The document discusses several air sampling devices used to collect airborne particles such as microorganisms, pollen, and spores. The slit sampler uses a rotating petri dish under a slit to directly impinge particles onto agar media. The Anderson sampler uses progressively smaller perforations to increase air speed and momentum to collect particles of different sizes on agar plates. The Burkard spore trap is a volumetric sampler that uses an adhesive tape to continuously trap particles over 24 hours to 1 week to analyze pollen and spore levels over time.

1. AIR SAMPLING DEVICES

2. AIR SAMPLING DEVICES

3. PRELIMINARY CONCERNS FOR
CONDUCTING AIR SAMPLING
• Consider the possible characteristics and conditions of the aerosol,
including size range of particles, relative amount of inert material,
concentration of microorganisms, and environmental factors.
• Determine the type of sampling instruments, sampling time, and
duration of the sampling program.
• Determine the number of samples to be taken.

4. SLIT SAMPLER
• The Slit sampler was developed by Bourdillon (1941).
• In this a rotating petridish containing suitable nutrient agar media is placed under a slit
through which air is drawn.
• Sampling is done for short time to avoid the interference of growth of one colony with
another. Slit sampler is one of several sampling methods used for quantitation of biological
aerosols.
• In this method, particles from the air are impinged directly on a rotating agar plate, the plate is
incubated, and the colonies that develop from the bacteria-laden particles are counted.
• Highly efficient device and can collect upto 95% of the water droplet particles sprayed into
air.

5. • An inexpensive slit sampler for collecting microorganisms has been designed
which utilizes a 150 x 20 mm culture plate possessing 2.2 times the area of the
standard Petri dish.
• This increased area permits collection of a much greater number of organisms
with this type of sampler and prevents drying out of the media.
• A simple timing device is incorporated in the design of the sampler which
permits rotation at the rate of 1 revolution per hour, and renders an accurate
time concentration relationship.
SLIT SAMPLER

6. SLIT SAMPLER

7. SLIT SAMPLER
❖The slit opening may be set at various widths, by means of two recessed
screws which hold the two metal plates on the slit tube in place.
❖The sampling box is a cylindrical container housing the culture dish and the
agar plate holder.
❖The dish containing the impingement media is commercially available.
❖The agar plate holder is a metallic platform containing four clips which
hold the plate securely in position.

8. ❖The drive shaft is ball bearing suspended and is mounted to the interval timer by
means of an adapter.
❖The function of the interval timer is to provide uniform rotation of the plate for a
period of 1 hour.
❖The housing for the interval timer is made gas-tight by means of an "O" ring placed in
a groove on the bottom exterior surface of the sampling box.
❖When the interval timer housing is screwed in position a gas-tight seal is secured. The
volume and rate of air flow are determined by a calibrated flowmeter.
SLIT SAMPLER

9. It draws in air from the environment at a fixed rate and causes the suspended particles to fall on the
surface of the agar plate.

10. USE OF SLIT SAMPLER FOR
AIR SURVEILLANCE
• Slit sampler is one of several
sampling methods used for
quantitation of biological aerosols.
• The particles from the air directly
settle on a rotating agar plate, the
plate is incubated, and the colonies
that develop from the bacteria-laden
particles are counted.

11. GRAVITY SLIDE
• The gravity slide was used by Blackley (1873).
• They are cheap, simple and can operate continuously.
• But they fail to estimate the airspora quantitatively and gives a distorted picture of airspora,
because they preferentially select the larger particles.
• To correct this distortion Scheppegrell (1922) tried to calculate the volumetric concentration
using a formula based on particle diameter which was later corrected by Cocke (1937) to
particle radius.
• But inspite of these defects it is widely used by aerobiologists and has contributed much
knowledge to the airspora.

