time weighted average values. A total of 111 personal samples
were analyzed, and the worker personal samples averaged approximately
221 min in duration.
The PCM personal worker sample analyses resulted in a mean of
0.010 f/ml sample concentration during disassembly and 0.008 f/ml
during assembly operations. Bystander concentrations were slightly
higher with 0.013 f/ml during disassembly and 0.014 f/ml during
assembly. The maximum sample concentration observed during all
testing was 0.050 f/ml, a bystander value during assembly operations.
It is unclear why the bystander concentrations are higher than
the worker concentrations other than the worker is in closer contact
with oils and other fluids while the bystander moved about dustier
storage locations. These PCM values represent all fibers present.
No asbestos fibers were detected by TEM in the analyses of the
personal samples. The proportion of asbestos fibers present among
all the fibers detected by TEM is used to adjust the PCM results to
reflect only the asbestos component, resulting in PCME concentrations.
Since zero (0) asbestos fibers were found in every sample,
the effective multiplier for the PCM results is zero. All of the fibers
counted in the PCM analyses were non-asbestos.
The average PCM concentration of area samples collected in the
vicinity of the work was 0.003 f/ml during both disassembly and
assembly. Asbestos fibers were detected on two (1.4%) of the 138
area samples by NlOSH 7402; no other asbestos was observed on
any area sample. Both samples were collected during assembly
operations. The two positive samples were further analyzed using
ISO 10312. One sample was determined to contain two chrysotile
fibers shorter than 5 lm; the other sample contained 1 chrysotile
fiber longer than 5 lm.
A statistical comparison of the PCM data indicates the worker
exposures were marginally higher during disassembly than during
assembly (p = 0.0626, Mann–Whitney U), reflecting that the engine
is dirty for the disassembly. This difference (disassembly higher
than assembly) extended to the area samples (p = 0.0002), but
not to the bystander samples (p = 0.35). There was no difference
in the outdoor air concentrations during either operation (p = 0.60).