[Dose-response relationship between different respirable coal dust exposures and pneumoconiosis risk].

Objective: To investigate the dose-response relationship between the cumulative dust exposures to anthracite, bituminous coal, and lignite and the cumulative prevalence rates of pneumoconiosis due to the exposures, respectively and provide a basis for scientific development of occupational health standards. Methods: Investigation on the exposure to coal dust and pneumoconiosis prevalence was conducted in 9 state-owned coal mines. The cumulative anthracite, bituminous coal, and lignite dust exposure specific cumulative prevalence rates of pneumoconiosis were calculated by life table method, respectively. The linear regression equations were used to control the unilateral interval to obtain the exposure concentration limits of the respirable coal dust, respectively. Results: A total of 21 000 coal miners in the 9 coal mines were included in the study. The detection rates of pneumoconiosis in coal miners in anthracite, bituminous coal and lignite mines were 11.27%, 21.32%, and 6.00%. The average lengths of exposure to coal dust at pneumoconiosis onset were 20.12 years, 22.88 years, and 25.21 years, respectively and the dose-response relationships between the cumulative respirable coal dust exposure and the cumulative prevalence rates were all linear regression equations, which are y=5.788x-16.043 (R(2)=0.949), y=5.679x-16.837 (R(2)=0.904), and y=6.465x-19.573 (R(2)=0.944), respectively. Supposing that the safety coefficient is 1.2, when the cumulative prevalence rate of pneumoconiosis after 30 years of exposure to dust is not higher than 1%, the exposure concentration limits of the three types of respirable coal dust are 1.7, 2.3, and 3.9 mg/m(3), respectively. Conclusions: The results of this study shows that the detection rate of pneumoconiosis, the average length of exposure to coal dust at pneumoconiosis onset, and the exposure concentration limits of the respirable coal dust varied with coal types. In the case of the same cumulative level of coal dust exposure, the lower the coal volatiles is (i.e. the higher the carbon content is), the higher the cumulative prevalence rate of pneumoconiosis is (anthracite>bituminous coal>lignite). It is suggested to develop national occupational health standards of coal dust exposure according to the grades of coal.目的： 探讨无烟煤、烟煤、褐煤呼吸性粉尘与尘肺病累计患病率的剂量-反应关系，为科学制定职业卫生标准提供依据。 方法： 对9处国有煤矿采煤工人的接尘和尘肺病患病情况进行调查研究，以寿命表法分别计算出无烟煤、烟煤、褐煤呼尘累计接尘量对应的累计患病率，利用线性回归方程进行单侧区间统计控制，得到呼尘接触浓度限值。 结果： 9处煤矿共21 000名采煤工人纳入研究，其中无烟煤、烟煤、褐煤煤矿采煤工人尘肺病检出率分别为11.27%、21.32%、6.00%，平均接尘工龄为20.12、22.88、25.21年。无烟煤、烟煤、褐煤煤矿采煤工人呼尘累计接尘量与尘肺病累计患病率的剂量-反应关系分别为线性回归方程y＝5.788x－16.043（R(2)＝0.949）、y＝5.679x－16.837（R(2)＝0.904）、y＝6.465x－19.573（R(2)＝0.944）。当接尘30年尘肺累计患病率≤1%时，以安全系数为1.2计算，三者呼尘接触浓度限值分别为1.7、2.3、3.9 mg/m(3)。 结论： 不同煤种的尘肺病检出率、平均接尘工龄、呼尘接触浓度限值均不同，在煤尘累计接尘量相似情况下，煤的挥发分越低（含碳量越高），累计患病率越高（无烟煤>烟煤>褐煤）。建议按照不同煤种分别制定国家职业卫生煤尘标准。.