2.
Portable Hi Vol Saiples
These samples will be used to assess local resuspension mediated by
human activicy.
The air samoling equipment is usually operated ac
selected sites in the field wnile the survey ceam is on station, and
removed when the survey team leaves.
The equiomenct consists of A. C.
operated high-volume blawer coupled to 8 x 10 inch filter media (usually
glass fiber).
The samplers should be installed as close as possible to people wark-
ing in a defined area, and chey should be biased toward
the downwind side
of the work area.
If possible, the samples should be operated only during
periods of human activity.
Flow races and operating times musc be logged
to determine the total volumes of air samples.
This equipment must be powered
by portable electric generators in the field.
3.
Aerosol Particle Sizing Samsies
Two high-volumeAndersen cascade impactors are available for particle
size-selective air sampling.
These samples will be used for assessments
of che respirable fractions of resuspended aerosols.
Two cascade impactors
are available:
a 4-sctage unit coupled co a standard Hi Vol blower, and
a 5-stazge sampling head which aust be operated with a positive displacemenc pump (such as tne Roots Slower, in the fixed-stacion sampling equipment).
The specifications for the cascade impactors are listed in the cable below:
Jet Place No.
1-1
Effective Cut-off (um-MMAD)
2-3
3~4
4-5
"Special (5-stage only)
5-8
Backup Filter
7.0
3.3
2.0
1.1
0.43
:
Collection Plate Only
1.1 (4-stage) or
0.43 (5-stage)
The 4-stage unit must be operated as a porcable air sampler while the survey
team is on-station; and it is genérally operated in association with the
portable Hi Vols.
The S-stage impactor has anodized jet plates, and may be
operated in the field for extended periods of time.
Long-cerm sampling is
desirable to perform radioassays of aerosols at very low activity concentracions.
Secup and Calibration or Instruments
lL.
aAndersen Cascade [mpactor
{a}
Cleaning of the Orifice Collection Plates
i.
ti.
iit.
clean each plate with a mild detergenc and warm water
rinse the plates with acetone or alcohol to remove
the water
handle the plates ac all times by che edges to prevent
gecting =xia oil on the orifice and collection places;
make sur.
the holes
ara noc plugged
“
(