Workplace exposure to airborne alumina nanoparticles associated with separation and packaging processes in a pilot factory

Abstract

Workplace exposure to airborne Al2O3 nanoparticles in a pilot factory was characterised by particle concentrations, size distribution, morphology and chemical composition, compared with background particles. Real-time variations in number concentration (NC20-1000 nm), respirable mass concentration (MC100-1000 nm), active surface area concentration (SAC10-1000 nm) and particle size were measured at production locations involved in separation and packaging activities. Measurements during stable production periods showed significant increases in the various concentrations of agglomerated Al2O3 nanoparticles (about 305 nm) at separation locations, compared to those of background particles (p < 0.01). The size distribution model for separation processes might switch to primary nanoparticles (21-26 nm) during periods of unstable production. Packaging activities also caused significant increases in different concentrations of Al2O3 nanoparticles (about 90 nm) compared to background particles (p < 0.01). These particles exhibited a bimodal size distribution and floccus or cloudy-like agglomerates of primary nanoparticles. NC20-1000 nm and active SAC10-1000 nm variations showed the same trend, and were temporally consistent with particle emission scenarios or worker activities, but differed from that for respirable MC100-1000 nm. There was strong correlation between active SAC10-1000 nm and NC20-1000 nm (r = 0.823), moderate correlation between active SAC10-1000 nm and respirable MC100-1000 nm (r = 0.666) and relatively weak correlation between NC20-1000 nm and respirable MC100-1000 nm (r = 0.361). These findings from the pilot factory suggest significant exposure to Al2O3 nanoparticles or their agglomerates, associated with separation and packaging processes. The number and active surface area concentrations may be distinct from mass concentration and might be more appropriate for characterizing exposure to airborne nanoparticles.

Exposure characterization and risk assessment of ultrafine particles from the blast furnace process in a steelmaking plant

“…In this study, the order of CR value at the location of slag releasing was: CR SAC (5.39) > CR total NC (2.87) > CR MC (2.22); the order of the correlation coefficients between the total NC, SAC, and respirable MC was R total NC and SAC (r = .681) > R SAC and total respirable MC (0.456) > R total NC and total respirable MC (0.424). These results were supported by our previous study [29][30][31]33 that examined the relationships among the NC, SAC, and MC of different nanoparticles in workplaces, and found that the total NC and SAC had a positive correlation (0.558-0.673), which were greater than the R SAC and MC or R NC and MC .…”

“…24 In addition, our previous field studies approved that the particle concentrations were significantly influenced by the sampling distance from sources, air velocity, background particles, and engineering control measures. [29][30][31] In this study, the personal NC was significantly higher than the total NC (Table 2), the reason might be that the personal NC was measured closer to the particle source. High wind velocity could enhance air exchange in the workshop, which was one of the main mechanisms for particle removal.…”

“…This finding was in agreement with our previous study that reported the bimodal size distribution of airborne alumina nanoparticles associated with separation and packaging processes in a pilot factory. 31 The total NC of particles less than 100 nm was approximately 10 times higher than that of particles above 100 nm. The results of personal sampling showed that the size of the particles decreased from 100 to 30 nm as the working activity started.…”

Characteristics and risk assessment of occupational exposure to ultrafine particles generated from cooking in the Chinese restaurant

“…The correlation between total NC and SAC was 0.786, the correlation between NC and MC was 0.218, the correlation between SAC and MC was 0.380. The correlations between total NC, SAC, and MC has been explored in previous studies about ultrafine particles using real-time measurements 36 , 37 , which supported our finding. The high correlation between NC and SAC might be related to the fact that the 3007 counts the number of particles, the AeroTrak charges particles in a unipolar charge and then converting the number of particles into surface area.…”

Critical Review on Toxicological Mechanisms Triggered by Inhalation of Alumina Nanoparticles on to the Lungs

“…Workers’ exposure to Al 2 O 3 NPs can mainly occur by inhalation. Occupational exposures to these dusts are described in the literature to have deleterious health effects on the respiratory and nervous systems [ 3 , 6 , 7 , 8 , 9 ]. Therefore, it is necessary to improve understanding of NPs toxicity in order to redesign strategies to mitigate/reduce environmental and/or health impact [ 10 ].…”