The results of several studies on the emission characteristics of methanol- and diesel-fueled buses are summarised. To facilitate comparison, the emissions test data at idle and in various driving cycles are presented on an hourly or per-mile basis and are ordered by the speed of the test. The emissions of specific pollutants from methanol-fueled test vehicles varied greatly with average speed and depended on the engine technology and the emission control devices used. The results suggest that the most likely substitution of methanol-fueled buses for diesel-fueled buses is not likely to result in net air quality improvements for very low-speed bus operations in an urban environment. Under these conditions, the negative effects of increases in carbon monoxide, formaldehyde, and hydrocarbons may offset the positive effects of particulate emissions reduction. In this paper, there is no attempt to weight emissions, estimate air quality, or quantify net emissions effects.
Samenvatting