Open AccessMass, Number and Surface Area Concentrations of α‐Quartz Exposures of Refractory Material Manufacturing Workers
Author(s) -
Chen JyhLarng,
Su LiFang,
Tsai ChingLang,
Liu HungHsin,
Lin MingHsiu,
Tsai PerngJy
Publication year - 2007
Publication title -
journal of occupational health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 59
ISSN - 1348-9585
DOI - 10.1539/joh.49.411
Subject(s) - quartz , aerodynamic diameter , particle size , mixing (physics) , raw material , geometric standard deviation , materials science , metallurgy , chemistry , aerosol , physics , organic chemistry , quantum mechanics
Mass, Number and Surface Area Concentrations of α‐Quartz Exposures of Refractory Material Manufacturing Workers: Jyh‐Larng C hen , et al . Department of Environmental Engineering and Health, Yuanpei University College of Health Science, Taiwan —This study set out to assess the respirable mass, surface area, and number concentrations of the α‐quartz content particles (C r‐m , C r‐s and C r‐n ) 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 r‐m , the exposure values in sequence were found as: mixing (68.1 µg/ m 3 )>packaging (55.9 µg/m 3 )>raw material handling (53.3 µg/m 3 )>furnace (31.0 µg/m 3 )>crushing (29.8 µg/ m 3 )>forming (22.4 µg/m 3 ). 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 3 ) 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 g ; =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 r‐m 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 r‐s (1.00: 1.74: 0.654: 0.530) and C r‐n (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.