Silica Dust Exposures During Selected Construction Activities

Abstract

This study characterized exposure for dust-producing construction tasks. Eight common construction tasks were evaluated for quartz and respirable dust exposure by collecting 113 personal task period samples for cleanup; demolition with handheld tools; concrete cutting; concrete mixing; tuck-point grinding; surface grinding; sacking and patching concrete; and concrete floor sanding using both time-integrating filter samples and direct-reading respirable dust monitors. The geometric mean quartz concentration was 0.10 mg/m(3) (geometric standard deviation [GSD]=4.88) for all run time samples, with 71% exceeding the threshold limit value. Activities with the highest exposures were surface grinding, tuck-point grinding, and concrete demolition (GM[GSD] of 0.63[4.12], 0.22[1.94], and 0.10[2.60], respectively). Factors recorded each minute were task, tool, work area, respiratory protection and controls used, estimated cross draft, and whether anyone nearby was making dust. Factors important to exposure included tool used, work area configuration, controls employed, cross draft, and in some cases nearby dust. More protective respirators were employed as quartz concentration increased, although respiratory protection was found to be inadequate for 42% of exposures. Controls were employed for only 12% of samples. Exposures were reduced with three controls: box fan for surface grinding and floor sanding, and vacuum/shroud for surface grinding, with reductions of 57, 50, and 71%, respectively. Exposures were higher for sweeping compound, box fan for cleanup, ducted fan dilution, and wetted substrate. Construction masons and laborers are frequently overexposed to silica. The usual protection method, respirators, was not always adequate, and engineering control use was infrequent and often ineffective.

Cell markers, cytokines, and immune parameters in cement mason apprentices

“…Such workers are responsible for mixing, pouring, spreading, sanding, and grinding hard concrete. The dust generated by masons working with concrete bricks, for example, has been shown to be composed of Ͼ12% silica (3). At high levels, silica results in silicosis, a condition characterized by radiographic changes, impaired pulmonary function, and increased risk of other respiratory diseases (4).…”

“…Both electricians and masons, not surprisingly, reported exposure to masonry dusts; however, as expected, masons reported a greater degree of such exposure, providing a degree of validation to the exposure metric. Future studies using personal monitoring and evaluating the extent and effectiveness of the use of respiratory protection, although historically minimally and ineffectively used in this setting (27), would allow for development of an individually based quantitative exposure metric.…”

In-depth survey report: control technology for dowel-pin drilling in concrete pavement.

“…Many construction tasks have been associated with overexposure to dust containing crystalline silica [Chisholm 1999, Flanagan et al 2003, Rappaport et al 2003, Woskie et al 2002. Among these tasks are tuckpointing, concrete cutting, concrete grinding, abrasive blasting, and road milling [Nash and Williams 2000, Thorpe et al 1999, Akbar-Kanzadeh and Brillhart 2002, Glindmeyer and Hammad 1988, Linch 2002, Rappaport et al 2003].…”

The effectiveness of DustBubbles on dust control in the process of concrete drilling

“…Dust from construction activities, particularly true for silica dust, has an adverse effect on the local environment and on the health of local residents, as well as on those working on the site. There is a long-term concern about the overexposure of construction workers to respirable crystalline silica (Chisholm, 1999;Flanagan et al, 2003;Valiante et al, 2004). The high exposure to crystalline silica, even over a short period, can lead to silicosis.…”