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Evolution of welding-fume aerosols with time and distance from the source: a study was conducted on the spatiotemporal variability in welding-fume concentrations for the characterization of first- and second-hand exposure to welding fumes.

Cena LG; Chen BT; Keane MJ

Welding J 2016 Aug; 95:280-s-285-s

https://s3.amazonaws.com/WJ-www.aws.org/supplement/WJ_2016_08_s280.pdf

20048443

Gas metal arc welding fumes were generated from mild-steel plates and measured near the arc (30 cm), representing first-hand exposure of the welder, and farther away from the source (200 cm), representing second-hand exposure of adjacent workers. Measurements were taken during 1min welding runs and at subsequent 5-min intervals after the welding process was stopped. Number size distributions were measured in real time. Particle mass distributions were measured using a micro-orifice uniform deposition impactor, and total mass concentrations were measured with polytetrafluorothylene filters. Membrane filters were used for collecting morphology samples for electron microscopy. Average mass concentrations measured near the arc were 45 mg/m3 and 9 mg/m3 at the farther distance. The discrepancy in concentrations at the two distances was attributed to the presence of spatter particles, which were observed only in the morphology samples near the source. As fumes aged over time, mass concentrations at the farther distance decreased by 31% (6.2 mg/m3) after 5 min and an additional 13% (5.4 mg/m3) after 10 min. Particle number and mass distributions during active welding were similar at both distances, indicating similar exposure patterns for welders and adjacent workers. Exceptions were recorded for particles smaller than 50 nm and larger than 3 um, where concentrations were higher near the arc, indicating higher exposures of welders. These results were confirmed by microscopy analysis. As residence time increased, number concentrations decreased dramatically. In terms of particle number concentrations, second-hand exposures to welding fumes during active welding may be as high as first-hand exposures.

Welding; Gas welders; Arc welding; Arc welders; Welding fumes; Exposure assessment; Employee exposure; Sampling; Morphology; Particle counters; Particle size; Electron microscopy; Membrane filters; Fumes; Particulates; Airborne particles; Aerosol particles; Author Keywords: Arc Welding; Exposure Assesment; Welding Aerosols; Spatiotemporal Variability; Morphology; Distance

L. G. Cena, West Chester University of Pennsylvania

WEJUA3

20160801

Journal Article

LCena@wcupa.edu

2016

0043-2296

HELD

Construction

Welding Journal

PA; WV