Analyzing on-road emissions of light-duty vehicles with portable emission measurement systems (PEMS)

Emissions testing in the laboratory forms an essential part of the European type approval procedure for light-duty vehicles. The approach yields reproducible and comparable emissions data and provides clear design criteria for vehicles that have to comply with applicable emission limits. Although emission limits have become increasingly stringent in the past decade, road transport remains the most important source of urban air pollution in Europe with respect to NOX (nitrogen oxides) and CO (carbon monoxide). Several studies have indicated that in particular on-road NOX emissions of light-duty diesel vehicles might substantially exceed emission levels as identified during emissions testing in the laboratory. Still, a comprehensive analysis of on-road emissions of light-duty diesel and gasoline vehicles is unavailable to date. This report addresses the existing knowledge gaps by using Portable Emission Measurement Systems (PEMS) to analyze the on-road emissions of 12 light-duty diesel and gasoline vehicles that comply with Euro 3-5 emission limits and comprise small and midsize passenger cars, two transporters, and a minivan. The selected vehicles where tested on four test routes, representing rural, urban, uphill/downhill, and motorway driving.