12. • Air sampling cassette/ slide is designed for the rapid collection of a wide range of airborne aerosols including
mold spores, pollen, insect parts.
• It collects both viable and non-viable sample specimens.
• After sampling is completed, the cassettes are sent to a laboratory, where the slides are removed and direct
microscopic analysis can be immediately performed.
GRAVITY SLIDE
•Bioaerosols: mold spores, pollen, insect parts, skin cell fragments
•Fibers: asbestos, fiberglass, cellulose, clothing fibers, synthetics
•Inorganic Particulate: ceramic, fly ash, copy toner, oil droplets, paint
•Other Opaque Particulates: products of combustion, rust, salts

13. • Particulate laden air is accelerated as it is drawn through
the cassettes tapered inlet slit and directed towards a small
slide containing the collection media, where the particles
become impacted, and the air flow continues out the exit
orifice.
• The adhesive nature of the collection media prevents the
collected particulate from blurring or being washed off
during the laboratory staining process, and eliminates
sample loss from vibration during handling and shipment.
• After sampling is completed, the cassettes are sent to a
laboratory, where the slides are removed and direct
microscopic analysis can be immediately performed.
• The collection media is compatible with a wide range of
biological stains and refractive index oils, allowing direct
quantitative analysis of organic and inorganic particulate.
GRAVITY SLIDE

14. ➢ This was first used by Rempe (1937) for trapping airborne pollen.
➢ It is a wind impaction sampler used for routine aerobiological survey and found to be very
inexpensive and effective for obtaining maximum information on the airborne microbiota.
➢ The vertical cylinder exposing unit consists of cylinder holder and a shelter which is a
modified design of the Durham type shelter.
➢ This has an "L" shaped steel angle with a cylinder holder device below and the unit is
covered on top by a circular aluminium plate which acts as a shield.
➢ The cylinder holding device is a 5 cm long iron tube which is provided with a screw on one
side near its upper end to hold the cylinder firmly in a vertical position.
➢ Sterile and clean glass rods of 13 cm length and 0.53 cm diameter were used in this study.
VERTICAL CYLINDER

15. VERTICAL CYLINDER

16. ❖Spores counted in the area scanned can be then converted to number per square centimeter for
comparison with other catches on cylinder traps.
❖The vertical trap is convenient and cheap but the main drawback is that it catches a negligible
amount of spore in still air and small spores at ordinary wind speed and so changes in catch occurs
with alteration in wind speed.
VERTICAL CYLINDER

17. HIRST SPORE TRAP
• Hirst-type spore traps (HTST) is a volumetric impaction sampler which permit to have
results of the air fungal spore load quickly.
• With this device, both viable and nonviable spores are impacted on a silicon strip, then
microscopically read, but the spores are not cultured.
• Thus, this device may have an interest to monitor fungal loads in air as no growing time is
needed.
• The Hirst spore trap is the most widely used sampler in aerobiological surveys for
monitoring fungal propagules and pollen grains.
• Recent studies have taken advantage of this device to perform DNA-based studies for
pollen identification.

18. ✓The Hirst spore trap was used for monitoring not only pollen but also fungal propagules
and airborne bacteria by high-throughput sequencing.
✓Detection, monitoring, and characterization of the wide diversity of biological entities
present in the air are difficult tasks that require time and expertise in different disciplines.
✓The Hirst spore trap (an instrument broadly employed in aerobiological studies), to detect
and identify these organisms by DNA-based analyses.
✓The results showed a consistent collection of DNA and a good concordance with traditional
methods for identification, suggesting that these devices can be used as a tool for
continuous monitoring of the airborne biodiversity, improving taxonomic resolution and
characterization together.
HIRST SPORE TRAP

19. • Hirst spore trap is an automatic volumetric spore trap to operate continuously
for 24 hr in the field.
• Later, a modified trap that would operate continuously for seven days.
• Samples are collected at a network of sites using volumetric spore traps that
are usually situated on flat rooftops away from obstructions and from local
sources of pollen.
• For work in plant pathology, traps are generally placed within or just
downwind of the crop to detect inoculum or to study the dispersal of plant
pathogens in the field.
• The choice of power supply is also a consideration.
• When the trap is run with a mains supply within reach, an armoured cable can
be used along with a waterproof and protected connection to the trap plug.
HIRST SPORE TRAP

21. Hirst spore trap
https://www.youtube.com/watch?v=b5bgHMEdzPw
https://www.youtube.com/watch?v=3_i2ldfYYmM
https://iul-instruments.com/product/spin-air-air-sampler/

22. AIR SAMPLING DEVICES
Dr. M. Sonia Angeline
Assistant Professor
Department of Life Sciences
KRISTU JAYANTI COLLEGE

23. • The rotorod sampler is a cheap, simple and portable air sampler.
• It consists of a U-shaped metal rod attached by a spindle to a battery-powered electric motor.
• The motor causes the upright arms of the metal rod to rotate at high speed.
• To use the sampler, the upright arms are covered with narrow strips of sticky tape, so that any spores in the air
will impact onto the tapes.
• Then the tapes are removed and examined microscopically to identify the spores and other particles such as
pollen grains in the air.
• This type of sampler is most effective for trapping relatively large particles (upwards of about 7 micrometres) such
as the larger fungal spores and pollen grains.
ROTOROD SAMPLER

