Examples of simple measurement
4. PTIO method
4.1. General Information
- This Sampler is reusable countless times. Only the pre-coated filter pad is
expendable.
- Absorbing solution, for both Nox and NO2 is available. It is strongly
suggested, however, that only pre-coated filter pads be used. This will insure
correct washing of blank filters, uniform coating and reduce possible variables
in the sampling procedure.
- All sampler components should be carefully washed before each use. This is an
important function, and special care should be taken to do this step carefully.
- Washing, assembly of sampler, and loading with the proper pre-coated filters
should be done in a clean area, free of Nox contamination.
- Ideal exposure time is 24 hours. This amount of time will develop results from
a few ppb to large quantities of ppbs. Shorter exposure times are practical
where the expected concentration is known to be high.
- When the point of research is outdoors, the sampler should be given reasonable
protection from the sun and rainfall.
- Direct exposure of individuals can be easily measured by using the clip to
attach the sampler as close to the face as possible.
- Satisfactory results have been obtained with concentrations as low as 2 ppb.
- The Sampler assembly : stack-up in each of the two chambers of the sampler,
starting at the inner position and progressing outward to the diffuser
progressing outward to the diffuser end cap, in as follows:
1. TEFLON DISK
2. TEFLON RING
3. STAINLESS SCREEN
4. COATEDCOLLECTIONFILTER
5. STAINLESS SCREEN
6. DIFFUSER END CAP
Figure 6.4.1
- After assembly, above, the loaded sampler is place in the resealable bag, and
then the bagged sampler is placed into the orange airtight vial, provided, and
taken to the exposure site.
After exposure, the above procedure in again followed to safely seal the used
sampler into the orange airtight vial, and then it is taken to the laboratory
for analysis
