Remote passive detection of aircraft exhausts at airports

摘要

Emissions from vented sources are often important inputs for the development of emission inventories and contribute to local air pollution and global enhancement of greenhouse gases. Aircraft engines are part of these emission sources. A passive measurement technique such as FTIR emission spectrometry is more cost effective and faster in operation for the determination of the composition of hot exhausts of this kind than other measurement systems as e.g. in situ techniques. Within the scope of aircraft emission investigations the measurements were performed from a measurement van which is equipped with an FTIR spectrometer of high spectral resolution coupled with a telescope and a two-axis movable mirror for rapid orientation towards the emission sources. At airports the emission indices of CO_2, CO and NO of main engines and auxiliary power units of standing aircraft were determined. The measurement time is about one minute. The accuracy is better than 30 % as found from burner experiments with calibration gases (CO and NO). The method is also applied to detect exhausts of flares and smoke stacks. Currently, a new scanning FTIR-system is developed. The system allows imaging of the exhaust gas and rapid automated alignment of the field of view. The goal of the new development is to measure aircraft exhausts during normal operations at the airport. The spectrometer is coupled with a camera giving an image of the scenery so that a rapid selection of the hottest exhaust area is possible. It is planned to equip the system with an infrared camera for automatic tracking of this area with the scanning mirror so that measurements of the exhausts of a moving aircraft are possible.