Six types of aerosol samplers were evaluated experimentally in a test chamber
with polydisperse fly ash. The Andersen sampler overestimates the mass of small
particles due to particle bounce between stages and therefore provides a conservative
estimate of respirable particulate mass and thoracic particulate mass. The TSP sampler
provides an unbiased estimate of total particulate mass. TSP/CCM provides no
information below ESD 2 õm and therefore underestimates respirable particulate mass.
The PM10 sampler provides a reasonable estimate of the thoracic particulate fraction.
The RespiCon sampler provides an unbiased estimate of respirable, thoracic, and
inhalable fractions. DustTrak and SidePak monitors provide relative particle
concentrations instead of absolute concentrations because it could not be calibrated for
absolute particle concentrations with varying particle shape, composition, and density.
Six sampler technologies were used to evaluate airborne dust concentrations
released from oilfield pipe rattling operations. The task sampled was the removal of
scale deposited on the inner wall of the pipe before it was removed from service in a
producing well. The measured mass concentrations of the aerosol samplers show that a Gaussian
plume model is applicable to the data of pipe rattling operations for finding an
attainment area. It is estimated that workers who remain within 1 m of the machine
centerline and directly downwind have an 8-hour TWA exposure opportunity of (13.3 ñ
9.7) mg/m3 for the Mud Lake pipe scale and (11.4 ñ 9.7) mg/m3 for the Lake Sand pipe
scale at 95 % confidence. At distances more than 4 m downwind from the machine
centerline, dust concentrations are below the TWA-TLV of 10 mg/m3 for the worker in
both scales. At positions crosswind or upwind from the machine centerline there is no
measurable exposure. Available data suggest that the attainment area for the public
starts at about 9 m downwind from the machine centerline in both scales, as 24 hour
average concentrations at these distances are smaller than the 0.15 mg/m3, the NAAQS
for unrestricted public access. The PSD of the suspended plume is dominated by
particles smaller than ESD 50 õm.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4357 |
| Date | 30 October 2006 |
| Creators | Park, Ju-Myon |
| Contributors | Rock, James C. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 4509172 bytes, electronic, application/pdf, born digital |
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