emissions for the electric utilities source category jump up between 1998 and 1999?

  The estimation method for PM emissions from fuel combustion sources was enhanced beginning with the 1999 National Emissions Inventory. Prior to 1999, the emissions measurement data methodology only included the filterable portion (which means the solid particle matter at elevated stack temperatures). Beginning with the 1999 NEI, both the filterable…

  • Last published: August 15, 2024