Air-O-Cell Users Guide

AIR-O-CELL ® Bioaerosol Sampling Cassette LA03040 Rev.2Laboratory & User Manual2Air-O-Cell® Sampling Cassette The Air-O-Cell is a unique sampling cassette speci? cally designed for the rapid collection and quantitative analysis of a wide range of airborne aerosols. It collects both viable and non-viable particulate such as mold spores, pollen, insect parts, skin cell fragments, ? bers (asbestos, ? berglass, cellulose, etc.) and inorganic particles. Suggested & potential applications include but are not limited to the following:APPLICATIONSIndoor Air Quality: Mold spores, pollen, insect parts, dust mites, skin cell frag-ments, plant fragments, dust, ? bers, combustion emissions, etc.Home Inspection: Mold Contamination before of after real estate transactions.Flood Restoration: Evaluation of mold spore contamination before, during, and after remediation.Allergy Testing: Mold spores, pollen, insect parts, dust mites.Clean Room Monitoring: Evaluation of low airborne dust and contaminants from personnel (skin cells, clothing ? bers, cosmetics, etc.)Fiber Analysis: Asbestos, ? berglass, cellulose, ceramics, etc.Stack Emissions: Fly ash, inorganic dust, etc.Air-O-Cell® ADVANTAGES• Provides excellent detection limits over conventional ? lter sampling utilizing 25 mm or 37 mm diameter ? lter cassettes.• Eliminates sample loss to cassette walls known to occur with ? lter samples from vibration or static charge during sampling and shipment.• Eliminates the need for direct handling or preparation of collection media or microscope slides in the ? eld.• Eliminates potential cross-contamination between samples and during ship-ping that may occur with other devices.• Unique optically transparent and smooth collection media allows direct stain-ing and examination by bright ? eld, dark ? eld, and phase contrast microscopy• The sampling media is compatible with a wide range of biological stains and refractive index oils allowing for direct quantitative analysis of biological and inorganic particles.• The Air-O-Cell will work with virtually any kind of sampling pumpcapable of pulling a 15 lpm (vacuum) air ? ow.3 PRINCIPLE OF OPERATIONThe Air-O-Cell operates on the well established principle of iner tial impaction. Particles in the air stream are accelerated as they approach the tapered inlet opening and drawn through a small slit aimed directly at a glass slide. This glass slide contains a sticky and optically clear sampling media which can permanently collect and hold particles. As the particles come through the slit, the air velocity forces the particles to impact into the sampling media, while the air stream makes a sharp 90o turn and proceeds around the slide and out of the cassette. The air ? ow path through the Air-O-Cell cassette is illustrated below in Figure 1.Figure 1 AIR FLOW PATH OF THE Air-O-Cell air fl ow into cassettesample slitcollection mediaglass slideexit orifi celateral view4RECOMMENDED SAMPLING PROCEDURESGeneral:The Air-O-Cell sampler is designed to operate at an optimal ? ow rate of 15 liters per minute. The user can employ any sampling pump capable of a minimum ? ow rate of 15 lpm. It is also capable of operating in any vertical or horizontal orientation, or in restricted access spaces smaller than 2 inches in diameter. As a result the Air-O-Cell is ideally suited for sampling in HVAC ducts, plenums, wall cavities, or other con? ned spaces.Sampling of Ambient Static Environments:A rotameter calibrated to a primary standard, soap bubble tube/meter or a dry bubble meter should be used to calibrate the sampling pump to a ? ow rate of 15 lpm. Some pumps only work with speci? c calibration devices. Please reference the owners manual for your pump to verify if any special calibration methods should be employed. Because the cassette does not produce signi? cantly measurable back pressure, the rotameter can optionally be connected directly to the pump (without the Air-O-Cell cassette in line) to calibrate the pump ? ow rate. To begin sampling, remove the tape seals covering the inlet and outlet and placed them on the side of the cassette. Then connect the Air-O-Cell cassette to the sam-pling pump using ? exible tubing. Turn the sampling pump on for an appropriate sample time ranging from 1 to 10 minutes and both seals replaced after sampling is complete. Unlike other spore trap impaction or ? lter devices, the Air-O-Cell cassette can be oriented in any vertical or horizontal direction, without concern for sample loss of large particles or vibration. “Outdoor background” samples should always be collected for comparison purposes.Sampling in HVAC Systems:The Air-O-Cell cassette design allows for isokinetic sampling of aerosols in Heating, Ventilation and Air Conditioning (HVAC) Systems. Sampling can be conducted at the supply diffuser or