Objective To survey free crystalline silica[SiO_2(F)]content,particle size and water-soluble components concentration in the sand-dust storm dust,in order to prevent large-scale non-occupational silicosis(desert lung) prevalence in northwest desert area of China.Methods Atmospheric dust(falldust) were collected in Hetian,Minqin,Zhongwei and Lanzhou city when sand-dust storm befallen and free crystalline silica,particle size ratio and water-soluble components were analyzed according to GB 5748—1985.Results The rate of SiO_2(F) component was over 50%in the original sand,the rate of SiO2(F) component was from 17.36% to 48.09%in the falldust of sand-dust storm,the falldust belongs to crystal dust.The inhaleble particle(particles with amedian diameter of 0.5-10μm) ratio was from 63.3%to 84.1%.The water-soluble components concentration increased as sand-dust storm moving.C1,SO_4~(2-) and NO_3~- content was from 220μg/g,870μg/g and 230μg/g of Hetian to 980μg/g,5 400μg/g and 1 400μg/g of Lanzhou(P0.01).Conclusion The falldust of sand storm inhalation is a high-risk factor for the local peoples to be attacked by non-occupational pneumoconioses.The further studies should be carried out in epidemiological and toxicological fields.

Objective To explore the damage on alveolar macrophages(AMs) induced by desert dust of Hetian and Minqin, China.Methods AMs were cultured with different concentrations of desert dust and SiO_2 respectively.AMs of the control group were cultured with normal DMEM culture medium.After 24 hours exposure,cells supernatant of culture media was collected and MDA content,GSH-Px activity,LDH activity and TGF-β_1 content was measured.Results Compared with the control group, survival rate of AMs decreased significantly in 400,800,1 600μg/ml desert dust groups of Hetian and 100,200,400,800,1 600μg/ml groups of Minqin,the content of MDA,GSH-Px activity and TGF-β_1 content in 200 and 400μg/ml desert dust groups of Hetian and Minqin increased significantly(P<0.05),while the activity of LDH in 100,200 and 400μg/ml groups of desert dust and SiO_2 group increased significant(P<0.01).Conclusion Desert dust from Hetian and Minqin has cytotoxicity to AMs,can enhance lipid peroxidation and releases fibrosis factor TGF-β_1.