An ERG project to collect and analyze vehicle exhaust emissions in Kansas City has been instrumental in updating the Environmental Protection Agency’s (EPA’s) fuel economy rating procedures. The project was also selected as the winner of EPA’s Science Achievement Award in Air Quality for significantly advancing the field of emissions characterization. The data gathered from the project will help EPA assess the accuracy of existing emission inventories and models, as well as lay the foundation for future emission models. The ERG team characterized the distribution of particulate matter (PM) emissions in the city’s fleet and identified the percentage of high emitters. In addition to supervising onsite dynamometer testing, ERG collected real-time, concurrent vehicle exhaust data using Portable Emissions Measurement Systems (PEMS).

Through a pilot study for the U.S. Environmental Protection Agency (EPA), ERG is collecting real-time emission data from construction equipment that will help refine estimation methods for future projects. The study integrates statistical sampling techniques, the latest emission measurement technology, and rigorous quality assurance procedures to characterize in-use, real-world emission and activity data from 50 nonroad diesel engines. The knowledge gathered during the study will be used to develop load versus emissions relationships in EPA’s Motor Vehicle Emissions Simulator (MOVES) model.

For the Texas Commission on Environmental Quality, ERG evaluated the performance of the state’s I/M program to ensure conformity with U.S. Environmental Protection Agency (EPA) guidelines. The project focused on process-based and results-based measures of performance. Process-based measures are coverage, inspection, repair, and enforcement. Results-based measures are determined from the repair-induced changes in emissions, as measured by the I/M program inspections and by onroad, remote sensing device measurements. To assess various aspects of program performance, the ERG evaluation team worked with remote sensing data, as well as data from the Vehicle Information Database and Department of Public Safety Station audits.

ERG developed a recent release of the EMFAC code, Emfac2007, for the California Air Resources Board (ARB). EMFAC is a computer model that uses mathematical formulas and collected data to estimate the emissions from various types of motor vehicles at different times of the day and season. ERG has been ARB’s main contractor for the development and upkeep of this model since 1999. Users have many new features including the use of special “what if” capabilities to edit constants, such as vehicle populations, trips per day, and climate data, to develop a series of estimation scenarios. Emfac2007 also includes substantial changes to the main calculation loop and the program constants and a rewrite of the user interface. To implement all of the improvements for Emfac2007, ERG has developed and modified the architecture of all three main calculation modes of the program.