inside most conventional ducts. The inlet of the cassette should always be facing into the ? ow stream. The inlet ori? ce has a cross-sectional area of approximately 11 mm x 15 mm (165.0 mm2) tapering to a slit with dimensions of 1.055 mm x 14.4 mm (15.19 mm2). The ? ow velocity can be increased up to 30 lpm with conventional sampling pumps, however, air ? ows exceeding 20 lpm may potentially damage some bioaerosols or cause “bounce off”. Isokinetic sampling can be conducted in most air duct system with ? ow rates of up to approximately 600 fpm. Approximate face velocities for the Air-O-Cell cassette are given below for both the entrance ori? ce and slit exit in Table 15Air-O-Cell Theoretical Face Velocities Flow Rate Ori? ce Face Ori? ce Face Slit Face Slit Face (lpm) Velocity Velocity Velocity Velocity (fpm) (mph) (fpm) (mph) 15.0 299 3.4 3110 35.3 20.0 399 4.5 4146 47.2 25.0 499 5.7 5183 59.0 28.3 (1 cubic ft.) 564 6.4 5867 66.8 30.0 598 6.8 6219 70.6 Table 1Recommended Sampling Time Intervals:Although the Air-O-Cell cassette can provide excellent detection limits over con-ventional ? lter sampling utilizing 25 mm or 37 mm diameter ? lter cassettes, it is also sensitive to overloading. In an appropriately loaded sample, the trace should be barely visible and transparent, but not opaque or dense. If the sample appears highly visible or opaque, additional shorter time interval samples should be collected. The recommended sampling ? ow rate is 15 liters per minute (lpm). As mentioned above, ? ow rates exceeding 20 lpm have been known to cause “bounce off” of large particles such as pollen grains. Flow rates lower than 10 lpm will not collect the small mold spores (such as Aspergillus and Penicillium) as ef? ciently. Recom-mended sampling times (at 15 lpm) for different environmental sampling conditions are given in Table 2.RECOMMENDED SAMPLING INTERVALS Sampling Time (minutes)Environmental Dust Conditions 15 lpm• Outdoor sampling on a clean windless day 10.0 - 60 min.• “Clean” of? ce environment or outdoors (no visible dust) 10.0 min.• “Indoor” environment, high activity personnel 5.0 min.• “Indoor” environment, evidence of drywall renovation, or industrial dust 1.0 min.• “Indoor” environment, visible dust emissions from point sources present 0.5 min. Table 26RECOMMENDED LABORATORY ANALYSISPROCEDURESSlide preparationOne to two (1-2) drops of staining or mounting media (lacto-phenol cotton blue is recommended for mold spore analysis) should be placed in the center of a clean pre-labeled slide. Air-O-Cell cassettes should only be opened in the laboratory. The sealing band should be cut, and the glass cover slip (containing the sample trace) removed and slowly placed on an angle with the media collection side down onto the staining solution. Do not press down on the slide during or after staining. Excess staining solution should be removed from around the edges of the cover slip with a tissue wipe or cotton swab after 10 minutes has elapsed. This will ensure even staining of the sample. It should be noted that the slide can also optionally be mounted media side up. To do this, use a drop of ? ngernail polish to secure the Air-O-Cell slide to the microscope slide. Then place a couple drops of stain on the media and place a cover slip on top.About StainsNumerous stains may be used during laboratory analysis. These include lacto-phenol cotton blue, anline blue, calbreras stain and acid fusion stain. The most common stain used for mold spore analysis is lacto-phenol cotton blue. To achieve the best clarity of the sample, using stains that have little or no water content is preferred. Water can cause the sample to appear cloudy. 7Microscopic ExaminationAnalysis of the collected sample should be performed by an experienced Microbiolo-gist, Aerobiologist, Mycologist or Environmental Microscopist. Counting and quanti-? cation of sample components is conducted by counting calibrated cross-sections of the deposited sample trace. The number and type of particles counted per cubic meter of air is calculated based on the length of the deposition trace, length of trace actually examined, volume of air collected, and number of particles counted. The Air-O-Cell particle deposition area at a ? ow rate of 15 lpm is approximately 1.1 mm wide by 14.5 mm long yielding an approximate area of 15.95 mm2. The width of the deposition trace will vary slightly with ? ow rate and media thickness, and will vary slightly in particle density from the middle to outer edges of deposi-tion. For this reason, using the deposition trace area is not recommended for direct calculation of particle concentrations. The recommended procedure for calculating particle concentrations is based on using the Air-O-Cell trace length and microscope ? eld diameter, and will be discussed below. One ? eld of view