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This is a single stage petri plate impacter that consists of an aluminum device held together by 3 spring clamps and is sealed with O-ring gaskets. A high volume of air is drawn through the sampler causing multiple jets of air to direct airborne particles toward the surface of the agar collection plate. This will lead to biological growth if any microorganisms are present in the air that is sampled. A short collection period (3-5 minutes @ 28.3 lpm) should be used to prevent the plates from being overgrown by microorganisms. The sampler should be disinfected with isopropyl alcohol between each use and you don not want to use media that’s expired, has visible cracks, or possible contamination.
Pros: Results relate directly to airborne exposures; qualitative and quantitative results; it is possible to speciate; specific organisms can be targeted since various types of media are available; results can be compared to bulk, tape, or swab results in order to find amplification sites.
Cons: Expensive; time consuming for sampling and analysis; only isolates viable (living) organisms; some fungi may overgrow others leading to an unclear picture about what is present; media has a short shelf-life; and the samples are perishable if not handled properly and carefully.
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This indoor air quality sampler is a particulate sampling cassette, Zefon Air-O-Cell Cassette, designed for rapid collection and analysis of a wide range of airborne aerosols including mold spores, pollen, insect parts and skin fragments. These types of samples are used to detect for total spore counts. It is useful for rapid analysis of airborne contaminants in IAQ testing, allergy testing and flood restoration monitoring.
Pros: Media is easy to store and has a long-shelf life; results are semi-quantitative and relates directly to airborne exposure; rapid analysis of results.
Cons: Differentiation between viable and non-viable organisms is difficult; can’t sample for bacteria; there is large lab to lab variation in analysis of results; and cannot speciate.
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These types of sample are applicable when there is visible contamination of building materials such as drywall, flooring, insulation, wood, etc. Materials are collected then sent directly to a lab for microbial identification. Bulk/ surface sampling is useful in verification of remediation.
Pros: Inexpensive; rapid spore count identification; can be quantitative; able to differentiate between viable and non-viable microorganisms; possible to culture and then speciate.
Cons: Destructive of building materials; may expose occupants during collection; results do not relate directly to airborne exposures; may not be the source of contamination.
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Wallchecks evaluate concealed spaces without being destructive.
Pros: Results are qualitative and quantitative; media is easy to store and has a long shelf-life, results relate directly to spacial contamination and to the contamination of the air behind the wall, cabinet space, etc; rapid analysis of results.
Cons: Differentiation between viable and non-viable is difficult; cannot collect samples for bacteria; lab to lab variation in results is great; cannot speciate; the lack of dilution ventilation may cause high levels for results that are not representative of the problem.
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Swab/Tape Sampling for Building Surfaces:
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A swab sample is collected with a sterile cotton “Q-tip” applicator that has been moistened with sterile growth media. The area to be swabbed should be performed by a person wearing sterile latex, surgical gloves and the cotton head of the applicator is broken off into the growth solution vial. The vial and swabbed applicator sent to a lab for plate culturing and counting.
Pros: Inexpensive; non-destructive; rapid analysis for spore counts; results can be quantitative and cultured for speciation; sampling can be performed on irregular surfaces.
Cons: Results do not relate directly to airborne exposures; fungal structures may be damaged during collection causing identification of the mold to be less accurate; spores may germinate before lab analysis; may miss presence of organisms in porous materials; and sample collection does not work well on dry surfaces.
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