A New Model for Producing Highly Resolved Mobile Source Emissions

University Of California-Davis, Davis CA

Investigators

Abstract

0302538 Niemeier The importance of improving the spatial and temporal inputs and methods associated with estimating mobile source inventories was recently identified as a key concern in a recent National Academy of Science report (National Research Council 2000). As the science behind the modeling of mobile emissions has advanced, it has become clear that new modeling developments at the interface between transportation and air quality modeling are needed to fully encompass contemporary scientific and technological insights. We propose to develop and test a new mobile source emissions inventory modeling platform. Specifically, three major advances will be incorporated into the model: 1) a new gridding algorithm that will improve the spatial representation of mobile emission generating activities and resolve current inventory scaling issues; 2) a new algorithm for estimating the emissions using more discrete vehicle operation (accel/decel) characteristics, and finally, 3) a new algorithm that will allow important emissions-related factors, such as control technology and vehicle distribution, to be specified at the grid scale. We will then apply the new model to the Sacramento region and compare the differences between the gridded inventory emissions under a base scenario and several alternative scenarios. By examining different scenarios, we will be able to characterize how emissions vary spatially due to two factors: the types of emission factors used and the modeling method used to disaggregate transportation activity. The new model will be capable of producing the inventories needed for more accurate gridded emissions for photochemical modeling as well as the inventories needed for regulatory purposes (e.g., state implementation plans (SIPs) and transportation air quality conformity). The model will include both current regulatory emission factors (i.e., those produced by EPA or approved by EPA as in the California case), which will allow comparison to current inventories, as well as new cutting edge emission factors that better account for emissions resulting from variability in discrete vehicle operations.