Adjusting MOVES’ Emission Factors in Light-duty Vehicles for a Specific Region Using Local Measurements

Abstract

It was initially observed that experimental and analytical emissions data exhibit cubic exponential behavior when expressed in terms of emissions mass flow vs. specific power (VSP). Consequently, for each year-model of a given technology, a representative experimental value of emissions at a given VSP is sufficient to fit that curve to reproduce the behavior over the entire VSP range. The experimental value can be obtained by measurements from inspection and maintenance programs, such as RSD or on rollers. As an illustrative example, this methodology was applied to the case of the city of Monterrey (MOVES MTY). Additionally, the tool's potential was illustrated by determining the vehicle emissions in each road of a reduced region (in this case, a university district) from traffic simulation data. The emissions inventory obtained showed that using unadjusted emission factors estimates 10.5% fewer CO emissions and 20.0% fewer NOx emissions than using the MOVES MTY emission factors.