A survey of size-fractionated dust

A survey of size-fractionated dust exposure was carriedout in 10 wood processing plants across the United Statesas part of a 5-year longitudinal respiratory health study.The facilities included a sawmill, plywood assembly plants,secondary wood milling operations, and factories producingfinished wood products such as wood furniture and cabinets.Size-fractionated dust exposures were determined using theRespiCon Personal Particle Sampler. There were 2430 validsets of respirable, thoracic, and inhalable dust samples collected.Overall, geometric mean (geometric standard deviation)exposure levels were found to be 1.44 (2.67), 0.35(2.65), and 0.18 (2.54) mg/m3, for the inhalable, thoracic,and respirable fractions, respectively. Averaged across allsamples, the respirable fraction accounted for 16.7% ofthe inhalable dust mass, whereas the corresponding figurefor thoracic fraction as a percentage of the inhalable fractionwas 28.7%. Exposures in the furniture manufacturingplants were significantly higher than those in sawmill andplywood assembly plants, wood milling plants, and cabinetmanufacturing plants, whereas the sawmill and plywoodassembly plants exhibited significantly lower dust levels thanthe other industry segments. Among work activities, cleaningwith compressed air and sanding processes producedthe highest size-fractionated dust exposures, whereas forkliftdrivers demonstrated the lowest respirable and inhalabledust fractions and shipping processes produced the lowestthoracic dust fraction. Other common work activities such assawing, milling, and clamping exhibited intermediate exposurelevels, but there were significant differences in relative rankingof these across the various industry segments. Processingof hardwood and mixed woods generally were associatedwith higher exposures than were softwood and plywood,although these results were confounded with industry segmentalso.

A survey of size-fractionated dust exposure was carried.Out in 10 wood processing plants across the United States.As part of a 5-year longitudinal respiratory health study.The facilities included a sawmill plywood assembly plants,,Secondary wood milling operations and factories, producing.Finished wood products such as wood furniture and cabinets.Size-fractionated dust exposures were determined using the.RespiCon Personal Particle Sampler. There were 2430 valid.Sets, of respirable thoracic and inhalable, dust samples collected.Overall geometric, mean (geometric standard deviation).Exposure levels were found to be 1.44 (2.67), 0.35.(2.65), and 0.18 (2.54) mg / m3 for the inhalable thoracic,,,And, respirable fractions respectively. Averaged across all.Samples the respirable, fraction accounted for 16.7% of.The inhalable dust mass whereas the, corresponding figure.For thoracic fraction as a percentage of the inhalable fraction.Was 28.7%. Exposures in the furniture manufacturing.Plants were significantly higher than those in sawmill and.Plywood assembly plants wood milling plants and cabinet,,,Manufacturing plants whereas the, sawmill and plywood.Assembly plants exhibited significantly lower dust levels than.The other industry segments. Among, work activities cleaning.With compressed air and sanding processes produced.The highest size-fractionated dust exposures whereas forklift,,Drivers demonstrated the lowest respirable and inhalable.Dust fractions and shipping processes produced the lowest.Thoracic dust fraction. Other common work activities such as.,, sawing milling and clamping exhibited intermediate exposure.Levels but there, were significant differences in relative ranking.Of these across the various industry segments. Processing.Of hardwood and mixed woods generally were associated.With higher exposures than were softwood, and plywoodAlthough these results were confounded with industry segment.Also.