Online monitoring of exhaust emissions using mid-infrared spectroscopy

Existing automotive sensors do not quantify the levels of pollutants entering the atmosphere; instead they merely indicate that pollution is occurring. However to meet European legislation on emission control, it is necessary to quantify the levels of each type of pollutant leaving the exhaust of a vehicle. This paper discusses the development of an optical sensor suitable for the detection of gas emissions from a motor vehicle based on mid-infrared spectroscopy. Initial tests to detect carbon dioxide using low-cost mid-infrared components are described and a detection system, which could be fitted to an automobile, is outlined.