Mobile Source Emission Inventory

This page last updated on December 30, 2014


The mobile source emissions inventory is ARB's tool for assessing the population, activity, and emissions from mobile sources. These inventories are constantly being revised and updated to support the latest air quality plans and regulations. Periodically these inventories are compiled and released to the public for use in transportation and air quality assessments both internal and external to the agency. Mobile source inventories are developed by the Mobile Source Analysis Branch in the Air Quality Planning and Science Division. In these web pages you will find two different ways of accessing current information. Data can be accessed for specific regulatory items by mobile source category or through the methods and in some cases models that are used to estimate emissions.

EMFAC2014 Public Release (New)

Click the link above to learn about EMFAC2014


November 7, 2014 workshop on updates to Mobile Source Emissions Inventory. Click link above for details.

Current Methods and Data

Click the link above to learn about the tools we use to estimate mobile source emissions


Click the link above to learn about EMFAC2011

Mobile Source Categories

Individual category-specific emissions estimates and documentation are developed for specific agency regulatory activities.  Categories include cars/light truck assessments for emissions standard development, heavy duty truck and in-use off-road emissions estimates for in-use diesel Rules, and category specific emissions estimates for ocean-going vessels, pleasure craft, and many other types of vehicles.

Previous Methods and Historical Documentation

Additional information is available for previous model versions, system documentation and archived information.