Filter Sampler
This page is a work in progress...
Filter Baking
1. The PSI group usually bakes their filters in the lab, and then ships/brings them to the field site.
2. Filter Baking Procedure (from Peter Zotter at PSI): A whole pack of filters (~30) is put in a quartz petri dish and put in the oven (8h at 800°C) and on the next morning after the filters have cooled down, they are wrapped in aluminum foil. So the whole procedure takes about 24h (8h prebaking and a long time cooling down) even thoug the only workstep which takes some time for me is wrapping the filters in foil (~30min up to 1h). Barend van Drooge suggests putting the filters in foil before baking, so the foil is cleaned as well and handling of filters is minimized.
BEACHON
- Sampling Times and Limits of Detection:
1. Chris Geron (U.S. E.P.A) measured OC levels are 0.5-2 ugC m-3 for 48-hr samples (July & August 2008)
2. Barend L. van Drooge (Molecular Tracers Analysis) needs approximately 100m3 sample. Doing the math, that means 13 1/3 hours sampling time, if we divide filters into quarters.
3. Andre Prevot (14C analysis) needs 12 hrs sampling time (Patrick Hayes has a spreadsheet from Peter Zotter with calculations). This is figured with 0.5 ug/m3 concentrations, and two (16.3 mm diameter) punches taken from a filter. The 14C analysis will require 1/2 a filter given the area of the punches (2 punches for TC, 2 for OC, and 2 for Sunsent ECOC, plus extra material as a precaution).
CONCLUSION: Sampling time should be a minimum of 12 hours, or 24 hours if one wants to be very cautious. That would correspond to 64 filter samples taken for BEACHON (32 days/12hours).
