mounting bracket stainless steel dome
PUF diskair circulation
   
 
 
 
 
   Methodology of passive air
sampling
Mgr. Ing. Jiří Kohoutek 
RNDr. Roman Prokeš, Ph.D.  
RNDr. Petra Přibylová, Ph.D. 
Prof. RNDr. Jana Klánová, Ph.D.  
Prof. RNDr. Ivan Holoubek, CSc. 
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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Methodology of passive air sampling
CONTENT:
1 Principle of method....................................................................................................... 2
2 Material............................................................................................................................. 2
2.1 Sampler (description, maintenance)........................................................................... 2
2.2 Filters (type, preparation)........................................................................................... 7
3 Sampling.......................................................................................................................... 7
3.1 Sampler site selection and sampler deployment ........................................................ 7
3.2 Duration of sampling.................................................................................................. 8
3.3 Filter installation ........................................................................................................ 8
3.4 Transport of filters.................................................................................................... 14
4 Analytical processing of filters................................................................................ 14
5 Results interpretation................................................................................................. 14
6 References .................................................................................................................... 14
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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1 Principle of method
Low sensitivity to accidental short-time changes in the concentration of pollutants is a basic
characteristic of passive samplers. They provide information about the long-term
contamination of the studied environmental compartment (for example air).
The air streams freely around a filter, membrane or other medium (sorbent), which captures
pollutants during the period of passive air sampling. It is possible to use polyurethane foam
(PUF) for persistent organic pollutant (POPs) sampling.
The relationship between the amount of POPs captured on PUF filter and their concentrations
in sampled air has not been mathematically fully described yet. Due to this reason only
empirical estimated information (for example based on parallel active and passive
measurements) is available for results interpretation. Passive air sampling is a cheap screening
method for a comparison of contamination on various sites or for verification of information
obtained by active samplers [1-3].
2 Material
2.1 Sampler (description, maintenance)
Passive air sampling device consists of two stainless steel bowls attached to the common axes
to form a protective chamber for the polyurethane foam filter. The filter is attached to the
same rod and it is sheltered against the wet and dry atmospheric deposition, wind and UV
light [4]. Exposure times between four and twelve weeks enable determination of many
compounds from the POPs group. Average sampling rate was estimated to be 7 m3
/day which
roughly corresponds to 200 m3
of air sampled during four weeks of deployment.
mounting bracket stainless steel dome
PUF diskair circulation
Scheme of the passive air sampling device
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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List of the parts positioned on the axis (from the top):
- hanging hook – to hang the sampler
- nut and safety-nut – to fix the upper bowl
- pad
- upper bowl (diameter 30 cm) placed up side down – it protects the filter from the
rainwater and solar radiation, stabilizes a stream of air around the filter
- pad
- nut – to fasten the upper bowl
- distance tube (longer) – to fix the filter position below upper bowl
- pad
- PUF filter equipped with the metal insert (15 mm length tube prepared in the lab)
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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- pad
- distance tube (shorter one) – to fix the filter position above lower bowl
- nut – to fix the distance tubes before mounting the lower bowl
- pad
- lower bowl (diameter 24 cm) placed the bottom down – it protects the filter against the
rain water and stabilizes stream of air around the filter (condensed water is drained
through four holes in the bottom of the bowl)
- pad
- nut and safety-nut – to fix of position of lower bowl
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- safety hook – protects the sampler against the falling apart due to vibrations caused by
the strong wind, simultaneously enables to stabilize the sampler in a vertical position
All parts of the sampler are made from the stainless steel and they do not require special
service. Removal of dirt and surface cleaning by ethanol are needed, especially inside the
bottom bowl, during the filter change. When ever possible with the respect to sampling plan we
could clean-up in laboratory is recommended before new filter installation. In this case,
we use the tap water for cleaning and consecutively hexane for better removal of smear from
the surface of the sampler.
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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2.2 Filters (type, preparation)
Filters made of white, non-colored polyurethane foam (PUF) with density 0.030 g.cm-3
(type
T - 3037; producer Molitan a.s., Czech Republic) are used as a sorbent for passive sampling
of POPs. Filters are at circular shape, thickness a 15 mm and diameter a 150 mm.
All filters are cleaned before the placement into the passive air sampler. Filters are extracted
8 hours in acetone and 8 hours in dichloromethane for POPs analysis, and for PBDEs analysis
(polybrominated dipfenyl ethers) are extracted 8 hours in acetone and 8 hours in toluene.
