Filter Handling
Filters should be handled delicately using non-serrated forceps, never using fingers (even
in laboratory gloves) to touch any part of the filter. When not in use, filters should be
stored in protective cartons in conditions of moderated temperature and relative humidity.
Filters should from the always be transported from the laboratory to the sampling
location in the filter cassette, which should be protected within a metal canister. These
canisters may be ordered directly from BGI.
Filter Cassette Handling
The filter cassettes provided for use with the PQ100 have been designed with an
interference fit to prevent the cassette from coming apart easily, therefore some care must
be exercised when opening and closing the cassette, especially when a filter is inside.
Always maintain the cassette in an upright position, especially if the filter has already
been used to collect particles. To open, place a clean, flat blade device (knife edge,
screwdriver blade) against the outside edge of the cassette between the upper and lower
halves and gently wedge them apart. DO NOT TWIST THEM APART, this could tear
the filter. Set the upper half of the cassette aside.
To close the cassette, place it the upper and lower halves together and gently press them
together, being careful not to twist them. When closed, the two halves should seat snugly
together with the backing screen securely held in place between the two halves.
Filter Weighing
Because of the small amounts of material collected, an extremely high quality
microbalance and carefully, temperature and humidity controlled filter weighing room are
recommended. For complete EPA recommended details, consult 40 CFR 50 Appendix
L8.0, Federal Register, July 18, 1997, and Section 2.12 of EPA=s Quality Assurance
Handbook.
The analytical balance used to weigh filters must be suitable for weighing the type and
size of filters specified and have a readability of ∀1μg. The balance should be calibrated
as specified by the manufacturer at installation and should be recalibrated immediately
prior to each weighing session.
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