Emissions Models and Other Methods to Produce Emission Inventories
An emissions inventory is a summary or forecast of the emissions produced by a group of sources in a given time period. Air pollution emission inventories are the basis for:
- trends analysis
- regional and local scale air quality modeling
- regulatory impact assessments
-
human exposure modeling.
Inventories of air pollution from mobile sources are often produced by emissions models such as the MOtor Vehicle Emission Simulator (MOVES). See the following resources for information and guidance on preparing mobile source inventories.
On this page:
- General Guidance for Preparing Inventories
- Estimating Commercial Marine Emission Inventories and Port Emissions
- Estimating Emissions from Locomotives
- Estimating Emissions from Aircraft
General Guidance for Preparing Inventories
- See EPA's policies and guidance for modelers producing mobile source air pollution inventories for regulatory purposes such as State Implementation Plans (SIPs) and conformity determinations.
- Procedures for Emission Inventory Preparation - Volume IV: Mobile Sources (pdf) (December 1992, EPA420-R-92-009) from National Transportation Library of the US Department of Transportation: the procedures it describes for highway vehicles and nonroad equipment are out-of-date, but the document may still be useful for creating inventories for some aircraft, and for reference on historical procedures for other mobile source categories.
Estimating Commercial Marine Emission Inventories and Port Emissions
EPA has developed new marine inventory techniques that are more similar to the techniques we use for mobile sources generally, and rely on emission factors, population estimates, and usage characteristics.
- Category 3 Marine Diesel Engines - Final Emission Standards Final Regulatory Support Impact Analysis (pdf) (December 2009, EPA420-R-09-019) Chapter 3, for EPA's 2010 rule, "Control of Emissions from New Marine Compression-Ignition Engines at or Above 30 Liters per Cylinder", contains our inventory estimates and a description of how those estimates were produced for Category 3 commercial marine vessels.
- Final Regulatory Impact Analysis: Control of Emissions of Air Pollution from Locomotives and Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder (pdf) (May 2008, EPA420-R-08-001a) for EPA's 2008 rule, "Control of Emissions of Air Pollution from Locomotives and Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder ", Chapter 3 contains our inventory estimates and a description of how those estimates were produced for Category 1 and 2 commercial marine vessels.
- Port Emissions Inventory Guidance: Methodologies for Estimating Port-Related and Goods Movement Mobile Source Emissions describes the latest, state-of-the-science methodologies for preparing port-related emissions inventory for the following mobile source sectors: ocean-going vessels, harbor craft, recreational marine, cargo handling equipment, onroad vehicles, and rail. This guidance may be used for regulatory, voluntary, and research purposes.
- Marine Emissions Tools Beta (April 2022) (zip) contains two R packages: Ship EF, and ShipPowerModel, which can be used to model emissions from Category 3 commercial marine vessels (CMV) given specific vessel information and operating conditions. These tools are currently beta versions, however, they are consistent with the EPA Port Emissions Inventory Guidance, and therefore they may be used for voluntary and research purposes, as well as to develop inventories to meet regulatory requirements. More information on how to install and use the tools is available on the Marine Emissions Tools GitHub page.
Estimating Emissions from Locomotives
- Emission Factors for Locomotives (pdf) (April 2009, EPA420-F-09-025): this fact sheet lists emission factors for locomotives and provides instructions for preparing locomotive emission inventories based on these factors and annual fuel consumption rates.
Estimating Emissions from Aircraft
Emissions from aircraft are usually estimated with a Federal Aviation Administration Model. Additional information on aviation emissions is available at the EPA Aviation website.