Characterization of In-Use Emissions from TxDOT's Non-Road Equipment Fleet

Understanding and pursuing methods to reduce emissions are important goals for the Texas Department of Transportation (TxDOT). Test results from this study showed that neither fuel additive (FA) nor hydrogen enrichment (HE) applications had a significant impact on nitrogen oxides (NOx) emissions or carbon monoxide emissions. Both technologies provided moderate reduction in hydrocarbon and particulate matter emissions. Due to the variability in the data and relatively few equipment units tested, results should be considered as indicative of the direction of changes achieved in emissions levels, not as conclusive evidence of the effectiveness of either FA or HE technologies. Since NOx reductions were the primary focus of this study, researchers do not recommend that TxDOT deploy either FA or HE to reduce emissions of the non-road equipment fleet. However, selective catalytic reduction (SCR) remains a promising option for NOx emissions reductions. The optimization methodology developed as a part of this project has future applicability if TxDOT finds suitable technologies (such as SCR) for deployment in the non-road fleet.