cess。 At this stage, it might not be able to know what led to the intrinsic differences in MMADf among three studied industrial processes because factors associated with the evo- lution of aerosols in the field were very complicated (such as saturated vapor pressure, surface tension, and molecular weights of the involved MWFs, etc。) [35]。 However, our results

(MMADf = 0。309−0。501 µm) are quite consistent with that found in a clutch manufacturing plant (MMADf = 0。1−1。0 µm) [33]。

3。3。

Estimating the concentrations of oil mists exposed to different regions of the respiratory tract for fastener manufacturing industry workers

Table 4 summarizes the concentrations (including AMMVUE and its 95% CI) of inhalable (Cinh), thoracic (Cthor) and res- pirable fractions (Cresp) of oil mists exposed to workers of the three-selected exposure groups。 All resultant concentra- tions for heat treatment process workers were the lowest among the three exposure groups (nonparametric Mann–Whitney test, p < 0。05)。 Although Cinh for the forming workers were signifi- cantly higher than that for the threading workers (nonparametric Mann–Whitney test, p < 0。05), no significant differences could be found in Cthor and Cresp (p > 0。05)。

Table 5 shows the concentrations of oil mists (including AMMVUE and its 95% CI) exposed to the head region (Chead), tracheobronchial region (Ctb), and alveolar region (Calv) of the respiratory tract for workers of the three selected exposure groups。 Again, all resultant concentrations for heat treatment process workers were the lowest among the three exposure groups (nonparametric Mann–Whitney test, p < 0。05)。 By com- paring the concentrations for both forming and threading process workers, a significant difference could be seen in both Chead and Ctb (nonparametric Mann–Whitney test, p < 0。05), but no signifi- cant differences were found in Calv (p > 0。05)。 Nevertheless, Calv was consistently higher than both Chead and Ctb in all three stud- ied exposure groups。 The above results clearly indicate that most oil mists generated from the fastener manufacturing process might be able to reach the deep lung (i。e。, the alveolar region)。 Here, it should be noted that the mean Calv for both forming andthreading process workers (1。34 and 1。40 mg/m3, respectively)论文网

were much higher than the level known for causing “increased risk of pulmonary injury” (0。2 mg/m3) [13]。 Our results clearly suggest that appropriate control measures should be taken by the fastener manufacturing industry, particularly for the abatement

of oil mist exposure concentrations of the respirable fraction to both forming and threading process workers。

4。Conclusions

We found that the inhalabe oil mist concentrations for workers in the fastener manufacturing industry were higher than those for workers in many other industries。 But theses values were still less than the limit value promulgated by OSHA, NIOSH, ACGIH, HSE, and Taiwan government。 We found that particle size distributions of oil mists occurred in workplaces were dom- inated by the fine mode。 The estimated mean alveolar oil mist exposures were much higher than the level known for causing “increased risk of pulmonary injury” (0。2 mg/m3) suggesting that appropriate control measures should be taken to reduce workers’ exposure to oil mists with fine particle sizes。

Acknowledgment

The authors wish to thank National Science Council in Tai- wan for funding this research project。

摘要本研究着手于油雾的粒径分布在成形，线程和热处理三个工作场所空气中的紧固件制造业和他们的风险评估工人。粒度偏析取样通过使用改性玛普莱8级联冲击器（在三个选定的工业过程的工作场所的气氛进行米-Marple）。我们发现，质量平均空气动力学直径精细模式（MMAD）和粗模式分别下降到范围0。309-0。501米和8。16-13。0微米。暴露在呼吸道不同区域吸入颗粒的分数发现，肺泡区域一直高于头部和气管地区在所有三个研究暴露组高。个人可吸入油雾取样是在三个选定过程对工人进行暴露了他们的暴露水平为：螺纹工（2。11毫克/立方米3）>成型工（1。58毫克/立方米3）>热处理工（0。0801毫克/米3） 。为形成和穿线工人所估计的吸入暴露浓度（1。34毫克/米3和1。40毫克/米3，分别）比对“增加肺伤害的风险”（0。20毫克/米已知的水平3），表明相应的应采取控制措施，立即减少其暴露于可呼吸部分的油雾。文献综述