24. • The Rotorod Sampler is a rotating-arm impactor that recovers airborne particles on two
rapidly moving plastic collector rods.
• The standard method for applying silicone grease to collector rods has been with one's
finger.
• A relatively high skill level is required, and significant intra preparer variability has been
observed.
• Collector rods were coated with silicone grease by dipping them into a solution consisting of
silicone grease and hexane.
• The Rotorod's collection efficiency appeared to be greatest at moderate windspeeds; lower
efficiencies occurred at both lower and higher windspeeds. Maximum changes in collection
efficiency ranged from 29% to 39% over the windspeeds employed.
ROTOROD SAMPLER

25. ROTOROD SAMPLER
• Models typically used have retracting rods
• Head rotates at 2400 rpm, leading edge of rod coated with silicon grease
• Pollen and spores impacted on greased surface
• Generally operated at 10% sampling time
• Efficient for pollen and spores >10 mm

26. ROTOROD
https://www.youtube.com/watch?v=qobfzn5sW3g

27. ❖ Andersen (1958) developed a sampler similar in principle to slit sampler.
❖ The Anderson sampler is an ingenious device for selectively trapping different sizes of particles
according to their size (momentum).
❖ This sampler consists of a stack of 8 metal sections that fit together with ring seals to form an air-
tight cylinder.
❖ Each metal section has a perforated base, and the number of perforations is the same in each
section, but the size of these perforations is progressively reduced from the top of the column to the
bottom.
❖ To use this sampler, open agar plates are placed between each metal section, resting on three studs.
ANDERSON SAMPLER

28. ✓ When fully assembled (with an open agar plate between each unit) an electric motor sucks air from the bottom of the unit,
causing spore-laden air to enter at the top and to pass down through the cylinder.
✓ Air sucked in at the top of the column travels at relatively low speed towards the first agar plate, and so only the largest
particles impact onto the agar surface.
✓ The air then travels round the edge of the agar plate and through the perforations to the second agar plate, and so on.
✓ As this process continues down the stack, the same volume of air is forced to travel through successively smaller
perforations, and so the air speed is progressively increased.
✓ The progressively increased air speed lower down the column raises the momentum of the air-borne particles, so that even
the very smallest particles (less than 3 micrometres diameter) can impact onto the lower agar plates.
✓ When the sampler has run for 5-15 minutes or more, the metal plates are separated and the Petri dishes are removed for
incubation to identify the colonies that develop.
ANDERSON SAMPLER

29. ❖ Bioaerosol Sampler is a cost effective, multi-stage, multi-orifice cascade impactor that measures
concentration and particle size distribution of aerosol-type bacteria and fungi in the ambient air.
❖ Based on the inertial impaction principle, the six stage viable impactor collects all particles, regardless of
physical size, shape, or density.
❖ The particles are aerodynamically sized in which there is a direct relationship to the penetration of the
lung.
❖ The Andersen Six Stage Viable Impactor has an aluminium inlet cone, six aluminium jet stages, glass Petri
dishes, and an aluminium base plate held together by three spring clamps and sealed with o-ring gaskets.
❖ Each stage has 400 precision machined jet orifices.
❖ The Six Stage Impactor has a corrosion resistant body and operates at a flow rate of exactly 28.3 lpm (1
CFM).
❖ The Six Stage Sampler ensures ease of operation: calibration, sterilisation, and setup
ANDERSON SAMPLER

30. ANDERSON SAMPLER

31. ANDERSON SAMPLER

32. ANDERSON SAMPLER
https://www.youtube.com/watch?v=thiKRrXzp6o
https://www.youtube.com/watch?v=SxLoqO8jL4I

33. The collection and assessment of aerosol samples is quite simple: Petri dishes containing an agar medium are
placed in the instrument and the sample of air is drawn in which the corresponding particulates are collected at
each stage on the agar medium. The Petri dishes are then removed, incubated and counted by an accepted
method.
APPLICATIONS
• Ambient Air Studies
• Indoor Air Studies
• Hospital & O.R. environments
• Virology investigations (including Influenza and SARS)
• Pharmaceutical production
• Filter and clean room efficiency studies
• Composting
• Wastewater treatment plants

