Beschreibung:
<jats:p><jats:bold>Mass, Number and Surface Area Concentrations of α‐Quartz Exposures of Refractory Material Manufacturing Workers: Jyh‐Larng C<jats:sc>hen</jats:sc>, <jats:italic>et al</jats:italic>. Department of Environmental Engineering and Health, Yuanpei University College of Health Science, Taiwan</jats:bold>—This study set out to assess the respirable mass, surface area, and number concentrations of the α‐quartz content particles (C<jats:sub>r‐m</jats:sub>, C<jats:sub>r‐s</jats:sub> and C<jats:sub>r‐n</jats:sub>) to which workers were exposed in six different exposure groups, the raw material handling (n=10), crushing (n=12), mixing (n=12), forming (n=10), furnace (n=10), and packaging (n=10), in a refractory material manufacturing plant. For C<jats:sub>r‐m</jats:sub>, the exposure values in sequence were found as: mixing (68.1 µg/ m<jats:sup>3</jats:sup>)>packaging (55.9 µg/m<jats:sup>3</jats:sup>)>raw material handling (53.3 µg/m<jats:sup>3</jats:sup>)>furnace (31.0 µg/m<jats:sup>3</jats:sup>)>crushing (29.8 µg/ m<jats:sup>3</jats:sup>)>forming (22.4 µg/m<jats:sup>3</jats:sup>). We also found that ~21.2–68.2% of the above Cr‐m exceeded the current TLV‐TWA for the α‐quartz content (50 µg/m<jats:sup>3</jats:sup>) suggesting a need for initiating control strategies immediately. We further conducted particle size‐segregating samplings in four workplaces: crushing (n=3), mixing (n=3), forming (n=3), and furnace (n=3). We found that all resultant particle size distributions shared a quite similar geometric standard deviation (σ <jats:sub>g</jats:sub>; =2.24–2.92), but the process area, associated with higher mechanical energy (i.e., crushing process), contained finer α‐quartz content particles (mass median aerodynamic diameter; MMAD=3.22 µm) than those areas associated with lower mechanical energy (i.e., mixing, forming, and furnace; MMAD=6.17, 5.95, and 8.92 µm, respectively). These results gave a ratio of C<jats:sub>r‐m</jats:sub> in the above four exposure groups (i.e., crushing: mixing: forming: furnace=1.00: 2.30: 0.753: 1.04) which was quite different from those of C<jats:sub>r‐s</jats:sub> (1.00: 1.74: 0.654: 0.530) and C<jats:sub>r‐n</jats:sub> (1.00: 1.27: 0.572: 0.202). Our results clearly indicate the importance of measuring particle size distributions for assessing workers' free silica exposures.</jats:p>