UC Irvine Institute of Transportation Studies

We extend a previous cost-effectiveness analysis of methanol versus other means of controlling emissions from urban transit buses, by developing a method to incorporate their effects on two end-product pollutants: ozone and nitrogen dioxide. Using published simulation results from an airshed grid model of ozone formation, we find that the measures we consider have varying effects on ozone at 23 sites in the Los Angeles air basin. The effects are offsetting, leading to a negligible net effect when aggregated across the basin's population; this is true assuming either that damage is proportional to concentration times population exposed, or that damage is represented by nonlinear concentration-response functions for specific health conditions. In contrast, either low-aromatic diesel fuel or methanol would lower ambient concentrations of nitrogen dioxide enough, relative to the federal or California ambient standard, to significantly affect cost-effectiveness comparisons.