A mobile laser-induced read more fluorescence spectrum (LIFS) lidar was developed for monitoring pollens floating in the atmosphere.The fluorescence spectrum of pollens excited at 355 nm was measured with a fluorescence spectrometer and the results suggested that in general they had peaks at around 460 nm and the ranges were 400–600 nm.A fluorescence spectrum database of 25 different pollens was made with the 355 nm excitation.Based on these results, we developed a LIFS lidar that had features in pollen species identification and daytime operation.
The former was achieved by the database and the latter was possible by introducing a synchronous-delay detection to a gated CCD spectrometer in an operation time of 200 ns.Fluorescence detection of pollens floating in the atmosphere was performed using the LIFS lidar in a field where cedars grow in the spring and ragweed in the autumn.The LIFS lidar system successfully detected fluorescence spectrums of the pollens at a distance of approximately redken shades 9gi 20 m away.We discussed the performance of the LIFS lidar by estimating the number of cedar pollens using a lidar equation, introducing a fluorescence cross section of cedar pollens and a sensitivity of the CCD spectrometer that was measured by ourselves.