Filters are dried after extraction and cleaned stainless steel insert (length 15 mm) is placed in
their middle to fix the filters to the axis of the sampler.
Filter with the insert is packed in two layers of aluminium foil after cleaning. Date of cleaning
and type of cleaning (TOL - only for filters, which were cleaned in toluene) are written with
permanent marker on the packed filter. Labeled filter is placed into lock up polyethylene bag
(zip-lock). Clean filters are stored in freezer at temperature –18 °C for up to three months.
3 Sampling
3.1 Sampler site selection and sampler deployment
Passive air samplers (their axis) are hanged only vertically with the bigger bowl up and placed
1.5 – 2.0 m above the ground in the man breathing zone. The metal constructions are
commonly used for placement of samplers. Open terrain location without significant obstacles
for free air stream around the sampler is optimal.
Placement of passive air sampler.
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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3.2 Duration of sampling
Duration of the passive air sampling (using PUF samplers) is four weeks (28 days). This time
may be prolonged up to 3 month (84 days) for special measurements. Interpretation of results
has to be done with the respect to this fact, especially when compared to the results obtained
in the four weeks sampling cycle.
3.3 Filter installation
First step in the filter exchange in the sampler is a removal and packing of the exposed filter.
Next step is an installation of the new clean filter using the following procedure:
1) detach the sampler from the hinge
2) remove the safety hook, nut, safety-nut and pad starting from the bottom
3) carefully remove the lower bowl without a contact with the filter
4) remove the pad and nut fixing the distance tubes
5) carefully remove the shorter distance tube and the pad next to the filter (again without
a contact with the filter)
6) using gloves or aluminium foil remove the filter including the stainless insert placed in
the centre and wrap it into two layers of aluminium foil
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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7) label the wrapped filter (date, site, number of sample) using permanent marker
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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8) place the labeled filter into the polyethylene bag and put it in the transport cooling
box.
9) carefully write all the data about the filter, (it means date of the beginning and the end
time of sampling, meteorological conditions during sampling period) to the sampling
protocol
10) control the visual state of the sampler and remove possible dirt before installation of
the new clean filter
11) write date and time of the beginning of the sampling, name, description and GPS
position of the site to the sampling protocol
12) pull the zip-lock polyethylene bag with the packed clean filter from the transport
cooling box and write the date of cleaning to the sampling protocol
13) control the position of the longer distance tube and the pad on the axis of the sampler
14) unpack filter including the insert in the centre from aluminium foil and mount it on
the axis of the sampler using gloves or aluminium foil
15) after the placement of the filter mount pad and the shorter distance tube on the axis of
the sampler, screw the nut fixing the distance tubes
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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16) mount the lower bowl between the pads and fix the whole sampler with the nut and the
safety-nut
17) insert the safety hook, and the place sampler on the hinge
At the beginning of sampling, remove the bottom part of sampler and follow the points 10 to
17. At the end of sampling, follow steps 1 to 9, then put the sampler together and take it to the
lab for cleaning.
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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3.4 Transport of filters
Filter including the central insert is wrapped in two layers of aluminium foil, labelled (date,
site, number of sample) using permanent marker and placed into the zip-lock polyethylene
bag after exposure. Packed filters are transported to the laboratory in the cooling box at
temperature 5 °C. Filters are kept in the freezer at temperature –18 °C till the analysis.
4 Analytical processing of filters
Processing of filters proceeds according to appropriate SOP of the analytical laboratory.
5 Results interpretation
Passive air samplers using PUF filter are suitable for the monitoring of some types of POPs.
Particularly, more volatile compounds from the group of polycyclic aromatic hydrocarbons
(PAHs; acenaphtylene – pyrene), polychlorinated biphenyls (PCBs), organochlorinated
pesticides (OCPs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs),
polybrominated dipfenyl ethers (PBDE) and perfluorooctanesulfonic acid (PFOS). Less
volatile compounds (for example high-molecular PAHs) are also collected on the filter, but
only partially (sorbate on captured dust particles).
6 References
[1]. Harner, T.; Pozo, K.; Gouin, T.; Macdonald, A. M.; Hung, H.; Cainey, J.; Peters, A.
Global pilot study for persistent organic pollutants (POPs) using PUF disk passive air
samplers. Environmental Pollution 2006, 144, 445-452.
[2]. Harner, T.; Bartkow, M.; Holoubek, I.; Klanova, J.; Wania, F.; Gioia, R.; Moeckel, C.;
Sweetman, A. J.; Jones, K. C. Passive air sampling for persistent organic pollutants:
Introductory remarks to the special issue. Environmental Pollution 2006, 144, 361-364.
Research Centre for Toxic Compounds in the Environment, Kamenice 753/5, Pavilion A29, 625 00 Brno
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[3]. Klánová, J.; Čupr, P.; Kohoutek, J.; Hamer, T. Assessing the influence of meteorological
parametrs on the performance of polyurethane foam-based passive air samplers.
Environmental Science & Technology 2008, 42, 550-555.
[4]. Shoeib, M.; Harner, T. Characterization and comparison of three passive air samplers for
persistent organic pollutants. Environmental Science & Technology 2002, 36, 4142-4151.