Historical Total and Respirable Silica Dust Exposure Levels in Mines and Pottery Factories in China

Historical exposure estimates of total dust and respirable silica were made in a recent nested case-referent study of lung cancer among mine and pottery workers in China. Exposure to total dust and respirable silica was assessed in 20 mines and 9 pottery factories. The average total dust concentration was 7.26 mg · m⁻³, with a range from 17.68 mg · ɻ³; in the 1950s to 3.85 mg · ɻ³; in the 1980s, while the average respirable silica dust was 1.22 mg · ɻ³;, with a range from 3.89 mg · ɻ³; in the 1950s to 0.43 mg · ɻ³; in the 1980s. The highest respirable silica dust occurred in the underground mining operations (1.43 mg · ɻ³;), particularly for manual drillers (9.03 mg · ɻ³;). Among all facility types, tungsten mines had the highest respirable silica dust exposure (1.75 mg · ɻ³;), while the lowest exposure occurred in copper-iron mines (0.32 mg · ɻ³;).