Research Projects

Off-road mobile sources powered by diesel engines have become increasingly greater contributors to the mobile source emissions inventories as emissions from on-road diesel engines have been reduced. However the emissions inventories for off-road sources are not as well characterized as on-road sources. One particular need is to be able to quantify emissions deterioration for in-use off-road engines as these engines accumulate hours of operation. The objective of this project is quantify engine and emissions deterioration for certain categories of off-road equipment. This objective will be accomplished by administering surveys to collect data to identify engine components that deteriorate as engine hours of operation accumulate, and by collecting emissions data from in-use engines operating in the South Coast Air Basin (SoCAB). The results from this project will be used to update and improve ARB's off-road emissions inventory model OFFROAD, and this revised model will provide ARB policy makers with improved emissions estimates for these source categories.