LASER POWER LOSS IN DUST CONDITIONS

With accordance to the classic physics and to the real experiment: photons with wave length (WL), smaller than the particle, will be absorbed or reflected. Photons with WL larger the particle size will go throw ignoring collision as absorption or interaction. 

On the basis of the shown graphics for the particle size and its concentration into the atmosphere
it indicates: that the typical size of the particle's spectrum belongs to the range  between 1 - 4 microns with the biggest concentration pick for 2-3 micron.