counted is de? ned as the calibrated diameter of the microscope ? eld of view (in mm) covering one cross-sectional pass or “traverse” across the sample deposition trace. A typical sample preparation and microscopic counting procedure is illustrated in Figure 2. Figure 2ILLUSTRATION OF Air-O-Cell COUNTING METHODmicroscopic slideAir-0-Cell™ slidesample particulateanalysis starts at 1st traverse - completes and moves to 2nd traverse8The calculation of particle concentration per cubic meter of air can be performed by using the following equations.First, determine the actual air volume collected in cubic meters (m3) by following the calculation given in Equation 1.EQUATION 1:Air volume (m3) = (Sampling rate (liters per minute) / 1000) x Number of minutes Second, determine the length of sample trace counted based on the microscope ? eld of view and number of ? elds of view counted. Accurately calibrate and measure the diameter of the microscope ? eld of view using a stage micrometer slide. Remember, each microscope is different, and each different combination of ocular and objec-tive lens must be calibrated separately. Stated lens magni? cations are rarely precise. The microscopist should then record the number of complete traverses examined across the width of the deposition trace and use the formula given in Equation 2 to calculate the actual length of the deposition trace examined. EQUATION 2:Trace Length Counted (mm2) = Microscope ? eld diameter (mm) x number of traverses The concentrations of particles (cts/m3) can then be determined by using Equation 3.EQUATION 3: Trace length (14.4 mm) 1Cts / m3 = _______________ x ___________ x # of particle counts Total length of Air Volume(m3) trace counted (From Equation 2) (From Equation 1) 9Two example calculations for mold spores and pollen grains are given below:Example 1 Mold Spore ExampleMicroscope ? eld diameter at (900X) = 0.240 mmNumber of traverses = 10Sample volume (15 lpm @10 minutes) = (15 / 1000) x 10 = 0.150 m3Mold spore counts = 50 14.4 mm 1 14.4_________ x _______ x 50 = _____ x 50 = 2000 ct/m30.240 x 10 0.15 0.36Example 2 Pollen ExampleMicroscope ? eld diameter at (200X) = 1.11 mmNumber of traverses = 10Sample volume (15 lpm @ 30 minutes) = (15 / 1000) x 30 = 0.450 m3Pollen counts = 25 14.4 mm 1 14.4________ x ______ x 25 = _____ x 25 = 72 grains/m3 1.11 x 10 0.45 5.010RECOMMENDED MICROSCOPIC COUNTING GUIDELINESCounting & Identi? cation GuidelinesPollen — Entire trace or 100 grains (whichever comes ? rst) should be examined at a minimum magni? cation of 200X. Iden-ti? cation and speciation should be performed at minimum magni? cation of 400X.Mold Spores — A minimum of 15% of the entire trace should be examined or a minimum of 100 mold spores counted (whichever comes ? rst). Identi? cation and spec ia t ion should be per formed at min imum magni? cation of 400X.Fibers — The entire trace or 100 ? bers, (whichever comes ? rst) should be examined at a minimum magni? cation of 200X.Other Aerosols — Skin cell fragments, combustion emissions, insect parts —A minimum of 10% of the entire trace should be examined or a minimum of 100 particles counted (whichever comes ? rst).All bioaerosol samplers are not created equal and will not provide the same results. Look for this seal on your product as assurance of validated, industry proven performance and the highest quality product.Storage & Operating ConditionsThis product should be stored at room temperature, between 60-82°F (15-28°C). Do not use product at temperatures below 32°F (0°C). If product has been exposed to freezing temperatures immediately before sampling, it is recom-mended to let the product acclimate to the sampling environment before use.11Ordering InformationField EquipmentProduct Number DescriptionZA0046 Cassette OpenerZA0050 Particle Spreader, “T” shaped, sterileZA0051 Syringe, sterile, 3ccZA0052 Alcohol wipes, 200/bxZA0054 Forceps, self closing, eachProduct Number DescriptionAOC010 Air-O-Cell® Cassettes, 10/boxAOC050 Air-O-Cell® Cassettes, 50/boxAOCWS10 Inner Wall Sampling Adapter, 10/boxAOC-CAL In-Line Calibration AdapterZBP-307 Zefon Bio-Pump® Bubble Tube for Air-O-CellZBP-200 Zefon Bio-Pump®APB-803300 mini-Buck IAQ CalibratorDCL-H Bios DryCal® DC-Lite CalibratorLaboratory EquipmentStorage & Operating ConditionsThis product should be stored at room temperature, between 60-82°F (15-28°C). Do not use product at temperatures below 32°F (0°C). If product has been exposed to freezing temperatures immediately before sampling, it is recom-mended to let the product acclimate to the sampling environment before use.125350 SW 1st Lane, Ocala, FL 34474 • www.zefon.comPhone: 800-282-0073 • 352-854-8080 • Fax: Fax: 352-854-7480© Copyright 2009 Zefon International, Inc. Via-Cell, Air-O-Cell, and BioPump are registered trademarks of Zefon International.