34. ➢ The Burkard Spore Trap (Burkard) is a volumetric air sampler that is one of the standard
devices for monitoring airborne pollen and spores.
➢ It is widely used by the allergy community and also the plant pathology community.
➢ The Burkard is a suction slit impactor used for pollen and spore sampling.
➢ The first sampler of this type was designed in 1952 by Dr. James Hirst a plant pathologist.
➢ As a result, samplers of this type are often referred to as a Hirst spore trap. In addition to
the Burkard, the Lanzoni sampler and others are also based on the Hirst design.
THE BURKARD SPORE TRAP

35. • In the Burkard, air is drawn into a 14 mm x 2 mm orifice at 10 liter per minute, and
any airborne particles with sufficient inertia are impacted on either a greased tape or a
greased microscope slide beneath the orifice.
• The impaction surface moves past the orifice at 2 mm per hour permitting time-
discriminate analysis.
• There is also a wind vane attached to the sampler head; since the head is able to rotate
the orifice is always oriented into the wind.
• The standard orifice on the Burkard sampler is efficient for particles down to 3.7 µm;
this means that all but the smallest spores will be efficiently trapped.
THE BURKARD SPORE TRAP

36. THE BURKARD SPORE TRAP
• The Burkard spore sampler acts on the same principle as the rotorod sampler, but is used
to give a continuous record of particles in the air over a period of 24 hours or up to 7
days.
• The apparatus consists of an air-sealed drum that contains a clockwork rotating disc
which makes a single revolution in 7 days.
• The surface of this disc is covered with adhesive tape, to trap spores that impact onto it.
• When the apparatus is assembled, air is sucked into the drum at high speed through a slit
orifice by means of a motor at the base of the apparatus.

37. ❑ Any particles in the air impact onto the sticky tape near the slit orifice, giving a record of
the particles in the atmosphere at a specific time of day.
❑ At the end of a 7-day run, the tape is removed, cut into sections representing hourly or
daily periods, then examined microscopically for counting and identification of pollen and
spores.
❑ In this way, it is possible to distinguish clearly between night-released and day-released
spores or other particles, and also to relate the types of particle to different weather
conditions (e.g. humid or dry periods) while the apparatus was running.
❑ The Burkard spore trap is commonly used for continuous monitoring of spore or pollen
loads in the air.
THE BURKARD SPORE TRAP

38. THE BURKARD SPORE TRAP

39. ❖ Impingers use a liquid medium for particle collection.
❖ Typically, sampled air is drawn by a suction pump through a narrow inlet tube into a small flask containing the collection
medium.
❖ This accelerates the air towards the surface of the collection medium and the flow rate is determined by the diameter of
the inlet tube.
❖ When the air hits the surface of the liquid, it changes direction abruptly and any suspended particles are impinged into the
collection liquid.
IMPINGERS

40. Once the sampling is complete the collection liquid can be cultured to enumerate viable microorganisms. Since the
sample volume can be calculated using the flow rate and sampling time, the result is quantitative.
• Glass Impingers have graduations in 5ml increments and available with a fritted nozzle to increase contact between
the air sample and the liquid.
• PFA impingers are unbreakable, inert to virtually all chemicals and perform well in high temperature and cryogenic
applications.
IMPINGERS
Glass Impingers PFA impingers

41. The sampling air bubbles through a nozzle plate into an
extraction liquid such as distilled water. The airborne
particles are transported into the liquid during the bubble
formation, release and rise.

42. • This is a means of sampling replacing the solid sorbent tube with a liquid.
• Impingers have a tapered outlet which allows particulate matter to exit at high velocity, hit the flask
bottom and be captured in solution.
• Bubblers are open or fritted to increase the surface area so the gases are absorbed into solution. This is a
preferred method.
• Impingers and bubblers can be positioned in an area, held or mounted in a holster.
Here is a typical sample train for an impinger/bubbler:
• After sampling the tubes or the sampled liquid are sealed and sent off to a laboratory for further analysis.
• The sorbent tubes are desorbed either chemically or thermally and for an impinger/bubbler, the sampled
liquid is analysed, generally by Gas chromatography.
ANALYSIS OF SAMPLE