Develop an Ammonia-Related Emissions Component for Inclusion In PART or MOBILE Emissions Models

Focus Area

Air Quality


Air Quality






1-2 years

Research Idea Scope

TERI Database Administrator Notes:  Not recommended at present time by 2009 Air Quality Subcommittee. 

PART5 calculates exhaust emission factors for primary emitted particulates, brake and tire wear emissions, and re-entrained road dust emissions. However, the PART5 model does not provide emission estimates for gas phase emissions that form as a result of chemical reactions in the atmosphere. These PM precursor emissions are at times a significant contributor to ambient PM in some regions (Turner, 1998). While EPA’s “MOBILE” model does estimate some PM precursor emissions (such as VOC and NOX), the MOBILE model does not estimate emissions of ammonia that is an important PM precursor.

This project will involve developing modeling procedures to estimate ammonia emissions and to incorporate these procedures into the MOBILE or PART5 models. Although work is still being undertaken on developing an air quality model that can accurately estimate the effects of precursor emissions on ambient PM, this project will help to provide the foundation for estimating the transportation contribution to all major PM precursors.

Urgency and Payoff

Ammonia is an important PM precursor emitted by transportation sources that is not currently included in emission models. If secondary formation is a major contributor to PM, planners need to estimate the impacts of transportation projects on PM precursor emissions and air quality.


Suggested By

FHWA Strategic Work Plan for Particulate Matter Research