Abstract: The distributions of fine and coarse particles in the air of boron processing plants,including the number concentration and mass concentration,were reported.The dust concentrations in the workshops of crushing,ball milling and Leimond milling are up to 28,33 and 23 mg/m3,respectively.The percentages of PM\-\10\ in the particles are repectively 62.1%,62.7% and 56.5%,whereas the percentages of fine particles in PM\-\10\ are relatively small,with 10.1%,14.2% and 9.22%,respectively.However,the mass concentrations of PM2.5 are respectively 1.76,2.94 and 1.20 (mg/m3.)In addition,the aerial boron concentrations in ball milling and Leimond milling workshops are analyzed with ICP-MS,with the results of 425.6 and 669.1 μg/m3,respectively,which indicates quite serious pollution.