Mobile on-line DOAS trace-gases monitoring system with fiber spectroscopy

摘要

The article mainly focused on mobile on-line air quality monitoring system. By deeply analyzed DOAS theory, we designed this new air quality monitoring system. It is mobile and may monitoring many pollution sources on-line everyday. The Differential Optical Absorption Spectroscopy (DOAS), based on the work by U. Platt and co-workers, is becoming increasingly popular for environment monitoring. DOAS may measure many trace gases like NO2, O3, BrO, NO3 , and SO2. It is designed for the measurement of primary and secondary urban air pollutants with high precision and little cross interference. In the DOAS technique, the spectrum of an artificial light source within a given bandwidth is measured after passing through the open atmosphere for between 100 m and 10 km. After removing the emission spectrum of the light source, the remaining differential absorption features are compared with the absorption cross sections of relevant trace gases. This allows both the qualitative and quantitative determination of their concentration in the light path. After deeply research, we design this new system. It uses fiber spectroscopy, and it is mobile. User may monitor many pollution sources in a car. This makes auto-monitoring more easily. Our DOAS system has these merits: New Light Emission-Receiver Unit which united emission, receiver and collimation lenses. New Background Elimination Fiber. And dynamic-feedback self-adapting program. In our experiment by this design idea, we get accurate data.