Worldwide Use of Remote Sensing to Measure Motor Vehicle Emissions

Development and use of remote vehicle emissions sensing has been growing in recent years. Early systems were pioneered by the University of Denver, funded initially by the Colorado Office of Energy Conservation and later by the California Air Resources Board (CARB) in the late 1980s. In the past decade, use of remote sensing has increased dramatically, especially in China.

Vehicle remote sensing technologies are emission-measurement systems that do not physically interact with the vehicle undergoing testing. Unlike testing using chassis dynamometers or portable emission measurement system (PEMS), where vehicle tailpipe emissions are directly measured, remote sensing measures pollutant concentrations in a vehicle’s exhaust plume via spectroscopy as the vehicle drives through a light beam or, alternatively, extracts a sample from the exhaust plume to measure with pollutant analyzers. The first method is much more prevalent and is the primary focus of this paper. Throughout this paper authors refer to the first method as “open path” remote sensing and the second as “extractive” remote sensing.

This paper details the current state of remote sensing technology, research, and deployment around the world, with a particular focus on evaluating barriers to its widespread deployment