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NIOSH
HAZARD REVIEW
Health
Effects of Occupational Exposure
to
Respirable Crystalline Silica
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<Back |
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Table
8
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Table
8. Intralaboratory results for evaluation of XRD silica method
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Item
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Filter
loading
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69.4
µg
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98.4
µg
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204
µg
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| Degrees
of freedom |
12
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11
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12
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| RSD
for sampling and analytical methods (%)*,† |
8.8
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6.3
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8.1
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Source:
NIOSH, BOM [1983].
*RSD = relative standard deviation. RSD for sampling and
analytical methods represents the RSD in mass estimates, accounting
for intersampler and analytical variability.
†Implications for XRD: Pooled filter levels and pump
error (assumed to be <5%) indicate that the overall imprecision
is as follows: Total RSD for sampling and analytical methods is 9.3%.
Therefore, the upper 95% confidence limit on the accuracy (35 degrees
of freedom) is 21%. |
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Table
9
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Table
9. Intralaboratory results for evaluation of IR silica method
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Item
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Filter
loading
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67.2
µg
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99.7
µg
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161µg
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| Degrees
of freedom |
10
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12
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11
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| RSD
for sampling and analytical methods (%)*,† |
5.8
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7.8
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7.4
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Source:
NIOSH, BOM [1983].
*RSD = relative standard deviation. RSD for sampling and
analytical methods represents the RSD in mass estimates, accounting
for intersampler and analytical variability.
†Implications for IR: Pooled filter levels and pump
error (assumed to be <5%) indicate that the overall imprecision
is as follows: Total RSD for sampling and analytical methods is 7.1%.
Therefore, the upper 95% confidence limit on the accuracy (33 degrees
of freedom) is 17%. |
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Table
10
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Table
10. XRD method evaluation: concentration ranges bracketing applicable
exposure limits for which the NIOSH accuracy criterion is met*
( µg/m3)
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Cyclone
and sampling rate
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Filter
loading
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Applicable
exposure limit
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69.4
µg
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98.4
µg
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204
µg
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| Nylon
cyclone, 1.7 L/min |
85
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121
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251
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100
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| GK2.69
cyclone, 4.2 L/min |
34
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49
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102
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50
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| *Eight-hour
sampled masses are combined with results of NIOSH, BOM [1983]. |
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Table
11
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Table
11. IR method: concentration ranges bracketing applicable exposure
limits for which the NIOSH accuracy criterion is met*
( µg/m3)
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Cyclone
and sampling rate
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Filter
loading
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Applicable
exposure limit
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6.72
µg
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99.7µg
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161
µg
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| Nylon
cyclone, 1.7 L/min |
83
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123
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198
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100
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| GK2.69
cyclone, 4.2 L/min |
34
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50
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80
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50
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| *Eight-hour
sampled masses are combined with results of NIOSH, BOM [1983]. |
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