ABSTRACT
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 0.5-10?m) 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 220?g/g,870?g/g and 230?g/g of Hetian to 980?g/g,5 400?g/g and 1 400?g/g of Lanzhou(P