Objective To compare the lung damag effect of quartz dusts of micrometer or nanometer particle size.
Methods The wet weight and hydroxyproline content of lungs of rats were compared after exposed to quartz dusts(20 mg/rat)of micrometer or nanometer particle size for 30 and 60 days.
Results The wet weight and hydroxyproline content of lungs exposed to micrometer dust are significantly higher than those of the controls, but those exposed to nanometer dusts are remarkably lower than those of the micrometer group and not significantly different from those of the controls.
Conclusion The lung damaging effect of quartz dust reduces as the particle size reduces from micrometer to nanometer scale.