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Comparison of nanoparticle exposures between fumed and sol-gel nano-silica manufacturing facilities.

Oh S, Kim B, Kim H - Ind Health (2014)

Bottom Line: Due to the high-temperature formation process, the particles exhibited a sintering coagulation.In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure).The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Employment and Labor, Republic of Korea.

ABSTRACT
Silica nanoparticles (SNPs) are widely used all around the world and it is necessary to evaluate appropriate risk management measures. An initial step in this process is to assess worker exposures in their current situation. The objective of this study was to compare concentrations and morphologic characteristics of fumed (FS) and sol-gel silica nanoparticles (SS) in two manufacturing facilities. The number concentration (NC) and particle size were measured by a real-time instrument. Airborne nanoparticles were subsequently analyzed using a TEM/EDS. SNPs were discharged into the air only during the packing process, which was the last manufacturing step in both the manufacturing facilities studied. In the FS packing process, the geometric mean (GM) NC in the personal samples was 57,000 particles/cm(3). The geometric mean diameter (GMD) measured by the SMPS was 64 nm. Due to the high-temperature formation process, the particles exhibited a sintering coagulation. In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure). The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

No MeSH data available.


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Comparison of nanoparticle exposures between fumed and sol-gel silica manufacturingfacilities.
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fig_004: Comparison of nanoparticle exposures between fumed and sol-gel silica manufacturingfacilities.

Mentions: The number concentration of the personal samples in the SS factory packing processfrequently exceeded the upper limit of the DiSCmini instrument, 1,000,000particles/cm3, during jet mill operation. Though the nanoparticleconcentration in the SS packing process could not be estimated accurately, an attempt wasmade to calculate the number concentration. The average GM number concentration wascalculated to be 72,000 particles/cm3 with an assumption of 1,000,000particles/cm3 when the upper limit is exceeded. It was at least 8 timeshigher than that of ambient concentrations. The GMD of nanoparticles in the workplace airwas 94 nm, nearly twice as large as that of ambient particles (47 nm). The concentrationincrease was observed in a broad range of particle sizes of 50–300 nm, particularly in the100–150-nm range. The 8hr-TWA mass concentration obtained by a filter method wasremarkably high for both personal and area samples, 27.6 mg/m3 and11.3 mg/m3, respectively. It showed that personal samples had approximately2.4 times greater mass concentration than the area samples (Table 1). Figure 4Fig. 4.


Comparison of nanoparticle exposures between fumed and sol-gel nano-silica manufacturing facilities.

Oh S, Kim B, Kim H - Ind Health (2014)

Comparison of nanoparticle exposures between fumed and sol-gel silica manufacturingfacilities.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4209587&req=5

fig_004: Comparison of nanoparticle exposures between fumed and sol-gel silica manufacturingfacilities.
Mentions: The number concentration of the personal samples in the SS factory packing processfrequently exceeded the upper limit of the DiSCmini instrument, 1,000,000particles/cm3, during jet mill operation. Though the nanoparticleconcentration in the SS packing process could not be estimated accurately, an attempt wasmade to calculate the number concentration. The average GM number concentration wascalculated to be 72,000 particles/cm3 with an assumption of 1,000,000particles/cm3 when the upper limit is exceeded. It was at least 8 timeshigher than that of ambient concentrations. The GMD of nanoparticles in the workplace airwas 94 nm, nearly twice as large as that of ambient particles (47 nm). The concentrationincrease was observed in a broad range of particle sizes of 50–300 nm, particularly in the100–150-nm range. The 8hr-TWA mass concentration obtained by a filter method wasremarkably high for both personal and area samples, 27.6 mg/m3 and11.3 mg/m3, respectively. It showed that personal samples had approximately2.4 times greater mass concentration than the area samples (Table 1). Figure 4Fig. 4.

Bottom Line: Due to the high-temperature formation process, the particles exhibited a sintering coagulation.In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure).The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Employment and Labor, Republic of Korea.

ABSTRACT
Silica nanoparticles (SNPs) are widely used all around the world and it is necessary to evaluate appropriate risk management measures. An initial step in this process is to assess worker exposures in their current situation. The objective of this study was to compare concentrations and morphologic characteristics of fumed (FS) and sol-gel silica nanoparticles (SS) in two manufacturing facilities. The number concentration (NC) and particle size were measured by a real-time instrument. Airborne nanoparticles were subsequently analyzed using a TEM/EDS. SNPs were discharged into the air only during the packing process, which was the last manufacturing step in both the manufacturing facilities studied. In the FS packing process, the geometric mean (GM) NC in the personal samples was 57,000 particles/cm(3). The geometric mean diameter (GMD) measured by the SMPS was 64 nm. Due to the high-temperature formation process, the particles exhibited a sintering coagulation. In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure). The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

No MeSH data available.


Related in: MedlinePlus