Abstract
The authors determined differences of the concentrations levels measured by two techniques, one nominated as optical remote sensing method, and the other as point source system. These divergences are caused by different volumes being scanned by the two methods: the remote - sensing method measures over a distance of 20-80 m, while the point-measurement method is focussing only in the middle position of the monitoring path, thus reflecting the local level of pollution, on this special location. This means that mobile pollutant sources are affecting the sensors of both instruments, at different time The IR DOAS long-path method reflects more the pollution along the path, while the stationary measuring point (NDIR) records the pollution in one point.
Keywords: remote sensing evaluation, point source measuring instruments, air quality, trafiic, correlation factors, best practice